Çad'da bulunan yeni bir kafatası fosili, evrim teorisini savunanları çıkmaza soktu. Darwinist bilim adamları, bu fosilin evrim teorisini kökünden sarstığını itiraf ediyorlar. "Maymundan insana uzanan evrim zinciri" masalı, bir kez daha çökmüş durumda.

Orta Afrika ülkesi Çad'da bulunan yeni bir kafatası fosili, evrim teorisinin insanın kökeni hakkındaki iddialarına yeni bir darbe indirdi. Dünyaca ünlü bilim dergilerinde ve gazetelerde geniş yer verilen bu yeni fosil, Darwinistlerin 150 yıldır ısrarla savundukları "insanın maymun benzeri canlılardan evrimleştiği" iddiasını kökünden sarsmış durumda. Fransız bilim adamı Michel Brunet tarafından keşfedilen fosile Sahelanthropus tchadensis adı verildi.

Ve bu fosil, Darwinizm dünyasını birbirine kattı. Dünyaca ünlü Nature dergisi, fosili duyuran haberinde, "bulunan yeni kafatası, insanın evrimi hakkındaki düşüncelerimizi tamamen batırabilir" itirafında bulundu.

Harvard Üniversitesi'nden Daniel Lieberman, bu yeni bulgunun "küçük bir nükleer bomba kadar etkili olacağı"nı söyledi.

Bunun nedeni, bulunan sözkonusu fosilin 7 milyon yıl yaşında olmasına rağmen, "insanın en eski atası" olduğu iddia edilen ve 5 milyon yıl yaşındaki Australopithecus türü maymunlardan daha "insansı" bir yapıya sahip olması.

Evrimciler, 1920'li yıllardan bu yana, söz konusu Australopithecus türü maymunların bazı özelliklerinin insana benzediğini iddia ediyor ve bu nedenle bu soyu tükenmiş canlıları sözde "insanın en ilkel atası" olarak gösteriyorlardı. Bu iddianın geçersizliğini gösteren pek çok delil ortaya çıkmış, örneğin Australopithecusların iddia edildiği gibi dik yürümedikleri, aynen diğer maymunlar gibi eğik bir yürüyüşe sahip oldukları 1990'lı yıllardaki bazı araştırmalarla ortaya çıkmıştı. Yeni bulunan Sahelanthropus tchadensis isimli fosil ise, Australopithecuslardan 2 milyon yıl önce yaşamış bir başka maymun türünün, evrimcilerin kıstaslarına göre daha "insansı" olduğunu gösteriyor. Yani tüm "evrim şeması"nı bozuyor.

Konunun aslı ise şudur:Geçmişte yaşamış ve bugün soyu tükenmiş olan pek çok farklı maymun türü vardır. Bunların bazılarının kafatası veya iskelet yapısı kısmen insanlara benzerlik göstermektedir. Ama bu benzerlikler bu canlıların insanlarla bir ilgisi olduğu anlamına gelmez. Evrimciler ise, bu soyu tükenmiş canlılara ait kafataslarını, teorilerinin gerektirdiği gibi art arda dizerek bir tür 'maymundan insana giden merdiven' oluşturma çabasındadırlar. Ancak bu konudaki araştırmalar derinleştikçe, ortada böyle bir merdiven bulunmadığı, sadece farklı dönemlerde farklı maymun türlerinin yaşadığı anlaşılıyor. Bunun sonucunda ise insanın arkasında hiç bir evrim süreci bulunmadan yeryüzünde bir anda ortaya çıktığı, yani yaratıldığı ortaya çıkıyor.

Washington'daki George Washington Ünivesitesi'nden evrimci antropolog Bernard Wood'un yeni bulunan fosil üzerine yaptığı açıklama ise, bu görüşü doğruluyor:

"Üniversiteye başladığım 1963 yılında, insanın evrimi bir merdiven gibi görülüyordu. Bu merdivenin basamakları, maymundan insana doğru ilerleyen ve her aşaması bir öncekinden daha az maymunsu olan bir seri ara formdan meydana geliyordu... Ama şimdi insanın evrimi (karmakarışık) bir çalıya benziyor... Fosillerin birbirleriyle nasıl bir ilişkisi olduğu ve herhangi birisinin gerçekten insanın atası olup olmadığı hala tartışmalı."

Kısacası sık sık gazetelerde veya dergilerde gördüğümüz "maymundan insana uzanan evrim merdiveni" çizimlerinin hiç bir bilimsel değeri yok. Bunlar sadece evrim teorisine körü körüne inanmış olan çevrelerin propagandası. Bu propaganda yürütülürken, bir taraftan da evrim teorisiyle çelişen bilimsel deliller toplumdan gizleniyor. Amerikalı biyolog Jonathan Wells, Amerika'da büyük bir tartışma başlatan "Evrimin İkonları: Bilim mi Efsane mi, Evrim Hakkında Öğrettiğimiz Pek Çok Şey Neden Yanlış" adlı 2000 yılı basımı kitabında bu propaganda mekanizmasını şöyle özetlemekte:

Toplumun geneli, insanın kökeni hakkındaki derin belirsizliğe dair bilimsel uzmanların yaptıkları açıklamalardan çok nadiren haberdar edilir. Bunun yerine, şu veya bu kimsenin en son teorisi ile besleniriz ve bize bizzat paleoantropologların bunun üzerinde anlaşamadıkları gerçeği aktarılmaz. Ve tipik olarak, teori mağara adamlarının veya "bol makyajlı" insan atalarının hayali resimleri ile süslenir... Görünen odur ki, bilimin hiç bir alanında bu kadar az bir malzeme üzerine bu kadar fazla bir kurgu yapılmamıştır.

Ancak artık Darwinizm efsanesi çökmek üzere. Bilim geliştikçe, bir 19. yüzyıl hurafesi olan Darwinizm'in yanlışlığı daha da açık şekilde ortaya çıkıyor. Ve bilim dünyası, en önemli gerçeğin farkına varıyor: İçinde yaşadığımız evreni ve içindeki canlı-cansız tüm varlıkları Allah yaratmıştır.



SABAH GAZETESİ KONUYU NEDEN ÇARPITTI?

Çad'da bulunan yeni kafatasının evrim teorisinin şimdiye kadarki tezlerini çürüttüğü, bu buluşu dünyaya duyuran ünlü bilim dergileri tarafından da itiraf edildi.

Örneğin dünyaca ünlü bilim otoritesi olan İngiliz Nature dergisinin konuyla ilgili başlığının hemen altında şöyle yazıyordu:
"YENİ BULUNAN KAFATASI İNSANIN EVRİMİ HAKKINDAKİ MEVCUT FİKİRLERİMİZİ BATIRABİLİR." (New-found skull could sink our current ideas about human evolution.)

National Geographic News ise haberi şu başlıkla duyuruyordu:
"ÇAD'DA BULUNAN FOSİL İNSANIN KÖKENİNİN YENİDEN DÜŞÜNÜLMESİNİ GEREKTİRİYOR". (Skull Fossil From Chad Forces Rethinking of Human Origins)

CNN.com ise bu kafatasının evrim teorisine "kafa tuttuğunu" şöyle ifade ediyordu:
"ESKİ KAFATASI İNSANIN KÖKENİNE MEYDAN OKUYOR." (Ancient skull challenges human origins)

Diğer ünlü bilimsel kaynaklarda veya önde gelen uluslararası medya kuruluşlarında bu konuda verilen haberlerin hemen hepsinde de, bulunan fosilin evrim teorisi adına çok şaşırtıcı ve beklenmedik olduğu vurgulanıyordu. Bu uluslararası kaynakların hiç birinde, bulunan kafatasının evrim teorisini desteklediği, hatta "kanıtladığı" iddia edilmedi.

Ama ne ilginçtir ki, Türkiye'de bir gazete konuyu büyük ölçüde çarpıtarak yayınladı. Sabah gazetesi, 12 Temmuz 2002 tarihli sayısında, Çad'da bulunan kafatasını "DARWIN'İN EVRİM TEORİSİ İSPATLANDI" gibi son derece gerçek dışı ve yanıltıcı bir başlıkla okuyucularına tanıttı.

Sabah gazetesinin bu konudaki çok önemli bir yanılgısı ise, tartışmalı bir kafatası fosilinden yola çıkarak Darwin'in teorisinin ispatlanabileceğini sanmasıdır. Evrim teorisi daha hayatın nasıl başladığını açıklamaktan yoksundur. Sadece bir hücre değil, hücreyi meydana getiren tek bir proteinin dahi tesadüflerle oluşmasının imkansız olduğu bugün bilinmektedir. Dolayısıyla, tek bir fosilden yola çıkarak, üstelik onu da yanlış ve çarpıtarak yorumlayarak, fosil hakkındaki farklı yorumları gündeme getirmeden "evrim teorisi ispatlandı" demek, sadece Sabah gazetesinin evrim teorisine nasıl körü körüne bağlı olduğunu gösterir.

Umarız gerek Sabah gazetesi gerekse Darwinizm lehinde yayın yapmayı alışkanlık haline getirmiş diğer bazı medya kuruluşları bu tavırlarından vazgeçer ve konuyu daha önyargısız şekilde değerlendirmeye başlarlar. Körü körüne Darwinizm propagandası yapmak, hem de bunun için gerçekleri çarpıtmak, hem basın ilkeleriyle hem de en temel dürüstlük kıstaslarıyla bağdaşmamaktadır çünkü.

Bilim ve yeni buluşlar,keşifler darwin teorisini çıkmaza sokmaz .Daima kuvvetlendirir.Bununla ilgili daha şimdiden çok yönlü incelemeler araştırmalar değerlendirmeler başladı bile.Her yeni buluntu yeni pencereler açıyor.
ama bu bilmcileri yani bizi ilgilendirir.
siz köhnemiş dumur eğlencelerinize devam edin.Bu işler sizi aşar.
Hadi bakim!

A new hominid from the Upper Miocene of Chad, Central Africa

MICHEL BRUNET*, FRANCK GUY*†, DAVID PILBEAM†, HASSANE TAISSO MACKAYE‡, ANDOSSA LIKIUS*‡, DJIMDOUMALBAYE AHOUNTA§, ALAIN BEAUVILAIN§, CÉCILE BLONDEL*, HERVÉ BOCHERENS, JEAN-RENAUD BOISSERIE*, LOUIS DE BONIS*, YVES COPPENS¶, JEAN DEJAX#, CHRISTIANE DENYS#, PHILIPPE DURINGER, VÉRA EISENMANN#, GONGDIBÉ FANONE§, PIERRE FRONTY*, DENIS GERAADS**, THOMAS LEHMANN*, FABRICE LIHOREAU*, ANTOINE LOUCHART††, ADOUM MAHAMAT§, GILDAS MERCERON*, GUY MOUCHELIN*, OLGA OTERO*, PABLO PELAEZ CAMPOMANES‡‡, MARCIA PONCE DE LEON§§, JEAN-CLAUDE RAGE#, MICHEL SAPANET, MATHIEU SCHUSTER, JEAN SUDRE, PASCAL TASSY#, XAVIER VALENTIN*, PATRICK VIGNAUD*, LAURENT VIRIOT*, ANTOINE ZAZZO¶¶ & CHRISTOPH ZOLLIKOFER§§

* Faculté des Sciences et CNRS UMR 6046, Université de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France
† Peabody Museum, Harvard University, 11 Divinity Avenue, Cambridge, Massachusetts 02138, USA
‡ Université de N'Djaména, BP 1117, N'Djaména, Tchad
§ Centre National d'Appui à la Recherche, BP 1228, N'Djaména, Tchad
Institut des Sciences de l'Evolution, CNRS UMR 5554, Université de Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5, France
¶ Collège de France, 3 rue d'Ulm, 75005 Paris, France
# Muséum National d'Histoire Naturelle et CNRS UMR 8569, rue Cuvier, 75005 Paris, France
Centre de Géochimie de la Surface, CNRS UMR 7517, Université Louis Pasteur, 1 rue Blessig, 67084 Strasbourg, France
Centre National de Recherche Scientifique UPR 2147, 44 rue de l'Amiral Mouchez, 75014 Paris, France
†† Centres des Sciences de la Terre, CNRS UMR 5125, Université Claude Bernard, 27-43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
‡‡ Museo de Ciencias Naturales, C/Guttierez Abascal 2, 28006 Madrid, España
§§ Anthropologisches Institut/Multimedia Laboratorium, Universität Zürich-Irchel, Winterthurer Str. 190, 8057 Zürich, Switzerland
Centre Hospitalier Universitaire, Université de Poitiers, rue de la Milétrie, 86021 Poitiers Cedex, France
¶¶ Centre National de Recherche Scientifique UMR 162, et Institut National de la Recherche Agronomique, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France


Correspondence and requests for materials should be addressed to M.B. (e-mail: michel.brunet@univ-poitiers.fr).




The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fauna suggest the fossils are between 6 and 7 million years old. The fossils display a unique mosaic of primitive and derived characters, and constitute a new genus and species of hominid. The distance from the Rift Valley, and the great antiquity of the fossils, suggest that the earliest members of the hominid clade were more widely distributed than has been thought, and that the divergence between the human and chimpanzee lineages was earlier than indicated by most molecular studies.


From their initial description in 19251 until 1995, hominids from the Pliocene (5.3–1.6 million years, Myr) and late Upper Miocene (7.5–5.3 Myr) were known only from southern and eastern Africa. This distribution led some authors to postulate an East African origin for the hominid clade (where the term 'hominid' refers to any member of that group more closely related to extant humans than to the extant chimpanzee, Pan)2, 3. The focus on East Africa has been especially strong in the past decade, with the description of several new forms from Kenya and Ethiopia, including Kenyanthropus platyops (3.5 Myr; ref. 4); Australopithecus anamensis (3.9–4.1 Myr; ref. 5); Ardipithecus ramidus ramidus (4.4 Myr; ref. 6); Ardipithecus ramidus kadabba (5.2–5.8 Myr; ref. 7) and Orrorin tugenensis (6 Myr; refs 8, 9). The discoveries of A. ramidus ramidus, A. r. kadabba and O. tugenensis have extended the human lineage well back into the Miocene. However, the discovery of Australopithecus bahrelghazali in Chad, central Africa10, 11, demonstrated a considerably wider geographic range for early hominids than conventionally expected.

Since 2001, the Mission Paléoanthropologique Franco–Tchadienne (MPFT), a scientific collaboration between Poitiers University, Ndjamena University and Centre National d'Appui à la Recherche (CNAR) (Ndjaména), has recovered hominid specimens, including a nearly complete cranium, from a single locality (TM 266) in the Toros-Menalla fossiliferous area of the Djurab Desert of northern Chad (Table 1). The constitution of the associated fauna suggests that the fossils are older than material dated at 6 Myr from Lukeino, Kenya8, 9. Preliminary comparison with the fauna from the Nawata formation at Lothagam, Kenya12, 13, suggests that the fossils are from the Late Miocene, between 6 and 7 Myr old. All six recovered specimens are assigned to a new taxon that is, at present, the oldest known member of the hominid clade.

Systematic palaeontology


Order Primates L., 1758
Suborder Anthropoidea Mivart, 1864
Superfamily Hominoidea Gray, 1825
Family Hominidae Gray, 1825
Sahelanthropus gen. nov.
Etymology. The generic name refers to the Sahel, the region of Africa bordering the southern Sahara in which the fossils were found.

Generic description. Cranium (probably male) with an orthognathic face showing weak subnasal prognathism, a small ape-size braincase, a long and narrow basicranium, and characterized by the following morphology: the upper part of the face wide relative to a mediolaterally narrow and anteroposteriorly short lower face; a large canine fossa; a small and narrow U-shaped dental arch; orbits separated by a very wide interorbital pillar and crowned with a large, thick and continuous supraorbital torus; a flat frontal squama with no supratoral sulcus but with a marked postorbital constriction; a small, posteriorly located sagittal crest and a large nuchal crest (at least, in presumed males); a flat and relatively long nuchal plane with a large external occipital crest; a large mastoid process; small occipital condyles; a short, anteriorly narrow basioccipital; the long axis of the petrous temporal bone oriented roughly 30° relative to the sagittal plane; the biporion line touching the basion; a round external auditory porus; a broad glenoid cavity with a large postglenoid process; a robust and superoinferiorly short mandibular corpus associated with a wide extramolar sulcus; a large, anteriorly opening mental foramen centred beneath lower teeth P4–M1, below midcorpus height; relatively small incisors; distinct marginal ridges and multiple tubercles on the lingual fossa of upper I1; small (presumed male) upper canines longer mesiodistally than buccolingually; upper and lower canines with extensive apical wear; no lower c–P3 diastema; upper and lower premolars with two roots; molars with low rounded cusps and bulbous lingual faces, M3 triangular and M3 rounded distally; enamel thickness of cheek teeth intermediate between Pan and Australopithecus.

Differential diagnosis. Sahelanthropus is distinct from all living great apes in the following respects: relatively smaller canines with apical wear, the lower showing a full occlusion above the well-developed distal tubercle, probably correlated with a non-honing C–P3 complex (P3 still unknown).

Sahelanthropus is distinguished as a hominid from large living and known fossil hominoid genera in the following respects: from Pongo by a non-concave lateral facial profile, a wider interorbital pillar, superoinferiorly short subnasal height, an anteroposteriorly short face, robust supraorbital morphology, and many dental characters (described below); from Gorilla by smaller size, a narrower and less prognathic lower face, no supratoral sulcus, and smaller canines and lower-cusped cheek teeth; from Pan by an anteroposteriorly shorter face, a thicker and more continuous supraorbital torus with no supratoral sulcus, a relatively longer braincase and narrower basicranium with a flat nuchal plane and a large external occipital crest, and cheek teeth with thicker enamel; from Samburupithecus14 by a more anteriorly and higher-placed zygomatic process of the maxilla, smaller cheek teeth with lower cusps and without lingual cingula, and smaller upper premolars and M3; from Ouranopithecus15 by smaller size, a superoinferiorly, anteroposteriorly and mediolaterally shorter face, relatively thicker continuous supraorbital torus, markedly smaller but mesiodistally longer canines, apical wear and large distal tubercle in lower canines, and thinner postcanine enamel; from Sivapithecus16 by a superoinferiorly and anteroposteriorly shorter face with non-concave lateral profile, a wider interorbital pillar, smaller canines with apical wear, and thinner cheek-teeth enamel; from Dryopithecus17 by a less prognathic lower face with a wider interorbital pillar, larger supraorbital torus, and thicker postcanine enamel.

Sahelanthropus is also distinct from all known hominid genera in the following respects: from Homo by a small endocranial capacity (preliminary estimated range 320–380 cm3) associated with a long flat nuchal plane, a longer truncated triangle-shaped basioccipital, a flat frontal squama behind a robust continuous and undivided supraorbital torus, a large central upper incisor, and non-incisiform canines; from Paranthropus18 by a convex facial profile that is less mediolaterally wide with a much smaller malar region, no frontal trigone, the frontal squama with no hollow posterior to glabella, a smaller, longer and narrower braincase, the zygomatic process of the maxilla positioned more posterior relative to the tooth row, and markedly smaller cheek teeth; from Australopithecus19-21 by a less prognathic lower face (nasospinale–prosthion length shorter at least in presumed males) with a smaller malar (infraorbital) region and a larger, more continuous supraorbital torus, a relatively more elongate braincase, a relatively long, flat nuchal plane with a large external occipital crest, non-incisiform and mesiodistally long canines, and thinner cheek-teeth enamel; from Kenyanthropus4 by a narrower, more convex face, and a narrower braincase with more marked postorbital constriction and a larger nuchal crest; from Ardipithecus6, 7 by upper I1 with distinctive lingual topography characterized by extensive development of the crests and cingulum; less incisiform upper canines not diamond shaped with a low distal shoulder and a mesiodistal long axis, bucco-lingually narrower lower canines with stronger distal tubercle, and P4 with two roots; from Orrorin8 by upper I1 with multiple tubercles on the lingual fossa, and non-chimp-like upper canines with extensive apical wear.

Type species. Sahelanthropus tchadensis sp. nov.

Etymology. In recognition that all specimens were recovered in Chad.

Holotype. TM 266-01-060-1, a nearly complete cranium with the following: on the right—I2 alveolus, C (distal part), P3–P4 roots, fragmentary M1 and M2, M3; and on the left—I2 alveolus, C–P4 roots, fragmentary M1–M3 (Fig. 1 and Tables 1, 2, 3, 4, 5). Found by D.A. on 19 July 2001.


Figure 1 Cranium of Sahelanthropus tchadensis gen. et sp. nov. holotype (TM 266-01-060-1). Full legend

High resolution image and legend (81k)



After study, the holotype and paratype series will be housed in the Département de Conservation des Collections, Centre National d'Appui à la Recherche (CNAR) in Ndjaména, Chad. The holotype has been dubbed 'Toumaï'; in the Goran language spoken in the Djurab Desert, this name is given to babies born just before the dry season, and means 'hope of life'.

Paratypes. See Table 1 for a list of paratypes, and Fig. 2 for illustrations.


Figure 2 Sahelanthropus tchadensis gen. et sp. nov. paratypes. Full legend

High resolution image and legend (49k)



Locality. Toros-Menalla locality TM 266, a single quarry of about 5,000 m2, 16° 14' 30"–16° 15' 30" N, 17° 28' 30"–17° 30' 00" E (western Djurab Desert, northern Chad).

Horizon. All hominid specimens were found in the Toros-Menalla anthracotheriid unit (AU) and come from a perilacustrine sandstone12. The associated fauna is biochronologically12 older than fossils from Lukeino, Kenya (6 Myr; refs 8, 9), and more closely resembles material from the Nawata formation at Lothagam, Kenya, which is radio-isotopically dated to 5.2–7.4 Myr (ref. 13). Biochronological studies are still underway and TM 266 fauna can be tentatively dated between 6 and 7 Myr (ref. 12).

Diagnosis. Same as for genus.

Preservation
All specimens are relatively well preserved, but almost the entire cranium has been flattened dorsoventrally and the entire right side is depressed. The cranium exhibits broken but undistorted bone units and matrix-filled cracks (Fig. 1). Estimated measurements are given from a preliminary three-dimensional reconstruction. It will soon be possible to use computer tomography (CT) scans to generate a definitive three-dimensional reconstruction and stereolithographic casts.

Comparative observations
Cranial comparisons of comparably aged hominids are limited to a fragmentary basicranium and temporal bone: ARA-VP1/500 and ARA-VP1/125 (ref. 6) from 4.4 Myr Ardipithecus ramidus ramidus. The next-oldest maxillary and cranial specimens are younger: KNM-KP-29283 (A. anamensis5, 20), KNM-WT40000 (Kenyanthropus platyops4), and A. afarensis specimens, which include the well-preserved AL 444-2 (ref. 21). The most notable anatomical features of the S. tchadensis cranium for comparative purposes are to be found in the face, which shows a mosaic of primitive and derived features. The face (Fig. 1a) is tall with a massive brow ridge, yet the mid-face is short (in the superoinferior dimension) and less prognathic than in Pan or Australopithecus (Table 3). This unusual combination of features is in turn associated with a relatively long braincase, comparable in size to those of extant apes (Fig. 1b, c). Preliminary comparisons with Pan suggest an endocranial volume of 320–380 cm3.

Although the Sahelanthropus cranium is considerably smaller than that of a modern male Gorilla, its supraorbital torus is relatively and absolutely thicker. This is probably a sexually dimorphic character (see Fig. 3), presumably reflecting strong sexual selection. If this is a male, then the combination of a massive brow ridge with small canines suggests that canine size was probably not strongly sexually dimorphic. The interorbital pillar is wide (Fig. 1a). The zygomatic process of the maxilla emerges above the mesial margin of M1 and is therefore more posterior relative to the cheek teeth than in Australopithecus19-21 and Paranthropus18. The infraorbital plane (from the lower orbital margin to the inferior malar margin) is similar to that of Pan and differs from both Gorilla and larger Australopithecus, in which this region is absolutely and relatively taller. The canine fossa is similar to that in AL 444-2 (ref. 21) and there is no diastema between the alveoli of I2 and C in the Chadian specimen. There is no supratoral sulcus. Between the temporal lines, the frontal squama is slightly depressed but not like the frontal trigone usually seen in P. boisei18. The temporal lines converge behind the coronal suture as in crested Pan, whereas their junction is more anterior than generally seen in some large A. afarensis (for example, AL 444-2; ref. 21). The sagittal crest is a little larger posteriorly than in either AL 444-2 (ref. 21) or KNM-WT 40000 (ref. 4). The compound temporal–nuchal crest is marked as in KNM-ER 1805 (ref. 22) and much larger than in the male A. afarensis AL 444-2 (ref. 21), suggesting a relatively large posterior temporalis muscle. The postorbital breadth (Fig. 1c) is absolutely smaller than the Pan–Gorilla average, and similar to that in AL 444-2 and AL 417-1 (ref. 21) (Table 5).


Figure 3 Vertical (superoinferior) thickness of the supraorbital torus in extant hominoids, A. africanus and S. tchadensis gen. et sp. nov. Full legend

High resolution image and legend (18k)



The basicranium (Fig. 1d) has small occipital condyles associated with an apparently large foramen magnum. Despite damage, the foramen magnum seems to be longer than wide, and not like the rounded shape typical of Pan. As in A. ramidus, the basion is intersected by the bicarotid chord; the basion is posterior in large apes and anterior in some of the later hominids. The Sahelanthropus basioccipital is correlatively short and shaped like a truncated triangle as in Ardipithecus6; it is not as triangular as in other early hominids.

Like Pan, Australopithecus21 and Ardipithecus6, the orientation of the petrous portion of the temporal is approximately 60° relative to the bicarotid chord, instead of 45° as is typical of Paranthropus and Homo. Unlike Gorilla, Pan and Ardipithecus6, the posterior margin of the tympanic tube does not have a crest-like morphology. Compared with known Ardipithecus (ARA-VP-1/500)6, the glenoid cavity is larger and the postglenoid process mediolaterally wider, so the pronounced squamotympanic fissure is situated more medially to the postglenoid process. The height of the relatively flat temporomandibular joint above the tooth row suggests a high ascending ramus of the mandible more similar in absolute size to Gorilla than to Pan. The large pneumatized mastoid process is anteroposteriorly long, more so than in Ardipithecus6 and Australopithecus (AL 444-2, AL 333)19, 21. The flat nuchal plane is relatively longer (Fig. 1b, d and Table 4) than in Pan, Gorilla, AL 444-2 and AL 333, and with crests as marked as those of Gorilla, implying the presence of relatively large superficial neck muscles. The horizontally oriented nuchal plane is much flatter than the convex nuchal plane of Pan. There is not yet sufficient information to infer reliably whether Sahelanthropus was a habitual biped. However, such an inference would not be unreasonable given the skull's other basicranial and facial similarities to later fossil hominids that were clearly bipedal.

Little is preserved of the mandibular corpus in TM-266-02-154-1 or the symphysis in TM-266-01-060-2 to permit much discussion of mandibular anatomy. However, the former, presumably a male, has a thick corpus with a wide extramolar sulcus (Fig. 2a).

In dentition, both lower incisor roots are small. The lingual surface of upper I1 displays distinct marginal ridges converging basally onto a narrow gingival eminence and with several tubercles extending incisally into the lingual fossa (Fig. 2a). The smaller upper I2 alveolus is situated, in frontal view, lateral to the lateral edge of the nasal aperture (Fig. 1a), a probable symplesiomorphy with Pan. The upper and lower canines are small (Tables 1, 2). Given the absolutely and relatively massive supraorbital torus of the cranium (Figs 1a and 3), possibly reflecting strong sexual selection, and the thick corpus of the mandible (Fig. 2b, c), which probably indicate male status, we infer that Sahelanthropus canines were probably weakly sexually dimorphic. The upper canine (Fig. 1d) has both distal and apical wear facets whereas M3 is unworn. The lower canine (Fig. 2d, e) has a strong distal tubercle that is separated from a distolingual crest by a fovea-like groove; the large apical wear zone at a level above this distal tubercle implies a non-honing C–P3 complex (the P3 is still unknown). The upper canine, judging from the steep, narrow distal wear strip reaching basally, we believe had a somewhat lower distal shoulder than Ardipithecus6, 7, suggesting an earlier evolutionary stage. Moreover, a small, elliptical contact facet for P3 on the distobuccal face of the distal tubercle indicates the absence of a lower c–P3 diastema. Sahelanthropus thus probably represents an early stage in the evolution of the non-honing C–P3 complex characteristic of the later hominids7.

The cheek teeth are small (Tables 1, 2), within the size range of A. ramidus and the lower end of A. afarensis. Lower c and the lower and upper premolars each have three pulp canals and two roots (Fig. 2c). The P3 has a 2R:MB + D pattern (terminology following ref. 22: R, root; M, mesial; MB, mesiobuccal; D, distal) with a small mesiobuccal root and two partially fused, larger oblique distal roots. The P4 has two transverse roots (2R:M + D), with the mesial one smaller than the distal; in both premolars the distal root has two pulp canals (Fig. 2c). The P4 teeth of Ardipithecus have more-derived root patterns, with either a Tome's root (A. r. kadabba)7 or a single root (A. r. ramidus)6. S. tchadensis has a P4 with a large talonid and well-marked grooves on the buccal face. The molar size gradient is M2 > M3 > M1. The upper molars have three roots, two buccal and one lingual, which is large and mesiodistally elongated. The M3 crowns are triangular whereas the M3 teeth are rectangular and rounded distally. The lower molar root pattern is 2R:M + D: a mesial root with two pulp canals and a distal root with only one canal (Fig. 2c).

The radial enamel thickness is 1.71 mm at paracone LM3 and 1.79 mm at hypocone LM2. The molar enamel is therefore thicker than in Pan, possibly thicker than in Ardipithecus ramidus ramidus, but thinner than in Australopithecus6. Given individual and intraspecific variation, further study using high-resolution imaging (CT scanning) is needed for useful comparisons7.

Discussion
Sahelanthropus has several derived hominid features, including small, apically worn canines—which indicate a probable non-honing C–P3 complex—and intermediate postcanine enamel thickness. Several aspects of the basicranium (length, horizontal orientation, anterior position of the foramen magnum) and face (markedly reduced subnasal prognathism with no canine diastema, large continuous supraorbital torus) are similar to later hominids including Kenyanthropus and Homo. All these anatomical features indicate that Sahelanthropus belongs to the hominid clade.

In many other respects, however, Sahelanthropus exhibits a suite of primitive features including small brain size, a truncated triangular basioccipital bone, and the petrous portion of the temporal bone oriented 60° to the bicarotid chord. The observed mosaic of primitive and derived characters evident in Sahelanthropus indicates its phylogenetic position as a hominid close to the last common ancestor of humans and chimpanzees. Given the biochronological age of Sahelanthropus, the divergence of the chimpanzee and human lineages must have occurred before 6 Myr, which is earlier than suggested by some authors23, 24. It is not yet possible to discern phylogenetic relationships between Sahelanthropus and Upper Miocene hominoids outside the hominid clade. Ouranopithecus15 (about 2 Myr older) is substantially larger, with quadrate orbits, a very prognathic and wide lower face, large male canines with a long buccolingual axis, and cheek teeth with very thick enamel. Samburupithecus14 (about 2.5 Myr older) has a low, posteriorly positioned (above M2) zygomatic process of the maxilla, cheek teeth with high cusps (similar to Gorilla), lingual cingula, large premolars and a large M3.

Sahelanthropus is the oldest and most primitive known member of the hominid clade, close to the divergence of hominids and chimpanzees. Further analysis will be necessary to make reliable inferences about the phylogenetic position of Sahelanthropus relative to known hominids. One possibility is that Sahelanthropus is a sister group of more recent hominids, including Ardipithecus. For the moment, productive comparisons of Sahelanthropus with Orrorin are difficult because described craniodental material of the latter is fragmentary and no Sahelanthropus postcrania are available. However, we note that in Orrorin, the upper canine resembles that of a female chimpanzee. The discoveries of Sahelanthropus along with Ardipithecus6, 7 and Orrorin8 indicate that early hominids in the late Miocene were geographically more widespread than previously thought.

Finally, we note that S. tchadensis, the most primitive hominid, is from Chad, 2,500 km west of the East African Rift Valley. This suggests that an exclusively East African origin of the hominid clade is unlikely to be correct (contrary to ref. 8). It will never be possible to know precisely where or when the first hominid species originated, but we do know that hominids had dispersed throughout the Sahel and East Africa10 by 6 Myr. The recent acquisitions of Late Miocene hominid remains from three localities, as well as functional, phylogenetic and palaeoenvironmental studies now underway, promise to illuminate the earliest chapter in human evolutionary history. Sahelanthropus will be central in this endeavour, but more surprises can be expected.

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Geology and palaeontology of the Upper Miocene Toros-Menalla hominid locality, Chad

PATRICK VIGNAUD*, PHILIPPE DURINGER†, HASSANE TAÏSSO MACKAYE‡, ANDOSSA LIKIUS*‡, CÉCILE BLONDEL*, JEAN-RENAUD BOISSERIE*, LOUIS DE BONIS*, VÉRA EISENMANN§, MARIE-ESTHER ETIENNE*, DENIS GERAADS, FRANCK GUY*¶, THOMAS LEHMANN*, FABRICE LIHOREAU*, NIEVES LOPEZ-MARTINEZ#, CÉCILE MOURER-CHAUVIRÉ, OLGA OTERO*, JEAN-CLAUDE RAGE§, MATHIEU SCHUSTER†, LAURENT VIRIOT*, ANTOINE ZAZZO** & MICHEL BRUNET*

* Faculté des Sciences et Centre National de Recherche Scientifique UMR 6046, Université de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France
† Centre de Géochimie de la Surface, CNRS UMR 7517, Université Louis Pasteur, 1 rue Blessig, 67084 Strasbourg, France
‡ Université de N'Djaména, BP 1117 N'Djaména, Tchad
§ Muséum National d'Histoire Naturelle et CNRS UMR 8569, rue Cuvier, 75005 Paris, France
Centre National de Recherche Scientifique UPR 2147, 44 rue de l'Amiral Mouchez, 75014 Paris, France
¶ Peabody Museum, Harvard University, 11 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
# Dept. Paleontología, Universidad Complutense, 28040 Madrid, Spain
Centre des Sciences de la Terre, CNRS UMR 5125, Université Claude Bernard, 27-43 Bd du 11 novembre 1918, 69622 Villeurbanne, France
Centre National de Recherche Scientifique UMR 162 et Institut National de la Recherche Agronomique, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France


Correspondence and requests for materials should be addressed to P.V. (e-mail: patrick.vignaud@univ-poitiers.fr).




All six known specimens of the early hominid Sahelanthropus tchadensis come from Toros-Menalla site 266 (TM 266), a single locality in the Djurab Desert, northern Chad, central Africa. Here we present a preliminary analysis of the palaeontological and palaeoecological context of these finds. The rich fauna from TM 266 includes a significant aquatic component such as fish, crocodiles and amphibious mammals, alongside animals associated with gallery forest and savannah, such as primates, rodents, elephants, equids and bovids. The fauna suggests a biochronological age between 6 and 7 million years. Taken together with the sedimentological evidence, the fauna suggests that S. tchadensis lived close to a lake, but not far from a sandy desert, perhaps the oldest record of desert conditions in the Neogene of northern central Africa.


Since 1994, the Mission Paléoanthropologique Franco-Tchadienne (MPFT), a scientific collaboration between Poitiers University, Ndjaména University and the Centre National d'Appui à la Recherche (CNAR), Ndjaména, has conducted several field expeditions in the Djurab Desert of northern Chad (Fig. 1). Numerous Miocene and Pliocene vertebrate sites have been discovered, corresponding to four fossiliferous areas, all dated biochronologically—that is, by the evolutive degree of their faunas. These areas are Koro Toro, estimated at around 3.0–3.5 million years (Myr), which has already yielded hominid remains1, 2; Kollé, between 4 and 5 Myr (ref. 3); and Kossom Bougoudi, dated close to the Mio-Pliocene boundary around 5.3 Myr (ref. 4). The fourth fossiliferous area, named Toros-Menalla, is the oldest: it was discovered in the western Djurab Desert by the MPFT in 1997. More than 300 vertebrate localities are already known from this area. One of them, TM 266, has yielded a vertebrate fauna (42 taxa) that includes more than 700 identifiable mammal fossils (24 taxa) and the oldest known hominid remains5.


Figure 1 Map of the Chad basin showing the location of the Toros-Menalla area. Full legend

High resolution image and legend (109k)



The Toros-Menalla fossiliferous area is located in the intracratonic Chad Basin (Fig. 1). This basin comprises a southern sub-basin that includes the present Lake Chad under semi-arid to wet conditions, and a northern sub-basin that forms the central Chad lowland, now a desert and subject to significant aeolian deflation. The Holocene 'Mega Lake Chad'6 constitutes the last main lacustrine event in this region before aeolian erosion and the onset of the current desert conditions. Sediments in the Chad Basin are mainly lacustrine, fluviatile and aeolian. Fluviatile deposits are mainly due to episodic flash floods. Until now, no perennial fluvial systems have been recognized in Miocene deposits of the northern sub-basin.

Sedimentology
The Toros-Menalla outcrops consist of large flat to weakly undulating surfaces, sometimes dissected in small outliers. Stratigraphic sections are rarely thicker than a few metres. Outcrops are situated in the centre of the northern sub-basin and consist mainly of thick monotonous terrigenous series dominated by sands and weakly indurated sandstones interbedded with argillaceous pelites and diatomites (Fig. 2).


Figure 2 Idealized section and palaeoenvironmental vertical evolution in the TM 266 hominid site. Full legend

High resolution image and legend (82k)



The section and the depositional facies described here (Fig. 2) correspond to the TM 266 hominid locality (1.5 km2, hominids quarry about 5,000 m2). Numerous sections (2–5 m thick) were examined and widely correlated. Having only small outliers, most of the sections were completed by excavations.

The lower part of the section (at least 4 m thick) is composed of fine to very fine white sands, poorly cemented, and is mainly constituted by numerous quartz grains, without matrix. The grains are well sorted, well rounded, matt and frosted, and are strong evidence for aeolian modelling. The foreset laminations (avalanche laminations in front of the aeolian dune) represent a typically aeolian deposit. These sands show cross-beddings that progressively decrease in size from the bottom (1–2 m) to the top (20 cm). This facies exhibits typical alternations of grain-fall and grain-flow laminations, characteristic of aeolian dune deposits7, 8. Our interpretation is confirmed by frequent wind ripples at the foot of the fossil dunes, whose crests are perpendicular to the direction of dune progradation. These fossil dunes are, to our knowledge, the oldest evidence for desert conditions in the southern Sahara area. The measured currents of the larger-scale cross-bedding of the fossil dunes show a unimodal distribution that indicates a major wind direction towards the west-south-west (Fig. 2). This facies contains numerous rhizoliths (rocks formed from plant roots), their number increasing gradually from the bottom to the top. In contrast to the others, this unit contains no vertebrate fauna. The erosional surface at its top marks the end of the true desertic episode.

The middle part of the section (about 2 m thick) is informally named the anthracotheriid unit (AU). This unit yielded the hominid cranium and all the terrestrial vertebrate remains (Table 1). The hominid was embedded in a poorly cemented sandstone in the lowest metre of the unit (Fig. 2). The deposit is a moderately to well-cemented sandstone, generally well sorted but with a variable quartz grain maturity. The sandstone is characterized by a mixing of both inherited aeolian sand showing matt and frosted quartz grains, and other grains resulting from the lacustrine reworking. In contrast to the lower part of the section, these sandstones are often matrix supported (mainly pelites and diatomites). There are many millimetre- to centimetre-scale lacustrine joints that contain clay. In contrast to the lower part of the section, the cross-bedding sets are always small (generally 5–10 cm, exceptionally 20 cm). This root-rich unit yielded almost all the vertebrate remains, common fossilized dung beetle brood balls and rare termitaries9, 10. In contrast to the lower aeolian facies, the occurrence of both current and wave ripples, as well as small sand bars of coarse pelitic sandstone, testify to water movements. However, in this unit the strong dispersion of the palaeocurrents in all directions (360°) (Fig. 2) is incompatible with a normal fluvial dynamic, in which currents never show such unusual dispersion (even in strongly meandering systems). This water circulation between the dunes represents the first manifestation of a northward lake transgression, which implicates episodic flooding and draining in a desert environment. The AU corresponds to a shallow perilacustrine environment, subject to frequent inundation due to recurrent lateral variations of the shoreline. For the present-day Lake Chad, such excursions may reach several tens of kilometres over one or two decades11. In this vegetated perilacustrine belt, numerous environments coexist, from aquatic habitats in the lake and along the shore, to very dry situations on the edge of the desert. The wide variation in palaeocurrent direction suggests the interdigitation and coexistence of lacustrine, perilacustrine and desert environments.

The upper part of the section (about 0.5 m thick) is weakly developed in the TM 266 site. It meets the middle part of the section at an erosional surface. It is a well-stratified green pelite and is interpreted as a true lacustrine environment. This upper unit yielded only aquatic vertebrates (fish and crocodilians).

Vertebrate fauna
The fauna recovered at TM 266 (Table 1) does not show evidence of fluviatile transport, consistent with the sedimentology.

There are more than ten taxa of freshwater fish. All identified taxa are known to have been present in the Nilo-Sudanese at least since the Upper Miocene; all have living representatives in Lake Chad except Sindacharax, which is a taxon from the Miocene and Pliocene of north equatorial Africa12. Turtles, lizards, snakes and crocodiles are represented by abundant skeletal material, but no bird remains have been recovered.

The carnivore fauna is particularly diverse. As in most Late Miocene localities, the hyaenids are the most numerous in both species and individuals. Three species can be identified: Hyaenictitherium cf. H. hyaenoides; Ictitherium sp., the size of I. taurinum but with different tooth morphology; and a third (Hyaenidae indet.) is small, like Protictitherium. The felid Machairodus cf. M. giganteus is represented only by very large mandibles. Machairodus is rare in Africa, and until now most of the referred material has been attributed to Dinofelis. Mustelids are represented only by a small species of lutrine (otter).

Except for the hominid remains5, primates are represented by a single damaged maxilla referred to an indeterminate colobine monkey. Rodent remains are mainly attributable to Murinae, but some Sciuridae (Xerus sp.) and Hystricidae (Hystrix sp.) are also present. Among aardvarks, cranial and postcranial remains can be referred to Orycteropus cf. O. gaudryi, a species known in the Late Miocene of the eastern Mediterranean area13. A medium-sized equid shows strong affinities with Hipparion abudhabiense from the Upper Miocene of the United Arab Emirates14. Fossil remains of proboscideans are abundant. Numerous teeth of both the gomphothere Anancus kenyensis and the elephantid Loxodonta sp. aff. L. sp. indet. 'Lukeino stage'15 have been found.

Suids are represented by Nyanzachoerus syrticus, smaller than N. kanamensis but larger than N. devauxi. The cheek teeth are very low crowned with robust premolars, including a double-rooted upper premolar P1. The third molars show primitive features: the talon of upper M3 comprises only one lingually located main cusp but lacks developed accessory cusps; the lower M3 talonid is also simple. Morphology and size are congruent with Nyanzachoerus syrticus from Lothagam (Nawata formation, lower member)16.

The AU receives its name from the abundance of anthracotheriid fossils (Fig. 2). These remains are referred to the north African Libycosaurus petrocchii. Together with the Anthracotheriidae, TM 266 yielded a new species of large hippopotamid, equivalent in size to Hexaprotodon harvardi from the Lothagam Nawata formation17. Nevertheless, mandibular morphology is dominated by a particularly high and massive symphysis, which clearly differs from the H. harvardi mandible. This primitive species is absent from the Miocene–Pliocene boundary and Early Pliocene sites in Chad, where a smaller and more-derived species is present.

Two giraffid taxa are represented, a large and a small form. The former, Sivatherium cf. S. hendeyi, is documented by mandibles and postcranial material. The latter is represented by postcranial bones, tentatively assigned to Giraffidae indet.

The hominid locality has yielded at least five bovid species, three of them being abundant. The smallest is a kob with short horns, similar to Kobus subdolus and K. darti from Langebaanweg (South Africa)18, Sahabi (Libya)19, Manonga (Tanzania)20 and Mpesida (Kenya)21, but smaller than in the first two sites. The teeth are more fully reduncine than in Langebaanweg18 but teeth from this site are perhaps not illustrative of the teeth of primitive reduncines. The other two common taxa are of uncertain tribal affinities. One is attributed to cf. Hippotragini gen. et sp. nov., with a rather primitive skull morphology and long curved horns with a large basal sinus. It is probably an early hippotragine. The teeth are not strongly derived, but would confirm this identification. This species might be the same as ?Hippotragus sp. from Sahabi. The last of the three common taxa is a little larger, with massive, almost parallel, slightly curved and not very long horn cores, no sinus in the pedicle and large supraorbital pits. There are some similarities with the ovibovine Palaeoryx from the eastern Mediterranean Turolian, but also some differences, which make a close relationship unlikely. For the time being, it is referred to aff. Palaeoryx sp. The two less-abundant species are an antilopine and a bovine with primitive teeth. The bovid fauna from the Lothagam Nawata formation (lower member)22 looks more modern than that of TM 266. It is dominated by the modern genus Aepyceros and by Boselaphini, which are absent from TM 266 but are known in other African sites close in age to the Miocene–Pliocene boundary, whereas two of the dominant TM 266 bovids (cf. Hippotragini and Ovibovini indet. aff. Palaeoryx sp.) are not present at Lothagam.

Biochronology
In the AU of TM 266, Nyanzachoerus syrticus is associated with an anthracotheriid (Libycosaurus). In younger sites from the Djurab area that have yielded Nyanzachoerus kanamensis (such as Kossom Bougoudi)4, anthracotheriids are always absent. The evolutionary level of the upper and lower third molars of Nyanzachoerus syrticus from the hominid locality is very similar to that of related remains from the Lothagam Nawata formation16. The age of the Nawata formation fauna is estimated at about 5.2–7.4 Myr (ref. 23). The biochronological age estimate for the hominid locality is also supported by the evolutionary levels of several other mammalian groups (Anthracotheriidae, Proboscidea, Equidae and Bovidae). The Libycosaurus anthracotheriids are similar to those from Sahabi24; the fauna from this site is consistent with an Upper Miocene age25. Anthracotheriids are unknown from this time in East Africa and the remains from Libya and Chad may represent their last known occurrences in Africa.

The co-occurrence of Anancus kenyensis with Loxodonta sp. indet. 'Lukeino stage' is also seen in the Lukeino Formation, Kenya (6 Myr)26, 27. However, the TM 266 proboscideans show more primitive characters than those from Lukeino15, 28 (thicker enamel and lower laminar frequency for Loxodonta sp. aff. L. sp indet. 'Lukeino stage'; a simpler crown pattern with less numerous tubercles and thicker enamel for A. kenyensis). These features support an older biochronological age for the TM 266 hominid site. This biochronological estimate is also supported by the presence of the equid Hipparion cf. H. abudhabiense, a species described from the Lower–Middle Turolian of Abu Dhabi14. Among carnivores, the co-occurrence of Machairodus cf. M. giganteus, small Hyaenictitherium and Ictitherium sp. is congruent with a Late Miocene age, equivalent to the European faunas of the Middle–Upper Turolian. Moreover, the five associated taxa of primitive bovids are also compatible with an Upper Miocene age. Among them, the two larger taxa do not fit easily into modern African bovid tribes, they suggest an earlier age than the Miocene–Pliocene boundary.

This evidence suggests that TM 266 is older than the Lukeino Formation26, 27, and may be equivalent in age with the base of the fossiliferous levels of the Nawata formation at Lothagam23. It is hoped that continuing studies on the fauna will clarify the precise chronological position of TM 266, but present evidence suggests that the faunal remains, including the hominid remains, were deposited between 6 and 7 Myr ago.

Environmental reconstruction
The diversity of aquatic and amphibious forms clearly demonstrates the presence of aquatic environments. Among fish, Hydrocynus (tiger fish) is a strict piscivore, hunting by sight in deep and well-oxygenated waters; many of the specimens are longer than 1 m, indicating extensive aquatic habitats. The frequency of piscivorous crocodilians, including Euthecodon and a new species of gavial, also clearly indicates large and permanent water bodies. Swampy, well-vegetated areas are suggested by the presence of the fish Polypterus, which can tolerate very poorly oxygenated waters. Likewise, Gymnarchus lives in swampy and turbid waters where its electrical sensorial system is advantageous. Moreover, there is a great abundance of taxa related to amphibious and bank habitats, particularly the well-preserved anthracotheriids and hippopotamids (including some complete skeletons), otters, trionychid turtles and the snake Python cf. P. sebae. The liana-like character of the papilionoid plants from TM 266 is compatible with a gallery forest bordering a lake.

The bovids represent about 55% of mammal remains from the TM 266 locality and amphibious mammals represent about 28%. The relatively high-crowned teeth of all the bovids and the lack of tragelaphines and boselaphines are strong evidence of open grassland. Thus, the faunal assemblage from the hominid site is compatible with a diversity of habitats including grassland (bovids), wooded savannah (proboscideans and giraffids), fresh water (fish, turtles, snakes, crocodilians, anthracotheriids, hippos and otters) and probably some gallery forest (primates).

The oldest known East African hominids (Ororrin, Ardipithecus) are contemporary with faunas associated with wooded environments26, 29, 30. Younger australopithecines lived in a wider range of habitats31. In contrast, the TM 266 vertebrate fauna contemporary of the Toros-Menalla hominid suggests a mosaic of environments from gallery forest at the edge of a lake area to a dominance of large savannah and grassland. Determining the precise habitat of the TM 266 hominid locality among the mosaic of environments available to it constitutes a research challenge to be met by further laboratory and field studies currently in progress.

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Received 13 March 2002;accepted 27 May 2002

Nature 418, 133 - 135 (2002); doi:10.1038/418133a


Palaeoanthropology: Hominid revelations from Chad

BERNARD WOOD

Bernard Wood is in the Department of Anthropology, The George Washington University, 2110 G Street NW, Washington DC 20052, USA.
e-mail: bwood@gwu.edu



The story of human origins in Africa takes a twist with the description of a 6–7-million-year-old cranium from Chad. The discovery hints at the likely diversity of early hominids.


A single fossil can fundamentally change the way we reconstruct the tree of life. More than 75 years ago, Raymond Dart's description1 of the Taung skull from southern Africa wrought such a transformation with regard to human evolution. Dart provided hard evidence to support Darwin's prediction that the roots of human evolutionary history run deepest in Africa.

A fossil cranium (Fig. 1), discovered by Michel Brunet and his colleagues and described in this issue, marks a similar turning point in our understanding of human origins. Discussion of the cranium and associated fossils is on page 145 (Brunet et al.2), with presentation of the contextual evidence (Vignaud et al.3) on page 152. The fossils — the cranium, a jaw fragment and several teeth — belong to a primitive human precursor, or hominid, that is an astonishing 6–7 million years old. The transformation wrought here is more nuanced than Dart's, but it is as fundamental. Here we have compelling evidence that our own origins are as complex and as difficult to trace as those of any other group of organisms.


Figure 1 The cranium of the newly described Sahelanthropus tchadensis and (below) the opening page of Raymond Dart's 1925 description of the Taung skull. Full legend

High resolution image and legend (111k)



For almost 150 years4 it has been suggested that modern humans are more closely related to the African apes than they are to the orang-utan. Nowadays, evidence from both bones and teeth5-7, and soft tissues (muscles, nerves, and so on)8, and from molecular and DNA analyses9, 10, support the view that modern humans and chimpanzees are particularly closely linked. When the DNA differences are calibrated by using palaeontological evidence, they indicate that the hypothetical ancestor of modern humans and the chimpanzee lived between about 5 and 7 million years ago.

The hominid fossil record outside Africa has stubbornly failed to break the 2-million-year barrier. Thus, if the 'molecular clock' keeps reasonably good time, between 3 and 5 million years or so of our independent evolution took place on the African continent. Four regional 'windows' provide fossil evidence relevant to our early evolutionary history. The southern African window was revealed by Dart in 1925 when the first (and only) hominid fossil from Taung, near Kimberley, was recognized; since then, neighbouring cave sites have provided a rich fossil record that stretches back to around 3–3.5 million years ago11. The East African window comprises sites along the Eastern, or Gregory, Rift Valley, from close to the Gulf of Aden in the north to northern Tanzania in the south. The sites are associated with sedimentary basins or the rivers that fed or drained them. Two of them, Middle Awash in Ethiopia12, 13 and Lukeino in Kenya14, have so far provided the oldest evidence of creatures that are plausible human ancestors.

The two remaining regions, Malawi and Chad, were, until now, more like spy-holes than windows. Malawi has provided evidence of one of the large-toothed hominid species, probably Paranthropus aethiopicus (see Fig. 2). The first 'early hominid' from Chad, Tchadanthropus uxoris, found in 1961, turned out to be the face of a modern human skull that had been so eroded by wind-blown sand that it mimicked the appearance of an australopith, a primitive type of hominid. The second Chad hominid, Australopithecus bahrelghazali, discovered15 at a site called Koro Toro in 1995, is an authentic australopith and alerted palaeontologists to the potential of central West Africa.


Figure 2 The known fossil record of hominids, including S. tchadensis, also showing ourselves (top left) and the chimpanzee (top right). Full legend

High resolution image and legend (39k)



Four areas in and around the Chad basin have yielded mammalian fossils, but it is one locality, TM 266, in the oldest of these areas — Toros-Menalla in the Djurab Desert — that provided Brunet's team with the fossils they describe in this issue. The discovery is a tribute to the tenacity of Brunet, Vignaud and their scientific colleagues, and to their intrepid local field team. The sand-laden wind blows incessantly and the fossil layers are difficult to detect: they are at most a few metres thick and a far cry from the banks of sediment that we are used to seeing in pictures of Olduvai Gorge in Tanzania, and the like. Yet, despite the harsh present-day environment, the vertebrate fossils are well preserved, and the hominid cranium (designated TM 266-01-060-1) is remarkably complete.

Absolute — isotope-based — dating methods cannot be applied to the fossil layers at Toros-Menalla because there are no ash layers to provide the necessary argon and potassium. Nor are the sediments suitable for magnetism-based dating methods. Instead, the team matched the rich vertebrate fossil record at TM 266, consisting of examples of 44 different groups, with the equivalent record from sites in East Africa that have absolute dates. The best matches are with two sites in Kenya: the Lukeino Formation of the Tugen Hills (which dates to about 6 million years ago) and the Nawata Formation at Lothagam (5.3–7.4 million years). The upshot is a reliable age estimate of about 6–7 million years for the Toros-Menalla fossils.

The researchers compared their new evidence with what has been published about two other claimants for the title of 'earliest hominid', Ardipithecus ramidus from the Middle Awash12, 13 and Orrorin tugenensis from Lukeino14. They satisfied themselves (and others, myself included) that the teeth of the new fossils are taxonomically distinctive, and accordingly assigned the fossils to a new species and genus, Sahelanthropus tchadensis.

What was the role of S. tchadensis in the evolution of chimpanzees and modern humans? The latter two look very different, but the differences between the earliest ancestors of chimpanzees and modern humans are likely to have been more subtle. The conventional presumption is that the human–chimp common ancestor, and the earliest members of the chimp lineage, or clade, would have been adapted for life in the trees, with the trunk held either horizontal or upright and with the forelimbs adapted for knuckle-walking on large branches or on the ground. This would have been combined with projecting faces that accommodated elongated jaws bearing relatively small chewing teeth and, in males, large upper canine teeth that would have worn against the lower premolars.

Early hominids at the base of our own clade, in contrast, would have been distinguished by at least some skeletal and other adaptations for an upright posture and bipedal walking and running, linked with a chewing apparatus that combined proportionally larger chewing teeth, modest-sized male canines that wore only at the tip of the crown, and some evidence of an increase in brain size. Against these criteria it is the face, jaw and canines of S. tchadensis that point to its being a hominid, at (or at least close to) the base of the modern human clade.

There are two current hypotheses about human origins and the early stages of hominid evolution. According to the linear, or 'tidy', model16, the distinctive hominid anatomy evolved only once, and was followed by a ladder-like ancestor–descendant series. In this model there is no branching (cladogenesis) until well after 3 million years ago. The bushy, or 'untidy', model sees hominid evolution as a series of successive adaptive radiations — evolutionary diversification in response to new or changed circumstances — in which anatomical features are 'mixed and matched' in ways that we are only beginning to comprehend17, 18. This model, to which I subscribe, predicts that because of the independent acquisition of similar shared characters (homoplasy), key hominid adaptations such as bipedalism, manual dexterity and a large brain are likely to have evolved more than once19. So the evidence of one, or even a few, of the presumed distinguishing features of hominids might not be enough to link a new species with later hominids, let alone to identify it as the direct ancestor of modern humans.

What is remarkable about the chimp-sized cranium TM 266-01-060-1 discovered by Brunet et al. is its mosaic nature. Put simply, from the back it looks like a chimpanzee, whereas from the front it could pass for a 1.75-million-year-old advanced australopith. The hominid features involve the structure of the face, and the small, apically worn, canine crowns. Other hominid features are found in the base of the cranium and in the separate jaw fragment. If we accept these as sufficient evidence to classify S. tchadensis as a hominid at the base, or stem, of the modern human clade, then it plays havoc with the tidy model of human origins. Quite simply, a hominid of this age should only just be beginning to show signs of being a hominid. It certainly should not have the face of a hominid less than one-third of its geological age. Also, if it is accepted as a stem hominid, under the tidy model the principle of parsimony dictates that all creatures with more primitive faces (and that is a very long list) would, perforce, have to be excluded from the ancestry of modern humans.

In contrast, the untidy model would predict that at 6–7 million years ago we are likely to find evidence of creatures with hitherto unknown combinations of hominid, chimp and even novel features. Moreover, because it acknowledges substantial amounts of homoplasy, the model would further predict that certain structures — such as substantial brow ridges (which S. tchadensis has, as is evident in Fig. 1) — are likely to be unreliable for reconstructing relationships because creatures can share features such as brow ridges without necessarily inheriting them from a common ancestor20. S. tchadensis is a candidate for the stem hominid, but in my view it will be impossible to prove that it is.

My prediction is that S. tchadensis is just the tip of an iceberg of taxonomic diversity during hominid evolution 5–7 million years ago. Its potentially close relationship with our own, hominid, twig of the tree of life is surely important. More notably, however, I think it will prove to be telling evidence of the adaptive radiation of fossil ape-like creatures that included the common ancestor of modern humans and chimpanzees. The fauna of the Burgess Shale in Canada, which samples a bewildering array of invertebrate groups some 500 million years ago, is a famous example of diversity at the base of an adaptive radiation. Does S. tchadensis belong to the African-ape equivalent of the Burgess Shale?

şekilleri de merak ediyorsanız.. www.nature.com dan bulabilirsiniz.

ingilizce ayaklarini Hegel...

Yemezler !

Fikrin varsa ve yiyorsa adam gibi ortaya koy...

Yada ebediyen sus ve muzunu TIKINMAYA devam et !

Hadi bakimm...

Yabanci dil konusan sebek seni !

evrimden geri maymun,

senin beynin maymunkiyle eş ya da yakın olduğuna göre ingiliz diline bile anlam ve gereken değeri vermemişsin ki, oturup öğren(e)memiş

ama üzülme, evrim seni de bir milyon yılda seni de geliştirecek, o zaman anlarsın neler yazdığını

maymunla insan arası, yarı gelişmiş, geri zekalı!..

senden daha iyi örnek var mı acaba eksik halka için?
seni de incelemeye alsalar keşke

sen git de sana dediğim kitabı oku, evrimine katkı olsun

Ne o yemedi mi?

Adam aynen Darrow denen evrimlesmemis sahis gibi getirmis yapistirmis...

Aha da yazi, ahlaksizlik yapmadan cevap verin...

Gosterin hunerlerinizi seyredelim...

Ornegin hamamda kari nasil bayilir...

Keh keh keh

Burda önemli olan benim zeka ya da dil sorunum mu,yoksa tam bir aldatmacayla herzamanki bayat ve düzeysiz demogojik çıkarımlara tokat gibi verien bilimsel cevap mı!
Ben web adresini verdim.Orjinal yazıyı paste ettim daha ne istiyorsunuz.
Göz göre göre yalan söyleniyor.Bunlar sökmez!
evrim teorisinde tartışılan,karanlıkta olan çok soru var.
Bunlar için acaip emekler harcanılıyor,çalışmalar yapılıyor.
Evrim teorisi ile ilgili düzenlenen bir konferansa katılım için gerekli kayıt parasından ya da sunumları okumanın bedelinden haberiniz var mı acaba?
Kaç papel istediklerinden.
Bilgiye ulaşmak o kadar kolay değil.
Ben daha önce de yazdım.
Hem iftiraya cevabı vermek,
Hemde ilgilenen insanlar okusunlar diye paste ettim yukardakileri.
Odunlar için ise kılımı bile kıbırdatmam zaten.
Bana ne!
ne haliniz varsa görün.

bilimsel veriler ve bulgular veya teoriler değişmez tabular değildir.teknolojinin bilimin geldiği her ileri aşamada geçmiş dönemde açıklanan bilimsel teorileri ya güçlendirir veya çürütebilir.Çad da ne
bulundu bilemiyorum insanla maymunun ortak atası aynı olmadığıda ortaya çıkabilir.ama şu gerçekki evrim teorisi hiç bir zaman çürütülemez.çünkü o bir gerçek hayatla vucut bulmuş olgudur.
Gelelim size bilim adamlarının yaptığı tesbitlerle yaratılış teorisini kurtaracağınızımı zannediyorsunuz.Size kalsa canlılığın yaşını bırak bütün evrenin yaşının 6000 yıl olduğunuzu inanan bir kitaba sahipsiniz,bu hangi akla ve bilime sığar,şimdi bana yok o öyle yazılmadı böyleydi demeyin,çünkü kitabınızın iddası eski din ve kitapların saptırıldığı
yanlış okunup ve yorumlandığı için ,tanrınız sizlere
yanlış okuyup yorumlamanız için apaçık arapça olarak indirmiş,diğer kitaplarına koruma getirmemiş ama bu kitabınaza bir tek harfinin dahil yanlış okunup yorumlanmaması için kiyamate kadar koruma getirmiştir.Ama yazılanlar yaşamla veya yaşanmışlıkla hiç uyuşmadığının farkında olmanız gerekir.ama farkında değilseniz ben ne deyim,allah akıl fikir versin

Adindaki agnostik spastike ihtar !

Bak oglum, öyle ucuz laflarla kafani yirtik dondan çikarip bilimsellik numaralarina yatma...

Git önce kendi varligindan süphe et.

Belki de sen yoksundur...

Yada insan olduguna inanan bir maymunsundur...

Ne malum?

Hadi gel bana öyle olmadigini ispat et !

Ben varim, de!

Ingilizce yazi asmakla kara cehaletini gizleyemezsin, a benim kafadan agnostik evladim...

Bunlar, cevabi olmayanlarin basvurdugu ucuz numaralar !

Yada en azindan astigin yaziyi özetleyeceksin.

Kendin çal kendin oyna yapmayacaksin !

Hadi bakim...

Simdi yaylan.

Ó adlı katılımcı ne de güzel söylemiş. Sana göre evren yaklaşık 6000 yaşında öyle mi?

hatta sen nuh tufanına bile inanıyorsundur,
hatta musa diye birinin yaşadığından bile eminsindir.
peki ya isa? elbette ona da inanıyorsundur.

zaten salakların şahı, dahi muhammed de senin
gibilerin bu dünyada bir hayli çok olduğunu biliyordu.
herşey bir yana, muhammed büyük adam. ama sen ve senin
gibiler çok ama çok küçük!..

kimin zavallı bir maymun olduğu ortada

ayrıca, henüz evrimleşemediğinden, ingilizce yazıların
benim değil hegel adlı katılımcı tarafından asılmış
olduğunun bile ayrımında değilsin

öyle zavallı ve öyle gafilsin ki

zavalli kucuk bi gafil soruyo

evren 6000 yasinda mi
kim diyo?
bu mesele bu iddiada bulunanlarin problemi
bu konu digerlerinden ayri tartisma mevzusu


fakat
nuh tufani olmadimi
musa yasamadimi
isa yokmu
hz muhammed ne demiski?

ates olmayan yerden duman cikmaz derler
ama
farz edelimki yukardakiler yok
ispatin mi var
delilin ne?

mesela dogan
var diyo
var olup olmamalarida dogan icin okadar onemli olmasada
var olduklarina inaniyorum
olmadiklarini bana kanitlasana


hatam varsa kucuklugume ver
buyukluk sende kalsin

hoscakal

istersen musa ile başlayalım...

kimdir musa?

ne zaman ve nerede ve ne koşullar altında yaşamıştır?

sakın bana o insanlık ayıbı sözde kutsal kitaplarınızı
delil olarak göstermeye kalkma.
bu davranışın şuna benzer:
arkadaşını öldüren adamın mahkemeye kendi eliyle yazılmış "ben öldürmedim" notuna benzer.
Yargıç da bu adama önce içinden ya da dışından küfrederek
KOVAR!.. (daha doğrusu yargısını verir ve çıkamayacağı bir deliğe tıkar)

şimdi dönelim musaya...

hangi tarihçi musa ile ilgili bir satır bir şey yazmış?
o aşağılık arap tayfasınınkiler (bu tayfaya elbette yahudiler de dahil) geçersiz, unutma

hangi mısırlı, yunanlı, hatta finikeli, asurlu, vs. tarihçinin kayıtlarında var musa karakteri?

yoksa yoksa, aşşağılık iki yahudi peygamberinin (işaya ve hezekielden bahsediyorum) zaten yüzyıllardır anlatıla gelen
ve tüm bölge halkı tarafından bilinen'bakkhos' masallarını, o her zamanki aşağılık ve barbarca tutumlarıyla finike ve asur yazılarından çaldıktan sonra allayıp pullayarak, sürgündeki pagan yahudi uyruklarına 'aha, bak yeni bir kitap bulduk, adı da tevrat, megerse biz şöyle bir tarihe sahipmişiz' gibi teranelerle yutturmaları ve o geri zekalının ötesi yamyam ve tefeci arap ırkından olan yahudilerin önüne koymaları meselesini hiç araştırdın mı?

bu dünya ne çektiyse bu arap ırkından çekti ve çekiyor
sonuçta yahudi diye lanet ettiğiniz de sizin amca çocuklarınız olduğunu unutma (ismael ve israel)

aynı sen ve senin kankaların gibi aşağılık insanlardan çok çekti bu dünya

zamanında tüm evrenin dünyanın etrafında döndüğüne inanıyordunuz ve sizin gibi inanmayan insanları gözünüzü bile kırpmadan öldürdünüz, hala da öldürüyorsunuz ya
sonra ne oldu? copernic, bunun böyle olmadığını tanıtladı, ve mubarek ağzınızdan çıktı, kulaklarınız da zil çaldı!..

daha sonra, dünyayı tepsi gibi zannettiniz ve öyle inandınız, sayısız insan öldürdünüz, hala da öldürüyorsunuz ya
sonra ne oldu?
galileo çıktı ve dünyanın yuvarlak olduğunu tanıtladı
üstelik muhammed o kadar zekasına ragmen bunun düşünememiş olduğundan, oruç ve namaz gibi ibadetleri güneşin hareketlerine göre belirledi (aslında bunlar muhammedden önce olan şeylerdi, o sadece hazıra kondu, tıpkı diğer aşşağılık yahudi peygamberleri gibi)
gel de kutuplara yakın bölgelerde oruç tut!..
bu da size giren ikinci mubarek oldu, artık nerenize değdi ucu bilemem!..

ne sanattan, ne matematikten (tefecilik hariç), ne geometriden, ne fizikten ve benzeri tüm bilimlerden anlayan bu arap uyruklarının esareti altında kaldınız ve diğerlerini de bırakmaya çalıştınız, hala da çalışıyorsunuz

emperyalizm nedir biliyor musun?

emperyalizm, "engellemecilik"tir.

o zaman sen ve senin gibi düşünen diğer aşşağılık ara türler, emperyalist değildir de nedir? bu insanlık dışı düşüncelerinizle, insanlığa, ulusa, bilime yapmış olduğunuz her tür menfi davranışınıza, insanlık adına LANET OLSUN!..

seni ve tüm senin gibileri, bu dünyadan KOVUYORUM!..

siktirin gidin, bırakın insanlar bu dünyada akıl yoluyla yaşasınlar

aşşağılık ara tür seni!..


bir tükiyeli, ana dili türkçe olan ve muhtemelen asyadan gelmiş atalara sahip olmaktan (milliyetçilik değil bu) seviniyorum

neden mi?

en azından bu ulus içinden böyle aşşağılık ve peygamber adı verilen insan müsvetteleri çıkmamış da ondan

hadi şimdi sana iyi yolculuklar (siktir git yani) !!!

Sen peki kur'an da dünyanın nasıl yaratılmış olduğunu ve aslında yuvarlak değil hatta eliptik bir yapıya sahip olduğunun yazıldığını biliyor musun? Hiç eline aldın mı ki nerden bileceksin? Peygamberimize bile akılsız ve kitaplara uydurma demeden önce bi açıp okuyaydın bari. Kur'anda dünya da önce göğün (7 kat olduğu da belirtilerek) sonra yerin düz bir şekilde yaratıldığı ve sonra Allahın onu devekuşu yumurtasına benzer şekile dönüştürdüğü yazıyor. Tabi o zamanlar elips falan bilinmediği için öyle örnek vermiş olacak. Yani imrendiin Galileo bulmadan önce bu zaten bize verilmiş bir bilgiydi.

Bu Darrow ismindeki agnostik spastik, yeni türemelerden. Dikkat ettiyseniz fikirle gelemiyor, önermelere bir cevap veremiyor, yirtik dondan basini çikarip onbasi selami veriyor ve sonra tabanlari yaglayip kümesine geri dönüyor.

Hele birkaç fikir kirintisiyla yaklassin, kendisine dünyanin kaç bucak oldugunu gösterip, beynine ateistsavar balyozlarimizdan indiririz evelallah.

Hos, bu davar DARROW, agnostik oldugunu ileri sürüp darbelerimizden kurtulacagini zannediyor. Onu mu kiracaz, biraz da agnostiksavar'lik yapariz

Len agnostik veled, sen kendinden de süphe ediyon mu len?

Belki de sen DARROW degilsindir, MARROW'sundur, ne malum ha ?

Yada hamamda bayilip diskoda ayilan bir maymun çesidi olmayasin?

Len DARROW, tekno dinleyip, kiçini saga sola da kivirtiyon mu len?

Kiçinin senin kiçin oldugundan da süphe ediyon mu?

Emin misin?

Hani agnostik olduguna göre ?

O kadar süpheci olma evladim, sonra karakolda kimin badanalattigindan da süphe edersin de, sendeki bu avanakliktan komiser amca bile istifade eder

Haydi simdi kümesine dönebilirsin!

Yallah !

(Süt veren Hollanda inekleriyle karistirilmasin


Yaw kardesim, birak iki satirlik eski ahit bilginle andavallik edip martaval okumayi !

Hz Musa'nin yasadigina dair delil var miymis falan filan !

Allah'in yokluguna(!) getirdigin delil ve gösterdigim önermelere verdigin yanit bu mu?

Yarin da bir arkeolog çikip Hz Musa'ya ait deliller bulsa ve gözünün içine soksa, ne bok yiyeceksin ?

Esek gibi anirip mahalle mahalle dolasacak ve sebek gibi hoplayip ziplayacak misin?

Fikri olmayinca insan zirvalar tabi, hos bu DARROW ineginin maymun olup olmadigi da belli degil !

Babasinin oglu oldugundan dahi süphe eden agnostik bir SIPA çesidi de olabilir!

Sonra,

Einstein'in bile arap rakamlariyla matematik hesabi yapip, Hawkings'in en zor meseleleri yine bu ilkel(!) araplarin buldugu rakamlarla çözdügünü, bu salak DARROW sebeki nereden bilecek ?

Len septik SIPA, Vatikan'daki Papa cenaplari bile arap rakamlariyla kâlkül yapiyo len, senin dünyadan haberin yok !

Bugün adamlar aya ayak basti ise, bunu El-Cabir'e borçlular, tipki o da kendinden önceki ilim adamlarina sükran borçlu oldugu gibi.

Sen kimin malini kime satiyon hödük ?

Evvela sunu kaz kafana sokacaksin:

Görünmemeklik, olmamakliga delil teskil edemez !

Yani,

Bugün somut herhangi bir delil olmamasi, Hz Musa'nin yasamadigina dair kesin bir kanit olamaz.

Kaldi ki isin içine sözlü rivayetler ve dini kaynaklar girmis. Dünyada (sinema, roman, belgesel, vs) en çok konusulan ve varligi milyarlar tarafindan kabul gören insanlardan birtanesi...

Sen bunlardan süphe edip böyle salak seyleri Allah'in yokluguna(!) kanit getirecegine...

Önce kendi KIT zekandan ve SAKAT mantigindan süphe et !

Burasi yalakalik yapma yeri degil...

Söyle bir dönüver de...

HACI+ALI gereken yerlerdeki çatlaklari firçayla geçiversin...

Bilmem anlatabildim mi

Hadi simdi yaylanarak olay mahallinden uzaklasiver.

Bi daha saçmaladigini görmiyim, daha fena yaparim !

Dangalak spastik seni...

Sonradan kazanilan ozelliklerin, eseysel hucrelere
ornegin sperme nasil aktarildigini bilimsel olarak aciklayabilecek varmi?
Eger boyle bir mekanizma yoksa evrimin nasil gerceklestigini dusunuyorsunuz?
not; mutasyon mucizelerine inanmiyorum.

Hacı mız senin ve senin gibilerin sorularını yanıtlamak için orada bekliyor.

Sorunun cevabi: Canlilarda- Sonradan kazanilan ozellikleri, gelecek nesile aktarabilecek bir mekanizma YOK.
Ustelik bu spekulasyon yapilabilecek bir konu deyil! Var diyorsan bilimsel olarak ispat edersin.
Oyleyse evrim nasil oldu?
Evrimci cevap: mutasyon sayesinde baligin kanatlari oldu uctu gibi birsey olmak zorundadir.
Ama bu konu mahremdir tartisilmaz, bunun yerine
Al iste kafatasi ben buldum, evrim olmus iste, Oyleyse evrim; bizim simdi kestiremedigimiz birsekilde islemis -yorumu yapilir ki bu onlarin "amentu bi-tekamulu"dur.

ateistsavar,

El-Cabir kim? Nereden cebirin babası oluyormuş?
Sıfır hakkında çeşitli görüşler varsa da, mucidi olarak bırak El-Cabir diye hayali bir kişiyi, Araplar'la bile ilgisi yok!
Bence sen isim benzerliğinden ötürü yanlış bir kanıya sahipsin (Cabir -> cebir)

Üzerinde durulan üç önemli düşünce var sıfırın mucidi olarak:
1- Hintliler
2- Sümerliler
3- Çinliler

Elbette bu iki uygarlığın mirasını paylaşmış Araplar da bu sistemi Avrupalılar'dan önce kullanmışlardır.
Ancak sıfırın mucidi değillerdir.

İngilizce bilginin olmadığını öğrenmiş olmamla birlikte, diğer katılımcıların bilgisine sunmak adına bu konuda yazılmış bir makaleyi aşağıya kopyalıyorum.


Tarihi öneme sahip Arap matematikçileri:

al-Khwarizmi
Ibrahim
Khayyam
Al-Jawhari
al-Uqlidisi
Aflah
al-Kindi
Abu'l-Wafa
al-Samawal
Hunayn
al-Quhi
al-Tusi, Sharaf
Banu Musa, Ahmad
Al-Khujandi
al-Tusi, Nasir
Banu Musa, al-Hasan
al-Sijzi
al-Maghribi
Banu Musa, Muhammad
Yunus
al-Samarqandi
Al-Mahani
Al-Karaji
al-Banna
Thabit
al-Haitam
al-Farisi
Ahmed
Mansur
al-Khalili
Abu Kamil
al-Biruni
Qadi Zada
al-Battani
Avicenna
al-Kashi
Sinan
al-Baghdadi
Ulugh Beg
Al-Nayrizi
Al-Jayyani
al-Umawi
Al-Khazin
Al-Nasawi
al-Qalasadi


Görmüş olduğun gibi tarihsel öneme sahip Arap matematikçileri içinde senin iddia etmiş olduğun gibi El-Cabir adında bir matematikçi yok.

Bu matematikçilerin detaylarını bilmek istersen de
http://www-groups.dcs.st-and.ac.uk/history/Indexes/Arabs.html
adresini kullanabilirsin.
Üzgünüm ama bu site de İngilizce, belki diğer katılımcılar için bu bilgi daha değerli olabilir.




A history of Zero


One of the commonest questions which the readers of this archive ask is: Who discovered zero? Why then have we not written an article on zero as one of the first in the archive? The reason is basically because of the difficulty of answering the question in a satisfactory form. If someone had come up with the concept of zero which everyone then saw as a brilliant innovation to enter mathematics from that time on, the question would have a satisfactory answer even if we did not know which genius invented it. The historical record, however, shows quite a different path towards the concept. Zero makes shadowy appearances only to vanish again almost as if mathematicians were searching for it yet did not recognise its fundamental significance even when they saw it.
The first thing to say about zero is that there are two uses of zero which are both extremely important but are somewhat different. One use is as a empty place indicator in our place-value number system. Hence in a number like 2106 the zero is used so that the positions of the 2 and 1 are correct. Clearly 216 means something quite different. The second use of zero is as a number itself in the form we use it as 0. There are also different aspects of zero within these two uses, namely the concept, the notation, and the name.

Neither of these uses has an easily described history. It just did not happen that someone invented the ideas, and then everyone started to use them. Also it is fair to say that the number zero is far from an intuitive concept. Mathematical problems started as 'real' problems rather than abstract problems. Numbers in early historical times were thought of much more concretely than the abstract concepts which are our numbers today. There are giant mental leaps from 5 horses to 5 "things" and then to the abstract idea of "five". If ancient peoples solved a problem about how many horses a farmer needed then the problem was not going to have 0 or -23 as an answer.

One might think that once a place-value number system came into existence then the 0 as a empty place indicator is a necessary idea, yet the Babylonians had a place-value number system without this feature for over 1000 years. Moreover there is absolutely no evidence that the Babylonians felt that there was any problem with the ambiguity which existed. Remarkably, original texts survive from the era of Babylonian mathematics. The Babylonians wrote on tablets of unbaked clay, using cuneiform writing. The symbols were pressed into soft clay tablets with the slanted edge of a stylus and so had a wedge-shaped appearance (and hence the name cuneiform). Many tablets from around 1700 BC survive and we can read the original texts. Of course their notation for numbers was quite different from ours (and not based on 10 but on 60) but to translate into our notation they would not distinguish between 2106 and 216 (the context would have to show which was intended). It was not until around 400 BC that the Babylonians put two wedge symbols into the place where we would put zero to indicate which was meant, 216 or 21 '' 6.

The two wedges were not the only notation used, however, and on a tablet found at Kish, an ancient Mesopotamian city located east of Babylon in what is today south-central Iraq, a different notation is used. This tablet, thought to date from around 700 BC, uses three hooks to denote an empty place in the positional notation. Other tablets dated from around the same time use a single hook for an empty place. There is one common feature to this use of different marks to denote an empty position. This is the fact that it never occured at the end of the digits but always between two digits. So although we find 21 '' 6 we never find 216 ''. One has to assume that the older feeling that the context was sufficient to indicate which was intended still applied in these cases.

If this reference to context appears silly then it is worth noting that we still use context to interpret numbers today. If I take a bus to a nearby town and ask what the fare is then I know that the answer "It's three fifty" means three pounds fifty pence. Yet if the same answer is given to the question about the cost of a flight from Edinburgh to New York then I know that three hundred and fifty pounds is what is intended.

We can see from this that the early use of zero to denote an empty place is not really the use of zero as a number at all, merely the use of some type of punctuation mark so that the numbers had the correct interpretation.

Now the ancient Greeks began their contributions to mathematics around the time that zero as a empty place indicator was coming into use in Babylonian mathematics. The Greeks however did not adopt a positional number system. It is worth thinking just how significant this fact is. How could the brilliant mathematical advances of the Greeks not see them adopt a number system with all the advantages that the Babylonian place-value system possessed? The real answer to this question is more subtle that the simple answer that we are about to give, but basically the Greek mathematical achievements were based on geometry. Although Euclid's Elements contains a book on number theory, it is based on geometry. In other words Greek mathematicians did not need to name their numbers since they worked with numbers as lengths of lines. Numbers which required to be named for records were used by merchants, not mathematicians, and hence no clever notation was needed.

Now there were exceptions to what we have just stated. The exceptions were the mathematicians who were involved in recording astronomical data. Here we find the first use of the symbol which we recognise today as the notation for zero, for Greek astronomers began to use the symbol O. There are many theories why this particular notation was used. Some historians favour the explanation that it is omicron, the first letter of the Greek word for nothing namely "ouden". Neugebauer, however, dismisses this explanation since the Greeks already used omicron as a number - it represented 70 (the Greek number system was based on their alphabet). Other explanations offered include the fact that it stands for "obol", a coin of almost no value, and that it arises when counters were used for counting on a sand board. The suggestion here is that when a counter was removed to leave an empty column it left a depression in the sand which looked like O.

Ptolemy in the Almagest written around 130 AD uses the Babylonian sexagesimal system together with the empty place holder O. By this time Ptolemy is using the symbol both between digits and at the end of a number and one might be tempted to believe that at least zero as an empty place holder had firmly arrived. This, however, is far from what happened. Only a few exceptional astronomers used the notation and it would fall out of use several more times before finally establishing itself. The idea of the zero place (certainly not thought of as a number by Ptolemy who still considered as a sort of punctuation mark) makes its next appearance in Indian mathematics.

The scene now moves to India where it is fair to say the numerals and number system was born which have evolved into the highly sophisticated ones we use today. Of course that is not to say that the Indian system did not owe something to earlier systems and many historians of mathematics believe that the Indian use of zero evolved from its use by Greek astronomers. As well as some historians who seem to want to play down the contribution of the Indians in a most unreasonable way, there are also those who make claims about the Indian invention of zero which seem to go far too far. For example Mukherjee in [6] claims:-

... the mathematical conception of zero ... was also present in the spiritual form from 17 000 years back in India.
What is certain is that by around 650AD the use of zero as a number came into Indian mathematics. The Indians also used a place-value system and zero was used to denote an empty place. In fact there is evidence of an empty place holder in positional numbers from as early as 200AD in India but some historians dismiss these as later forgeries. Let us examine this latter use first since it continues the development described above.
In around 500AD Aryabhata devised a number system which has no zero yet was a positional system. He used the word "kha" for position and it would be used later as the name for zero. There is evidence that a dot had been used in earlier Indian manuscripts to denote an empty place in positional notation. It is interesting that the same documents sometimes also used a dot to denote an unknown where we might use x. Later Indian mathematicians had names for zero in positional numbers yet had no symbol for it. The first record of the Indian use of zero which is dated and agreed by all to be genuine was written in 876.

We have an inscription on a stone tablet which contains a date which translates to 876. The inscription concerns the town of Gwalior, 400 km south of Delhi, where they planted a garden 187 by 270 hastas which would produce enough flowers to allow 50 garlands per day to be given to the local temple. Both of the numbers 270 and 50 are denoted almost as they appear today although the 0 is smaller and slightly raised.

We now come to considering the first appearance of zero as a number. Let us first note that it is not in any sense a natural candidate for a number. From early times numbers are words which refer to collections of objects. Certainly the idea of number became more and more abstract and this abstraction then makes possible the consideration of zero and negative numbers which do not arise as properties of collections of objects. Of course the problem which arises when one tries to consider zero and negatives as numbers is how they interact in regard to the operations of arithmetic, addition, subtraction, multiplication and division. In three important books the Indian mathematicians Brahmagupta, Mahavira and Bhaskara tried to answer these questions.

Brahmagupta attempted to give the rules for arithmetic involving zero and negative numbers in the seventh century. He explained that given a number then if you subtract it from itself you obtain zero. He gave the following rules for addition which involve zero:-

The sum of zero and a negative number is negative, the sum of a positive number and zero is positive, the sum of zero and zero is zero.
Subtraction is a little harder:-
A negative number subtracted from zero is positive, a positive number subtracted from zero is negative, zero subtracted from a negative number is negative, zero subtracted from a positive number is positive, zero subtracted from zero is zero.
Brahmagupta then says that any number when multiplied by zero is zero but struggles when it comes to division:-
Positive or negative numbers when divided by zero is a fraction the zero as denominator. Zero divided by negative or positive numbers is either zero or is expressed as a fraction with zero as numerator and the finite quantity as denominator. Zero divided by zero is zero.
Really Brahmagupta is saying very little when he suggests that n divided by zero is n/0. Clearly he is struggling here. He is certainly wrong when he then claims that zero divided by zero is zero. However it is a brilliant attempt from the first person that we know to try to extend arithmetic to negative numbers and zero.
In 830, around 200 years after Brahmagupta wrote his masterpiece, Mahavira wrote Ganita Sara Samgraha which was designed as an updating of Brahmagupta's book. He correctly states that:-

... a number multiplied by zero is zero, and a number remains the same when zero is subtracted from it.
However his attempts to improve on Brahmagupta's statements on dividing by zero seem to lead him into error. He writes:-
A number remains unchanged when divided by zero.
Since this is clearly incorrect my use of the words "seem to lead him into error" might be seen as confusing. The reason for this phrase is that some commentators on Mahavira have tried to find excuses for his incorrect statement.
Bhaskara wrote over 500 years after Brahmagupta. Despite the passage of time he is still struggling to explain division by zero. He writes:-

A quantity divided by zero becomes a fraction the denominator of which is zero. This fraction is termed an infinite quantity. In this quantity consisting of that which has zero for its divisor, there is no alteration, though many may be inserted or extracted; as no change takes place in the infinite and immutable God when worlds are created or destroyed, though numerous orders of beings are absorbed or put forth.
So Bhaskara tried to solve the problem by writing n/0 = . At first sight we might be tempted to believe that Bhaskara has it correct, but of course he does not. If this were true then 0 times must be equal to every number n, so all numbers are equal. The Indian mathematicians could not bring themselves to the point of admitting that one could not divide by zero. Bhaskara did correctly state other properties of zero, however, such as 02 = 0, and 0 = 0.
Perhaps we should note at this point that there was another civilisation which developed a place-value number system with a zero. This was the Maya people who lived in central America, occupying the area which today is southern Mexico, Guatemala, and northern Belize. This was an old civilisation but flourished particularly between 250 and 900. We know that by 665 they used a place-value number system to base 20 with a symbol for zero. However their use of zero goes back further than this and was in use before they introduced the place-valued number system. This is a remarkable achievement but sadly did not influence other peoples.

You can see a separate article about Mayan mathematics.

The brilliant work of the Indian mathematicians was transmitted to the Islamic and Arabic mathematicians further west. It came at an early stage for al-Khwarizmi wrote Al'Khwarizmi on the Hindu Art of Reckoning which describes the Indian place-value system of numerals based on 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0. This work was the first in what is now Iraq to use zero as a place holder in positional base notation. Ibn Ezra, in the 12th century, wrote three treatises on numbers which helped to bring the Indian symbols and ideas of decimal fractions to the attention of some of the learned people in Europe. The Book of the Number describes the decimal system for integers with place values from left to right. In this work ibn Ezra uses zero which he calls galgal (meaning wheel or circle). Slightly later in the 12th century al-Samawal was writing:-

If we subtract a positive number from zero the same negative number remains. ... if we subtract a negative number from zero the same positive number remains.
The Indian ideas spread east to China as well as west to the Islamic countries. In 1247 the Chinese mathematician Ch'in Chiu-Shao wrote Mathematical treatise in nine sections which uses the symbol O for zero. A little later, in 1303, Chu Shih-Chieh wrote Jade mirror of the four elements which again uses the symbol O for zero.
Fibonacci was one of the main people to bring these new ideas about the number system to Europe. As the authors of [12] write:-

An important link between the Hindu-Arabic number system and the European mathematics is the Italian mathematician Fibonacci.
In Liber Abaci he described the nine Indian symbols together with the sign 0 for Europeans in around 1200 but it was not widely used for a long time after that. It is significant that Fibonacci is not bold enough to treat 0 in the same way as the other numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 since he speaks of the "sign" zero while the other symbols he speaks of as numbers. Although clearly bringing the Indian numerals to Europe was of major importance we can see that in his treatment of zero he did not reach the sophistication of the Indians Brahmagupta, Mahavira and Bhaskara nor of the Arabic and Islamic mathematicians such as al-Samawal.
One might have thought that the progress of the number systems in general, and zero in particular, would have been steady from this time on. However, this was far from the case. Cardan solved cubic and quartic equations without using zero. He would have found his work in the 1500's so much easier if he had had a zero but it was not part of his mathematics. By the 1600's zero began to come into widespread use but still only after encountering a lot of resistance.

Of course there are still signs of the problems caused by zero. Recently many people throughout the world celebrated the new millennium on 1 January 2000. Of course they celebrated the passing of only 1999 years since when the calendar was set up no year zero was specified. Although one might forgive the original error, it is a little surprising that most people seemed unable to understand why the third millennium and the 21 century begin on 1 January 2001. Zero is still causing problems!


Article by: J J O'Connor and E F Robertson


http://www-groups.dcs.st-and.ac.uk/history/Indexes/Arabs.html
adresinden alınmıştır.

SIFIR üzerindeki muhalif tartismalardan benim de haberim var...

Önemli olan, araplari asagilamakla kendini yükselttigini sanan bir gerzege, Aya ayak basmak için yapilan hesaplamalarda, araplarin buldugu rakamlardan yararlanildigini göstermekti !

Ayrica benim yabanci dilim ingilizce ve fransizca'dir ve arapçayi yazma ve okuma derecesinde bilirim.

Bilmeyenleri de düsünmek zorunda oldugumuzu hatirlatmak için bir çikis yaptim, hepsi bundan ibaret!

Yazıda da açıklandığı gibi ve benim de bu konu üzerine iletiyi hazırlamaktaki amacım,

'SIFIR' RAKAMINI ARAPLARIN BULMADIĞINI AÇIKLAMAKTI.

Ama sen yine talihsiz bir şekilde diyorsun ki, sıfırı Araplar bulmuştur.

Sıfırı kimin bulduğunun tartışması bir yana, uzaya gidenler de Araplar değil, Ruslar ve Amerikalılar olmuştur ve Fransa önderliğinde Avrupa Topluluğu da yakın zamanda gidecektir.

Araplar ne yapmıştır? Ya da neden yapamamıştır?

El insaf!

Ben öyle demiyorum;

Sen öyle anliyorsun...

Arada jüpiter gezegeni kadar küçük bir fark var!

Araplarin ne yaptigindan çok,

Bundan sonra ne yapmasi gerektigi...

Bence çok daha önemli !

Bir gün adamın biri yurtdışına iş gezisine giderken hayvanları çok seven karısı kocasına:
― Hayatım bir sincap istiyorum ama Türkiye'de bulunmuyor, lütfen bana gittiğin ülkelerin birinden bir sincap al...
diye yalvarmış.
Karısını kırmak istemeyen adam hemen kabul etmiş ve evden çıkmış. Ülkesine geri dönerken sincabı almış, ancak havaalanındaki görevliler sincabı gümrükten geçiremeyeceğini, yasak olduğunu söylemişler. Buna sinirlenen adam tam bir kavgaya tutuşacakmış ki, yanındaki arkadaşı kolundan çekerek adamı tuvalete sürüklemiş:
― Kavga etmeye ne gerek var? Çıkar şu hayvanı kutusundan, aç pantolonunun fermuarını koy içine, uçağa kadar sabret...
deyince, adam çaresiz kabul etmiş ve arkadaşıyla gümrükten geçmişler... Kontroller yapılmış... Otobüse binmişler, tam uçağın merdivenlerinin önüne geldiklerinde adam açmış fermuarını çıkarmış sincabı, tekmeleyerek öldürmüş hayvanı.
Arkadaşı:
― Ne yaptın çıldırdın mı? İki adım kaldıydı şuracıkta...
deyince de, adam başlamış olanları anlatmaya:
― Dayanamadım. Artık yeter!.. Fermuarı açtık içine koyduk buraya kadar tamam. Orada bir dal buldu sallandı sallandı, bir şey demedim... Sonra daha da aşağıya indi, iki tane ceviz buldu, kırmaya uğraştı beceremedi, kemirdi beceremedi, yine sesimi çıkarmadım... Sonra biraz daha aşağıya indi, bir yuva buldu girdi çıktı, girdi çıktı, ona da bir şey demedim... Ama ne zaman ki cevizleri yuvaya taşımaya karar verdi, işte o zaman dayanamadım.

Fikran hos olmus, ama bos olmus

Sen bi zahmet bana söyleyiversen:

Enisten seni bakkala RAKI, sucuk vede koç yumurtasi almaya yolladiginda,

Hani kafan hesap kitap islerine basmadigi için söylüyorum...

Roma rakamlariyla mi, yoksa arap rakamlariyla mi toplama çikarma yaparsin ?

Cevap vermesen de olur...

Öncelikle fıkradaki 'sincap' sensin, ben değil!

İkincisi, eniştem yok, rakı içmem, sucuk ve hele koç yumurtasından da hiç hazzetmem.

Sen Arap alfabesiyle yazıp, arap rakamlarıyla hesap yapma konusunda özgürsün

Ama ben latin alfabesine dahil edilen rakamlarla hesap yapıyorum

Yıl 1928, Harf Devrimi (hatırladın mı?)

Son kez söylüyorum, umarım bu kez anlarsın:

SIFIR RAKAMINI ARAPLAR FİLAN BULMAMIŞLARDIR, EL-CABİR DİYE DE BİR ARAP MATEMATİKÇİ YOKTUR.

Ok?


Bu yanıta değmezdin ya, neyse!

Oysa ki ben fikrayla veda ettin sanmistim

Ne güzel, hos geldin !

El-cabir'in SIFIRI bulduguna dair yazmis oldugum cümleyi göster, sana sucuklu yumurta ismarlayayim...

Listede ismi geçmedi diye Al-cabir matematikçi degildir diye iddia edebilir misin ?

Ayrica sen arap rakamlari kullanmiyordun degil mi

De get baba...

Burasi çocuk bahçesi degil !

Cevap yazmasan da olur...

Allah, rızasına uyanları bununla (Kuran ile) kurtuluş yollarına ulaştırır ve onları Kendi izniyle karanlıklardan nura çıkarır. Onları dosdoğru yola yöneltip-iletir. (Maide Suresi, 16)

Türk nettte tartışırken
harun yahya nın
kitaplarına düştüğü dipnotların
nasıl uydurma olduğunu kanıtlamıştık
burada da
başlık sahibi
bir dergi yazısına gönderme yapmış
ve derginin bir iddası olduğunna dayanarak

kelam eylemiş

sevgil ihegel de
bilimsel bir tavırla dergiyi
internette aramış ve
oradaki yazıyı buraya aktarmış.

Şimdi
yabancı dildeki bu makalaler
gösteriyor ki
ya başlık sahibi kandırılmış
yada
bu sayfalarda birilşerini kandırmaya çalışıyor
bu rahatsız edici bir durum değildir..

Ama rahatsız edici durum
konuyu
DİL engelini bahane ederek(ki kendisi planet mlanet yabancı sözcük kullanmayı pek sever)
Görmeden gelmeye çalışarak
belki de istenmeden ortaya çıkmış bir argıyı
Ahlaksızlık boyutua taşyor..

Şİmdi dil engelini
idda eden ahlaksıza soruyorum:
Gerçekten tartışmak mı ,istiyorsun
öyleyse
imanın kadar önemsediğin bu konuda üçbeş kuruşa neden bu makaleleri tercüme etirmiyorsun?
BUna cesaret in var mı?

Yüreğin kaldırır mı?

Onun bunun iffetine leke sürerek
iman olacağını mı sanıyorsun
işte bir idda
ve kanıtları..

Ben diyorum ki
başlıkta
anlatılan ile
yzının orjinalinde(ki bir tek makale yok)
içerik farklılğı var..

Behey
ahlaksız
başlık sahibi değil mi ki
bizzat nature dergisisni refrans veren...


işte aktarıyorum:
Dregide
anlatılan konu
evrim teorisinde zamansal olarak bilinen yargıların değiştiğidir. Eğer başlık sahibi yazıyı bir yerden aldı ise
teyidini yapmadığından
kandırılmıştır..
Yok eğer
bizzat
dergiden aktardığı iddasında ise
yalancıdr..

Hadi
tartışalım
refransı veren başlık sahibi
Nature dergisi
www.nature.com

yüreğin yeter mi
ey israiliyatçı


ben senin mösülüman olduğun safsatasına inanmıyorum
müslümanlar mı inanacak sanıyorsun
seni manuplatör seni...

Kuran evrimle çelişmez...
Evrim baştan sona yanlış olsa da çelişmez...



hodri kuran hodri nature
hodri modiri

edepsizliğne de hodri