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1.
The chronometric framework developed for Plio-Pleistocene deposits of the northern Turkana Basin is reviewed in light of recent advances in lithostratigraphy, geochemical correlation, paleomagnetic stratigraphy, and isotopic dating. The sequence is tightly controlled by 20 precise ages on volcanic materials. These ages are internally consistent but are at variance with estimates for the boundaries of the magnetic polarity time scale by about 0.07 my. This discrepancy can be only partially resolved at present. Based on the established chronometric framework and stratigraphic sequences, depositional ages can be estimated for significant marker beds. These ages can in turn be used to constrain the 449 hominid specimens thus far reported from the basin. Ages for most hominid specimens can be estimated with a precision of +/- 0.05 my. In addition, the chronometric framework will be applicable to other paleontological collections, archeological excavations, and future discoveries in the basin.  相似文献   

2.
Previous research by this author and others has indicated that species-level differentiation within the hominines can be detected in the femur. The femoral shaft of Homo erectus, relative to H. sapiens, demonstrates small anteroposterior diameters, a distally placed point of minimum shaft breadth, and increased cortical thickness resulting in medullary stenosis. This pattern has been identified in specimens from Choukoutien (I and IV), Olduvai (OH 28), and Lake Turkana (KNM ER 737). Findings reported here include anatomical comparisons and univariate and multivariate analyses based on external and internal shaft morphology. These results indicate that the femoral pattern characteristic of H. erectus can be identified in KNM ER 1481a recovered at Lake Turkana below the KBS tuff. Recent dating of that tuff indicates a date of ca. 1.8 mya, thereby yielding a date for KNM ER 1481a of ? 2.0 mya. Known H. erectus femora extend over a broad span and yet show very low, variability; this pronounced stasis would strongly suggest that, at least in this portion of the postcranium, H. erectus was in a period of profound morphological stasis.  相似文献   

3.
Cranial, dental, and mandibular remains of eight Olduvai hominids are described in detail. Four individuals were recovered in situ in Beds II to IV, while three more are most probably derived from Bed IV, the Masek Beds and the Lower Ndutu Beds. One specimen is of uncertain provenance. Deposits from which the fossils were collected range from late Lower Pleistocene to Middle Pleistocene in age. Of particular interest are three fragmentary lower jaws, which can be compared to mandibles of Homo erectus known from localities in Northwest Africa and China. Olduvai hominid 22, a nearly complete half mandible with crowns of P3-M2 in place, shares many anatomical features with fossils from Ternifine and Choukoutien. This individual is also similar to a jaw from the Kapthurin Formation west of Lake Baringo, Kenya. How best to interpret these comparisons is not clear, but in view of marked similarities between specimens representing geographically diverse populations from different time periods, it may be unwise to rely on mandibular evidence alone to document the presence of regional lineages. Gradual change and continuity within a sequence of Northwest African Homo fossils has been endorsed by many workers, but such hypotheses cannot be tested adequately with the fragmentary jaws available.  相似文献   

4.
The hominine cranium KNM-ER 1813, from the late Plio/Pleistocene of Koobi Fora, has been regarded recently by some authors as a female ofHomo habilis Leakey, Tobias, andNapier, 1964 and by others as an enigma. Reassessment of its cranial morphology, dental metrics, proportions, and a new detailed determination of its sex indicates that it does not conform with the diagnosis forH. habilis, and is probably a male. It is sympatric withH. habilis yet shows more primitive features and rather a closer affinity to the smaller, more primitive chronospeciesH. antiquus Ferguson, 1984, and is thus the first, nearly complete skull of our oldest known human ancestor.  相似文献   

5.
Thirty-five new fossil hominid specimens are described. They were recovered from the Plio-Pleistocene sediments to the east of Lake Turkana (formerly Lake Rudolf). They include cranial and mandibular parts, teeth, and postcranial bones of upper and lower limbs. Parts of a single skeleton are also described. All of the specimens are described in anatomical detail and selected measurements are given. Some of the specimens are illustrated. It is proposed that they should be attributed to the family Hominidae, with genus and species undetermined until detailed comparative studies have been undertaken.  相似文献   

6.
New specimens of Plio-Pleistocene Australopithecus boisei are described from east and west Lake Turkana in Northern Kenya. These include a cranium and partial mandible from deposits close to 2.5 Myr and two partial crania and two mandibles from later horizons. The earlier fossils enable us to decipher, for the first time, some of the in situ evolution of this species within the Turkana Basin. The following are among the important changes in the cranium through time: 1) increase in size and change in shape of the braincase, 2) changes in the meningeal vessel pattern and possibly in the venous drainage pattern, 3) increased flexion of the cranial base and decreased prognathism, and 4) changes in the temporal bone to bring about a more vertical posterior face of the petrous pyramid and the development of a strong articular eminence.  相似文献   

7.
A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. © 1994 Wiley-Liss, Inc.  相似文献   

8.
Four partial mandibles and three isolated teeth of Homo from East Rudolf, Kenya, are described. They represent only part of the 1972 fossil collection that has been assigned to Homo; results of detailed studies of this material will be published in a monograph.  相似文献   

9.
A hominid mandible, KNM-ER 1482, is described. Provisionally it has not been assigned to any existing species or genus. However, after detailed anatomical and comparative studies have been carried out, its taxonomic status will be reviewed.  相似文献   

10.
A new fossil hominid partial skeleton (KNM-ER 803) that was discovered from the Plio-Pleistocene sediments to the east of Lake Rudolf is described. It includes parts of a femur, two tibiae, an ulna, two radii, a third metatarsal and several toe bones. There are also two teeth, an upper canine and an upper central incisor. A second new fossil hominid (KNM-ER 164) is represented by a parietal fragment, two vertebrae and some hand bones. A third is represented by a massive left femur (KNM-ER 999). The specimens are described in anatomical detail, some are illustrated and selected measurements are given. It is concluded that they should be attributed to the genus Homo sp. indet. Detailed comparative studies will be published in due course.  相似文献   

11.
Reassessment of the hominine cranium, KNM-ER 1813, from the Plio/Pleistocene of Koobi Fora, in Kenya, shows that it is not a small-brained, extreme female variant ofH. habilis Leakey, Tobias, & Napier, 1964. Its cranial and dental morphology, morphometrics, and proportions do not conform with eitherH. habilis orH. antiquus Ferguson, 1984. On the basis of its distinctive morphological pattern and mensural gaps which distinguish it fromH. habilis andH. antiquus, the cranium KNM-ER 1813 is described as a common variant representing a male of a small-brained, intermediate population linkingH. habilis 1.83 Myr BP withH. antiquus 2.9 Myr BP, and a new paleospecies of the genusHomo. A key to the Homininae is provided and the phylogenetic relationship of KNM-ER 1813 toH. habilis andH. antiquus is discussed. This paper is dedicated to the memory of my wife,Grace, whose assistance will be sorely missed.  相似文献   

12.
Tropodiaptomus turkanae sp. nov. is described from Lake Turkana (formerly Lake Rudolph), Kenya. After years of confusion with T. banforanus , the identity of this taxon as an endemic of Lake Turkana is established. The species is described, and its relationship with other Tropodiaptomus species discussed.  相似文献   

13.
This paper describes cercopithecid craniodental and postcranial fossils recovered by L. S. B. Leakey at Kanam East, Kenya during the early 1930s. These fossil monkeys have been generally assumed to have been derived from early Pliocene horizons, but their exact geographical and stratigraphical provenience is unknown. Although the question of the evolutionary significance of these specimens must await the recovery of more securely dated material from Kanam East, some general conclusions can be drawn concerning their taxonomic affinities and paleobiology. Based on comparative studies of the craniodental material, at least three extant genera are represented—Colobus,Lophocebus, andCercopithecus. The postcranial fossils include a number of hindlimb specimens, as well as the manubrium of a sternum and a caudal vertebra. Identification of the postcranial remains to particular genera is not possible, but they are similar in morphology to modern arboreal and semiterrestrial cercopithecid monkeys of small to medium size. It is evident that Kanam East had a diverse cercopithecid community, similar to those found today in forested and woodland habitats, and this may be of some significance in reconstructing the paleoecology of the site. Because the fossil record of most extant cercopithecid genera is rather sparse at Plio-Pleistocene sites in Africa, Kanam East represents one of only a few sites that has yielded material that can be assigned toColobus,Lophocebus, orCercopithecus. The fossil monkeys from the site, therefore, provide additional evidence to help reconstruct the paleobiology, as well as the patterns of species diversity and community structure that characterized the cercopithecid radiation during the Plio-Pleistocene.  相似文献   

14.
AHomo erectus individual (KNM-ER 1808) from Koobi Fora, Kenya dating from 1·6 ± 0·1 million years exhibits pathological apposition of bone on long bone shafts. This was originally attributed to hypervitaminosis A from the consumption of carnivore livers. Bee brood has a sufficiently high concentration of vitamin A that protracted ingestion could theoretically produce hypervitaminosis A. The ecology of the East African bee,Apis mellifera scutelatta, is investigated to show that the density of nests with their brood contents within a reasonable foraging area of earlyHomo erectus would yield an ample and reliable energy source with deleteriously high vitamin A content. A potential role of honey gathering and insect larvae consumption in hominine behavioural and physical evolution is discussed.  相似文献   

15.
16.
Neotaphonomic studies have determined the patterns of bone damage created by larger mammalian carnivores when consuming mammalian carcasses. Typically, mammalian carnivores gnaw and break bones to various degrees in order to access marrow, grease, and brain tissue. In contrast, crocodiles attempt to swallow whole parts of mammal carcasses, inflicting in the process tooth marks and other feeding traces on some of the bones they are unable to ingest. Although crocodiles are major predators of larger mammals along the margins of protected tropical rivers and lakes, their feeding traces on bone have received little systematic attention in neotaphonomic research. We present diagnostic characteristics of Crocodylus niloticus damage to uningested mammal bones resulting from a series of controlled observations of captive crocodile feeding. The resulting bone assemblages are composed of primarily complete elements from articulating units, some of which bear an extremely high density of shallow to deep, transversely to obliquely oriented tooth scores over often large areas of the bone, along with shallow to deep pits and punctures. Some of the tooth marks (bisected pits and punctures, hook scores) have a distinctive morphology we have not observed to be produced by mammalian carnivores. The assemblages are also characterized by the retention of both low- and high-density bone portions, an absence of gross gnawing, and minimal fragmentation. Together, the damage characteristics associated with feeding by crocodiles are highly distinctive from those produced by mammalian carnivores. Modern surface bone assemblages along the Grumeti River in Tanzania's Serengeti National Park contain a mixture of specimens bearing damage characteristic of crocodiles and mammalian carnivores. Comparison of Plio-Pleistocene fossil bones from Olduvai Gorge, Tanzania, to bones damaged by captive and free-ranging Nile crocodiles reveals direct evidence of fossil crocodilian feeding from larger mammal bones associated with Oldowan stone artifacts.  相似文献   

17.
The species Proconsul (Xenopithecus) hamiltoni was based on two weathered molars in a maxillary fragment from the Erageleit beds, Lothidok, Turkana District, Kenya. New fossils from Lothidok show a unique suite of features indicating generic distinction of this taxon from other known large early catarrhines. A new generic diagnosis is given. The new genus, although still poorly known, may be the first Oligocene hominoid from East Africa. It retains many primitive features, but the few derived ones hint that it may be related to the Afropithecus group.  相似文献   

18.
The cranium of a robust australopithecine, KNM WT 17000, was discovered from the Plio/Pleistocene deposits west of Lake Turkana in Kenya, and assigned to the speciesAustralopithecus boisei Leakey, 1959. A comparative morphological study shows that it does not conform with the diagnosis forA. boisei. It is characterized by having a much smaller brain, a low hyperprognathous facial skeleton, and a less developed masticatory apparatus. Its unique morphological pattern justifies its placement in a new taxon which is calledAustralopithecus walkeri n. sp.  相似文献   

19.
A relatively complete skeleton of the fossil papionin, Theropithecus brumpti, from the site of Lomekwi, west of Lake Turkana, Kenya, is here described. The specimen, KNM-WT 39368, was recovered at the site of LO 5 (3°51′N and 35°45′E), from sediments dated to approximately 3·3 Ma. The skeleton is that of an old adult male and preserves a number of articulated elements, including most of the forelimbs and tail. The cranial morphology is that of a large, early T. brumpti, exhibiting a deep mandible with a deeply excavated mandibular corpus fossa, and mandibular alveoli and cheek teeth arrayed in a reversed Curve of Spee. The forelimb skeleton exhibits a unique mixture of characteristics generally associated with a terrestrial locomotor habitus, such as a narrow scapula and a highly stable elbow joint, combined with those more representative of habitual arborealists, such as muscle attachments reflecting a large rotator cuff musculature and a flexible shoulder joint. The forelimb of KNM-WT 39368 also presents several features, unique toTheropithecus , which represent adaptations for manual grasping and fine manipulation. These features include a large, retroflexed medial humeral epicondyle (to which large pronator, and carpal and digital flexor muscles attached) and proportions of the digital rays that denote capabilities for precise opposition between the thumb and index finger. Taken together, these features indicate that one of the earliest recognized representatives of Theropithecus exhibited the food harvesting and processing anatomy that distinguished the genus through time and that contributed to its success throughout the later Pliocene and Pleistocene. Based on the anatomy of KNM-WT 39368 and the known habitat preference of T. brumpti, the species is reconstructed as being a generally terrestrial but highly dexterous, very large-bodied, sexually dimorphic, and possibly folivorous papionin. T. brumpti was adapted for propulsive quadrupedal locomotion over generally even ground, and yet was highly adept at manual foraging. The estimate of 43·8 kg body mass for KNM-WT 39368 renders unlikely the possibility that the species, or at least adult males of the species, were highly arboreal. T. brumpti, as represented by KNM-WT 39368, is seen as a large, colorfully decorated, and basically terrestrial papionin that was restricted to riverine forest habitats in the Lake Turkana Basin from the middle to latest Pliocene.  相似文献   

20.
In 1994 a hominid frontal bone fragment was found in the river floor of the Brangkal River, the Sangiran area, Central Java. The original stratigraphic level is not known at present stage of the research. But it is possible that the bone was derived from the Grenzbank zone of the Bapang Formation (Lower/Middle Pleistocene). Morphological features of the bone, such as a thick and continuous supraorbital torus, a wide and flat supratoral plane, and a flat and strongly inclined frontal squame suggest that the bone is assigned to JavaneseHomo erectus, especially to the Sangiran and Trinil group of it.  相似文献   

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