Morphology of Turkanapithecus kalakolensis from Kenya

The type specimen of Turkanapithecus kalakolensis recently recovered from northern Kenya preserves a partial cranium and mandible. This specimen, together with postcranial elements that are probably associated with it, and two additional specimens are described. The collection is compared with other Miocene hominoids.     

New hominids from East Turkana,Kenya

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.     

Further hominids from the Plio-Pleistocene of Koobi Fora, Kenya

Fifty-eight new fossil hominids from Plio-Pleistocene sediments east of Lake Turkana, Kenya, are described. They include cranial, mandibular, dental, and postcranial parts. Some are illustrated.     

New Australopithecus boisei specimens from east and west Lake Turkana, Kenya

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.     

New evidence for canine dietary function in Afropithecus turkanensis

Despite considerable post-cranial and cranial morphological overlap with Proconsul, Afropithecus turkanensis is distinguished from that taxon by a suite of anterior dental and gnathic characters shared in common with extant pitheciin monkeys (i.e. low crowned, robust and laterally splayed canines, procumbent incisors, prognathic premaxilla, powerful temporalis muscles, reduced or absent maxillary sinuses, and deep mandibular corpora). Pitheciins are unique among living anthropoids because their canines serve a habitual dietary function and are not strictly influenced by inter-male competition. Given the functional association between pitheciin canine morphological specializations and sclerocarp foraging, a feeding strategy where the hard pericarps of unripe fruit are mechanically deformed by the canines, it has been suggested that Afropithecus may also have used its canines in a dietary context. This is confirmed by quantitative morphometric analyses of Afropithecus canine curvature and basal dimensions demonstrating that Afropithecus and extant pitheciins (Chiropotes, Cacajao) are distinguished from all other anthropoids by pronounced and evenly distributed mesial canine crown contours as well as greater resistance to canine bending in both the mesiodistal and labiolingual axes. In addition, Afropithecus, Chiropotes and Cacajao are also shown to have significantly longer and more curved premaxillae with greater incisor procumbency that effectively isolates the incisor and canine functional complexes. These morphological similarities are a result of convergence and not a shared derived ancestry. Despite their considerable morphological overlap, it is unlikely that Afropithecus and extant pitheciin diets are identical given significant dissimilarities in their post-canine morphology, maximum angular gape and body size. Nevertheless, Afropithecus canine dietary function is unique among hominoids and may have been a key component for the expansion of hominoids into Eurasia at the end of the early Miocene.     

Enamel thickness,microstructure and development in Afropithecus turkanensis

Afropithecus turkanensis, a 17-17.5 million year old large-bodied hominoid from Kenya, has previously been reported to be the oldest known thick-enamelled Miocene ape. Most investigations of enamel thickness in Miocene apes have been limited to opportunistic or destructive studies of small samples. Recently, more comprehensive studies of enamel thickness and microstructure in Proconsul, Lufengpithecus, and Dryopithecus, as well as extant apes and fossil humans, have provided information on rates and patterns of dental development, including crown formation time, and have begun to provide a comparative context for interpretation of the evolution of these characters throughout the past 20 million years of hominoid evolution. In this study, enamel thickness and aspects of the enamel microstructure in two A. turkanensis second molars were quantified and provide insight into rates of enamel apposition, numbers of cells actively secreting enamel, and the time required to form regions of the crown. The average value for relative enamel thickness in the two molars is 21.4, which is a lower value than a previous analysis of this species, but which is still relatively thick compared to extant apes. This value is similar to those of several Miocene hominoids, a fossil hominid, and modern humans. Certain aspects of the enamel microstructure are similar to Proconsul nyanzae, Dryopithecus laietanus, Lufengpithecus lufengensis, Graecopithecus freybergi and Pongo pygmaeus, while other features differ from extant and fossil hominoids. Crown formation times for the two teeth are 2.4-2.6 years and 2.9-3.1 years respectively. These times are similar to a number of extant and fossil hominoids, some of which appear to show additional developmental similarities, including thick enamel. Although thick enamel may be formed through several developmental pathways, most Miocene hominoids and fossil hominids with relatively thick enamel are characterized by a relatively long period of cuspal enamel formation and a rapid rate of enamel secretion throughout the whole cusp, but a shorter total crown formation time than thinner-enamelled extant apes.     

Nacholapithecus skeleton from the Middle Miocene of Kenya

An almost entire skeleton of a male individual of Nacholapithecus kerioi (KNM-BG 35250) was discovered from Middle Miocene (approximately 15 Ma) sediments at Nachola, northern Kenya. N. kerioi exhibits a shared derived subnasal morphology with living apes. In many postcranial features, such as articular shape, as well as the number of the lumbar vertebrae, N. kerioi resembles Proconsul heseloni and/or P. nyanzae, and lacks suspensory specializations characteristic of living apes. Similarly, N. kerioi shares some postcranial characters with Kenyapithecus spp. However, despite the resemblance, N. kerioi and Proconsul spp. are quite different in their body proportions and some joint morphologies. N. kerioi has proportionally large forelimb bones and long pedal digits compared to its hindlimb bones and lumbar vertebrae. Its distinctive body proportions suggest that N. kerioi was more derived for forelimb dominated arboreal activities than P. nyanzae and P. heseloni. On the other hand, it exhibits a mixture of derived and primitive cranio-dental and postcranial features relative to the contemporaneous Kenyapithecus and Early MioceneMorotopithecus. While the phylogenetic position of N. kerioi is unsettled, it seems necessary to posit parallel evolution of cranio-dental and/or postcranial features in fossil and living apes.     

New reconstruction of the moroto hominoid snout and a reassessment of its affinities toAfropithecus turkanensis

Two previous reconstructions of the Moroto hominoid palate and face made during the late 1960s suffer from several errors, in particular the angle at which the facial skeleton was hafted onto the palate, and the orientation of the canines, among others. A new reconstruction is based on the discovery that there is a good contact about 1cm logn between the palatal and facial pieces, which reveals that the snout was low and elongated as inAfropithecus turkanensis. Addition of a fragment of the right orbit reveals that the interorbital region was wide as inA. turkanensis. The remaining differences between the skulls from Moroto and Kalodirr are due to five factors:−1) pathology of the Moroto right premaxilla following ante-mortem loss of the right I¹, which led to abnormal enlargement of the right half of the nasal cavity, 2) the incisive foramina of the Moroto palate are damaged, making them appear considerably larger than they were in life, 3) damage to the upper portions of the nasal aperture making it look higher than it would in life, 4) plastic deformation and crushing of the Kalodirr specimen has greatly reduced the width of the palate and has led to the cheek tooth rows converging to the rear, and 5) the slightly larger and ontogenetically older status of the Moroto individual. Resemblances between the Moroto and Kalodirr specimens far outweight the purported or real differences and it is concluded thatMorotopithecus bishopi is a junior subjective synonym ofAfropithecus turkanensis. The sites of Moroto and Kalodirr are unlikely to differ greatly in age (certainly not as much as 4 Ma).     

New material of Ouranopithecus macedoniensis from late Miocene of Macedonia (Greece) and study of its dental attrition

During the last five years our continued excavations in the known late Miocene mammal localities of Macedonia (Greece) provided several new specimens of the hominoid primate Ouranopithecus macedoniensis. This new material includes maxillary and mandibular remains and it is described and compared to the old material of Ouranopithecus in the present article. The material of Ouranopithecus from the three known localities “Ravin de la Pluie” (RPl), “Xirochori 1” (XIR) and “Nikiti 1” (NKT) includes a complete series of tooth rows representing all wearing stages. Thus, the study of the dental wear of Ouranopithecus upper and lower teeth is studied and compared to that of the recent hominoids Gorilla and Pan, as well as to Australopithecus afarensis. The latter species is well known by a series of tooth rows of different wearing stages. The canine’s attrition of Ouranopithecus has a more derived pattern than that of the recent hominoids (Gorilla and Pan) and less derived than A. afarensis. The p3 of Ouranopithecus has similar attrition to that of A. afarensis, the attrition of the molars in Ouranopithecus, A. afarensis and Pan follows a similar pattern, while in Gorilla it is different.     

Age at first molar emergence in early Miocene Afropithecus turkanensis and life-history evolution in the Hominoidea

Among primates, age at first molar emergence is correlated with a variety of life history traits. Age at first molar emergence can therefore be used to broadly infer the life histories of fossil primate species. One method of determining age at first molar emergence is to determine the age at death of fossil individuals that were in the process of erupting their first molars. This was done for an infant partial mandible of Afropithecus turkanensis (KNM-MO 26) from the approximately 17.5 Ma site of Moruorot in Kenya. A range of estimates of age at death was calculated for this individual using the permanent lateral incisor germ preserved in its crypt, by combining the number and periodicity of lateral enamel perikymata with estimates of the duration of cuspal enamel formation and the duration of the postnatal delay in the inception of crown mineralization. Perikymata periodicity was determined using daily cross striations between adjacent Retzius lines in thin sections of two A. turkanensis molars from the nearby site of Kalodirr. Based on the position of the KNM-MO 26 M(1)in relation to the mandibular alveolar margin, it had not yet undergone gingival emergence. The projected time to gingival emergence was estimated based on radiographic studies of M(1)eruption in extant baboons and chimpanzees.The estimates of age at M(1)emergence in KNM-MO 26 range from 28.2 to 43.5 months, using minimum and average values from extant great apes and humans for the estimated growth parameters. Even the absolute minimum value is well outside the ranges of extant large Old World monkeys for which there are data (12.5 to <25 months), but is within the range of chimpanzees (25.7 to 48.0 months). It is inferred, therefore, that A. turkanensis had a life history profile broadly like that of Pan. This is additional evidence to that provided by Sivapithecus parvada (Function, Phylogeny, and Fossils: Miocene Hominoid Evolution and Adaptations, 1997, 173) that the prolonged life histories characteristic of extant apes were achieved early in the evolutionary history of the group. However, it is unclear at present whether life-history prolongation in apes represents the primitive catarrhine pace of life history extended through phyletic increase in body mass, or whether it is derived with respect to a primitive, size-adjusted life history that was broadly intermediate between those of extant hominoids and cercopithecoids. Life history evolution in primates as a whole may have occurred largely through a series of grade-shifts, with the establishment of fundamental life-history profiles early in the histories of major higher taxa. These may have included shifts that were largely body mass dependent, as well as those that occurred in the absence of significant changes in body mass.     

New evidence of the genus Homo from East Rudolf,Kenya (III)

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.     

The deciduous dentition of Griphopithecus alpani from Paşalar, Turkey

Seventy-four hominoid primary teeth have been recovered from the middle Miocene site of Pa?alar, Turkey, constituting the largest sample of deciduous teeth for any species of fossil ape. Morphological features that characterize the permanent teeth of Griphopithecus alpani from the site have also been identified in some of these deciduous teeth, including a lingual pillar on the di(1)s. These features plus the overwhelming preponderance of G. alpani permanent teeth at the site suggest that all of the deciduous teeth belong to this species. Contrary to the situation in the permanent teeth, nothing in the morphology of the primary dentition suggests the representation of a second species. The age profile of the non-adult hominoids was reconstructed based on the degree and type of wear recorded on the dp4s, the most abundant deciduous tooth in the sample, assuming a similar eruption chronology to that of Pan troglodytes. This analysis indicates underrepresentation of very young individuals in the sample and high mortality for individuals belonging to the 3-5-years age cohort, a situation that could be due to the effects of stress related to weaning. The coefficient of variation and range-index values obtained for the majority of tooth types are equal to or greater than the comparable values in a sample of P. troglodytes, in some cases at much smaller sample sizes. One possible explanation for this is that there was greater sexual dimorphism in the G. alpani deciduous dentition than in Pan, which would mirror the condition of the permanent dentition.     

Functional morphology and anatomy of cervical vertebrae in Nacholapithecus kerioi, a middle Miocene hominoid from Kenya

This paper describes the morphology of cervical vertebrae in Nacholapithecus kerioi, a middle Miocene primate species excavated from Nachola, Kenya in 1999-2002. The cervical vertebrae in Nacholapithecus are larger than those of Papio cynocephalus. They are more robust relative to more caudal vertebral bones. Since Nacholapithecus had large forelimbs, it is assumed that strong cervical vertebrae would have been required to resist muscle reaction forces during locomotion. On the other hand, the vertebral foramen of the lower cervical vertebrae in Nacholapithecus is almost the same size as or smaller than that of P. cynocephalus. Atlas specimens of Nacholapithecus resemble those of extant great apes with regard to the superior articular facet, and they have an anterior tubercle trait intermediate between that of extant apes and other primate species. Nacholapithecus has a relatively short and thick dens on the axis, similar to those of extant great apes and the axis body shape is intermediate between that of extant apes and other primates. Moreover, an intermediate trait between extant great apes and other primate species has been indicated with regard to the angle between the prezygapophyseal articular facets of the axis in Nacholapithecus. Although the atlas of Nacholapithecus is inferred as having a primitive morphology (i.e., possessing a lateral bridge), the shape of the atlas and axis leads to speculation that locomotion or posture in Nacholapithecus involved more orthograde behavior similar to that of extant apes, and, in so far as cervical vertebral morphology is concerned, it is thought that Nacholapithecus was incipiently specialized toward the characteristics of extant hominoids.     

A Rangwapithecus gordoni mandible from the early Miocene site of Songhor,Kenya

A mandible of Rangwapithecus gordoni from the early Miocene site of Songhor, Kenya, provides additional information about this relatively poorly known taxon. The R. gordoni sample is small, being composed of dental and a few gnathic parts. The fossil described here provides examples of previously unknown dental and mandibular anatomy, and confirms former reassignments of isolated anterior teeth based on less certain evidence. The phylogenetic status of Rangwapithecus, its distribution, and paleobiology are briefly reviewed. Rangwapithecus shows a suite of dental and gnathic features that warrants its generic distinction from Proconsul. Derived features shared with Nyanzapithecus and Turkanapithecus indicate that it is an early member of the subfamily Nyanzapithecinae. Its molar morphology suggests a considerable component of folivory in its diet. A review of the hypodigm shows Rangwapithecus to be restricted to Songhor. This distribution parallels that of Limnopithecus evansi, and is mirrored by Limnopithecus legetet and Micropithecus clarki suggesting that Songhor may have differed ecologically from other more or less contemporary sites in the region.     

Miocene cercopithecoidea from the Tugen Hills, Kenya

Miocene to Pleistocene fossiliferous sediments in the Tugen Hills span the time period from at least 15.5 Ma to 0.25 Ma, including time periods unknown or little known elsewhere in Africa. Consequently, the Tugen Hills deposits hold the potential to inform us about crucial phylogenetic events in African faunal evolution and about long-term environmental change. Among the specimens collected from this region are a number of discoveries already important to the understanding of primate evolution. Here, we describe additional cercopithecoid material from the Miocene deposits in the Tugen Hills sequence, including those from securely dated sites in the Muruyur Beds (16-13.4 Ma), the Mpesida Beds (7-6.2 Ma) and the Lukeino Formation (∼6.2-5.7 Ma). We also evaluate previously described material from the Ngorora Formation (13-8.8 Ma). Identified taxa include Victoriapithecidae gen. et sp. indet., cf. Parapapio lothagamensis, and at least two colobines. Specimens attributed to cf. Pp. lothagamensis would extend the species’ geographic range beyond its type locality. In addition, we describe specimens sharing derived characters with modern African colobines (Tribe: Colobina), a finding that is congruent with previous molecular estimates of colobine divergence dates. These colobine specimens represent some of the earliest known members of the modern African colobine radiation and, in contrast to previous hypotheses, suggest that early African colobines were mainly arboreal and that semi-terrestrial Late Miocene and Plio-Pleistocene colobine taxa were secondarily derived in their locomotor adaptations.     

New hominid fossils from the Swartkrans formation (1979-1986 excavations): craniodental specimens

Seventy-two individually numbered hominid craniodental fossils from recent excavations at Swartkrans are described. All derive from in situ decalcified breccia and/or unconsolidated sediments. A total of 20 specimens, representing 13 to 16 individuals derive from Member 1 "Lower Bank," two teeth derive from sediments along the Member 1-2 Interface, 38 fossils representing 19 to 24 individuals come from Member 2, and 12 teeth representing 9 to 11 individuals derive from Member 3. All but four of the specimens are attributable at the generic level; one specimen from Member 1 "Lower Bank" and five specimens from Member 2 are attributed to Homo, while the others represent Paranthropus. The proportional representation of Homo in the Swartkrans Formation is markedly higher in Member 2 (c. 33%) than in the Member 1 "Lower Bank" (c. 8%) and Member 1 "Hanging Remnant" (c. 5%) samples.     

Our ancestors' ancestor: Ouranopithecus is a greek link in human ancestry

Recent discoveries of the late Miocene hominoid Ouranopithecus shed new light on the evolution of hominids. These discoveries result from the strategy of the Allied armies during the First World War. In the midst of “the war to end all wars,” the North African soldiers of Camille Arambourg excavated the first mammalian fossils found in northern Greece, in the region of Macedonia, the country of Alexander the Great. On the tracks of these strange paleontological pioneers, a modern French and Greek team has unearthed a large hominoid primate, a missing link between fossilapes and primitive Australopithecus, which lived in southeastern Europe 9 to 10 million years ago. A reconstruction of Ouranopithecus and its surroundings gives us a rare glimpse into the world of the earliest hominids.     

The beaver (Mammalia,Castoridae) from the Miocene of Sandelzhausen (southern Germany)

The Early/Middle Miocene boundary locality Sandelzhausen (MN5, southern Germany) yielded three beaver teeth: one lower incisor fragment and two strongly worn upper premolars, a right and a left one. The latter are so similar in wear, height, size, and enamel pattern that they probably represent one individual. Although the teeth have been referred to Chalicomys jaegeri Kaup, 1832 (e.g., Hugueney 1999, Fahlbusch 2003), it seems more likely that they belong to Steneofiber depereti Mayet, 1908. However, the assignment of the present material to either one of these species is difficult, because in the advanced wear stage some diagnostic characteristics cannot be assessed. As to ecological implications for the locality Sandelzhausen the taxonomic identity of these two beaver species may not be important. Both are known from riverine, lacustrine or swamp sediments, and it can be assumed that they usually lived in close vicinity to water. Thus, the presence of beaver remains supports the presence of water at Sandelzhausen. However, the teeth might have an allochthonous origin from creeks of the rising Alps.      

Partial skeleton of Theropithecus brumpti (Primates, Cercopithecidae) from the Chemeron Formation of the Tugen Hills, Kenya

Here we describe a complete skull and partial skeleton of a large cercopithecoid monkey (KNM-TH 46700) discovered in the Chemeron Formation of the Tugen Hills at BPRP Site #152 (2.63 Ma). Associated with the skeleton was a mandible of an infant cercopithecoid (KNM-TH 48364), also described here. KNM-TH 46700 represents an aged adult female of Theropithecus brumpti, a successful Pliocene papionin taxon better known from the Omo Shungura Formation in Ethiopia and sites east and west of Lake Turkana, Kenya. While the morphology of male T. brumpti is well-documented, including a partial skeleton with both cranial and postcranial material, the female T. brumpti morphotype is not well-known. This skeleton represents some of the first associated evidence of cranial and postcranial female T. brumpti remains. In addition to the complete skull, postcranial material includes elements of the axial skeleton and lower limb. While aspects of the skeleton conform to those of specimens previously assigned to T. brumpti, other features on the femur and tibia appear to differ from those previously described for this species. It is unclear whether these differences represent general variation within the T. brumpti population, variation between the sexes in T. brumpti, or the incorrect assignment of previous isolated hindlimb specimens. In total, the observable morphological features of the hindlimb suggest that KNM-TH 46700 was a terrestrial quadruped similar to modern savannah baboons (Papio). From the available evidence, it is difficult to assess whether or not KNM-TH 46700 frequently engaged in the specialized squatting and shuffling behavior observed in extant geladas (Theropithecus gelada).     

Miocene fossil cercopithecoids from Kenya

Fossil cercopithecoid material from Ngeringerowa, Ngorora, and Nakali, dated at between 8.5 and 10.5 m.y., is described. The specimens are the only cercopithecoid remains dated between 15 and 6 m.y. from sub-Saharan Africa. The mandible of asmall colobine from Ngeringerowa (similar in size to Colobus verus) is assigned to a new genus and species, Microcolobus tugenensis. Unlike other colobine genera, the symphysis of Microcolobus lacks an inferior transverse torus. A colobine lower M_{1 or 2} from Nakali is longer and narrower than molars of M. tugenensis, indicating that it may belong to a distinct taxon. A P₄ from Ngorora cannot be assigned confidently to subfamily, due to its unique metaconid morphology. The relationship between the new genus and other Miocene monkeys is considered.