Observations on mid-tertiary hominoids Sivapithecus and Ramapithecus

Detailed palaeontological analyses of the hominoids of the Miocene indicate the occurrence of forms belonging to Pongidae and Hominidae. Of these, Sivapithecus (Pongidae) with three contained species and Ramapithecus (Hominidae) with two distinct species can be recognized. These two families Pongidae and Hominidae were sufficiently well defined and distinct by the late Miocene about 14 million years ago. The author has discussed in brief the status of a few interesting finds of Sivapithecus and Ramapithecus based on the study of the originals preserved in India and America.     

Notes on Ramapithecus, the earliest known hominid, and Dryopithecus

Recent paleontological analysis of the Higher Primate subfamily Dryopithecinae shows that fossils in this group can be referred to two genera, Ramapithecus and Dryopithecus. Ramapithecus is known from India and East Africa in Late Miocene or Early Pliocene time (about 14 m. years ago). The remains of Ramapithecus resemble closely the equivalent parts of the later Hominidae and contrast with those of the Pongidae. It is concluded that Ramapithecus is the earliest known hominid, some 5 or 6 times older than the oldest Pleistocene hominids. Dryopithecus is a pongid and contains as subgenera (Dryopithecus), (Proconsul), and (Sivapithecus). Probably part of (Proconsul) is ancestral to the chimpanzee and part to the gorilla, while part of (Sivapithecus) is ancestral to the orang-utan.     

Rudabánya: A late miocene subtropical swamp deposit with evidence of the origin of the African apes and humans

Rudabánya, a rich late Miocene fossil site in northern central Hungary, has yielded an abundant record of fossil primates, including the primitive catarrhine Anapithecus and the early great ape Dryopithecus. While the affinities of Anapithecus are not clear, Dryopithecus is clearly a great ape sharing numerous characteristics of its dental, cranial and postcranial anatomy with living great apes. Like all Miocene hominids (great apes and humans), Dryopithecus is more primitive in a number of ways than any living hominid, which is probably related to the passage of time since the divergence of the various lineages of living hominids, allowing for similar refinements in morphology and adaptation to take place independently. On the other hand, Dryopithecus (and Ouranopithecus) share derived characters with hominines (African apes and humans), and Sivapithecus (and Ankarapithecus) share derived characters with orangutans, thus dating the split between pongines and hominines to a time before the evolution of these fossil great apes. Pongines and hominines follow similar fates in the late Miocene, the pongines moving south into Southeast Asia from southern or eastern Asia and the hominines moving south into East Africa from the Mediterranean region, between 6 to 9 Ma.     

Primates from Rudabánya: allocation of specimens to individuals, sex and age categories

Fossil primates have been known from the late Miocene locality of Rudabánya since 1965. Numerous campaigns of collecting, sampling and excavation have been carried out since that time by several teams of researchers, but the sample of primates has never been fully catalogued and published. Here we provide a comprehensive list of all primate specimens from Rudabánya with provenience data and allocation to individuals. At the main locality of R II 16 individuals are attributed to Anapithecus and nine to Dryopithecus, based on dental remains. Anapithecus comes mostly from a layer of gray to black marl and Dryopithecus is found mostly in a less consolidated overlying black mud. However, both taxa are found in both layers. Anapithecus is represented by larger proportions of juveniles and females, and Dryopithecus by more adult and subadult males. Both species are represented primarily by dental remains, but those of Dryopithecus are more commonly associated with mandibles and maxillae, while in Anapithecus most individuals are represented by associated dentitions. Dryopithecus is better represented by postcrania other than phalanges. Anapithecus age and sex frequency distributions are more typical of those of carnivore and chimpanzee prey assemblages than Dryopithecus.     

Isotopic reconstructions of habitat change surrounding the extinction of Sivapithecus,a Miocene hominoid,in the Siwalik Group of Pakistan

This research presents an isotopic study of a wide range of mammalian taxa from the Miocene Siwalik Group of Pakistan, with a focus on two time intervals—9.3–9.2 Ma, when the hominoid Sivapithecus was present, and 8.1–8.0 Ma, shortly after Sivapithecus became extinct. The purpose of this investigation is to reconstruct the vegetation mosaic at both time levels in order to determine what Sivapithecus habitat was like and what changes in habitat and climate may have taken place by the time Sivapithecus went extinct. Both carbon and oxygen stable isotopes were sampled from inorganic carbonate in tooth enamel. Results indicate a vegetation mosaic of both closed and open habitat at both time intervals, but a decrease in forest accompanied by an increase in open habitat (including C₄ grasses) during the younger interval. Individuals from many species cluster with each other with respect to both carbon and oxygen isotope values, indicating a spectrum of feeding adaptations exploiting different parts of the habitat. Isotopic values for Sivapithecus suggest that it fed in the forest upper canopy. Taxa feeding in the most closed, wet habitat become extinct by 8.1 Ma. Furthermore, higher δ¹⁸O values over time suggest a change in climate with a reduction in annual rainfall, perhaps accompanied by changes in precipitation sources or rainfall regime as well. These results suggest that forests became fragmented over time. While still present in the younger level, much of the forest was replaced by open habitat, including patches of C₄ grass. Forest loss and fragmentation is a likely cause of the extinction of Sivapithecus.     

Paleoenvironment of Dryopithecus brancoi at Rudabánya, Hungary: evidence from dental meso- and micro-wear analyses of large vegetarian mammals

The environment of the hominoid Dryopithecus brancoi at Rudabánya (Late Miocene of Hungary) is reconstructed here using the dietary traits of fossil ruminants and equids. Two independent approaches, dental micro- and meso-wear analyses, are applied to a sample of 73 specimens representing three ruminants: Miotragocerus sp. (Bovidae), Lucentia aff. pierensis (Cervidae), Micromeryx flourensianus (Moschidae), and one equid, Hippotherium intrans (Equidae). The combination of meso- and micro-wear signatures provides both long- and short-term dietary signals, and through comparisons with extant species, the feeding styles of the fossil species are reconstructed. Both approaches categorize the cervid as an intermediate feeder engaged in both browsing and grazing. The bovid Miotragocerus sp. is depicted as a traditional browser. Although the dental meso-wear pattern of the moschid has affinities with intermediate feeders, its dental micro-wear pattern also indicates significant intake of fruits and seeds. Hippotherium intrans was not a grazer and its dental micro-wear pattern significantly differs from that of living browsers, which may suggest that the fossil equid was engaged both in grazing and browsing. However, the lack of extant equids which are pure browsers prevents any definitive judgment on the feeding habits of Hippotherium. Based on these dietary findings, the Rudabánya paleoenvironment is reconstructed as a dense forest. The presence of two intermediate feeders indicates some clearings within this forest; however the absence of grazers suggests that these clearings were most likely confined. To demonstrate the ecological diversity among the late Miocene hominoids in Europe, the diet and habitat of Dryopithecus brancoi and Ouranopithecus macedoniensis (Greece) are compared.     

Gigantopithecus and its relationship to Australopithecus

Gigantopithecus blacki and G. bilaspurensis are compared to P. gorilla and Australopithecus. The total morphological pattern of Gigantopithecus mandibles is more similar to Australopithecus than to P. gorilla. Two major points are raised. (1) G. blacki might be considered an aberrant hominid rather than an aberrant pongid. (2) G. bilaspurensis can be considered an equally likely candidate, along with Ramapithecus, for possible hominid ancestry.     

Further observations on the primate community at Rudabánya II (late Miocene, early Vallesian age), Hungary

It has been proposed that the pliopithecid Anapithecus hernyaki was hunted by the ape Dryopithecus brancoi based on analyses of the age and sex distribution of 25 individuals from the late Miocene site of Rudabánya, Hungary (ca. 10 Ma). In this study, the minimum number of individuals (MNI) and age distribution of the assemblage are recalculated and considered in relation to their sedimentary context. We suggest that Dryopithecus juveniles may be underrepresented in the assemblage as a consequence of taphonomic loss of deciduous teeth. Furthermore, we find that while Dryopithecus and Anapithecus were contemporaneous, there was little spatial overlap between them, as each taxon is primarily associated with a separate lithofacies. We conclude that when the revised estimates of MNI and age distribution of these primates are reconsidered in conjunction with their context of burial, the case for the Dryopithecus hunting hypothesis cannot be sustained.     

The Late Miocene hominoids Ouranopithecus and Graecopithecus. Implications about their relationships and taxonomy

Two Late Miocene hominoids are known from Greece. The first, Graecopithecus freybergi, is known by a single mandible with the worn m2 from the locality of Pyrgos Vassilissis, near Athens. The other, Ouranopithecus macedoniensis, is known from Axios Valley and Chalkidiki (Macedonia, Greece) by a partial skull and a set of maxillary and mandibular remains. Some authors consider these two hominoids as synonyms and in the present article a detailed comparison of them is given. The morphology and size of the symphysis, the more robust mandible, the more open dental arcade of Ouranopithecus distinguishes it clearly from Graecopithecus. Moreover, the incompleteness of the mandible of Graecopithecus with the doubtful morphology and size, the limited material and the uncertain geological age of the locality cannot allow precise and clear comparisons with the rest extant and extinct hominoids. Thus in our opinion there are not enough data to support the similarity, and therefore, the synonymy of the two genera. The Pyrgos mandible must remain as a separate and isolated genus with one species, which only includes this sole mandible.     

Additional non-avian theropod and bird remains from the early Late Cretaceous (Santonian) of Hungary and a review of the European abelisauroid record

Hitherto unpublished remains of non-avian and avian theropods from the Late Cretaceous (Formation Csehbánya, Santonian) Iharkút locality (western Hungary) are described. Non-avian theropod remains include an abelisaurid femur, which confirms the presence of this theropod family at Iharkút, and a metacarpal and a tibiotarsus from a paravian which may belong to Pneumatoraptor fodori, previously described from Iharkút. Birds are represented by two femora which clearly belong to enantiornithines, possibly to Bauxitornis, previously described from Iharkút. The abelisauroid record from the Cretaceous of Europe is reviewed.     

Knuckle-walking in Sivapithecus? The combined effects of homology and homoplasy with possible implications for pongine dispersals

Sivapithecus is a Miocene great ape from South Asia that is orangutan-like cranially but is distinctive postcranially. Work by others shows that the humerus resembles large terrestrial cercopithecoids proximally and suspensory hominoids distally, but most functional interpretations nevertheless situate Sivapithecus in an arboreal setting. We present a new quantitative analysis of the Sivapithecus capitate and hamate. Though the functional morphology of both bones suggests some degree of arboreality, the overall morphology is most similar to knuckle-walking African apes. Other features of the Sivapithecus humerus and hind limb are also functionally consistent with knuckle-walking, and we suggest that this locomotor behavior is a valid alternative functional interpretation of the postcranial morphology. We speculate that knuckle-walking in Sivapithecus would have evolved independently from African apes, perhaps for similar ecological reasons. The discovery of a possible pongine knuckle-walker challenges the hypotheses that (1) knuckle-walking evolved only once in hominoids and (2) knuckle-walking is too highly specialized to be the positional behavior from which human bipedalism evolved. The possibility of knuckle-walking in Sivapithecus may help to explain not only the curious combination of characters that typify the postcranium but also the unique postcranial morphology of extant Pongo. Furthermore, it may clarify the distribution of fossil pongines across many ecological zones in Eurasia in the Miocene and Pleistocene, as well as, independently, the spread of African apes across a diversity of environments in equatorial Africa.     

Prevention of the Disrupted Enamel Phenotype in Slc4a4-Null Mice Using Explant Organ Culture Maintained in a Living Host Kidney Capsule

Slc4a4-null mice are a model of proximal renal tubular acidosis (pRTA). Slc4a4 encodes the electrogenic sodium base transporter NBCe1 that is involved in transcellular base transport and pH regulation during amelogenesis. Patients with mutations in the SLC4A4 gene and Slc4a4-null mice present with dysplastic enamel, amongst other pathologies. Loss of NBCe1 function leads to local abnormalities in enamel matrix pH regulation. Loss of NBCe1 function also results in systemic acidemic blood pH. Whether local changes in enamel pH and/or a decrease in systemic pH are the cause of the abnormal enamel phenotype is currently unknown. In the present study we addressed this question by explanting fetal wild-type and Slc4a4-null mandibles into healthy host kidney capsules to study enamel formation in the absence of systemic acidemia. Mandibular E11.5 explants from NBCe1^−/− mice, maintained in host kidney capsules for 70 days, resulted in teeth with enamel and dentin with morphological and mineralization properties similar to cultured NBCe1^+/+ mandibles grown under identical conditions. Ameloblasts express a number of proteins involved in dynamic changes in H⁺/base transport during amelogenesis. Despite the capacity of ameloblasts to dynamically modulate the local pH of the enamel matrix, at least in the NBCe1^−/− mice, the systemic pH also appears to contribute to the enamel phenotype. Extrapolating these data to humans, our findings suggest that in patients with NBCe1 mutations, correction of the systemic metabolic acidosis at a sufficiently early time point may lead to amelioration of enamel abnormalities.     

Chimpanzee fauna isotopes provide new interpretations of fossil ape and hominin ecologies

Carbon and oxygen stable isotopes within modern and fossil tooth enamel record the aspects of an animal''s diet and habitat use. This investigation reports the first isotopic analyses of enamel from a large chimpanzee community and associated fauna, thus providing a means of comparing fossil ape and early hominin palaeoecologies with those of a modern ape. Within Kibale National Park forest, oxygen isotopes differentiate primate niches, allowing for the first isotopic reconstructions of degree of frugivory versus folivory as well as use of arboreal versus terrestrial resources. In a comparison of modern and fossil community isotopic profiles, results indicate that Sivapithecus, a Miocene ape from Pakistan, fed in the forest canopy, as do chimpanzees, but inhabited a forest with less continuous canopy or fed more on leaves. Ardipithecus, an early hominin from Ethiopia, fed both arboreally and terrestrially in a more open habitat than inhabited by chimpanzees.     

Les primates hominoides du Vallésien de Macédoine (Grèce). Étude de la machoire inférieure

The locality of the Ravine of the Rain is located in Lower Macedonia (Greece); it has yielded an important mammalian fauna of Vallesian age (Upper Miocene). An hominoid Primate is present with a lot of well preserved jaws. It is one of the better set of specimens never found in the same locality. His features and caracters are described and compared with those of the others tertiary Hominoids. This is a species which is near of Sivapithecus, Bodvapithecus and Ramapithecus and also it is very near of the ancestry of Gigantopithecus. All these Primates have had a particular ecology and this is probably the set in which we shall find the root of the plio-pleistocen Hominids.     

Palatine fenestrae,the orangutan and hominoid evolution

Although most mammals develop relatively large double anterior palatine fenestrae that patently communicate with the nasal cavity, four extant primates—Homo sapiens, Pongo, Pan andGorilla—do not. While these four have closed-down these foramenal structures,Homo sapiens andPongo are unique in forming a single foramen palatally. Among fossil taxa,Homo, Australopithecus, Sivapithecus (=Ramapithecus) andRudapithecus also develop a single foramen palatally. Dryopithecines, the presumed fossil apes, preserve the two patent fenestrae. In light of dental features that are considered diagnostically “hominid,” which are also found in the orangutan, it is suggested that this “ape,” rather thanPan, is phylogenetically closer toHomo.     

A comment on relative molar breadth in Ramapithecus

The evidence for broad molars in Ramapithecus is reviewed in this study. Extensive comparisons are made with living and fossil pongids and the earliest undoubted hominids, the australopithecines. These comparisons suggest that Ramapithecus is like its closely related Indian relatives, D. indicus and D. sivalensis. Trends in molar shape are discussed as well as some problems in the interpretation of the adaptive meaning of relative molar breadth in hominoids.     

The carnivoran community from the Miocene of Sandelzhausen (Germany)

From the Bavarian Early/Middle Miocene (MN5) site Sandelzhausen, nine species of carnivoran mammals are identified including the hemicyonine ursid Hemicyon stehlini, the amphicyonids Amphicyon cf. major and Pseudarctos bavaricus, the mustelids Ischyrictis zibethoides and Martes cf. munki, the mephitid Proputorius pusillus, the viverrid Leptoplesictis cf. aurelianensis, the felid Pseudaelurus romieviensis, and finally the recently described barbourofelid Prosansanosmilus eggeri. With these taxa present, Sandelzhausen shows a carnivoran community typical, though deprived, for the Lower to Middle Miocene of Europe, but different from roughly contemporary Mediterranean faunas such as those from Çandir or Pa?alar in Turkey.     

Problems in the interpretation of Ramapithecus: with special reference to anterior tooth reduction

The dental proportions of Ramapithecus specimen FT 1271-2 (from Fort Ternan, Kenya) have been compared with undoubted fossil pongids from the Miocene of East Africa. Compared to its Miocene pongid contemporaries, Ramapithecus exhibits distinct anterior tooth reduction both in its incisor and canine dimensions. This distinction is most clearly seen in comparisons of Ramapithecus with pongids of similar cheek tooth size, i.e., Dryopithecus africanus and Pan paniscus. The differences in dental proportions between the phylogenetic lines of D. africanus to Pan and Ramapithecus to Homo are discussed in terms of various dietary hypotheses. The similarities in dental proportions of Gorilla and Ramapithecus illustrate their non-frugivorous dietary preferences, but have little or no value as far as the taxonomic assessment of Ramapithecus is concerned.     

Dental development and life history in Anapithecus hernyaki

The sample of Anapithecus from Rudabánya, Hungary, is remarkable in preserving a large number of immature individuals. We used perikymata counts, measurements of root length and cuspal enamel thickness, and observations of the sequence of tooth germs that cross match specific developmental stages in Anapithecus to construct the first composite picture and time scale for dental development in a pliopithecoid (Catarrhini, Primates). We conclude that the age of eruption of M1 in Anapithecus was similar to various macaque species (approximately 1.45 months), but that M2 and M3 emergence were close to 2.2 and 3.2 years, respectively (both earlier than expected for similarly sized cercopithecoids). There may have been little difference in individual tooth formation times between cercopithecoids and Anapithecus, but the degree of molar overlap during M1, M2, and M3 crown development, which is extreme in Anapithecus, is fundamentally different. Overall dental development in Anapithecus was very rapid. Old World monkeys appear derived in lacking significant molar overlap, and hominoids may be derived in having longer tooth formation times, both resulting in longer overall dental development times. This is consistent with the general conclusion that the Pliopithecoidea is an outgroup to the Cercopithecoidea and the Hominoidea. On the other hand, rapid dental formation in Anapithecus may be an apomorphy indicative of an unusually rapid life history or unique pressures related to diet and maturation. Folivory and/or predation pressure may be responsible for generating selection to more rapidly erupt permanent teeth and possibly attain adult body masses in Anapithecus. Whatever the case, Anapithecus, with an M3 emergence of approximately 3.2 years, is dramatically faster than any extant catarrhine of similar body mass. This represents yet another unusual attribute of this poorly known fossil catarrhine.