Miocene Hominoids Research Articles

Lufengpithecus inner ear provides evidence of a common locomotor repertoire ancestral to human bipedalism

Various lines of evidence have been used to infer the origin of human bipedalism, but the paucity of hominoid postcranial fossils and the diversity of inferred locomotor modes have tended to confound the reconstruction of ancestral morphotypes. Examination of the bony labyrinth morphology of the inner ear of extinct and living hominoids provides independent evidence for inferring the evolution of hominoid locomotor patterns. New computed tomography data and morphometric analyses of the Late Miocene ape Lufengpithecus indicate that it and other stem great apes possess labyrinths similar to one another and show that hominoids initially evolved from a positional repertoire that included orthogrady, below-branch forelimb suspension and progression, above-branch bipedalism, climbing, clambering, and leaping (hylobatid-like) to one that comprised above-branch quadrupedalism, below-branch forelimb suspension, vertical climbing, limited leaping, terrestrial quadrupedal running and walking, possibly with knuckle walking, and short bouts of bipedalism (chimpanzee-like). The bony labyrinth morphology of Lufengpithecus indicates that it probably conforms more closely to the last common ancestors of crown hominoids and hominids in its locomotor behavior than do other Miocene hominoids. Human bipedalism evolved from this common archetypal Lufengpithecus-like locomotor repertoire. The low evolutionary rate of semicircular canal morphology suggests that Lufengpithecus experienced a relative stasis in locomotor behavior, probably due to the uplift of the Tibetan Plateau, which created a stable environment in the Miocene of southwestern China.

New materials of Khoratpithecus, a late Miocene hominoid from Nakhon Ratchasima Province, Northeastern Thailand, confirm its pongine affinities

New materials of Khoratpithecus, a late Miocene hominoid from Nakhon Ratchasima Province, Northeastern Thailand, confirm its pongine affinities

New femoral remains of Nacholapithecus kerioi: Implications for intraspecific variation and Miocene hominoid evolution

The middle Miocene stem kenyapithecine Nacholapithecus kerioi (16–15 Ma; Nachola, Kenya) is represented by a large number of isolated fossil remains and one of the most complete skeletons in the hominoid fossil record (KNM-BG 35250). Multiple fieldwork seasons performed by Japanese–Kenyan teams during the last part of the 20th century resulted in the discovery of a large sample of Nacholapithecus fossils. Here, we describe the new femoral remains of Nacholapithecus. In well-preserved specimens, we evaluate sex differences and within-species variation using both qualitative and quantitative traits. We use these data to determine whether these specimens are morphologically similar to the species holotype KNM-BG 35250 (which shows some plastic deformation) and to compare Nacholapithecus with other Miocene hominoids and extant anthropoids to evaluate the distinctiveness of its femur. The new fossil evidence reaffirms previously reported descriptions of some distal femoral traits, namely the morphology of the patellar groove. However, results also show that relative femoral head size in Nacholapithecus is smaller, relative neck length is longer, and neck–shaft angle is lower than previously reported for KNM-BG 35250. These traits have a strong functional signal related to the hip joint kinematics, suggesting that the morphology of the proximal femur in Nacholapithecus might be functionally related to quadrupedal-like behaviors instead of more derived antipronograde locomotor modes. Results further demonstrate that other African Miocene apes (with the exception of Turkanapithecus kalakolensis) generally fall within the Nacholapithecus range of variation, whose overall femoral shape resembles that of Ekembo spp. and Equatorius africanus. Our results accord with the previously inferred locomotor repertoire of Nacholapithecus, indicating a combination of generalized arboreal quadrupedalism combined with other antipronograde behaviors (e.g., vertical climbing).

Sharks and rays (chondrichthyes, elasmobranchii) from the miocene sediments of Kutch, Gujarat, India: paleoenvironmental and paleobiogeographic implications

ABSTRACT We report here a diverse assemblage of sharks and batoids representing the genera Carcharhinus, Rhizoprionodon, Galeocerdo, Sphyrna, Myliobatis, Aetobatus, Dasyatis, Pastinachus, Himantura and Pristis from Tapar and Jangadia the two late and early Miocene sites, respectively, of Kutch (Gujarat, India). The shark Rhizoprionodon and batoids, Dasyatis rugosa, D. cf. probsti, Dasyatis sp., Pastinachus and Himantura are being reported for the first time from the Miocene of western coast of India. The presence of Carcharhinus sp., Rhizoprionodon sp., Lamna sp., Negaprion sp., Sphyrna lewini, Myliobatis sp., Aetobatus sp. in the early Miocene Khari Nadi Formation exposed at Jangadia suggest existence of lagoonal, near shore to outer shelf environment. The rich batoid assemblage at the Late Miocene hominoid (Sivapithecus) bearing site of Tapar indicates the presence of a fresh to brackish water environmental condition. The faunal similarity of Miocene chondrichthyan of Indian Ocean and the Mediterranean Sea regions has been assessed using the beta diversity (Sørensen–Dice coefficient) data. The early Miocene elasmobranchs from Kutch shows close affinities with those from Mediterranean Sea. Similarly, in the Indian Ocean region Miocene fauna of Kutch shows close similarity with those of Baripada Beds, Orissa, Bhuban Formation of Mizoram, Gogha Coast, Piram Island and Madagascar.

Late Miocene Climate Cooling Contributed to the Disappearance of Hominoids in Yunnan Region, Southwestern China

AbstractThe relationship between long‐sequence climate change and Miocene hominoid evolution in the Yunnan region of southwestern China has recently received some attention, partly because this region has been regarded as a “refugium” for hominoids at the end of the Miocene. Here, we carry out a high‐resolution reconstruction of climate evolution in the Zhaotong Basin of Yunnan through the late Miocene to Pliocene using chemical weathering indices and other proxies. The results reveal gradual cooling within generally warm and humid conditions from 8.8–6.2 Ma; three more marked cooling episodes from 6.2–5.0 Ma; cool and humid conditions from 5.0–2.8 Ma; finally, cold and humid conditions from 2.8–2.62 Ma. The evidence is compatible with a scenario in which terminal Miocene cooling episodes within a prevailing warm and humid climate, and associated changes in vegetation, may have been critical factors in the disappearance of hominoids from this region.

Great apes and humans evolved from a long-backed ancestor

There is current debate whether the Homo/Pan last common ancestor (LCA) had a short, stiff lumbar column like great apes or a longer, flexible column observed in generalized Miocene hominoids. Beyond having only four segments, three additional features contribute to lumbar stiffening: the position of the transitional vertebra (TV), orientation of the lumbar spinous processes, and entrapment of lumbar vertebrae between the iliac blades. For great apes, these features would be homologous if inherited from a short-backed LCA but likely functionally convergent through dissimilar phenotypes if evolved from a long-backed LCA. We quantitatively and qualitatively analyzed human, ape, and monkey thoracic and lumbar vertebrae using 3D surface scanning and osteological measurements to compare spinous process morphology and sacral depth. We also used a large sample of hominoid vertebral counts to assess variation in the position of the TV and lumbosacral boundary. All extant hominoids modally place the TV at the ultimate thoracic. However, humans and orangutans place the TV at the 19th postcranial vertebral segment, whereas other apes place the TV at the 20th. Furthermore, chimpanzees, gorillas, and orangutans each have distinct patterns of spinous process angulation and morphology associated with lumbar stiffening, while human spinous process morphology is similar to that of longer backed gibbons, monkeys, and Miocene hominoids Morotopithecus and Pierolapithecus. Finally, chimpanzees are unique compared with other hominoids with a greater sacral depth facilitating lumbar entrapment, and there are differences among African apes with respect to the mechanisms governing variation in the lumbosacral boundary. These differences suggest that lumbar stiffening is convergent among great apes and that human bipedalism evolved from a more generalized long-backed ancestor. Such a model is more consistent with evidence of TV placement in Australopithecus.

The Westernmost Asian Record of Pythonids (Serpentes): The Presence of Python in a Miocene Hominoid Locality of Anatolia

Pythonids are fascinating extant reptiles comprising exclusively non-venomous Old-World taxa and including some of the largest known snakes (Murphy and Henderson, 1997). Being thermophilous reptiles, they are distributed in tropical and sub-tropical areas in sub-Saharan Africa, southern and southeastern Asia, Philippines, Indonesia, New Guinea, and Australia (Schleip and O’Shea, 2010; Wallach et al., 2014; Head, 2015). The most wellknown genus is Python, which recent molecular studies have nevertheless suggested partitioning into different genera (e.g., Rawlings et al., 2008; Reynolds et al., 2014). The fossil record of Python (sensu lato) is not adequately known; however, it still denotes a more extensive geographic distribution with the genus reaching Europe (Romer, 1870; Rage, 1976, 1984, 2003; Ivanov, 2000; Szyndlar and Rage, 2003; Head, 2015). Accordingly, in Asia the genus achieved a broader geographic distribution during the Neogene and Quaternary, with sporadic finds having been described during the past 130 years (Lydekker, 1888; Noetling, 1901; Hoffstetter, 1964; Rage, 1982; Rage et al., 2001; Head, 2005). Here we describe fossil vertebrae attributable to Python from the middle Miocene (late MN 5) hominoid locality of Pasalar, Turkey, which is one of the richest and most diverse mammal localities of that age across Eurasia (Andrews and Tobien, 1977; Alpagut, 1990; Alpagut et al., 1990, 2016; Andrews, 1990, 1995; Andrews and Alpagut, 1990; Ersoy et al., 2008; Kelley et al., 2008; Valenciano et al., 2019). The Pasalar Python represents the first fossil record of the genus from Anatolia. The material shows some general resemblance to the geographically proximate but enigmatic early Miocene Greek taxon Python euboicus, but due to the fact that the latter species is poorly known and its holotype and only known specimen is lost, we refrain from assigning the Anatolian specimens to that species and only refer them as Python sp. The Pasalar specimens represent the westernmost Asian occurrence of Python, confirming a rather wide Palearctic occurrence of the genus during the early and middle Miocene. Institutional Abbreviations—BP, Bursa-Pasalar collection, Pasalar Excavation Site, ustafakemalpasa, Turkey; EUNMH PV, Natural History Museum of Ege University, Izmir, Turkey; GMH, Geiseltalmuseum of Martin-Luther Universitat Halle-Wittenberg, now referred to as the Geiseltalsammlung, housed as part of the Zentralmagazin Naturwissenschaftlicher Sammlungen, Halle, Germany; HNHM, Hungarian Natural History Museum, Budapest, Hungary; MDHC, Massimo Delfino Herpetological Collection, University of Torino, Torino, Italy; MNCN, Museo Nacional de Ciencias Naturales, Madrid, Spain; MNHN, Museum national d’Histoire Naturelle, Paris, France; NHMUK, Natural History Museum, London, United Kingdom; NHMW, Naturhistorisches Museum Wien, Vienna, Austria; PIMUZ, Palaontologisches Institut und Museum der Universitat Zurich, Zurich, Switzerland; ZPW, Institute of Palaeontology, Wroclaw University, Poland; ZZSiD, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Krakow, Poland

Knee function through finite element analysis and the role of Miocene hominoids in our understanding of the origin of antipronograde behaviours: the Pierolapithecus catalaunicus patella as a case study

AbstractAlthough extensive research has been carried out in recent years on the origin and evolution of human bipedalism, a full understanding of this question is far from settled. Miocene hominoids are key to a better understanding of the locomotor types observed in living apes and humans. Pierolapithecus catalaunicus, an extinct stem great ape from the middle Miocene (c. 12.0 Ma) of the Vallès‐Penedès Basin (north‐eastern Iberian Peninsula), is the first undoubted hominoid with an orthograde (erect) body plan. Its locomotor repertoire included above‐branch quadrupedalism and other antipronograde behaviours. Elucidating the adaptive features present in the Pierolapithecus skeleton and its associated biomechanics helps us to better understand the origin of hominoid orthogrady. This work represents a new biomechanical perspective on Pierolapithecus locomotion, by studying its patella and comparing it with those drawn from a large sample of extant anthropoids. This is the first time that the biomechanical patellar performance in living non‐human anthropoids and a stem hominid has been studied using finite element analysis (FEA). Differences in stress distribution are found depending on body plan and the presence/absence of a distal apex, probably due to dissimilar biomechanical performances. Pierolapithecus’ biomechanical response mainly resembles that of great apes, suggesting a similar knee joint use in mechanical terms. These results underpin previous studies on Pierolapithecus, favouring the idea that a relevant degree of some antipronograde behaviour may have made up part of its locomotor repertoire. Moreover, our results corroborate the presence of modern great ape‐like knee biomechanical performances back in the Miocene.

Enamel thickness and dental development in Rudapithecus hungaricus

The fossil record of middle and late Miocene Eurasian hominoids has expanded considerably over the past few decades, particularly with the recovery of numerous isolated teeth and jaws. Scholars have turned to assessments of internal tooth structure and growth to make sense of the evolutionary radiations of these primates as well as their affinities to the living great apes (hominids). Here we characterize full-dentition enamel thickness and dental development in several juvenile Rudapithecus hungaricus individuals using multiple imaging modalities. Relative enamel thickness (RET) values for the anterior teeth and premolars of Rudapithecus are broadly akin to those of gorillas and chimpanzees and are thinner than those of orangutans. First molar RET values are most similar to chimpanzees, while posterior molar values are closer to thicker-enameled orangutans. When compared to Miocene hominoids, Rudapithecus shows an intermediate molar RET condition that is especially similar to other dryopithecines. Long-period line periodicity values are comparable to African apes and most Miocene hominoids, and lower than living and fossil orangutans. The mean cuspal daily secretion rate is similar to that of several other Miocene hominoids but is greater than extant great apes. Cusp-specific molar crown formation times generally exceed those of chimpanzees, are lower than those of orangutans, and are broadly like those of other Miocene apes. While Rudapithecus appears to have a somewhat unique pattern of enamel thickness and dental development relative to individual great ape genera, these structural and developmental features are consistent with its designation as a hominid.

First record of the Miocene hominoid Sivapithecus from Kutch, Gujarat state, western India.

Hominoid remains from Miocene deposits in India and Pakistan have played a pivotal role in understanding the evolution of great apes and humans since they were first described in the 19th Century. We describe here a hominoid maxillary fragment preserving the canine and cheek teeth collected in 2011 from the Kutch (= Kachchh) basin in the Kutch district, Gujarat state, western India. A basal Late Miocene age is proposed based on the associated faunal assemblage that includes Hipparion and other age-diagnostic mammalian taxa. Miocene Hominoidea are known previously from several areas of the Siwalik Group in the outer western Himalayas of India, Pakistan, and Nepal. This is the first record of a hominoid from the Neogene of the Kutch Basin and represents a significant southern range extension of Miocene hominoids in the Indian peninsula. The specimen is assigned to the Genus Sivapithecus, species unspecified.

Using machine learning to classify extant apes and interpret the dental morphology of the chimpanzee-human last common ancestor

Author(s): Monson, Tesla A.; Armitage, David W.; Hlusko, Leslea J. | Abstract: Machine learning is a formidable tool for pattern recognition in large datasets. We developed and expanded on these methods, applying machine learning pattern recognition to a problem in paleoanthropology and evolution. For decades, paleontologists have used the chimpanzee as a model for the chimpanzee-human last common ancestor (LCA) because they are our closest living primate relative. Using a large sample of extant and extinct primates, we tested the hypothesis that machine learning methods can accurately classify extant apes based on dental data. We then used this classification tool to observe the affinities between extant apes and Miocene hominoids. We assessed the discrimination accuracy of supervised learning algorithms when tasked with the classification of extant apes (n=175), using three types of data from the postcanine dentition: linear, 2-dimensional, and the morphological output of two genetic patterning mechanisms that are independent of body size: molar module component (MMC) and premolar-molar module (PMM) ratios. We next used the trained algorithms to classify a sample of fossil hominoids (n=95), treated as unknowns. Machine learning classifies extant apes with greater than 92% accuracy with linear and 2-dimensional dental measurements, and greater than 60% accuracy with the MMC and PMM ratios. Miocene hominoids are morphologically most similar in dental size and shape to extant chimpanzees. However, relative dental proportions of Miocene hominoids are more similar to extant gorillas and follow a strong trajectory through evolutionary time. Machine learning is a powerful tool that can discriminate between the dentitions of extant apes with high accuracy and quantitatively compare fossil and extant morphology. Beyond detailing applications of machine learning to vertebrate paleontology, our study highlights the impact of phenotypes of interest and the importance of comparative samples in paleontological studies.

Sexual dimorphism of body size in an African fossil ape, Nacholapithecus kerioi

Sexual size dimorphism in the African fossil ape Proconsul nyanzae (18 million years ago, 18 Ma) has been previously documented. However, additional evidence for sexual dimorphism in Miocene hominoids can provide great insight into the history of extant hominoid mating systems. The present study focused on body mass (BM) sexual dimorphism in Nacholapithecus kerioi from the Middle Miocene (16–15 Ma) in Africa. Bootstrap analysis revealed that P. nyanzae BM sexual dimorphism was lower than that in Pan troglodytes, which exhibits moderate sexual dimorphism, as reported previously. The same simulation revealed that BM sexual dimorphism of N. kerioi was comparable with that in Gorilla spp.; i.e., the males were approximately twice as large as the females. High sexual dimorphism in extant apes is usually indicative of a polygynous social structure (gorilla) or solitary/fission-fusion social system (orangutan). However, because of the high proportion of adult males in this fossil assemblage, the magnitude of dimorphism inferred here cannot be associated with a gorilla-like polygynous or oranguran-like solitary/fission-fusion social structure, and may reflect either taphonomic bias, or some other social structure. Extant hominoids have a long evolutionary history owing to their deep branching, comprising only a few existing members of the original highly successful group. Therefore, it is not surprising that the mating systems of extant hominoids fail to provide fossil apes with a perfect “model”. The mating systems of extinct hominoids may have been more diverse than those of extant apes.

FOSSO DELLA FITTAIA: THE OLDEST TUSCO-SARDINIAN LATE MIOCENE ENDEMIC VERTEBRATE ASSEMBLAGES (BACCINELLO-CINIGIANO BASIN, TUSCANY, ITALY)

The late Miocene continental successions of the Baccinello-Cinigiano basin (Grosseto), one of the longest and most continuous vertebrate-bearing continental successions in the Neogene Italian record, yielded at least four superimposed vertebrate assemblages bracketed in the time span 8.3 - 6.4 Ma. The Baccinello-Cinigiano basin is famous for recording endemic vertebrate assemblages that include the youngest European Miocene hominoid, Oreopithecus bambolii . The late Miocene endemic vertebrate fauna known as the Baccinello V0 assemblage is the oldest vertebrate fauna within the Baccinello-Cinigiano basin succession, being correlated to the European mammal Neogene unit MN11. Recent field surveys along the Trasubbie river allowed studying in detail the basal Baccinello-Cinigiano sedimentary succession, and sampling fossiliferous level bearing microvertebrates along the small creek Fosso della Fittaia. The sample “Fosso della Fittaia 2013” yielded about 170 fossil remains improving our documentation of the oldest vertebrate assemblages from the Baccinello-Cinigian basin. As far as rodents are concerned, in addition to the already recognized murid Huerzelerimys and glirid Anthracoglis , a few dental remains are assigned to a new genus and species of giant dormouse. It is further worth noting the occurrence in the sample of shrew remains (the first described from the Baccinello-Cinigiano basin) identified as cf. Lartetium . The latter attests the presence of a crocidosoricine in the Fosso della Fittaia 2013 assemblage, postdating the youngest known occurrences of the subfamily by at least 1 my. The vertebrate assemblage is completed by a diverse herpetofauna and the first fish remains reported from the basin.

Correction to: New Fossil Suid Specimens from the Terminal Miocene Hominoid Locality of Shuitangba, Zhaotong, Yunnan Province, China

The original version of this article unfortunately contained mistakes. Table 5 is the comparison of upper and lower molars. However, the published edition only showed the sub-title of the upper molars, and the sub-title of the lower molars are missing.

New Fossil Suid Specimens from the Terminal Miocene Hominoid Locality of Shuitangba, Zhaotong, Yunnan Province, China

Fossil suid specimens recovered from the latest Miocene site of Shuitangba, Zhaotong Basin, Yunnan Province, provide new information on the classification and relationship of Chinese Miocene Suinae. Most of the recovered specimens are referred to a relatively advanced and large species of Suinae, Propotamochoerus hyotherioides, based on dental dimensions and morphology. Detailed morphological comparisons were made between the Shuitangba Pr. hyotherioides and other Asian Miocene suines. From these comparisons, we suggest that Pr. hyotherioides from Shuitangba and northern China may be relatively derived compared to the specimens from Lufeng and Yuanmou, southern China and that Pr. hyotherioides and Pr. wui represent separate branches of the genus in China. Furthermore, Microstonyx differs from Pr. hyotherioides in p4/P4 and m3/M3 characters. Molarochoerus is suggested to represent a relatively derived taxon due to the uniquely molarized upper and lower fourth premolars. Miochoerus youngi is suggested to have a closer relationship to Sus and Microstonyx than to Propotamochoerus due to its small size and p4 morphology. Hippopotamodon ultimus, Potamochoerus chinhsienense, Dicoryphochoerus medius, and D. binxianensis exhibit complex morphologies that variously resemble Propotamochoerus, Microstonyx, and Sus and are suggested to be possible transitional forms between Propotamochoerus, Microstonyx, and Sus. However, the resolution of their classification requires further analysis when more material is recovered.

La simiente de la evolución (1966, BAC): El desarrollo de la Paleontología Humana en España en las últimas tres décadas

La paleontologia humana en Espana ha experimentado un crecimiento extraordinario en las ultimas decadas. En este trabajo indagamos la influencia que el libro La evolucion (1966) y sus editores, Miquel Crusafont, Bermudo Melendez y Emiliano Aguirre, han podido ejercer en esta explosion de resultados. Dos areas han protagonizado un especial desarrollo: el estudio de los hominoideos del Mioceno, vinculable en su origen a la figura de Crusafont y a los yacimientos de la cuenca del Valles-Penedes (Barcelona), y el de las primeras ocupaciones humanas en Europa, intimamente relacionado con la figura de Aguirre y las excavaciones de Atapuerca (Burgos). Diferentes factores han contribuido a este progreso, pero la inercia investigadora de La evolucion y sus fundamentos conceptuales han sido clave para el desarrollo de la disciplina.

Evolution of the Human Pelvis.

No bone in the human postcranial skeleton differs more dramatically from its match in an ape skeleton than the pelvis. Humans have evolved a specialized pelvis, well-adapted for the rigors of bipedal locomotion. Precisely how this happened has been the subject of great interest and contention in the paleoanthropological literature. In part, this is because of the fragility of the pelvis and its resulting rarity in the human fossil record. However, new discoveries from Miocene hominoids and Plio-Pleistocene hominins have reenergized debates about human pelvic evolution and shed new light on the competing roles of bipedal locomotion and obstetrics in shaping pelvic anatomy. In this issue, 13 papers address the evolution of the human pelvis. Here, we summarize these new contributions to our understanding of pelvic evolution, and share our own thoughts on the progress the field has made, and the questions that still remain. Anat Rec, 300:789-797, 2017. © 2017 Wiley Periodicals, Inc.

Habitat, climate and potential plant food resources for the late Miocene Shuitangba hominoid in Southwest China: Insights from carpological remains

The late Miocene is a sub-epoch when hominoids became rare worldwide but managed to survive in a few refugia. Investigating the living conditions of the late Miocene hominoids is therefore crucial for a better understanding of how they survived in those refugia. In this study, we present relevant palaeobotanical evidence regarding the habitat, climate and possible plant food resources for the Shuitangba hominoid (Lufengpithecus cf. lufengensis) from the late Miocene Zhaotong Basin, Southwest China. A total of 14 plant taxa were recognized from carpological remains newly recovered from the Zhaotong Basin, among which ten taxa were not reflected in the previous pollen record. These new plant taxa expand our knowledge of the flora and indicate how diverse the ecosystem in the late Miocene Zhaotong Basin was. Based on our carpological taxa, we hypothesize that the Shuitangba hominoid lived in a stratified mixed forest composed of trees, shrubs, lianas, herbs and grasses, near a lake occupied by various aquatic plants. The quantitative palaeoclimate reconstruction using the Coexistence Approach (CoA) indicates that the late Miocene Zhaotong Basin had a mean annual temperature (MAT) of 11.3–17.6°C and a mean annual precipitation (MAP) of 1042–1547mm, suggesting a mildly warm and humid climate for the Shuitangba hominoid. It also indicates that the hominoid had warm and wet summers but cool and dry winters, under the influence of the Asian monsoon. Edible and nutritious fruits and seeds of a considerable size, e.g., nuts of Carya and Corylus, fruits of Euryale and Trapa, were possibly exploited by the Shuitangba hominoid. The harder fruits, e.g., nuts of Carya and Corylus, might have benefited the hominoid as a fallback resource in winter when foods were scarce.

Upper incisor morphology of the Late Miocene hominoid <i>Ouranopithecus macedoniensis</i> from Axios Valley (Macedonia, Greece)

The upper incisor lingual morphology of the late Miocene Greek hominoid Ouranopithecus macedoniensis was almost unknown, as the described earlier maxillary remains preserve only worn incisors. During the most recent excavations in the type locality of Ouranopithecus, Ravin de la Pluie (RPl) of Axios Valley (Macedonia, Greece), four little-worn upper central incisors were recovered. This material and a few additional worn upper incisors, discovered recently, are described and compared in this article. Even though a morphological comparison with the old RPl material, lacking unworn or little worn incisors, is impossible, the metrical comparison and the monospecific character of the RPl hominoid sample suggest that the described incisors can be assigned to Ouranopithecus macedoniensis. The described upper central incisors are separated in two size-groups which in general have similar morphology except for some minor differences such as the presence of a pronounced mesial lingual pillar in the small-sized specimens. The observed significant size difference among the studied incisors is attributed to the strong sexual dimorphism of Ouranopithecus, which is also well expressed in the other teeth. The lingual morphology of the upper incisors of Ouranopithecus are not identical to those of extant great apes, though they have some similarities with those of the African great apes (Gorilla and Pan), while they are clearly different from those of the Asian great ape (Pongo). Even though they have some morphological similarities, the O. macedoniensis central incisors are probably not identical to those of the Eurasian Miocene hominoids; the most similar central incisor is that of Ouranopithecus turkae. Among the known African Miocene hominoids, Nakalipithecus upper central incisor is quite similar in morphology and size to that of Ouranopithecus.

A morphometric mapping analysis of lower fourth deciduous premolar in hominoids: Implications for phylogenetic relationship between Nakalipithecus and Ouranopithecus

Clarifying morphological variation among African and Eurasian hominoids during the Miocene is of particular importance for inferring the evolutionary history of humans and great apes. Among Miocene hominoids, Nakalipithecus and Ouranopithecus play an important role because of their similar dates on different continents. Here, we quantify the lower fourth deciduous premolar (dp4) inner morphology of extant and extinct hominoids using a method of morphometric mapping and examine the phylogenetic relationships between these two fossil taxa. Our data indicate that early Late Miocene apes represent a primitive state in general, whereas modern great apes and humans represent derived states. While Nakalipithecus and Ouranopithecus show similarity in dp4 morphology to a certain degree, the dp4 of Nakalipithecus retains primitive features and that of Ouranopithecus exhibits derived features. Phenotypic continuity among African ape fossils from Miocene to Plio-Pleistocene would support the African origin of African apes and humans (AAH). The results also suggest that Nakalipithecus could have belonged to a lineage from which the lineage of Ouranopithecus and the common ancestor of AAH subsequently derived.