Ramapithecus and hominoid evolution (2023)

Hominoids diverged from cercopithecoids during the Oligocene in Afro-Arabia, initially radiating in that continent and subsequently dispersing into Eurasia. From the Late Miocene onward, the geographic range of hominoids progressively shrank, except for hominins, which dispersed out of Africa during the Pleistocene. Although the overall picture of hominoid evolution is clear based on available fossil evidence, many uncertainties persist regarding the phylogeny and paleobiogeography of Miocene apes (nonhominin hominoids), owing to their sparse record, pervasive homoplasy, and the decimated current diversity of this group. We review Miocene ape systematics and evolution by focusing on the most parsimonious cladograms published during the last decade. First, we provide a historical account of the progress made in Miocene ape phylogeny and paleobiogeography, report an updated classification of Miocene apes, and provide a list of Miocene ape species-locality occurrences together with an analysis of their paleobiodiversity dynamics. Second, we discuss various critical issues of Miocene ape phylogeny and paleobiogeography (hylobatid and crown hominid origins, plus the relationships of Oreopithecus) in the light of the highly divergent results obtained from cladistic analyses of craniodental and postcranial characters separately. We conclude that cladistic efforts to disentangle Miocene ape phylogeny are potentially biased by a long-branch attraction problem caused by the numerous postcranial similarities shared between hylobatids and hominids—despite the increasingly held view that they are likely homoplastic to a large extent, as illustrated by Sivapithecus and Pierolapithecus—and further aggravated by abundant missing data owing to incomplete preservation. Finally, we argue that—besides the recovery of additional fossils, the retrieval of paleoproteomic data, and a better integration between cladistics and geometric morphometrics—Miocene ape phylogenetics should take advantage of total-evidence (tip-dating) Bayesian methods of phylogenetic inference combining morphologic, molecular, and chronostratigraphic data. This would hopefully help ascertain whether hylobatid divergence was more basal than currently supported.

Recent humans and their fossil relatives are classified as having thick molar enamel, one of very few dental traits that distinguish hominins from living African apes. However, little is known about enamel thickness in the earliest members of the genus Homo, and recent studies of later Homo report considerable intra- and inter-specific variation. In order to assess taxonomic, geographic, and temporal trends in enamel thickness, we applied micro-computed tomographic imaging to 150 fossil Homo teeth spanning two million years. Early Homo postcanine teeth from Africa and Asia show highly variable average and relative enamel thickness (AET and RET) values. Three molars from South Africa exceed Homo AET and RET ranges, resembling the hyper thick Paranthropus condition. Most later Homo groups (archaic European and north African Homo, and fossil and recent Homo sapiens) possess absolutely and relatively thick enamel across the entire dentition. In contrast, Neanderthals show relatively thin enamel in theirincisors, canines, premolars, and molars, although incisor AET values are similar to H.sapiens. Comparisons of recent and fossil H.sapiens reveal that dental size reduction has led to a disproportionate decrease in coronal dentine compared with enamel (although both are reduced), leading to relatively thicker enamel in recent humans. General characterizations of hominins as having ‘thick enamel’ thus oversimplify a surprisingly variable craniodental trait with limited taxonomic utility within a genus. Moreover, estimates of dental attrition rates employed in paleodemographic reconstruction may be biased when this variation is not considered. Additional research is necessary to reconstruct hominin dietary ecology since thick enamel is not a prerequisite for hard-object feeding, and it is present in most later Homo species despite advances in technology and food processing.

The quantitative immunological technique of microcomplement fixation was used to examine serum albumin evolution among members of the order Crocodylia. The cross-reactivity of the albumin antisera and antigens employed in this study had been examined previously using the qualitative technique of immunodiffusion. The phylogenetic conclusions derived from these two data sets are highly congruent, including support of the families Alligatoridae and Crocodylidae, with the placement of Gavialis as the sister taxon of Tomistoma. Both methods provide similar information on the relative amounts of amino acid sequence divergence between albumin molecules; however, the data obtained from microcomplement fixation comparisons are more discriminating than those derived from immunodiffusion. The estimated divergence times within the Crocodylia derived from the fossil record are examined in light of divergence times predicted by the microcomplement fixation-based albumin clock. The traditional phylogenetic placement of Gavialis outside the remaining extant crocodilians is inconsistent with all molecular data sets and we suggest that a careful reexamination of both the extant and the fossil morphological data is warranted.

The magnetostratigraphy of the Chinji Formation (Siwalik Group, Pakistan) provides age estimates for the earliest occurrence of hominoids attributable toSivapithecus. This report documents a new earliest occurrence for the genus and provides age estimates for other Chinji Formation specimens described previously. These middle Miocene primates have figured prominently in discussions of the course and timing of hominoid evolution.Sivapithecus shares with the living orang-utan (Pongo) a number of derived craniofacial features indicating that they are sister taxa. The newly discovered specimens from the Chinji Formation therefore provide a minimum estimate for the time of the initial divergence between the Asian and African large hominoid clades. Large-bodied hominoids first appear in the Siwaliks at 12·5 m.y.a., with specimens preserving the derived craniofacial features dated at ∼ 12 m.y.a. This age estimate can be used to calibrate branching times of extant hominoids as determined from comparative molecular data.

Journal of Human Evolution, Volume 151, 2021, Article 102928

Australopithecus anamensis, among the earliest fully bipedal hominin species, lived in eastern Africa around 4Ma. Much of what is currently known about the paleoecology of A.anamensis comes from the type locality, Kanapoi, Kenya. Here, we extend knowledge of the range of environments occupied by A.anamensis by presenting the first multiproxy paleoecological analysis focusing on Bovidae excavated from another important locality where A.anamensis was recovered, locality 261-1 (ca. 3.97Ma) at Allia Bay, East Turkana, Kenya. Paleoenvironments are reconstructed using astragalar ecomorphology, mesowear, hypsodonty index, and oxygen and carbon isotopes from dental enamel. We compare our results to those obtained from Kanapoi. Our results show that the bovid community composition is similar between the two fossil assemblages. Allia Bay and Kanapoi bovid astragalar ecomorphology spans the spectrum of modern morphologies indicative of grassland, woodland, and even forest-adapted forms. Dietary reconstructions based on stable isotopes, mesowear, and hypsodonty reveal that these bovids' diet encompassed the full C₃ to C₄ dietary spectrum and overlap in the two data sets. Our results allow us to confidently extend our reconstructions of the paleoenvironments of A.anamensis at Kanapoi to Allia Bay, where this pivotal hominin species is associated with heterogeneous settings including habitats with varying degrees of tree cover, including grasslands, bushlands, and woodlands.

Ethnozoology, 2018, pp. 95-118

Hunting constitutes one of the most ancient and important practices in the history of mankind, impacting the various aspects of human life. In this chapter we briefly discuss historical features of hunting, its importance to civilization, the motivations that drives people to practice this activity and their hunting strategies, the diverse ways of using game animals, and the ecological implications of hunting. Identifying the importance of hunting and its effects, it is a key to search for strategies that allow the conservation of exploited species and at the same time permit the proper subsistence of human communities that rely on exploited species for their survival.

Quaternary International, Volume 431, Part B, 2017, pp. 53-63

Journal of Archaeological Science: Reports, Volume 33, 2020, Article 102475

The Cro-Magnon human remains, associated with the Mid Upper Paleolithic (MUP), have been commingled since 1868. Only one comprehensive attempt to reassociate the bones and partial description of them, now more than fifty years old, has been published. This article provides a comprehensive description and reassessment of the adult upper limb remains. We used a visual and morphometric approach, combined with virtual anthropology, to allocate 14 of the 24 upper limb bones to four individuals. This analysis illustrates the relative morphological homogeneity of the MUP sample and highlights the striking differences between MUP individuals and the more recent Upper Pleistocene human groups in western Eurasia. This study also reinforces the hypothesis of gender roles during the MUP, with women more frequently than men involved in physical activities requiring both upper limbs.

Biomedical and Environmental Sciences, Volume 27, Issue 5, 2014, pp. 385-387

The aim of the study was to investigate whether the expression of obestatin in gastric body mucosa in abdominal obesity patients with normal body mass index (BMI) is different compared with healthy controls. Twenty abdominal obesity patients with normal BMI and twenty healthy controls were included in the study. The number of obestatin-positive cells in gastric body mucosa was significantly lower in abdominal obesity patients with normal BMI than that in healthy subjects. There was a positive correlation between the numbers of obestatin-positive cells in the gastric body mucosa and plasma obestatin levels in abdominal obesity subjects and control group.

Journal of Human Evolution, Volume 94, 2016, pp. 83-91