The reconstructed cranium of Pierolapithecus and the evolution of the great ape face

L. Copes, L. Lucas, and the Museum of Comparative Zoology provided access to scans for MCZ 38018 (DOI: 10.17602/M2/M4399), MCZ 38019 (DOI: 10.17602/M2/M4398), MCZ 38020 (DOI: 10.17602/M2/M4397), and MCZ 31619 (DOI: 10.17602/M2/M4892). These scans were downloaded from MorphoSource. The Duke Lemur Center (DLC), Division of Fossil Primates granted access to the three Aegyptopithecus specimens via MorphoSource: DPC 2803 and DPC 3161, the collection of which was funded by NSF BCS 1231288 (to E.R. Seiffert, G. F. Gunnell, D. M. Boyer, and J. G. Fleagle) and NSF DBI 1458192 (to G. F. Gunnell, R. F. Kay and D. M. Boyer), and DPC 8794, the collection of which was funded by NSF DBI 2023087. This work is part of R+D+I projects PID2020- 116908GB- I00, PID2020- 117289GB- I00, PID2020- 117118GB- I00, funded by the Agencia Estatal de Investigación (AEI) of the Ministerio de Ciencia e Innovación (MCIN) from Spain (MCIN/AEI/10.13039/501100011033/), and it has been further sup-ported by the Generalitat de Catalunya/CERCA Programme (Research Centres of Catalonia) and research support grants (SGR) of the Agència de Gestió d'Ajuts Universitaris i de Recerca (Generalitat de Catalunya) to consolidated research groups (2021 SGR 01184, 2021 SGR 01188, and 2021 SGR 00620). S.A.C. is supported by BID PICT 2019- 03675 and J.F. is supported by a Ramón y Cajal grant [RYC2021- 032857- I] financed by MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR. This is NYCEP Morphometrics Contribution #120.Author affiliations: aDepartment of Anthropology, Brooklyn College, City University of New York, Brooklyn, NY 11210; bDivision of Anthropology, American Museum of Natural History, New York, NY 10024; cNew York Consortium in Evolutionary Primatology, New York, NY 10024; dUnidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas—Fundación Miguel Lillo, San Miguel de Tucumán 4000, Argentina; eFacultad de Ciencias Naturales e Instituto Miguel Lillo, Universi
Pierolapithecus catalaunicus (~12 million years ago, northeastern Spain) is key to understanding the mosaic nature of hominid (great ape and human) evolution. Notably, its skeleton indicates that an orthograde (upright) body plan preceded suspensory adaptations in hominid evolution. However, there is ongoing debate about this species, partly because the sole known cranium, preserving a nearly complete face, suffers from taphonomic damage. We 1) carried out a micro computerized tomography (CT) based virtual reconstruction of the Pierolapithecus cranium, 2) assessed its morphological affinities using a series of two-dimensional (2D) and three-dimensional (3D) morphometric analyses, and 3) modeled the evolution of key aspects of ape face form. The reconstruction clarifies many aspects of the facial morphology of Pierolapithecus. Our results indicate that it is most similar to great apes (fossil and extant) in overall face shape and size and is morphologically distinct from other Middle Miocene apes. Crown great apes can be distinguished from other taxa in several facial metrics (e.g., low midfacial prognathism, relatively tall faces) and only some of these features are found in Pierolapithecus, which is most consistent with a stem (basal) hominid position. The inferred morphology at all ancestral nodes within the hominoid (ape and human) tree is closer to great apes than to hylobatids (gibbons and siamangs), which are convergent with other smaller anthropoids. Our analyses support a hominid ancestor that was distinct from all extant and fossil hominids in overall facial shape and shared many features with Pierolapithecus. This reconstructed ancestral morphotype represents a testable hypothesis that can be reevaluated as new fossils are discovered.
Depto. de Biodiversidad, Ecología y Evolución
Fac. de Ciencias Biológicas
TRUE
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