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Reconstructing cranial evolution in an extinct hominin

Citation

Baab, Karen (2021), Reconstructing cranial evolution in an extinct hominin, Dryad, Dataset, https://doi.org/10.5061/dryad.5qfttdz32

Abstract

Homo erectus occupies a central position in human evolution as a likely ancestor of the modern human (Homo sapiens) and Neanderthal / Denisovan lineages and the first hominin species with a truly cosmopolitan distribution. Understanding the evolutionary population dynamics of Homo erectus has larger implications for the emergence of later Homo lineages in the Middle Pleistocene. Quantitative genetics models provide a means of interrogating aspects of longstanding Homo erectus population history narratives. For the current study, cranial fossils were sorted into six major paleodemes from sites across Africa and Asia spanning 1.8 to 0.1 Ma. Three-dimensional shape data from the occipital and frontal bones were used to test population genetic hypotheses. Results indicate that Homo erectus had higher individual and group variation than Homo sapiens, likely reflecting different levels of genetic diversity and population history in these spatially disperse species. This study also revealed distinct evolutionary histories for frontal and occipital bone shape in Homo erectus,with a larger role for natural selection in the former. One scenario consistent with these findings is climate-driven facial adaptation in Homo erectus, which is reflected in the frontal bone through integration with the orbits.

Methods

Data are 3D landmarks and semilandmarks from the frontal bone (all_coord_f2.csv) and occipital bone (all_coord_o2.csv) of Homo erectus (extinct hominin) fossils and comparative Homo sapiens (recent humans). Data were collected with a 3D Microscribe digitizer. Missing landmarks were estimated using several procedures (described in SI of original article).

Also included are files required to 'slide' the semilandmarks (sliders_Frt.csv and sliders_occ.csv)

The final file is R code for performing anlyses presented in article.

Usage Notes

The following human population abbreviations were used: Aust = Aboriginal Australians; Lach = Lachish, Israel; Anda = Andamanese Islanders; Teit = Teita, Kenya; Ngui = New Guinea; Chin = Chinese; Grgl = Grand Gulch, Utah (Anasazi); Ipiu = Ipiutak from Point Hope, Alaska.

Columns in landmark files: indiv = fossil abbreviation; spp = species; pop = population; pop_simp = not used in current study; V1-V3 = x, y, and z coordinates of landmark 1, and so on