Postcranial morphology of the middle Pleistocene humans from Sima de los Huesos, Spain
- aCentro Mixto Universidad Complutense de Madrid - Instituto de Salud Carlos III de Evolución y Comportamiento Humanos, 28029 Madrid, Spain;
- bDepartamento de Paleontología, Facultad Ciencias Geológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain;
- cLaboratorio de Evolución Humana, Departamento de Ciencias Históricas y Geografía, Universidad de Burgos, 09001 Burgos, Spain;
- dÀrea de Prehistòria, Departament d’Història i Història de l’Art, Universitat Rovira i Virgili, 43002 Tarragona, Spain;
- eInstitut Català de Paleoecologia Humana i Evolució Social, 43007 Tarragona, Spain;
- fDepartamento Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Universidad del País Vasco–Euskal Herriko Unibertsitatea, 48080 Bilbao, Spain;
- gIkerbasque, Basque Foundation for Science, 48013 Bilbao, Spain;
- hUMR 7194, CNRS, Département Préhistoire, Muséum National d’Histoire Naturelle, Musée de l’Homme, 75016 Paris, France;
- iÁrea de Antropología Física, Departamento de Ciencias de la Vida, Universidad de Alcalá, 28871 Alcalá de Henares, Spain;
- jCentro Nacional de Investigación Sobre la Evolución Humana, 09002 Burgos, Spain;
- kDepartment of Anthropology, Binghamton University, State University of New York, Binghamton, NY 13902-6000;
- lDivision of Anthropology, American Museum of Natural History, New York, NY 10024-5192;
- mDepartamento Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco–Euskal Herriko Unibertsitatea, 48080 Bilbao, Spain;
- nÁrea de Paleontología, Departamento de Geografía y Geología, Universidad de Alcalá, 28871 Alcalá de Henares, Spain;
- oPaleontología, Aragosaurus–Instituto de Investigación en Ciencias Ambientales de Aragón and Facultad Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain;
- pInstitute of Vertebrate Paleontology and Paleoanthropology of Beijing, 100044 Beijing, China
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Contributed by Juan Luis Arsuaga, July 29, 2015 (sent for review May 20, 2015; reviewed by Trenton W. Holliday and Christopher B. Ruff)

Significance
The middle Pleistocene Sima de los Huesos (SH) fossil collection provides the rare opportunity to thoroughly characterize the postcranial skeleton in a fossil population, comparable only to that obtained in the study of the Neandertal hypodigm and recent (and fossil) modern humans. The SH paleodeme can be characterized as relatively tall, wide, and muscular individuals, who are less encephalized than both Neandertals and modern humans. Some (but not all) Neandertal derived traits are present, which phylogenetically links this population with Neandertals. Thus, the full suite of Neandertal features did not arise all at once, and the evolution of the postcranial skeleton could be characterized as following a mosaic pattern.
Abstract
Current knowledge of the evolution of the postcranial skeleton in the genus Homo is hampered by a geographically and chronologically scattered fossil record. Here we present a complete characterization of the postcranium of the middle Pleistocene paleodeme from the Sima de los Huesos (SH) and its paleobiological implications. The SH hominins show the following: (i) wide bodies, a plesiomorphic character in the genus Homo inherited from their early hominin ancestors; (ii) statures that can be found in modern human middle-latitude populations that first appeared 1.6–1.5 Mya; and (iii) large femoral heads in some individuals, a trait that first appeared during the middle Pleistocene in Africa and Europe. The intrapopulational size variation in SH shows that the level of dimorphism was similar to modern humans (MH), but the SH hominins were less encephalized than Neandertals. SH shares many postcranial anatomical features with Neandertals. Although most of these features appear to be either plesiomorphic retentions or are of uncertain phylogenetic polarity, a few represent Neandertal apomorphies. Nevertheless, the full suite of Neandertal-derived features is not yet present in the SH population. The postcranial evidence is consistent with the hypothesis based on the cranial morphology that the SH hominins are a sister group to the later Neandertals. Comparison of the SH postcranial skeleton to other hominins suggests that the evolution of the postcranium occurred in a mosaic mode, both at a general and at a detailed level.
Footnotes
- ↵1To whom correspondence should be addressed. Email: jlarsuaga{at}isciii.es.
Author contributions: J.L.A., J.M.B.d.C., and E.C. codirected the Atapuerca excavations and research project; J.L.A. designed research; J.L.A., J.-M.C., C.L., A.G.-O., A.P., L.R., R.G.-G., A.B., R.M.Q., A.P.-P., I.M., A.A., A.G.-T., E.P.-R., N.S., N.G., A.A.d.V., G.C.-B., J.M.B.d.C., and E.C. performed research; J.L.A., J.-M.C., C.L., A.G.-O., A.P., L.R., R.G.-G., A.B., R.M.Q., A.P.-P., I.M., A.A., A.G.-T., E.P.-R., N.S., N.G., A.A.d.V., and G.C.-B. analyzed data; and J.L.A., J.-M.C., C.L., A.G.-O., A.P., L.R., R.G.-G., A.B., R.M.Q., A.P.-P., and I.M. wrote the paper.
Reviewers: T.W.H., Tulane University; and C.B.R., The Johns Hopkins University School of Medicine.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1514828112/-/DCSupplemental.
Freely available online through the PNAS open access option.
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