Journal of Human Evolution 76 (2014) 63e76
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Human calcanei from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain) n Pablos a, b, c, *, Ignacio Martínez b, d, Carlos Lorenzo e, f, b, Nohemi Sala b, Adria llez b, d, Juan Luis Arsuaga b, g Ana Gracia-Te a n Humana (LEH), Departamento de Ciencias Histo ricas y Geografía, Universidad de Burgos, Edificio IþDþi, Laboratorio de Evolucio ~ uelos s/n, 09001 Burgos, Spain Plaza Misael Ban b n sobre Evolucio n y Comportamiento Humanos, c/Monforte de Lemos, 5, 28029 Madrid, Spain Centro Mixto UCM-ISCIII de Investigacio c n sobre la Evolucio n Humana (CENIEH), Paseo Sierra de Atapuerca s/n, 09002 Burgos, Spain Centro Nacional de Investigacio d , 28871 Alcala de Henares, Madrid, Spain Area de Paleontología, Departamento de Geología, Geografía y Medio Ambiente, Universidad de Alcala e Area de Prehistoria, Universitat Rovira i Virgili, Avinguda de Catalunya 35, 43002 Tarragona, Spain f de Paleoecologia Humana i Evolucio Social, c/Marcel.lI Domingo s/n, 43007 Tarragona, Spain IPHES, Institut Catala g Departamento de Paleontología, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
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Article history: Received 3 February 2014 Accepted 7 May 2014 Available online 21 June 2014
The existence of calcanei in the fossil record prior to modern humans and Neandertals is very scarce. This skeletal element is fundamental to understanding the evolution of the morphology of the foot in human evolution. Here we present and metrically and comparatively describe 29 calcaneus remains from the Middle Pleistocene site of Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These calcanei belong to 15 individuals (nine adults, two adolescents and four immature individuals). The metric and morphological differences in the calcanei among Middle and Late Pleistocene hominins tend to be subtle. However, the calcanei from SH are broad and robust with large articular surfaces and most significantly, exhibit a very projected sustentaculum tali. A biomechanical and phylogenetic interpretation is proffered to explain the observed morphology of these calcanei. It has been possible to propose tentative sex assignments for the SH calcanei based on size, using methods similar to those used to establish sex from the talus bones from SH. The estimation of stature based on the calcaneus provides a mean of 175.3 cm for males and 160.6 for females, which is similar to that obtained using other skeletal parts from the site. In sum, the SH calcanei are robust with a proportionally long tubercle and a projected sustentaculum tali, which are traits shared by Neandertals. © 2014 Elsevier Ltd. All rights reserved.
Keywords: Heel Foot Calcaneus Homo heidelbergensis Homo neanderthalensis Stature Western Europe
Introduction The calcaneus has traditionally been considered an important bone in palaeoanthropology due to its role in locomotion and weight transmission and because it serves as a proxy of body size in Middle Pleistocene hominins, Neandertals and modern humans (Arandes and Viladot, 1953; Trinkaus, 1975a, 1983a; Vandermeersch, 1981; Berillon, 1997; Bidmos and Asala, 2005; Raichlen et al., 2011; Pablos et al., 2013a). There are several calcanei in the Pleistocene Homo record, including specimens from Africa and Eurasia that have been previously studied and allow for morphological comparisons (Day and Napier, 1964; Endo and
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[email protected] (A. Pablos). http://dx.doi.org/10.1016/j.jhevol.2014.05.005 0047-2484/© 2014 Elsevier Ltd. All rights reserved.
Kimura, 1970; Trinkaus, 1975a, 1983a; Vandermeersch, 1981; Lu et al., 2011; Pablos et al., 2012a). Studies of the Middle Pleistocene calcanei (84.J.A.23 and 84.J.A.28) and foot from Jinniushan, for example, reveal a degree of robusticity that clearly distinguishes them from modern humans, and it is suggested that the Jinniushan specimens resemble the well-represented Neandertal foot (Lu et al., 2011). In contrast, previous research has indicated that the Neandertal calcanei are similar in overall size and proportion to those of modern humans and are thus indistinguishable in their implied locomotor capabilities (Trinkaus, 1975a, 1983a; Trinkaus and Stewart, 1980; Vandermeersch, 1981). Neandertal calcaneal morphology differs from anatomically modern humans in having relatively large articular surfaces, a long calcaneal body and very projected sustentaculum tali (Trinkaus, 1975a, 1983b; Trinkaus and Stewart, 1980; Trinkaus et al., 2010; Raichlen et al., 2011).
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A. Pablos et al. / Journal of Human Evolution 76 (2014) 63e76
One of the oldest calcanei in the genus Homo found outside of Africa is the Lower Pleistocene fragment ATD6-117 from the TD6 level of Gran Dolina, Spain, which is too incomplete to allow detailed morphological studies to be conducted (Pablos et al., 2012a). Here we present comparative descriptions of 29 new calcaneus remains recovered from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain). These fossils exhibit an exceptional state of preservation. Due to the paucity of human calcanei available in the Homo fossil record prior to Neandertals, the sample from Sima de los Huesos (SH) is very important for the characterization of the morphology and evolution of the calcaneus during this period. Important information can be extracted from the SH calcanei that is relevant to understanding the evolution of the Neandertal foot, due to the evolutionary and morphological relationship between Neandertals and the SH sample (Arsuaga et al., 1993, 1997a; Carretero et al., 1997; Martínez mez-Olivencia et al., 2010; Martino n-Torres and Arsuaga, 1997; Go et al., 2013; Pablos et al., 2013b). Objectives Our main objective is to morphologically and metrically describe the important sample of calcanei from SH in the context of the evolution of the genus Homo. The observed morphology will be discussed from a biomechanical and phylogenetic point of view. We update the inventory of the calcanei from SH and provide estimates of stature and a tentative sexual assignment of the SH hominins based on the size of the calcaneus. Some associations between the individual calcanei from SH are proposed based on their morphology, dimensions, and state of development. Finally, we offer a comparative study of other known calcaneus specimens from the Middle Pleistocene (i.e., Jinniushan). Material and methods The Sima de los Huesos (SH) site The SH site is located deep inside the Cueva Mayor karstic complex of the Sierra de Atapuerca (Burgos, Spain) (Arsuaga et al., 1997b). The Sima de los Huesos has yielded more than 6500 human fossils (Martínez et al., 2013) belonging to at least 28 individuals of different ages at death (Bermúdez de Castro et al., 2004). Morphologically, these fossils are believed to represent an ancestral European population that evolved into the Neandertals (Arsuaga et al., 1991; Martínez and Arsuaga, 1997). Despite the morphological similarities between SH and Neandertals, the mitochondrial DNA was recently postulated as being more similar to the Upper Pleistocene Denisovan population than to the Neandertals (Meyer et al., 2014). The human fossils from SH were directly dated by a combined Uranium (U-) series and electron spin resonance (ESR) to 300 ka (thousands of years ago) by Bischoff et al. (1997). An age >300 ka seems very likely considering the macro and micromammal associations as well as the morphology of the human fossils themselves, which display some incipient Neandertal traits (García et al., 1997; Martínez and Arsuaga, 1997; Arsuaga et al., s and García, 2007). Luminescence and 1997a; Cuenca-Besco paleomagnetic dating suggest a minimum age for the SH hominins of 430 ka (Arnold et al., 2014). This date is in broad agreement with the evidence provided for the ancient mitochondrial DNA for bears (Dabney et al., 2013) and humans (Meyer et al., 2014). Inventory and description of SH calcanei Similar to other anatomical areas in the site, the calcaneus fossils from the SH site are characterized by their exceptional
preservation. All of the remains studied here are listed and described in Table 1 and depicted in Figs. 1 and 2. A Nikon SMZ800 stereoscopic zoom microscope was used to study surface modification on all bone remains. For the quantification of the calcaneus sample, the number of remains (NR), the minimum number of elements (MNE), the minimum number of individuals (MNI) and the relative abundance of the sample were calculated. The age at death for the SH calcanei has been estimated based on the developmental patterns of modern humans (Scheuer and Black, 2000; Cardoso and Severino, 2010). These specimens are classified as either adult (approximately >17 years old), adolescent (between 11 and 17 years old that have a partially fused posterior tubercle) or immature (17 years old), Ado ¼ Adolescent (calcaneal tuber partially fused; 11e17 years old), I ¼ Immature (
