INTRAPOPULATIONAL BODY-SIZE VARIATION AND CRANIAL CAPACITY VARIATION IN MIDDLE PLEISTOCENE HUMANS - THE SIMA DE LOS HUESOS SAMPLE (SIERRA DE ATAPUERCA, SPAIN)

A sexual dimorphism more marked than in living humans has been claimed for European Middle Pleistocene humans, Neandertals and prehistoric m odern humans. In this paper, body size and cranial capacity variation are studied in the Sima de los Huesos Middle Pleistocene sample. This is the largest sample of non-modern humans found to date from one sing le site, and with all skeletal elements represented. Since the techniq ues available to estimate the degree of sexual dimorphism in small pal aeontological samples are all unsatisfactory, we have used the bootstr aping method to asses the magnitude of the variation in the Sima de lo s Huesos sample compared to modern human intrapopulational variation. We analyze size variation without attempting to sex the specimens a pr iori. Anatomical regions investigated are scapular glenoid fossa; acet abulum; humeral proximal and distal epiphyses; ulnar proximal epiphysi s; radial neck; proximal femur; humeral, femoral, ulnar and tibial sha ft; lumbosacral joint; patella; calcaneum; and talar trochlea. In the Sima de los Huesos sample only the humeral midshaft perimeter shows an unusual high variation (only when it is expressed by the maximum rati o, not by the coefficient of variation). In spite of that the cranial capacity range at Sima de los Huesos almost spans the rest of the Euro pean and African Middle Pleistocene range. The maximum ratio is in the central part of the distribution of modern human samples. Thus, the h ypothesis of a greater sexual dimorphism in Middle Pleistocene populat ions than in modern populations is not supported by either cranial or postcranial evidence from Sima de los Huesos. (C) 1998 Wiley-Liss, Inc .