engleski

An infant vertebral column of Homo naledi

Homo naledi is represented by abundant remains from Rising Star Cave in South Africa, dating to 236–335 kya. The fragmentary and commingled nature of most specimens hinders understanding of this species’ biology, especially growth and development. Here we report unpublished immature vertebral remains from the 2013 excavations of the Dinaledi Chamber, and attempt to reject the hypothesis that these remains represent a single individual, using provenience, developmental, and osteometric data. The immature vertebral specimens include ~60 fragments comprising mostly neural arches and pedicles, and represent all vertebral regions. Specific vertebral levels cannot be assigned to all fragments ; however, these remains represent minimally three cervical, twelve thoracic, five lumbar, and one sacral elements, indicating a minimum of one individual. Sufficiently preserved laminae are all fused, while neurocentral junctions of two cervical pedicles are unfused, consistent with an age of 1–3 years when compared with modern humans. Because of this developmental consistency, close spatial association, and lack of clearly duplicated elements, we cannot reject the hypothesis that these vertebrae come from a single individual. Immature lamina heights are at the low end of variation for modern humans aged 1–3 years. Thoracic lamina heights average ~43% the size of adult H. naledi from Dinaledi, while lumbar laminae are ~52% the size of the Lesedi "Neo" adult’s measurements. Articular facet dimensions are ~50% the size of adult H. naledi. New developmental datasets and analytical approaches are needed to uncover the full implications for H. naledi growth and development.

H. naledi ; immature remains ; vertebrae

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