Three-dimensional morphometrics of thoracic vertebrae in Neandertals and the fossil evidence from El Sidrón (Asturias, Northern Spain)

摘要

Well preserved thoracic vertebrae of Neandertals are rare. However, such fossils are im portant as t heirthree-dimensio nal (3D) spatial con ¿ guration can contr ibute to the under standing of the size and shapeof the thoracic spine and the entire thorax. This is be cause the verteb ral body and t ransverse processesprovid e the articulati on and attachme nt si tes for the ribs . Dorsal ori entation of the transverse processesrelative to the vertebral body also rotates the attache d ribs in a way that could affe ct thorax wi dth.Previous research indicates pos sible evide nce for greater dorsal orien tation of the transverse processesand small vertebral body heig hts in Neandertals, but their 3D verteb ral str ucture has not yet be enaddressed. Here we present 15 new vertebral remains from the El Si dr on Neandertals (Ast urias, NorthernSpain ) and used 3D geometric morph ometri cs to address the above issues by comp aring two par ticularlywell preserved El Sidr on remains (SD-1619, SD-16 41) with thoracic vertebrae from ot her Neandertals anda sa mple of anatomically mod ern human s. Centroid size s of El Si dron vertebrae are withi n the humanrange. Neandertals have larger T1 and probably also T2. The El Sidron vertebrae are similar in 3D shap e tothose of other Neandertals, wh ich differ from Homo sapien s par ticularly in central-lower regions (T6e T10) of the thoracic spine. Differences in clude more dorsal ly and cranially oriented t ransverse pro-cesse s, less cau dally ori ented spino us processes, and vertebral bodies that are anteroposter iorly andcraniocaudally short. The results ¿ t wit h current reconstruc tions of Neandertal t horax morphology