2023-11-07 ノースカロライナ州立大学(NCState)
◆この恐竜は地下で過ごす生活に適しており、地下での食物探しに優れた嗅覚を活用していた可能性が高い。一方、聴覚能力は制約があるため、地下で過ごすことでT. neglectusは生存を図っていたと考えられる。この研究は、恐竜の感覚能力と生活様式の関連性を示す初の研究である。
<関連情報>
- https://news.ncsu.edu/2023/11/dig-this-neglected-dinosaur-had-super-senses/
- https://www.nature.com/articles/s41598-023-45658-3
白亜紀後期のテスケロサウルス・ネグレクトス(新石器時代:テスケロサウルス科)の神経解剖学的特徴から、恐竜界における新たな生態学的特殊性が明らかになった。 Neuroanatomy of the late Cretaceous Thescelosaurus neglectus (Neornithischia: Thescelosauridae) reveals novel ecological specialisations within Dinosauria
David J. Button & Lindsay E. Zanno
Scientific Reports Published:06 November 2023
DOI:https://doi.org/10.1038/s41598-023-45658-3
Abstract
Ornithischian dinosaurs exhibited a diversity of ecologies, locomotory modes, and social structures, making them an ideal clade in which to study the evolution of neuroanatomy and behaviour. Here, we present a 3D digital reconstruction of the endocranial spaces of the latest Cretaceous neornithischian Thescelosaurus neglectus, in order to interpret the neuroanatomy and paleobiology of one of the last surviving non-avian dinosaurs. Results demonstrate that the brain of Thescelosaurus was relatively small compared to most other neornithischians, instead suggesting cognitive capabilities within the range of extant reptiles. Other traits include a narrow hearing range, with limited ability to distinguish high frequencies, paired with unusually well-developed olfactory lobes and anterior semicircular canals, indicating acute olfaction and vestibular sensitivity. This character combination, in conjunction with features of the postcranial anatomy, is consistent with specializations for burrowing behaviours in the clade, as evidenced by trace and skeletal fossil evidence in earlier-diverging thescelosaurids, although whether they reflect ecological adaptations or phylogenetic inheritance in T. neglectus itself is unclear. Nonetheless, our results provide the first evidence of neurological specializations to burrowing identified within Ornithischia, and non-avian dinosaurs more generally, expanding the range of ecological adaptations recognized within this major clade.
