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Congenital Malformations of the Vertebral Column in Ancient Amphibians
Author(s) -
Witzmann F.,
Rothschild B. M.,
Hampe O.,
Sobral G.,
Gubin Y. M.,
Asbach P.
Publication year - 2014
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/ahe.12050
Subject(s) - vertebral column , tetrapod (structure) , vertebra , anatomy , geology , paleozoic , paleontology , permian , biology , structural basin
Summary Temnospondyls, the largest group of Palaeozoic and Mesozoic amphibians, primitively possess rhachitomous vertebrae with multipartite centra (consisting of one horse‐shoe‐shaped inter‐ and paired pleurocentra). In a group of temnospondyls, the stereospondyls, the intercentra became pronounced and disc‐like, whereas the pleurocentra were reduced. We report the presence of congenital vertebral malformations (hemi, wedge and block vertebrae) in Permian and Triassic temnospondyls, showing that defects of formation and segmentation in the tetrapod vertebral column represent a fundamental failure of somitogenesis that can be followed throughout tetrapod evolution. This is irrespective of the type of affected vertebra, that is, rhachitomous or stereospondylous, and all components of the vertebra can be involved (intercentrum, pleurocentrum and neural arch), either together or independently on their own. This is the oldest known occurrence of wedge vertebra and congenital block vertebra described in fossil tetrapods. The frequency of vertebral congenital malformations in amphibians appears unchanged from the Holocene.