A glimpse into the evolution of the ophidian brain

SCANFERLA, AGUSTÍN

The Origin and Early Evolution of Snakes

Cambridge University Press

Año: 2022; p. 1 - 19

The origin and evolution of snakes has long been the focus of scientificenquiry, mostly addressed through skeletal transformations associated withlimblessness and the feeding system. Little research has focused on soft-tissueorgans such as the brain, which has been studied largely based oncytoarchitecture. Here I report data from dissections and 3D reconstructions ofthe endocasts of diverse species, including the Cretaceous stem snake Dinilysia patagonica in order to providea comparative evolutionary framework for the snake brain. Snakesrepresent a special case among reptiles because the braincase almost entirelyencloses the whole brain, thusendocasts provide a realistic representation of brain size and shape. Diversityof brain gross anatomy among snakes is remarkable, encompassing two major cerebrotypesoccurring in surface-dwelling and burrowing species. Therepeated acquisition of the burrowing cerebrotype in different and phylogeneticallydistant snake clades suggests that brain gross anatomy is surprisingly evolutionarylabile in snakes. Brain gross anatomy and otherfeatures such as body size and the absence of any unequivocal osteologicalfeature related to burrowing is interpreted as evidence that D. patagonicawas a surface-dwelling form, and that at least some of the early history ofsnakes occurred above ground.@font-face{font-family:"ＭＳ 明朝";mso-font-charset:78;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:1 134676480 16 0 131072 0;}@font-face{font-family:"ＭＳ 明朝";mso-font-charset:78;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:1 134676480 16 0 131072 0;}@font-face{font-family:Cambria;panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1073743103 0 0 415 0;}@font-face{font-family:"MS Mincho";mso-font-alt:"ＭＳ 明朝";mso-font-charset:128;mso-generic-font-family:modern;mso-font-pitch:fixed;mso-font-signature:-536870145 1791491579 18 0 131231 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Cambria;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Cambria;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES-AR;mso-fareast-language:EN-US;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-family:Cambria;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"ＭＳ 明朝";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-fareast-language:JA;}div.WordSection1{page:WordSection1;}