The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash

Snakes are an extremely modified and long-lived clade of lizards that have either lost or highly altered many of the synapomorphies that would clearly link them to their closest sister-group among squamates. We focus here on one postcranial morphological complex, the intercentrum system which in mos...

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Autores principales: Garberoglio, F.F., Gómez, R.O., Simões, T.R., Caldwell, M.W., Apesteguía, S.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_20452322_v9_n1_p_Garberoglio
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spelling todo:paper_20452322_v9_n1_p_Garberoglio2023-10-03T16:38:32Z The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash Garberoglio, F.F. Gómez, R.O. Simões, T.R. Caldwell, M.W. Apesteguía, S. anatomy article Cretaceous female fossil morphology nonhuman skeleton snake Snakes are an extremely modified and long-lived clade of lizards that have either lost or highly altered many of the synapomorphies that would clearly link them to their closest sister-group among squamates. We focus here on one postcranial morphological complex, the intercentrum system which in most non-ophidian squamates is limited to the cervical and caudal regions. The Cervical Intercentrum System (CeIS) is composed of a single intercentral element that sometimes articulates with a ventral projection (hypapophyses) of the centrum; the Caudal Intercentrum System (CaIS) is formed by an intercentral element, the haemal arch/chevron bone, and paired ventral projections of the centrum, the haemapophyses. In modern snakes, the intercentrum element of the CeIS is considered lost or fused to the hypaphophysis, and the chevron bone in CaIS is considered lost. Here, we describe new specimens of the early snake Dinilysia patagonica, and reinterpret previously known specimens of Dinilysia and Najash rionegrina, that do not show the expected snake morphology. The anatomy of these fossil taxa unambiguously shows that free cervical and caudal intercentra attached to distinct downgrowths (hypapophyses and haemapophyses) of the centra, are present in basal fossil snakes, and agrees with the proposed loss of post atlas-axis intercentra in later evolving snakes. © 2019, The Author(s). JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_20452322_v9_n1_p_Garberoglio
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic anatomy
article
Cretaceous
female
fossil
morphology
nonhuman
skeleton
snake
spellingShingle anatomy
article
Cretaceous
female
fossil
morphology
nonhuman
skeleton
snake
Garberoglio, F.F.
Gómez, R.O.
Simões, T.R.
Caldwell, M.W.
Apesteguía, S.
The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
topic_facet anatomy
article
Cretaceous
female
fossil
morphology
nonhuman
skeleton
snake
description Snakes are an extremely modified and long-lived clade of lizards that have either lost or highly altered many of the synapomorphies that would clearly link them to their closest sister-group among squamates. We focus here on one postcranial morphological complex, the intercentrum system which in most non-ophidian squamates is limited to the cervical and caudal regions. The Cervical Intercentrum System (CeIS) is composed of a single intercentral element that sometimes articulates with a ventral projection (hypapophyses) of the centrum; the Caudal Intercentrum System (CaIS) is formed by an intercentral element, the haemal arch/chevron bone, and paired ventral projections of the centrum, the haemapophyses. In modern snakes, the intercentrum element of the CeIS is considered lost or fused to the hypaphophysis, and the chevron bone in CaIS is considered lost. Here, we describe new specimens of the early snake Dinilysia patagonica, and reinterpret previously known specimens of Dinilysia and Najash rionegrina, that do not show the expected snake morphology. The anatomy of these fossil taxa unambiguously shows that free cervical and caudal intercentra attached to distinct downgrowths (hypapophyses and haemapophyses) of the centra, are present in basal fossil snakes, and agrees with the proposed loss of post atlas-axis intercentra in later evolving snakes. © 2019, The Author(s).
format JOUR
author Garberoglio, F.F.
Gómez, R.O.
Simões, T.R.
Caldwell, M.W.
Apesteguía, S.
author_facet Garberoglio, F.F.
Gómez, R.O.
Simões, T.R.
Caldwell, M.W.
Apesteguía, S.
author_sort Garberoglio, F.F.
title The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
title_short The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
title_full The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
title_fullStr The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
title_full_unstemmed The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
title_sort evolution of the axial skeleton intercentrum system in snakes revealed by new data from the cretaceous snakes dinilysia and najash
url http://hdl.handle.net/20.500.12110/paper_20452322_v9_n1_p_Garberoglio
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