TY - JOUR
T1 - Neurocranial bones are key to untangling the sea cow evolutionary tree
T2 - osteology of the skull of Sobrarbesiren cardieli (Mammalia: Pan-Sirenia)
AU - Díaz-Berenguer, Ester
AU - Moreno-Azanza, Miguel
AU - Badiola, Ainara
AU - Canudo, José Ignacio
N1 - info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04035%2F2020/PT#
info:eu-repo/grantAgreement/FCT/OE/SFRH%2FBPD%2F113130%2F2015/PT#
Financial support was provided by the Ministerio de Economia y Competitividad (CGL2013-47521-P) and by the Ministerio de Ciencia e Innovacion (CGL201785038-P, Ministerio de Economia y Competitividad/Fondo Europeo de Desarrollo Regional, Union Europea, UE), the Research Groups of the Gobierno Vasco/Eusko Jaurlaritza (IT834-13, IT1004-16 and IT418-19), the Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (PPG17/04 and GIU18/163), the Geoparque de Sobrarbe, the European Regional Development Fund, the Government of Aragon (`DGA' and `Grupos de Referencia' E18_ 17R) .
R. Glasgow edited the English. We thank the anonymous reviewer and the Editor, Dr Maarten Christenhusz, for their comments, which greatly improved our manuscript.
© The Author(s) 2022. Published by Oxford University Press on behalf of The Linnean Society of London. All rights reserved.
PY - 2022/12
Y1 - 2022/12
N2 - The pan-sirenian Bauplan is conservative, probably owing to the constraints of adaptation to an aquatic lifestyle. Gathering morphological data from extinct forms is complex, resulting in poorly resolved phylogenies for stem pan-sirenians. Extant sirenians ossify the falx cerebri and the tentorium cerebelli, membranes of the dura mater of the brain attached to the parietal bone. Nevertheless, these ossifications are not present in some pan-sirenians. The basioccipital bone has received little attention in the literature except for establishing the relative age of individuals. Here, we present new cranial elements and a detailed description of the skull of Sobrarbesiren cardieli, a stem pan-sirenian from the Lutetian of Spain represented by eight individuals; we study its intraspecific variation and palaeoecological implications and explore the evolution of the endocranial structures and the basioccipital bone in pan-sirenians. Six new phylogenetic characters are added to the latest pan-sirenian dataset, resulting in a well-resolved topology where Sobrarbesiren is recovered close to the root, in a clade with Prototherium and Eotheroides aegyptiacum. The basioccipital bone and the ossified endocranial membranes have a phylogenetic signal, and the absence of such endocranial structures represents the plesiomorphic condition for pan-sirenians and is not diagnostic for the family Protosirenidae as previously believed.
AB - The pan-sirenian Bauplan is conservative, probably owing to the constraints of adaptation to an aquatic lifestyle. Gathering morphological data from extinct forms is complex, resulting in poorly resolved phylogenies for stem pan-sirenians. Extant sirenians ossify the falx cerebri and the tentorium cerebelli, membranes of the dura mater of the brain attached to the parietal bone. Nevertheless, these ossifications are not present in some pan-sirenians. The basioccipital bone has received little attention in the literature except for establishing the relative age of individuals. Here, we present new cranial elements and a detailed description of the skull of Sobrarbesiren cardieli, a stem pan-sirenian from the Lutetian of Spain represented by eight individuals; we study its intraspecific variation and palaeoecological implications and explore the evolution of the endocranial structures and the basioccipital bone in pan-sirenians. Six new phylogenetic characters are added to the latest pan-sirenian dataset, resulting in a well-resolved topology where Sobrarbesiren is recovered close to the root, in a clade with Prototherium and Eotheroides aegyptiacum. The basioccipital bone and the ossified endocranial membranes have a phylogenetic signal, and the absence of such endocranial structures represents the plesiomorphic condition for pan-sirenians and is not diagnostic for the family Protosirenidae as previously believed.
KW - basioccipital bone
KW - Eocene
KW - falx cerebri
KW - internal occipital protuberance
KW - marine mammals
KW - palaeoecology
KW - phylogeny
KW - sea cows
KW - Spain
KW - systematics
KW - tentorium osseum
U2 - 10.1093/zoolinnean/zlac021
DO - 10.1093/zoolinnean/zlac021
M3 - Article
SN - 0024-4082
VL - 196
SP - 1671
EP - 1703
JO - Zoological Journal Of The Linnean Society
JF - Zoological Journal Of The Linnean Society
IS - 4
ER -