[dinosaur] Tetraceratops (Sphenacodontia) skull lacks therapsid traits (free pdf)
Ben Creisler <[email protected]> Fri, 10 Jan 2020 09:36:53 -0800
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--000000000000228faa059bcc9327 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: Quoted-printable Ben [email protected]=0D=0A=0D=0AA new paper with free pdf:= =0D=0A=0D=0AFree pdf:=0D=0A=0D=0AFrederik Spindler (2020)=0D=0AThe skull of= Tetraceratops insignis (Synapsida, Sphenacodontia).=0D=0APalaeovertebrata = 43 (1)-e1.=0D=0Adoi: 10.18563/pv.43.1.e1=0D=0Ahttps://urldefense.proofpoint= .com/v2/url?u=3Dhttps-3A__www.palaeovertebrata.com_Articles_view_377&d=3DDw= IBaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9= MyZgecRCKHn5g4z1CYJgFW9SI&m=3DVvr2xV2fMcTyNkKfs2bWXt8tqwtso3iYWGRpqLWefMo&s= =3DHjXqeOstURyP_nD_yR0Ds7U6Rgjgz3ljEXjyBO6bpOU&e=3D =0D=0A=0D=0A=0D=0A=0D= =0ATetraceratops insignis is known from a single, crushed skull from the Lo= wer=0D=0APermian of Texas. Its unique proportions and osteological details = gained=0D=0Acentral meaning in the question of the origins of Therapsida si= nce this=0D=0Aearly synapsid has been determined as the oldest and less der= ived=0D=0Atherapsid. Apart from Tetraceratops, the 'mammal-like' Therapsida= and their=0D=0Asister, the pelycosaur-grade Sphenacodontidae, are separate= d by one of the=0D=0Alongest ghost lineages in tetrapod fossil record. Howe= ver, the minor,=0D=0Athough well justified critique faced insistent publica= tion regarding the=0D=0Atherapsid hypothesis. A careful re-evaluation of th= e holotypic skull=0D=0Areveals that therapsid traits cannot be supported, i= ncluding a rejection of=0D=0Athe formerly supposed adductor shelf in the te= mporal fenestra. Increased=0D=0Aunderstanding of 'pelycosaur' character var= iation underlines a=0D=0Ahaptodontine-grade or, less likely, sphenacodontid= position for=0D=0ATetraceratops.=0D=0A=0D=0A=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =0D=0A= --000000000000228faa059bcc9327 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: Quoted-printable <div dir=3D"ltr"><br><div>Ben Creisler</div><div><a href=3D"mailto:bcreisle= [email protected]">[email protected]</a></div><div><br></div><div>A new paper w= ith free pdf:</div><div><br></div><div>Free pdf:</div><div><br>Frederik Spi= ndler (2020)<br>The skull of Tetraceratops insignis (Synapsida, Sphenacodon= tia).<br>Palaeovertebrata 43 (1)-e1. <br>doi: 10.18563/pv.43.1.e1<br><a hre= f=3D"https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.palaeoverte= brata.com_Articles_view_377&d=3DDwMFaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5B= OUHhpN0H8p7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&= ;m=3DVvr2xV2fMcTyNkKfs2bWXt8tqwtso3iYWGRpqLWefMo&s=3DHjXqeOstURyP_nD_yR= 0Ds7U6Rgjgz3ljEXjyBO6bpOU&e=3D">https://www.palaeovertebrata.com/Articl= es/view/377</a></div><div><br></div><div><br><br>Tetraceratops insignis is = known from a single, crushed skull from the Lower Permian of Texas. Its uni= que proportions and osteological details gained central meaning in the ques= tion of the origins of Therapsida since this early synapsid has been determ= ined as the oldest and less derived therapsid. Apart from Tetraceratops, th= e 'mammal-like' Therapsida and their sister, the pelycosaur-grade S= phenacodontidae, are separated by one of the longest ghost lineages in tetr= apod fossil record. However, the minor, though well justified critique face= d insistent publication regarding the therapsid hypothesis. A careful re-ev= aluation of the holotypic skull reveals that therapsid traits cannot be sup= ported, including a rejection of the formerly supposed adductor shelf in th= e temporal fenestra. Increased understanding of 'pelycosaur' charac= ter variation underlines a haptodontine-grade or, less likely, sphenacodont= id position for Tetraceratops. <br><br>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br></= div></div>=0A= --000000000000228faa059bcc9327--