Re: [dinosaur] Hypselohaptodus, new sphenacodontian synapsid from Lower Permian of England
Nick Pharris <[email protected]>
| Newsgroups | gmane.science.dinosaurs.general |
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| Message-ID | <[email protected]> |
That did throw me for a bit of a loop. “Phenacodontians” would be synapsids, too, of course—though a close relative of Phenacodus from the Lower Permian would be quite a find! —Nick P. Sent from my iPhone > On Aug 15, 2019, at 8:32 AM, Ben Creisler <[email protected]> wrote: > > Ooops1 > > Correction to subject line... > >> On Thu, Aug 15, 2019 at 8:31 AM Ben Creisler <[email protected]> wrote: >> >> Ben Creisler >> [email protected] >> >> >> A new paper: >> >> Hypselohaptodus gen. nov. >> Hypselohaptodus grandis (Paton, 1974) >> Haptodus grandis Paton, 1974 >> >> >> Frederik Spindler (2019) >> Re-evaluation of an early sphenacodontian synapsid from the Lower Permian of England. >> Earth and Environmental Science Transactions of The Royal Society of Edinburgh (advance online publication) >> DOI: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1017_S175569101900015X&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=YOHbYG8Ih3X_ipaHdzachTMN7IRcDPpRTYXTbtj4Ogo&s=wJNo4X-6H_jU--w_rBdvoRm_wR_Ok14vM-mpfQaQbFY&e= >> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.cambridge.org_core_journals_earth-2Dand-2Denvironmental-2Dscience-2Dtransactions-2Dof-2Droyal-2Dsociety-2Dof-2Dedinburgh_article_reevaluation-2Dof-2Dan-2Dearly-2Dsphenacodontian-2Dsynapsid-2Dfrom-2Dthe-2Dlower-2Dpermian-2Dof-2Dengland_CEF6308931532407FCF5D6E956815C1C&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=YOHbYG8Ih3X_ipaHdzachTMN7IRcDPpRTYXTbtj4Ogo&s=5Ps2VrkND2PxmM27Q0G7HG-l1XPVIeYgjR_TUWWpzJA&e= >> >> >> >> The holotypic isolated maxilla of the early sphenacodontian Haptodus grandis from the Cisuralian of England is revisited. A unique character combination includes haptodontine-grade traits like less specialised teeth and a high number of precanines, but at the same time a shortened lacrimal that is separated from the naris, which is strongly diagnostic of Sphenacodontoidea. As the specimen cannot be assigned to any known taxon, the new taxon Hypselohaptodus grandis gen. nov. is proposed. Comparison with other sphenacodontians reveals a mosaic distribution of maxillary features, most significantly regarding the precanine region. Preliminary character histories preclude Hypselohaptodus from Sphenacodontidae, but suggest a haptodontine-grade or basal therapsid position. The latter hypothesis is substantiated by an ecological model of episodic wet phases in an overall trend of aridification throughout the Permian, to explain the rareness of non-sphenacodontid sphenacodontians in the fossil record. Also from the early Permian of England, an isolated dentary has previously been assigned to Ophiacodon, but can be shown to be either a sphenacodontian, possibly affiliated with Hypselohaptodus, or a robust, Stereorhachis-like ophiacodontid. The absence of Ophiacodon in the intramontaneous Permian basis of Europe is explained by a narrow environmental tolerance range requiring limnic connection with lowland basins. >> >> >> Virus-free. www.avg.com