[dinosaur] Hypselohaptodus, new phenacodontian synapsid from Lower Permian of England

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=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=dmaIEm-7EKT3GtJBIkRK-8M4DG2BryLQuKGykrz8-B8&s=YaUEpJZXrLSqSQi8Q8CR3DzQ7rhwZThyJ30YPWI1444&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=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=dmaIEm-7EKT3GtJBIkRK-8M4DG2BryLQuKGykrz8-B8&s=BbjvddIiNCu9dADmq2Dy4CBqJD9la6OK9jxpGmMN3xU&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.


<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.avg.com_email-2Dsignature-3Futm-5Fmedium-3Demail-26utm-5Fsource-3Dlink-26utm-5Fcampaign-3Dsig-2Demail-26utm-5Fcontent-3Dwebmail&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=dmaIEm-7EKT3GtJBIkRK-8M4DG2BryLQuKGykrz8-B8&s=FWmO5rE5nBfRFer1NT1IKDC4Cwcc8HnKbrT-kX-DJIw&e= >
Virus-free.
www.avg.com
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.avg.com_email-2Dsignature-3Futm-5Fmedium-3Demail-26utm-5Fsource-3Dlink-26utm-5Fcampaign-3Dsig-2Demail-26utm-5Fcontent-3Dwebmail&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=dmaIEm-7EKT3GtJBIkRK-8M4DG2BryLQuKGykrz8-B8&s=FWmO5rE5nBfRFer1NT1IKDC4Cwcc8HnKbrT-kX-DJIw&e= >
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>