Microsphenodon

{{Short description|Extinct rhynchocephalian reptile}} {{Automatic taxobox | fossil_range = Late Triassic | image = Microsphenodon.PNG | image_caption = Paratype specimen | taxon = Microsphenodon | authority = Chambi-Trowell ''et al.'', 2021 | type_species = †'''''Microsphenodon bonapartei''''' | type_species_authority = Chambi-Trowell ''et al.'', 2021 }}

'''''Microsphenodon''''' is an extinct genus of sphenodontian from the Late Triassic of Brazil. The type species is '''''Microsphenodon bonapartei'''''.<ref name=":0">{{Cite journal|last1=Chambi-Trowell|first1=Sofia A. V.|last2=Martinelli|first2=Agustín G.|last3=Whiteside|first3=David I.|last4=Vivar|first4=Paulo R. Romo de|last5=Soares|first5=Marina Bento|last6=Schultz|first6=Cesar L.|last7=Gill|first7=Pamela G.|last8=Benton|first8=Michael J.|last9=Rayfield|first9=Emily J.|date=2021-06-03|title=The diversity of Triassic South American sphenodontians: a new basal form, clevosaurs, and a revision of rhynchocephalian phylogeny|journal=Journal of Systematic Palaeontology|volume=19|issue=11|pages=787–820|doi=10.1080/14772019.2021.1976292|s2cid=240487298|issn=1477-2019|doi-access=free|bibcode=2021JSPal..19..787C |hdl=1983/af14affc-a26e-426b-83ca-e1833e355882|hdl-access=free}}</ref> It is a small sphenodontian with a skull roughly 20 mm long, and represents a unique mosaic of characteristics shared by both early diverging sphenodontians (such as a broad parietal table, multiple tooth rows on the palate, and an elongated premaxillary process) and eusphenodontian characters (full acrodont dentition, high coronoid process and anterior successional teeth, including the earliest known caniniforms in a lepidosaur). Specimens of this taxon were first identified by Bonaparte and Sues (2006) <ref>{{Cite journal |last1=Bonaparte |first1=Jose F. |last2=Sues |first2=Hans-Dieter |date=2006 |title=A new species of Clevosaurus (Lepidosauria: Rhynchocephalia) from the Upper Triassic of Rio Grande do sul, Brazil |journal=Palaeontology |volume=49 |issue=4 |pages=917–923 |doi=10.1111/j.1475-4983.2006.00568.x |s2cid=26483165 |issn=0031-0239|doi-access=free |bibcode=2006Palgy..49..917B }}</ref> but were misidentified as juvenile ''Clevosaurus brasiliensis'', characteristics such as differences in the configuration of the teeth on the palate, and the unique form of tooth implantation seen in ''C. brasiliensis'', helped differentiate these two co-occurring sphenodontian taxa.<ref name=":0" />

Cladogram following Chambi-Trowell ''et al.'', 2021<ref name=":0" />

{{clade |label1=Rhynchocephalia |1={{clade |1=''Gephyrosaurus'' |2={{clade |1=''Penegephyrosaurus'' |label2=Sphenodontia |2={{clade |1=''Paleollanosaurus'' |2=Vellberg rhynchocephalian |3=''Diphydontosaurus'' |label4=Acrosphenodontia |4={{clade |1=''Planocephalosaurus'' |2={{clade |1=''Godavarisaurus'' |2={{clade |1=''Polysphenodon'' |2={{clade |1='''''Microsphenodon''''' |2=Eusphenodontia }}}}}}}}}}}}}}}}

== References == {{Reflist}}

Category:Rhynchocephalia Category:Prehistoric reptile genera Category:Fossil taxa described in 2021