New morganucodontans from an Early Jurassic fissure filling in Wales (United Kingdom)

摘要: :  Two new genera and species of morganucodontans, Bridetherium dorisae Paceyodon davidi, are recognized as members the Morganucodon-sphenodont fauna preserved in a fissure filling (Pant 4) exposed Pant Quarry, Vale Glamorgan, southern Wales. Both taxa based on isolated molariforms. Mode occlusion upper lower molariforms B. dorisae differs from embrasure shearing pattern Megazostrodon offset characteristic Morganucodon. Lack clear correlation between different patterns morphologies their supports working hypothesis that close function morphology molars therian mammals, for example, was not present morganucodontans. P. davidi is an morganucodontan molariform significantly larger than any yet discovered. Several morganucodontan-like cannot be referred to these taxa. The Welsh morganucodontans added records other sites indicate group achieved considerable taxonomic diversity near global distribution by Early Jurassic.