Transitional Fossil Molar Tooth From Morganucodont Mammaliaform Hallautherium Found From Norian/Rhaetian Triassic Poland

Mammal-like tooth from the Upper Triassic of Poland

Authors:

Świło et al

Abstract:

Recent Triassic discoveries have extended the record of near-mammals (Mammaliaformes) back to the Norian, about 215 Ma, and reveal a significant diversity of Late Triassic (Norian-Rhaetian) forms. We now add to this Late Triassic diversity a nearly complete double-rooted right lower molariform tooth (ZPAL V.33/734) from the Polish Upper Triassic that is significant because it comes from uppermost Norian–lower Rhaetian rocks and is the first discovery of a mammal-like tooth in the Mesozoic of Poland. The described tooth shows transitional dental morphology between advanced cynodonts and mammaliaforms and it appears to represent a basal mammaliaform (genus Hallautherium), probably belonging to Morganucodonta.

Megazostrodon chenali & Rosierodon anceps: new Rhaetian Triassic Morganucodont Mammals From France

Earliest known European mammals: a review of the Morganucodonta from Saint-Nicolas-de-Port (Upper Triassic, France)

Authors:

Debuysschere et al

Abstract:

The Rhaetian locality of Saint-Nicolas-de-Port (France) has yielded the most abundant and diverse mammalian assemblage known from the Late Triassic. Most of the material remains undescribed. We review here the morganucodonts from Saint-Nicolas-de-Port. We identify the upper and lower molariforms of the genus Brachyzostrodon. We also identify in the site Morganucodon peyeri, previously known from the Late Triassic of Hallau (Switzerland), as well as the genera Paceyodon and Paikasigudodon. The description of the new species Megazostrodon chenali sp. nov. extends the stratigraphical and geographical range of the genus, previously known from the Early Jurassic of southern Africa. Finally, another new morganucodont, Rosierodon anceps gen. et sp. nov., is described. The Morganucodonta is recognized as the most diverse order of Late Triassic mammals. Current fossil data suggest that Europe was the centre of initial diversification of morganucodonts at the end of the Triassic, and that morganucodonts were not much affected by the extinction event at the Triassic/Jurassic transition.