Post-Jurassic mammal-like reptile from the Palaeocene

Area of Science:

• Paleontology
• Zoology
• Vertebrate Evolution

Background:

• Therapsida, mammal-like reptiles, are crucial for understanding mammal origins from synapsids.
• Previously, therapsids were thought to have gone extinct by the Middle Jurassic.

Purpose of the Study:

• To report the discovery of a therapsid fossil significantly younger than previously known specimens.
• To extend the known stratigraphic and temporal range of the order Therapsida.

Main Methods:

• Excavation and identification of fossilized therapsid remains (dentary and isolated teeth).
• Stratigraphic analysis of fossil-bearing beds within the Paskapoo Formation, Alberta, Canada.
• Dating of associated mammalian fauna to determine the age of the therapsid discovery.

Main Results:

• Discovery of a therapsid fossil from the late Paleocene, approximately 100 million years after the previously accepted extinction date.
• The fossils represent the first Cenozoic record of therapsids.
• The new taxon extends the stratigraphic range of therapsids significantly.

Conclusions:

• Therapsids persisted much later into the Cenozoic than previously understood.
• This discovery necessitates a revision of the extinction timeline for therapsids.
• The find highlights the potential for uncovering new fossil evidence that reshapes our understanding of vertebrate evolution.