- Tytuł:
- New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars
- Autorzy:
-
Pascual, R
Goin, F.J.
Balarino, L.
Udrizar Sauthier, D.E. - Powiązania:
- https://bibliotekanauki.pl/articles/21782.pdf
- Data publikacji:
- 2002
- Wydawca:
- Polska Akademia Nauk. Instytut Paleobiologii PAN
- Tematy:
-
Monotremata
molar
Paleocene
Gondwana
triangulate molar
Monotrematum sudamericanum
monotreme
molar structure
evolution
Patagonia
paleontology - Opis:
- We describe an additional fragmentary upper molar and the first lower molar known of Monotrematum sudamericanum, the oldest Cenozoic (Paleocene) monotreme. Comparisons suggest that the monotreme evolution passed through a stage in which their molars were “pseudo−triangulate”, without a true trigonid, and that the monotreme pseudo−triangulate pattern did not arise through rotation of the primary molar cusps. Monotreme lower molars lack a talonid, and consequently there is no basin with facets produced by the wearing action of a “protocone”; a cristid obliqua connecting the “talonid“ to the “trigonid” is also absent. We hypothesize that acquisition of the molar pattern seen in Steropodon galmani (Early Cretaceous, Albian) followed a process similar to that already postulated for docodonts (Docodon in Laurasia, Reigitherium in the South American sector of Gondwana) and, probably, in the gondwanathere Ferugliotherium.
- Źródło:
-
Acta Palaeontologica Polonica; 2002, 47, 3
0567-7920 - Pojawia się w:
- Acta Palaeontologica Polonica
- Dostawca treści:
- Biblioteka Nauki
Artykuł