Schowalteria
| Schowalteria Temporal range:LateCretaceous
| |
|---|---|
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Placentalia(?) |
| Order: | †Taeniodonta |
| Genus: | †Schowalteria Fox & Naylor, 2003[1] |
| Type species | |
| †Schowalteria clemensi Fox & Naylor, 2003[1]
| |
Schowalteriais a genus of extinct mammal from theCretaceousofCanada.It is the earliest known representative of orderTaeniodonta,a specialised lineage ofeutherianmammals otherwise found inPaleoceneandEocenedeposits. It is notable for its large size, being among the largest ofMesozoicmammals,[1][2]as well as its speciation towards herbivory, which in some respects exceeds that of its later relatives.[3]
Description[edit]
Currently,Schowalteriais considered to be amonotypicgenus, with only one species,S. clemensi.It is known from only one skull.Schowalteriashares some speciations with later taeniodonts, namely similarcanineandincisormorphology, similar facial proportions andzygomatic archconstruction, though unlike them itsocclusal surfaceis worn nearly completely flat, and the wear facet completely encompasses the paracone and metacone, leaving only an outline of the buccal side of the bases of these cusps remaining, differing radically from the more "normal" teeth wearing patterns of other taenidonts.[3]Based on the skull's proportions, it was initially comparared in size toDidelphodon vorax,making it one of the largest mammals of the Mesozoic at the time of its discovery,[1]and posterior measurements have cited larger sizes;Anne Weilposits a range similar (though not confirmed) toRepenomamus giganticus,[2]while posterior analysis showcase it to be as large as latter taeniodonts.[4]
Range[edit]
Schowalteriaoccurs in theTrochudeposits ofAlberta,dating to theMaastrichtianstage of theCretaceousperiod. This site is part of the largerEdmonton Group,that probably represented a warm,temperateenvironment. Mammal remains are very common in this site, such as variousmetatheriansandmultituberculates.
Classification[edit]
Schowalteriais a taeniodont eutherian. It was initially recovered as a fairly derived member related tostylinodonts,[1]but more recent examinations show it to be a more basal species within the group, less related to them thanOnychodectes.[3]
Phylogeny[edit]
| Placentalia |
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Biology[edit]
In spite of being a basal taeniodont,Schowalteriais fairly derived, perhaps more so than later taenidonts. It shares with them similar speciations towards herbivory and possibly fossoriality,[1]but unlike them it also possesses evidence of transverse (ungulate-like)mastication,making it even more specialised towards processing vegetation.[3]
As one of the largest mammals of its time period and a rather specialised herbivore,Schowalteriawas a rather spectacular species among thedinosaur-rich faunas of the end of the Cretaceous.
References[edit]
- ^abcdefFox, Richard C.; Naylor, Bruce G. (2003). "A Late Cretaceous taeniodont (Eutheria, Mammalia) from Alberta, Canada".Neues Jahrbuch für Geologie und Paläontologie.229(3): 393–420.doi:10.1127/njgpa/229/2003/393.
- ^abWeil, Anne (2005). "Living large in the Cretaceous".Nature.433(7022): 116–117.Bibcode:2005Natur.433..116W.doi:10.1038/433116b.PMID15650725.S2CID52869101.
- ^abcdWilliamson, T. E.; Brusatte, S. L. (2013). Viriot, Laurent (ed.)."New Specimens of the Rare TaeniodontWortmania(Mammalia: Eutheria) from the San Juan Basin of New Mexico and Comments on the Phylogeny and Functional Morphology of "Archaic" Mammals ".PLOS ONE.8(9): e75886.Bibcode:2013PLoSO...875886W.doi:10.1371/journal.pone.0075886.PMC3786969.PMID24098738.
- ^Rook, Deborah L.; Paul Hunter, John (2011). "Phylogeny of the Taeniodonta: Evidence from Dental Characters and Stratigraphy".Journal of Vertebrate Paleontology.31(2): 422–427.Bibcode:2011JVPal..31..422R.doi:10.1080/02724634.2011.550364.S2CID83801989.
