Chimaerasuchidae

From Wikipedia, the free encyclopedia

Chimaerasuchidae
Fossil range: Cretaceous

Simosuchus

Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Subclass:	Diapsida
Infraclass:	Archosauromorpha
(unranked)	Mesoeucrocodylia
Suborder:	Notosuchia
Family:	Chimaerasuchidae

Genus

Chimaerasuchus
Simosuchus

The family Chimaerasuchidae ("Chimera crocodiles") that was erected in 2004 by Carvalho et al. It contained two genera of small (~1 metre long), possibly herbivorous crocodylians from the Cretaceous. Their considered to be potentially herbivorous as both had short-snouted heads with multicusped teeth.

However, the Carvalho et al. (2004) paper phylogeny is not without its faults, the most noticeable is the lack of any neosuchians in the analysis. When neosuchians are included in analyses with these two genera they do not appear as sister taxa (Pol 2003; Candeiro & Martinelli 2006). In fact Chimaerasuchus is the sister taxon to Sphagesaurus. As Sphagesaurus has its own family, Sphagesauridae, which was named earlier than Chimaersasuchidae, then under ICZN rules of priority of names Chimaerasuchidae is a junior synonym of Sphagesauridae.

In a recent contribution, Marinho & Carvalho (2007) did a revision of the Sphagesauridae and noticed that Chimaerasuchus do not have any of the synapomorphies of this family that was originally erected by Kuhn (1968). In this new paper, the authors propose an emended diagnosis for the Sphagesauridae, pointing new synapomorphies for this taxon and propose that the Chimaerasuchidae would be a valid family in spite of the poor phylogenetic analysis of Carvalho et al. (2004) paper.

[edit] References

Pol, D. (2003). New remains of Sphagesaurus huenei (Crocodylomorpha: Mesoeucrocodylia)from the Late Cretaceous of Brazil. Journal of Vertebrate Paleontology 23: 817-831
Carvahlo, I.S., Ribeiro, L.C.B. and Avilla, L.S. (2004). Uberasuchus terrificus sp. nov., a new Crocodylomorpha from the Bauru Basin (Upper Cretaceous), Brazil. Gondwana Research 4: 975-1002
Candeiro, C.R.A. & Martinelli, A.G. (2006). A review of paleogeographical and chronostratigraphical distribution of mesoeucrocodylian species from the upper Cretaceous beds from the Baurus (Brazil) and Neuquén (Argentina) groups, Southern South America. Journal of South American Earth Sciences 22:116-129
Kuhn, O. 1968. Die Vortzeitlichen Krokodile. Verlag Oeben, Krailing, München, 124 p.
Marinho, T.S. & Carvalho, I.S. (2007). Revision of the Sphagesauridae Kuhn, 1968 (Crocodyliformes, Mesoeucrocodylia). In: Paleontologia: Cenários de Vida. Vol. 1:581-591.