Gnathorhizidae

Taxobox
name = Gnathorhizidae
fossil_range = Late Carboniferous - Middle Triassic
regnum = Animalia
phylum = Chordata
subphylum = Vertebrata
classis = Sarcopterygii
subclassis = Dipnoi
subclassis_authority = Müller, 1844
familia = Gnathorhizidae
subdivision_ranks = Genera
subdivision =
* "Gnathorhiza"
* "Monongahela"
* "Beltanodus"
* ?"Microceratodus"
* "Namatozodia"The Gnanthorhizidae are an extinct family of lungfish that lived from the late Carboniferous until the middle Triassic. Gnathorhizid fossils have been found in North America, Madagascar, Australia, and possibly Eastern Europe and South Africa. They are characterized by high-ridged toothplates that form cutting blades and a reduction in cranial bones.

Distribution

Gnathorhizids are found in North America, Eastern Europe, Australia, and Africa. Gnathorhizids from North America range from the Gzhelian through the Roadian. In Africa, gnathorhizids are found in Olenekian of Madagascar and possibly South Africa. Lungfish teeth attributed to gnathorhizids have been reported from the Lopingian to the Olenekian in Poland and Western Russia. It is likely, then, that gnathorhizids had a Pangean distribution throughout the late Paleozoic and early Mesozoic.

Paleoecology and behavior

Gnathorhizids are found primarily in paleosols representing ephemeral wetlands. Additionally, gnathorhizids, unlike most groups of fossil lungfish, are often found in association with regular burrow structures, suggesting that this group of lungfish may have estivated during the dry season, much like modern African and South American lungfish.

Unlike most fossil lungfish, but again, like modern South American and African lungfish, gnathorhizids have bladelike toothplates. This suggests that gnathorhizids were active predators unlike most lungfish, which feed primarily on benthic invertebrates.

References

* Berman, D. S., 1976, "Cranial morphology of the Lower Permian lungfish Gnathorhiza (Osteichthyes: Dipnoi): Journal of Paleontology", v. 50(6), p.1020-1033.
* Cunningham, C. R. and Dickson, E. D III, 1996, "Distributions of Kansas Permo-Carboniferous vertebrate assemblages as a function of wet and dry seasons: Transactions of the Kansas Academy of Science", v. 99(1-2), p. 16-28.
* Huttenlocker, A.K. "et al.", 2005, "An earliest Permian nonmarine vertebrate assemblage from the Eskridge ormation, Nebraska:
* Lucas, S.G. and Zeigler, K.E., eds., 2005, "The Nonmarine Permian, New Mexico Museum of Natural History and Science Bulletin No. 30"., pp.133-143.