Changing Definitions
The name Reptiliomorpha was coined by Professor Gunnar Säve-Söderbergh in 1934 to designate various types of late Paleozoic reptile-like labyrinthodont "amphibians." However Alfred Sherwood Romer used the name Anthracosauria instead. In 1970, the German paleontologist Panchen reverted to Säve-Söderberghs definition, but Romer's terminology is still in use, e.g. Carroll 1988 and 2002, and Hildebrand & Goslow 2001. Some cladistic also work prefer Anthracosauria.
In 1956, Friedrich von Huene included both amphibians and anapsid reptiles in the Reptiliomorpha. This included the following orders: 1. Anthracosauria, 2. Seymouriamorpha, 3. Microsauria, 4. Diadectomorpha, 5. Procolophonia, 6. Pareiasauria, 7. Captorhinidia, 8. Testudinata.
In 1997, Michel Laurin and Robert Reisz (1997) adapted the term in a cladistic sense. Michael Benton (2000, 2004) made it the sister-clade to Batrachomorpha. However, when considered a linnean ranking, Reptiliomorpha is given the rank of superorder and only includes reptile-like amphibians, not their amniote descendants. More recently Reptiliomorpha has been adopted as the term for the largest clade that includes – according to the technical definitions of the phylocode which only refers to species or genus level organisms – Homo sapiens but not Ascaphus truei (a primitive frog) (Laurin, 2001; Vallin and Laurin, 2004); or is, as Toby White (Palaeos website) puts it, more like dogs than frogs (i.e. mammals but not amphibians). However, given the lack of consensus of the phylogeny of the labyrinthodonts in general, and the origin of modern amphibians in particular, the actual content of the Reptiliomorpha under the latter definition is uncertain.
Read more about this topic: Reptiliomorpha
Famous quotes containing the words changing and/or definitions:
“One’s condition on marijuana is always existential. One can feel the importance of each moment and how it is changing one. One feels one’s being, one becomes aware of the enormous apparatus of nothingness—the hum of a hi-fi set, the emptiness of a pointless interruption, one becomes aware of the war between each of us, how the nothingness in each of us seeks to attack the being of others, how our being in turn is attacked by the nothingness in others.”
—Norman Mailer (b. 1923)
“What I do not like about our definitions of genius is that there is in them nothing of the day of judgment, nothing of resounding through eternity and nothing of the footsteps of the Almighty.”
—G.C. (Georg Christoph)