Talk:Casineria

Amphibia/Reptilia (uncertain)

The Taxobox lists a claim that the classification of this species is uncertain, and that it may be either a member of class "Amphibia" or "Reptilia". This uncertainty is not supported in the text. The text discusses that it has some features of both grades, and that it is a reptiliomorph outside crown Amniota. This seems to suggest it is definitely an "Amphibian" sensu lato. Is there any source to support its placement as an Amniote/"Reptile"? Or is "reptile" here being used to include stem-amniotes with some key reptilian character? If so, this needs to be reflected in the text with sources (maybe a classification section). Right now I get the impression that this is unnecessary waffling, like listing Archaeopteryx as Reptilia/Aves (uncertain). MMartyniuk (talk) 11:21, 12 August 2013 (UTC)

Reptile here means reptile as normally understood and like in the WP article reptile, i.e. all amniotes who are neither mammals, nor birds. Both the Science News and the Nature article express uncertainty as to whether Casnieria had an amniotic or amphibian reproductive mode. Several other sources express the same uncertainty: Brian K. Hall (2008): Finns to limbs, Dale. A. Russell (2009): Islands in the Cosmos: The Evolution of Life on Land, Palaeos and Palaeocritti. The general uncertainty of phylogenetic placement is referred to by Clack 2009: The Fish–Tetrapod Transition: New Fossils and Interpretations, though she is not explicit about the it's status as an amniote. Exactly where the anamniote/amniote border lies is uncertain, but there is not reason to suggest it is at the synaspid/sauropsid spilt, as both the earliest synapsids and sauropsids are larger than the "ur-amniote" is thought to have been (Carroll 1991, Laurin 2004). I suppose I should flesh out the text a bit. Petter Bøckman (talk) 12:52, 12 August 2013 (UTC)

Ok, thanks. So it sounds like there's uncertainty about whether it has an amnion (i.e. the apomorphy) but there is consensus that it is not a crown amniote? Yeah, this should be discussed explicitly, preferably in a way also understandable to those of us used to speaking cladistic ;) Basically the difference between "amniote" (member of the clade or other taxon Amniota) and "amniote" (animal with amniotic reproduction) needs to be explained. MMartyniuk (talk) 17:34, 12 August 2013 (UTC)