Talk:Batrachomorpha

Wow! I'm cited in Wikipedia! -- I made the last few edits (basically typos).

David Marjanović david.marjanovic_at_gmx.at 2005/12/13 18:23 CET

Phylogenetics

This section doesn't look right:

"In his scheme, Batracomorpha is a subclass of Amphibia, containing the following orders:"

Crown tetrapods are conventionally divided into two subclades: batrachomorphs and reptiliomorphs. Crown tetrapods are defined as the nearest common ancestor of all living amphibians, reptiles, birds, and mammals, along with all the descendents of that ancestor. Batrachomorphs are all animals that share a more recent common ancestry with living amphibians than with living amniotes (reptiles, bird, and mammals). Reptiliomorphs are all animals that share more recent common ancestor with living amniotes than with living amphibians.

These definitions are not part of Linnaean taxonomy but part of cladistics. In cladistics there is no such thing as an order or subclass. Both Batrachomorpha and Reptiliomorphs are subclades of Tetrapoda (by the node-based definition, i.e., the crown group). Incidentally, pure cladists use Tetrapoda exclusively to mean crown tetrapods and use Stegocephalia to refer to tetrapods by the trait-based definition. Pure cladists use Amphibia as a synonym for Batrachomorpha.

Paleontologists frequently switch back and forth between Linnaean and cladistic terminology. This is like telling someone where you live in terms of a street address, and then giving your precise latitude and longitude. Both systems work so long as you keep them separate.

In this case, they are mixed up. As far as I know, the cladistic definition of Batrachomorpha is the only one currently in use. Also, whether or not it includes temnospondyls or lepospondyls has nothing to do with the current definition Batrachomorpha, since the clade is defined entirely in terms of living animals. Zyxwv99 (talk) 22:03, 9 June 2015 (UTC)

You are entirely right. The problem here is Batrachomorpha is used extremely inconsistently, and the actual underlying phylogeny is not well understood. As a systematic unit, Batrachomorpha is next to useless because any definition is necessarily going to be fussy, either in content or definition. Petter Bøckman (talk) 13:42, 23 November 2017 (UTC)

I feel most of the inconsistency is caused by limiting the term to basal forms. That's a habit we can disregard here. I adapted the intro to emphasise the implicit Bentonian definition.--MWAK (talk) 06:19, 3 June 2022 (UTC)