Reptilia disappeared: does this have any impact on higher taxonomy in TB?

[myrmoteras]

@gsautter Catalogue of Life discontinued Reptilia. We need to check what the alternatives are, and what we need to do to react.

[gsautter]

What do you mean "They discontinued Reptilia"?

[myrmoteras]

Doesn't exist as a taxon, if I understand rightly

[gsautter]

Just randomly using crocodiles as an entry point, I found this:

Looks more like an aggregation sanfu to me than anything else ... a suborder being the direct descendant of a class is strange enough, and I've seen this kind of mix-up before ... semantics-unaware tree optimization feels like it might have played a role.

[gsautter]

Digging a bit further reveals that there might actually be something in motion ... the GBIF backbone lists "Reptilia" as a partial synonym, and Wikipedia (I'm well aware it's not a scientific source) reports some recent developments going on around "Reptilia" and "Aves" ... guess we need to either ask domain specialists, or simply wait what's to come ...

[flsimoes]

@gsautter Reptilia is technically a paraphyletic group (not valid), but researchers have avoided moving away from using it as it is so engrained in everyone's brains. It is not surprising that they would be finally making the change, though it did strike me as odd... What could have finally triggered the change?

[gsautter]

@gsautter Reptilia is technically a paraphyletic group (not valid), but researchers have avoided moving away from using it as it is so engrained in everyone's brains. It is not surprising that they would be finally making the change, though it did strike me as odd... What could have finally triggered the change?

Good question ... ChecklistBank only aggregates, though, and the decision might well have happened in ReptileDB, which to my best knowledge is their definitive source for that part of the taxonomic tree.

Could you detail a bit on what a "paraphyletic group" is, though? Don't feel like I fully grasp the term ...

[flsimoes]

This image summarizes it:

A Monophiletic group (also known as Natural) is a valid group, i.e. it includes all the common descendants from the ancestral.
On the other hand, a Paraphyletic group does not include all the common descendants; in the case of Reptilia, it does no include Aves (the birds) which it should. Sauropsida is the actual group that includes "Reptiles" + Aves.
There's also Poliphyletic groups which is even worse, such as grouping bats and birds because they have wings.

[deepreef]

I'm not sure if this is relevant, but there never was a "requirement" that nomenclatural classifications must strictly follow monophyletic groupings. Indeed, there are many taxonomists who acknowledge that we can discuss hypothesized phylogenetic relationships using cladograms and other communication tools, while mantaining stable/historical classifications using the Linnean nomenclatural system, even when such nomenclatural classifications maintain what are interpreted by the majority of modern taxonomists as paraphyletic groups. This is why there is (or at least has been) broad acceptance among taxonomists that "Reptilia" (exclusive of Aves) is still a useful way to classify life using Linnean nomenclature, even when there is overwhelming consensus among phylogenetically-inclined taxonomists that "Reptilia" is paraphyletic.

Again... not sure this is relevant to the current discussion; but when it comes to mapping a classification using Linnean-style names to a group of organisms, there is no "correct" answer; even when there is broad/universal consensus about the true phylogeny. The only thing most people seem to agree on is that even Linnean nomenclature should not be used to label polyphyletic groups (once consensus is reached that polyphyly is involved).

[gsautter]

@flsimoes thanks for the illustration and explanation ... another gap in my understanding of taxonomic terminology filled.

@deepreef thanks for the expert opinion ... seems as though this issue might be with us for a while until we reach a sensible conclusion, anywhere between using "correct" higher taxa, maintaining system interoperability, and not breaking tons of existing data all over the place ...

[gsautter]

On a related note; aren't birds warm-blooded, while what we call reptiles are cold-blooded? hard to grasp they are in the same group with such fundamental differences in their metabolism ... just from a curious layman's point of view.

[myrmoteras]

since we use COL for higher categories, we just follow whatever they decide. We do not have any input into how COL makes decisions.

I mentioned this, because some of the higher categories u will have to change, updated following this change in COL (see big batch) https://tb.plazi.org/GgServer/srsStats/stats?outputFields=tax.classEpithet&groupingFields=tax.classEpithet&FP-tax.classEpithet=%25eptilia%25&format=HTML

and could be part of the big batch? #73