Talk:Elasmobranchii

Adding Technical template

The Description section is far too technical for a general encyclopedia article. The long second paragraph, in particular, is practically incomprehensible. Here is just a small sample from that paragraph:

Finally, in euhyostyly, also known as true hyostyly, the mandibular cartilages lack a ligamentous connection to the cranium. Instead, the hyomandibular cartilages provide the only means of jaw support, while the ceratohyal and basihyal elements articulate with the lower jaw, but are disconnected from the rest of the hyoid.

None of those bizarre terms have links to other articles explaining what they mean.

Someone who can bridge the yawning gap between the information presented in this paragraph and the English language should rewrite the whole paragraph.--Jim10701 (talk) 14:47, 1 May 2011 (UTC)

Are not skates types of rays?

The article says that the elasmobranchii consists of sharks, skates and rays, but is not the skate a type of ray?ACEOREVIVED (talk) 22:14, 14 February 2013 (UTC)

I agree, rays and skates is a term that should be interchangeable. Order Raji12voltlighting (talk) 04:26, 9 February 2014 (UTC)

External links modified

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Merge Neoselachii into this article

I redirected this, but because it was reverted (without a reasonable explanation, I might add) I am forced to create this merge/redirect request. Per the paper "What is an ‘elasmobranch’? The impact of palaeontology in understanding elasmobranch phylogeny and evolution" by Maisey in 2012 [1],Wikipedia Library link, Neoselachii is essentially equivalent to Elasmobranchii in the sense used by most taxonomists. To quote Maisey: A revised, apomorphy-based definition of elasmobranchs is presented in which they are considered the equivalent of neoselachians, i.e. a monophyletic group of modern sharks and rays which not only excludes all stem and crown holocephalans, but also many Palaeozoic shark-like chondrichthyans and even close extinct relatives of neoselachians such as hybodonts. There's not really a widely used clade that encompasses the total group of Elasmobranchii (Euselachii covers part of it, but not all) so it makes sense to have one article covering both the Elasmobranchii total group as well as Neoselachii (Elasmobranchii sensu stricto). Hemiauchenia (talk) 16:45, 25 January 2024 (UTC)

FotW5 has "Infraclass ELASMOBRANCHII (= NEOSELACHII)" so I think the merger is warranted unless there is some newer source with a compelling reason to treat them separately.

However, there is another issue. FotW5 has subclass Euselachi and infraclass Elasmobranchi (=Neoselachii) with Division Selachii within it. Isn't it a bit strange for the Eu-taxon to be higher than the taxon? Currently the taxononomy templates are not following FotW5 and have the hierarchy Elasmobranchi > Euselachii > Neoselachii > Selachimorpha (with no Selachii). Are the Chondrichthys using a different taxonomy source? If so, how do they treat Neoselachii? If not the taxonomy templates need fixing. —  Jts1882 | talk  09:18, 31 January 2024 (UTC)

And this is the problem. As I previously stated, there is no widely used alternative clade that covers the entire total group of Elasmobranchii, despite many papers suggesting that there are non-euselachian total-group elasmobranchs like xenacanths, ctenacanths, etc. Some researchers use Elasmobranchii to cover the entire total group, e.g. [2] and I don't really see any good alternative to this arrangement, other than maybe a new "Elasmobranchii (total group)" clade template. Hemiauchenia (talk) 14:51, 31 January 2024 (UTC)

@Jts1882: as far as I'm aware Quetzal1964 has been doing almost all of the work that has been done to bring Wikipedia into alignment with FotW5. But there are a bunch of groups they haven't worked on (including Chondrichthyes). You did comment on the thread I started on their talk page where I asked what groups they'd worked on. I have some notes at User:Plantdrew/Animal_automatic_taxobox_progress#Extant_fish_orders where I've indicated what Quetzal1964 has worked on (if you've checked any other orders to ensure they're following FotW5, please let me know). Plantdrew (talk) 21:20, 1 February 2024 (UTC)

@NGPezz: who has some expertise in fossil chondrichthyans. Hemiauchenia (talk) 15:01, 31 January 2024 (UTC)

I don't really have too much expertise beyond that of Hemiauchenia, but the Elasmobranchii/Euselachii/Neoselachii dilemma is a classic example of how a set of closely "related" taxonomic category can have inconsistent definitions through history relative to different authorities. The system of FotW5 has already been mentioned for the non-chimaera side of Chondrichthyes.

• WoRMS uses (Class Elasmobranchii (Subclass Neoselachii (Infraclasses Selachii and Batoidea))) with no mention of Euselachii.
• FishBase and Eschmeyer's Catalog of Fishes also use Class Elasmobranchii without much elaboration.
• PBDB uses (Subclass Chondrichthyes(Subclass Elasmobranchii)) but also with Subclass Selachii, Clade Euselachiiformes, and Infraclass Euselachii floating around within Elasmobranchii on equal terms, as well as Clade Neoselachii within Euselachii. In other words, an unvetted mess.
• My personal copy of the Princeton Field Guide to Sharks of the World, 2005, has (Subclass Elasmobranchii (unranked Euselachii (various orders of sharks along with rays, ctenacanths, hybodonts, etc. in a polytomy))) with no mention of Neoselachii or Selachii.
• Apparently Chondrichthyes isn't even discussed in Phylonyms, 2020.

I think merging Elasmobranchii/Euselachii/Neoselachii into one article is the best approach so that we can discuss the differing definitions and their historical precedence. Elasmobranchii is the broadest and most common of the three, and it has the most precedence so it should be the title name. The Maisey (2012) paper linked by Hemiauchenia is a good place to start for untangling the nomenclature. Once that's done we can revise the taxonomy template based on our understanding of consensus. NGPezz (talk) 17:51, 31 January 2024 (UTC)