Talk:Pancrustacea

Merger

These seem to be two names for the same clade (Crustacea + Hexapoda). Is there any reason why the two articles should not be merged? Pancrustacea seems to be the favoured name at the present. --Stemonitis (talk) 20:36, 7 December 2010 (UTC)[reply]

Done --Stemonitis (talk) 14:17, 8 December 2010 (UTC)[reply]

History of the idea

Who was the first to propose close relationship between Crustacea and Hexapoda? It was in 80-ties. This original view was based exclusively on morphological data. I think such a piece of information would be valuable for readers.

178.235.146.84 (talk) 18:10, 9 June 2017 (UTC)[reply]

Discuss Old References

This article extensively discusses unresolved questions about the relationships of the clades mentioned. The article currently cites 5 DNA studies all done within 4 years. It is now 8 years since the most recent reference. If DNA studies have been published at that same rate there should be 10 more papers, all of which are not referenced here. I suspect that many if not all of the questions mentioned here have been resolved by now. Nick Beeson (talk) 23:12, 2 June 2022 (UTC)[reply]

"most studies recovering Hexapoda within Crustacea" or recovering Hexapoda and Crustacea as sister clades?

Both within the same group, but more of a split rather than hexapods being a subgroup of more derived crustaceans. The cited article at some point puts: "suggests the following hypotheses for Ecdysozoa: (outgroups, (Priapulida, (Arthropoda, (Tardigrada, Onychophora)))), and Arthropoda: (outgroups, (Chelicerata, (Myriapoda, (Hexapoda, Crustacea))))."

To me that seems to indicate sister groups, whereas "Hexapoda within Crustacea" would be phrased as "[...] (Crustacea, (Hexapoda [...]." But I may be missing something. 45.167.98.230 (talk) 15:31, 9 October 2023 (UTC)[reply]

The phrasing "comprises all crustaceans, including hexapods" also seems to imply that hexapods belong within the more restrict group crustacea rather than both belonging to pancrustacea/tetraconata, with neither being within the other. — Preceding unsigned comment added by 45.167.98.230 (talk) 15:36, 9 October 2023 (UTC)[reply]

It should be "includes crustaceans and hexapods". Then the relationship is either as sister groups, which I believe was the original proposal for Pancrustacea, or nested more deeply within a paraphyletic crustacea, which is strongly supported by recent morphological and molecular studies. They are alternative hypotheses. — Jts1882 | talk 17:03, 9 October 2023 (UTC)[reply]

Should there be a Fruit fly (Drosophila melanogaster) image on this page?

That belongs to the Phylum Insecta - is there a good reason for it being on this page? Not an expert on the topic, apologies if there's an obvious reason. Saisuman (talk) 21:28, 2 March 2024 (UTC)[reply]

@Saisuman: It is now well accepted that insects are closely related to crustaceans. The taxon Pancrustacea was created to describe the group containing the Crustacea and Hexapoda (which contains Class Insecta) as sister groups, which makes the choice of a crustacean image and an insect image appropriate. It is now known that insects are nested deep in the phylogenetic tree, with crustaceans forming a grade (paraphyletic group) with respect to Hexapoda. Insects can be considered derived terrestrial crustaceans (even as flying shrimp). — Jts1882 | talk 07:24, 3 March 2024 (UTC)[reply]

Understood. Many thanks for the detailed reply. 52.119.85.98 (talk) 09:49, 4 March 2024 (UTC)[reply]

First sentence - very slightly unclear if hexapods are crustaceans?

An interesting fact I encountered is that pillbugs are not insects, but crustaceans. Non-biologists like me may find their way to this page because of this - to know what the relationship between insects and crustaceans is.

The first sentence of the article currently is:

> Pancrustacea is the clade that comprises all crustaceans, including hexapods (insects and relatives).

This does answer the question, and I understand that this fact is explained within that same introductory paragraph with:

> ... most studies recovering Hexapoda within Crustacea.

however, I think given this interesting fact about insects is counterintuitive and surprising, could the article use a clearer "yes you read that right, insects are crustaceans"?

Two things might help it slightly. First, using 'Crustacea' and 'Hexapoda' in the first sentence (perhaps in brackets after 'crustaceans' and 'hexapods') to make the terms more clearly related to the later explanatory sentence. Second, linking 'recovering' because this sounds like it has a domain-specific meaning that a non-biologist would need to understand in order to get that this is an explanation/confirmation of what is said in the opening sentence. Tmutimer (talk) 15:27, 15 September 2024 (UTC)[reply]

Hexapods are definitely not crustaceans. This is why the term pan- was added to the beginning. In phylogenetics, pan- is used as a prefix to indicate a paraphyletic condition - that some, but not all, of the members are of the described type. In this case, crustacean has become paraphyletic. I believe this is actually explained farther down in the article. - Kaz (talk) 22:37, 19 October 2024 (UTC)[reply]

Pancrustacea or just Crustacea?

Is it really true that most phyllogenetic studies use the term 'Pancrustacea' instead of just 'Crustacea' (in the broad sense)?

I find it hard to believe that the 'Pan-' term would be misused this way to such an extent - sorry if I'm simply being ignorant about certain conventions, that's why I'm asking about this. IvarTheBoneless123 (talk) 10:31, 17 December 2024 (UTC)[reply]

I do not understand your question. When do you see the term 'Pancrustacea' used mistakenly, in your opinion? --cyclopia ^speak! 10:41, 17 December 2024 (UTC)[reply]

I think he's taking the view that Pan-taxa include fossil stem taxa, which is a proposal that has become quite popular. As such extant crustaceans wouldn't be part of the pan-taxon. But I think Pancrustacea was named before this convention was introduced or became widely accepted. Iirc, the initial proposal had Crustacea and Hexapoda as sister taxa. As far as I can tell, most people (nearly all?) working on these taxa use Pancrustacea. Similar thinking would reevaluate the use of Pan-Arthropoda and I don't see that happening either. — Jts1882 | talk 13:25, 17 December 2024 (UTC)[reply]

Ah, I see! But that would be pan-Crustacea, not Pancrustacea, or am I wrong? However it seems the issue is really being debated. cyclopia ^speak! 16:31, 17 December 2024 (UTC)[reply]

Usually, but I'm not sure how strict they are on form, Pantaxon versus Pan-Taxon, However, a Pan-Crustacea could be considered exclusive of Hexapoda, so we'd need Pan-Pancrustacea. Fortunately, we just need to follow the sources and Pancrustacea is widely used. — Jts1882 | talk 18:53, 17 December 2024 (UTC)[reply]

Yes. I apologize for lack of clarity. I was unaware that the 'Pan- group' convention (stem + crown groups) became popular only relatively recently; now the whole situation makes a lot more sense. - IvarTheBoneless123 (talk) 10:16, 19 December 2024 (UTC)[reply]