# Talk:Eurypterid

I've tweaked a few bits, may add a few more bits of detail later - trying to keep it basic enough to keep people interested while retaining everything factually correct.
Will also update the list of eurypterids at some point, as it is terribly out of the date and the taxonomy has changed quite a lot. I happen to work on this group, and have some papers in press that, once published, will alter things further, and I shall update the page with any changes once they have been published.
Severan (talk) gg 29 January 2009 (UTC)

I'm amazed! I add a little to the eurypterid stub from my off-hand knowledge, intending to come back and add to it in a more scientific manner, and here a few hours later it's nearly all been filled in! Great!
One quarrel though, 

   "They also had a pair of pincers, known as chelicera."

I do believe the pincers constitute pedipalps, not chelicerae (singular chelicera), which are more like mouthparts/fangs. I won't change it, though.
umm, '8 pairs of walking legs' ? i believe it's 4 pairs, 8 total.
the thing is i remember entering 8 pairs, as a typographical error, and correcting it later.. so if that's still there, someone must be challenging it?
I am adding to the discussion:
Pedipalps like the ones in scorpions are homologous to the first pair of walking legs in Eurypterus. The chelicerae in scorpions are anterior to the pedipalps and smaller. In the case of scorpions both the chelicerae and the pedipalps have pincers (chelae), but in spiders for example, the pedipalps are non-chelate. In male spiders the pedipalp carries a spermatheca. In horseshoe crabs, and apparently in some eurypterids, the first pair of legs in males has a hook-like modified distal segment specialized for holding onto the female carapace during mating. Horshoe crabs have the same number of prosomal appendages as Eurypterids and scorpions (6), but the walking legs with the exception of the last pair are chelate. One has to specify "prosomal" appendages because these animals have also abdominal appendages (gills). It is tricky to be precise, and at the same time concise and plain-spoken.  
Concerning the walking legs in eurypterids, the total number of prosomal appendages is always six, but the number of walking legs is variable, because some appendages are specialized for uses other than walking: swimming, grasping. Thus, Eurypterus and Pterygotus have four pairs of walking legs, one pair of swimming appendages or paddles, plus the chelicera with pincers at the front end. Stylonurus has five pairs of walking legs, plus the chelicera and Mixopterus and Megalograptus have two pairs of grasping appendages, two pairs of walking legs and one pair of swimming appendages plus the chelicera. Thanks for reading.
Manuel O. Diaz

Ah, I see. How strange, arthropod limbs seem quite interchangable (especially centipedes!) but... Many pictures I've seen of eurypterids had a smaller 'first pair of legs' right at the mouth, with the pincers further back than those (but still quite up front). Are we sure these pincers were right AT the mouth, making them chelicerae? I know I've seen arachnids with pincerlike chelicerae, but it's so odd...  —Preceding unsigned comment added by 64.122.63.142 (talk) 17:44, 13 May 2008 (UTC)

As mentioned, it varies. The holotype of the clade - Eurypterus had tiny chelicerae hidden near the mouthparts used for tearing food. In other species like the Pterygotus the chelicerae were massive and looked more like those from modern scorpions or spider crabs. Do note that chelicerae forms vary and ALL chelicerate arthropods have them (and conversely do not have antennae). They do not need to be tiny or close to the mouth, but they do need to be the first pair of legs. From primitive pincerlike ones in scoprions, eurypterids, pseudoscorpions and allies to the more modern fangs/jacknife chelicera of spiders. Eurypterid chelicerae were more like those to the right from an Opiliones (Harvestman).
A more detailed anatomy of the Eurypterus is seen here: http://www.palaeos.com/Invertebrates/Arthropods/Eurypterida/eurypt-morphology.gif
An also important thing to note, in Pterygotids, the chelicerae are massive. The 'pincers' are actually not pincers homologous to those found on scorpions. They are actually the chelicerae, homologous more to spider fangs and the tiny mouth claws of scorpions. To put it more clearly, these pincers of the Pterygotids were the FIRST pair of limbs and thus chelicerae, while the pincers of scorpions and pseudoscorpions arise from the second pair of limbs (they possess chelicerae as well, but theirs are tiny). Their function is for grasping prey but they can still be folded back towards the mouth to serve more like other chelicerae. -Obsidi♠nSoul 23:48, 5 November 2010 (UTC) 

"Eurypterids were the most fearsome swimming predators of the Palaeozoic." Well, let's see -- "The largest [eurypterids], such as Pterygotus, reached 2 m or more in length ..." Compare with Placoderm fish such as Dunkleosteus, "around 8 to 10 m (27 to 33 feet) long", "scientists at the Field Museum of Natural History and the University of Chicago concluded that Dunkleosteus had the most powerful bite of any fish, well ahead of sharks, including the Great White. Dunkleosteus could concentrate a pressure of up to 8,000 pounds-force per square inch (55 megapascals) at the tip of its mouth, effectively placing Dunkleosteus in the league of Tyrannosaurus rex and modern crocodiles as having the most powerful known bite." -- 201.51.231.176 20:28, 6 March 2007 (UTC)

Well that might be true for a preserved specimen, in should be staed that of all fossilised species discovered so far.....etc. As you know not all species are preserved and there might have been bigger, meaner, nasties things alive back then. But you are generally correct. I think the statement comes from the show, 'Walking with Sea Monsters. Enlil Ninlil 03:53, 7 March 2007 (UTC)

I've replaced "Anomalocarids" with "Arthropleurids" in the first sentence, since the Anomalocarids were probably not true arthropods and were, in any event, probably less massive than either Pterygotus or Arthropleura, with much of the length of the biggest specimens being made up of the tail. PenguinJockey 20:22, 13 May 2007 (UTC)

There's some errors, i do believe Pterygotus wasn't the largest arthropod, it's rivaled by Arthropleura, which I think is larger. Just noting be more careful what you say. Ammonight423 00:50, 12 October 2007 (UTC)

Isnt there also Jeakilopterus and Agirocassis (even though it isnt a true arthropod I think) ScavengerR9 (talk) 13:52, 5 April 2022 (UTC)

Reading the physiology part of this article, the section ends by noting that the Horseshoe crab was once believed to be a close relative, but arachnids are now believed to be more closely related.
In the very next section, on fossils, it asserts that the Horseshoe crab is the close relative. It either is, or it isn't, and it doesn't bear mentioning twice. I leave the actual edit to someone more informed on the subject. 24.136.171.150 (talk) 23:14, 17 November 2007 (UTC)

I've made an edit to straighten out the conflicts and redundancies. However, one problem remains. I'll give it it's own heading below.  —Preceding unsigned comment added by 138.23.134.119 (talk) 00:03, 15 May 2009 (UTC)

http://news.yahoo.com/s/ap/20071121/ap_on_sc/biggest_bug_ever  —Preceding unsigned comment added by 216.46.209.197 (talk) 02:38, 26 November 2007 (UTC) 

Hmm... what are we going to do about this? I think the list in this article is better than the list I made, but I also think a list of Eurypterids deserves its own page. What are your thoughts? Abyssal leviathin (talk) 04:21, 21 December 2007 (UTC)

Your list is fine and is in line with other lists, if you wan't you can make a taxonomical list by cuting this one out. As the article expands it will need to be moved. Enlil Ninlil (talk) 05:03, 26 December 2007 (UTC)

The eurypterids definitely went extinct at the P-T boundary. That was 251 mya. The header for the page, however, states that they lived until 248 mya. That's impossible if they went extinct at the P-T boundary; a 3 million year discrepancy might not seem like much, but plainly something is screwy here. 138.23.134.119 (talk) 00:05, 15 May 2009 (UTC)

I added anatomically descriptive material from the TIP.  I may go over the rest of the section to ensure accuracy and consistency.--Digthepast (talk) 07:50, 24 November 2009 (UTC)

I added a list of Families and Genera, based on the TIP.  Doubtless, a lot has occurred in this exciting field since 1955, including a reclassification of at least some, if not all, of the Hughmilleriidae.  I do not have sources available to me for this, so if anyone has good source material for recent changes, by all means, please step up.--Digthepast (talk) 15:43, 29 November 2009 (UTC)

I have now added pages for the following eurypterid families: Pterygotidae, Eurypteridae, and Carcinosomatidae.  Each page contains a description of the anatomical characteristics common to the family, and a list of member genera.  My plan is to continue with this.--Digthepast (talk) 04:19, 1 December 2009 (UTC)

The intro says: "They are members of the extinct class Eurypterida (Chelicerata)." However, in the sidebox, Eurypterida is listed as their Order and Chelicerata as their Subphylum. I am not sure what to make of this. — Epastore (talk) 14:40, 26 December 2009 (UTC)
It is an order; I have changed the introduction accordingly -- instantn00dle 15:42, 15 November 2010 (UTC)

I have added a phylogeny based on Tetlie's 2007 tree; it involved a lot of chucking out of little outgroups and the like to simplify it and ignoring most of the genus level classification. I hope everyones happy with it; I kept the notes next to the tree where they are easy to see although I guess this looks messy.-- instantn00dle 15:48, 15 November 2010 (UTC)

I think the phylogeny presented is unfairly biased towards Pterygotids, and ideally a more complete one will get uploaded eventually. Some of the 'minor' groups that got chucked out are actually the most important in terms of understanding the evolution of the group.

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Ichthyovenator, I've been thinking in creating several articles that have other clades that could serve us and the readers to better understand the history and other things of eurypterids. For example, a template that contains all the genera grouped in their corresponding clades, like this one. While it can be done in the current template, that would widen the image a lot, probably not allowing an image to be placed. I have also thought about a "timeline of eurypterid research", like the same page applied to dromaeosaurids, or a eurypterid glossary, like this one (personally, I think this one is essential and useful, it would help us to link those rare words without an article). Do you agree? Do you have any suggestion? Super Ψ Dro 16:33, 27 August 2018 (UTC)

Super Dromaeosaurus I'm not sure a template with every single genus is fully necessary but I could experiment a bit with how to make one that isn't overcrowded. A "Timeline of eurypterid research" is a very good idea, we'd have to start it out with a lot of stuff already in place, might be something to work on a bit before creating the article. I don't think we need a "Glossary of eurypterid terms", many of the anatomical terms used are not specific to eurypterids (maybe something like a "Glossary of chelicerate terms" would be better? I don't know) and as far as I know the most relevant terms are already discussed in this article pretty well and linking to the "morphology" section should work fine? Ichthyovenator (talk) 15:06, 29 August 2018 (UTC)
I think the chelicerate terms would be considerably more difficult but it could also be done. With the rest I agree. When would we start the timeline? Super Ψ Dro 17:23, 29 August 2018 (UTC)
Yeah, as I said I'm not sure a glossary article would be needed at all. We could start working on a timeline article straight away, maybe under one of our userpages. Ichthyovenator (talk) 17:44, 29 August 2018 (UTC)
I'm going to try to finish Strabops soon. I can not finish Paleomerus until they pass me a document. Afterwards, we can work in my sandbox. Super Ψ Dro 17:56, 29 August 2018 (UTC)
I preferred to publish the article first and work it there (link). Super Ψ Dro 15:31, 3 September 2018 (UTC)
Got it! I'll join in and help expand it in the coming days. Ichthyovenator (talk) 20:04, 3 September 2018 (UTC)

This review is transcluded from Talk:Eurypterid/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: Dunkleosteus77 (talk · contribs) 19:19, 16 October 2018 (UTC)

A head's up, responses to comments may be slow until next week for personal reasons, hope that's okay. Ichthyovenator (talk) 20:36, 16 October 2018 (UTC)

Yeah don’t worry. It’s a really well-written article so all I have are a bunch of small grammar things. Are you planning on getting this to FA?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Sorry for missing this reply, thanks! I hope to get either this one or one of the genera that's already GA to FA eventually. Not sure which would be best to go with first. Ichthyovenator (talk) 14:22, 28 October 2018 (UTC)
I think Jaekelopterus would be the best option for FA. Super Ψ Dro 16:15, 28 October 2018 (UTC)


### Comments by Dunkleosteus77
So first and foremost, I don’t think “eurypterid” is a common name for Eurypterida, it’s just shorthand, so you can either call the article Eurypterida or Sea scorpion (and if you pick the latter, change all “eurypterid” to “sea scorpion”)   User:Dunkleosteus77 |push to talk  19:19, 16 October 2018 (UTC)
I guess it's shorthand in the same way "dinosaur" is shorthand for Dinosauria? I don't see why the name of the article would need to be changed, they are referred to as "eurypterids" all the time within and outside of academic papers. I'm pretty sure "sea scorpion" isn't preferred seeing as they weren't actual scorpions. Ichthyovenator (talk) 20:36, 16 October 2018 (UTC)
Yeah, but Dinosaur is a common name now and a shorthand, eurypterid is just shorthand (and sometimes an adjective), so it shouldn’t be the article title. It’s either Eurypterida or Sea scorpion. Common names are seldom entirely accurate. But in any case, we should probably save this for last because changing the name will archive the GA review for a day or so   User:Dunkleosteus77 |push to talk  03:09, 17 October 2018 (UTC)
I still don't see why it would be necessary and I'd like more than your opinion on it if I'm going to change the name of the article (no offense). But yes, this discussion could be saved for later. Ichthyovenator (talk) 06:57, 17 October 2018 (UTC)
We have articles such as Trilobite (instead of Trilobita), Hadrosaurid (instead of Hadrosauridae), Nautiloid (instead of Nautiloidea) etc., so I don't see how this is any different. Perhaps there are some naming conventions out there, but we would need to find them before deciding what to do here. FunkMonk (talk) 23:39, 19 October 2018 (UTC)
Is the Darriwilian in the late Ordovician or early?   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
It's middle Ordovician. Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
”...90% of all known eurypterid specimens,” just checking, is it specimens or species?   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Specimens is correct, it has a lot of species too but there are eurypterid genera with even more. Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
This is optional but you don’t need to get so specific with the dates as 3 decimal places, rounding to the nearest number or even tens is enough   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Okay, probably better with just 251.9 anyway. Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
Is Jaekelopterus one of the largest or the largest?   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
It's the largest, rephrased this in the lead.
You wikilink chelicerate twice and neither of them are the first mention   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Linked "chelicerate" at first mention now. I'm unable to find the other two places where it is linked? Ctrl+f and "chelicerat"... doesn't give any more linked uses (except in an image caption). Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
You don’t need to say “by eurypterid researchers”   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Right, removed. Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
”differently developed, but the same organs as the fangs of spiders” this is optional but you could just say “homologous to the fangs of spiders”   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Yeah, probably better. Changed. Ichthyovenator (talk) 19:27, 19 October 2018 (UTC)
”relating to gills” is there any way to say this in adjective form?   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Not sure, english isn't my first language. Pretty sure "branchial" is an adjective form but not sure if there is a simpler one, "respiratory"? Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
are you trying to say “gill-like”?   User:Dunkleosteus77 |push to talk  21:34, 19 October 2018 (UTC)
You use “gill tract” later in a caption so you could say “...creating a gill tract between preceding...”
Yes, gill tract would be correct, changed it. Ichthyovenator (talk) 16:35, 23 October 2018 (UTC)
you should be consistent in italicizing German
I think I've italicized all instances of German language now. Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
”The appendages... are fused,” is it supposed to be present tense?   User:Dunkleosteus77 |push to talk  00:53, 18 October 2018 (UTC)
Must have missed this one before, changed it to past tense. Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
I think it’s off-topic to mention the smaller ones were also formidable predators in the Size section   User:Dunkleosteus77 |push to talk  15:48, 18 October 2018 (UTC)
Maybe, but I think it's worthwile to mention. Could it fit better under "feeding"? Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
that’d be the place to do it   User:Dunkleosteus77 |push to talk  21:34, 19 October 2018 (UTC)
Moved the statement. Ichthyovenator (talk) 16:35, 23 October 2018 (UTC)
You don’t need “whilst the largest exceeded 2 meters (6.6 ft)” because you go into this in the next paragraph   User:Dunkleosteus77 |push to talk  15:48, 18 October 2018 (UTC)
Removed. Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
Do you know the chelicerae to body size ratio?   User:Dunkleosteus77 |push to talk  15:48, 18 October 2018 (UTC)
I'll see if I can find it. Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
Looked it up in the source, which just says "If the relative proportion of the chelicerae and body length in Jaekelopterus were as in the closely related genera Acutiramus and Pterygotus (see §1)". Don't know what "§1" is referring to but there is no ratio to be found in the text, the figures or in the supplementary information. Ichthyovenator (talk) 14:22, 28 October 2018 (UTC)
Does this article use American or British spelling because I see “meter” but I also see “moulting”   User:Dunkleosteus77 |push to talk  15:48, 18 October 2018 (UTC)
Not a native english speaker, there is a risk that the article shifts from American to British quite a bit. I was going for American english but there might be words with British spelling here and there. Ichthyovenator (talk) 19:36, 19 October 2018 (UTC)
noted, I’ll change the spelling if I see more British English   User:Dunkleosteus77 |push to talk  21:34, 19 October 2018 (UTC)
”whilst” is British English, use “while”   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Changed all instances of "whilst" to "while". Ichthyovenator (talk) 16:35, 23 October 2018 (UTC)
You have parentheses inside of parentheses in the Locomotion section so you should probably use dashes   User:Dunkleosteus77 |push to talk  15:48, 18 October 2018 (UTC)
Done. Ichthyovenator (talk) 19:38, 19 October 2018 (UTC)
Don’t use spaces with dashes   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Removed spaces. Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
”the ventral body wall (the underside of the opithosoma) was the location of the respiratory organs,” note, I like passive voice but nobody else does, so use, “the respiratory organs were located...”   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Done. Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
What’s a surface area of cuticle?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Here referring to that the spinules would give the organ a large surface area. I've rephrased it, is it better now? Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
Instead of, “such veins are yet to be found...” and so on, you could just say, “as in related groups,” and the sentence it’s in is a fragment   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Done. Removed the "though" in the beginning of the sentence which should mean it's no longer a fragment. Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
For the Strobilopterus picture, do the left and right use the same scale?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
They do not, added a "not to scale" to the caption. Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
Instead of “xiphosura,” use, “horseshoe crab,” and instead of, “pycnogonids,” use, “sea spiders”   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Done for pycnogonids -> sea spiders but not for Xiphosura. Horeshoe crabs are on of several groups of xiphosurans (the only living one, but one among many either way). Ichthyovenator (talk) 16:46, 23 October 2018 (UTC)
You say whether they were direct or hemianamorphic developers is controversial but then say point-blank they were direct developers
Meant to say that it had been controversial in the past, does that now. Ichthyovenator (talk) 16:52, 23 October 2018 (UTC)
”Most, if not all, eurypterids are thought to have been carnivorous,” seems unnecessary with the sentence after   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Agreed, removed the first sentence. Ichthyovenator (talk) 16:52, 23 October 2018 (UTC)
Briefly explain what stereoscopic vision is   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Done. Ichthyovenator (talk) 16:52, 23 October 2018 (UTC)
”Eurypterids, lacking these specialized appendages...” didn’t only derived Pterygotioidea lack the appendages?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
This was meant to say "other eurypterids", referring to those groups that did not have enlarged frontal appendages. Fixed now. Ichthyovenator (talk) 16:52, 23 October 2018 (UTC)
instead of saying “appendages” in the Feeding section, use “spines” or “claws” depending on which you’re referring to   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
"Appendage" refers to the entire limb, "spines" and "claws" are already used where applicable? Ichthyovenator (talk) 16:52, 23 October 2018 (UTC)
”Though a potential anal opening has been reported from a specimen of Buffalopterus,” how does this statement contradict the next statement?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
I forgot to put in the location the opening had been reported from, the statement should make sense now. Ichthyovenator (talk) 16:58, 23 October 2018 (UTC)
”further reinforcing the idea that some eurypterids may have been cannibalistic,” seems redundant. You should probably just merge those two sentences about coprolite into one   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:22, 28 October 2018 (UTC)
which sex has a larger size and more ornamentation?   User:Dunkleosteus77 |push to talk  15:48, 20 October 2018 (UTC)
Males appear to have been larger than females. I'm not sure if there is a consistent "rule" in regards to the ornamentation and if there is I have been unable to find it thus far. Ichthyovenator (talk) 14:22, 28 October 2018 (UTC)
You might wanna quickly explain what demersal means   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:32, 28 October 2018 (UTC)
The Evolutionary history section seems to also serve as a Paleobiology section   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Maybe, but I'm not sure if paleobiology information could be separated from it in a good way, can't evolutionary adaptations (e.g. biology) be covered in evolutionary history?
"The group saw elevated extinction rates during the Frasnian (extinction of four families) and Famennian (extinction of five families) stages," seems unnecessary considering you already said Late Devonian extinction   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Might be worth mentioning that not all families died out at the same time but yes, I missed that the Late Devonian is just composed of the Frasnian and Famennian. I've rephrased it. Ichthyovenator (talk) 14:32, 28 October 2018 (UTC)
"The decline occurred chiefly in marine groups, which primarily impacted the eurypterine eurypterids," you already said this   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Hadn't previously mentioned that the eurypterines were the most affected, rephrased to be less repetitive. Ichthyovenator (talk) 14:32, 28 October 2018 (UTC)
Why do you use Frasnian and Famennian instead of Late Devonian?   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Explained above, changed to "Late Devonian". Ichthyovenator (talk) 14:32, 28 October 2018 (UTC)
Instead of agnathans you can use jawless fish   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:32, 28 October 2018 (UTC)
You should move the "Only three eurypterid families" part to the Carboniferous and Permian section   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:45, 28 October 2018 (UTC)
What new niche did the mycteroptid occupy?   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
The same niche as the hibbertopterids. I must've mixed up Hibbertopteridae with Hibbertopteroidea (a frequently used synonym of Mycteropoidea, to which both families belong). Fixed this. Ichthyovenator (talk) 14:45, 28 October 2018 (UTC)
Instead of Limulus, use Atlantic horseshoe crab   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:45, 28 October 2018 (UTC)
Explain paraphyly   User:Dunkleosteus77 |push to talk  20:36, 27 October 2018 (UTC)
Done. Ichthyovenator (talk) 14:45, 28 October 2018 (UTC)


### Comments by Super Dromaeosaurus
I would like to add some suggestions about the article.

The meaning of Eurypterida is only mentioned in the lead, it could also be placed somewhere in the "History of study". Super Ψ Dro 16:15, 28 October 2018 (UTC)
Of course, added the etymology of Eurypterus (since it's the same). Ichthyovenator (talk) 16:38, 28 October 2018 (UTC)
Gigantostraca could also be discussed somewhere.
Gigantostraca is strangely obscure and appears to be synonymous with either Eurypterida (as commonly stated and probably by its original definition) or "Merostomata" (as per the 1912 The Eurypterida of New York) depending on the researcher but I will see what I can track down. Ichthyovenator (talk) 19:06, 1 November 2018 (UTC)
Gigantostraca is now discussed under Classification. Ichthyovenator (talk) 10:49, 6 November 2018 (UTC)
I think you could add something else in the History of study, which ends in 1912, it is too early. Perhaps you could say something about the revision of Stylonurida by Kjellesvig-Waering of 1966 or about the revision of the whole order by Tollerton of 1989?
I added major post-1912 studies under Classification with those relating to internal relationships being discussed under Internal relationships. The 1966 revision of Stylonurida would probably be better discussed in Stylonurina. Ichthyovenator (talk) 16:38, 28 October 2018 (UTC)
Oh, I'm sorry for not noticing before.
I am surprised that the article lacks a section of paleoecology with the multitude of documents that speak about it. From what I see, a section like that is not usually used in other articles of this taxonomic range. But why does this happen?
Pretty sure Paleoecology is generally left out of higher-level taxa articles since in many cases an entire order of animals will have very divergent and ecologically unique animals within it and it would be more appropriate to discuss ecology in the articles of families or individual genera. There is some discussion on ecology under Evolutionary history and Feeding.
Okay then.
As a drive-by comment, I just came across a photo of an eurypterid trackway on Flickr[1], and thought it would be pretty interesting to show and discuss such in the article? And perhaps name-drop some ichotaxa, such as Palmichnium. FunkMonk (talk) 00:39, 29 October 2018 (UTC)
I agree, you could mention some ichnotaxa. Super Ψ Dro 18:18, 29 October 2018 (UTC)
There is a Hibbertopterus trackway discussed pretty in-depth under Locomotion and some discussion on information inferred from a Mixopterus trackway as well. We also have images of the Hibbertopterus track (1) that could potentially be used. I will see if I can find stuff to add on Palmichnium and other ichnotaxa, in case the new Palmichnium image could also be used. Ichthyovenator (talk) 18:51, 1 November 2018 (UTC)
It seems from the file that Palmichnium is the largest known track maker, so that seems it would be notable... FunkMonk (talk) 19:40, 1 November 2018 (UTC)
Yes, I remember reading something about over one meter (or even two). Speaking of ichnogenera, I have been investigating a little Palmichnium and there is a lot of information available and I would be interested in expanding it in the future. FunkMonk, is there any GA about ichnogenera or any expanded article that can serve as an example? The most comprehensive thing I have found to date is Grallator. Super Ψ Dro 21:34, 1 November 2018 (UTC)
Our ichnotaxon articles are all a mess... So whoever takes it up will create the standards, hehe... Jens Lallensack is an expert on dinosaur tracks, maybe he has some ideas on structure (though it is of course not the same)... I wrote a bunch of ichnotaxon history stuff for the Dilophosaurus FA, maybe it can be of use. FunkMonk (talk) 21:51, 1 November 2018 (UTC)
That only motivates me more! Thanks, I'll take a look. Super Ψ Dro 22:12, 1 November 2018 (UTC)
No clear idea how to write such an article; I would say: Just go ahead and try! I would be happy to have a look when its done, just let me now. --Jens Lallensack (talk) 21:17, 2 November 2018 (UTC)
There is now a new additional paragraph on fossil trackways and ichnogenera (all three eurypterid ichnogenera are mentioned as well) under Locomotion. Ichthyovenator (talk) 11:37, 11 November 2018 (UTC)
Nice! I do not see anything else to fix or add, everything depends on Dunkleosteus77. Super Ψ Dro 13:05, 11 November 2018 (UTC)
I also wonder if it would be correct to include another image of a stylonurid appendage VI to make a comparison with the swimming leg of Bassipterus.
Could be good to have, yes. Do we have any images in the same style of an appendage VI in any stylonurine though? Ichthyovenator (talk) 11:46, 6 November 2018 (UTC)
I do not remember if we have but this would be very easy to do and I could take care of it. Do you have any preference? Super Ψ Dro 19:12, 6 November 2018 (UTC)
Your choice! Might be good to go for something with reference images already in our image archive or with easily findable reference images elsewhere. Ichthyovenator (talk) 21:13, 6 November 2018 (UTC)
So looks like a discussion on ichnotaxa is the only thing left   User:Dunkleosteus77 |push to talk  19:43, 9 November 2018 (UTC)
Yes! I haven't had much time to write one yet but I should be able to this weekend or early next week. Ichthyovenator (talk) 20:54, 9 November 2018 (UTC)
Here is it! I selected Parastylonurus ornatus. I can remove some space if you want. Super Ψ Dro 19:03, 9 November 2018 (UTC)
Nice! I've added it to the article. Yeah, maybe it could be cropped just a little bit more. Ichthyovenator (talk) 19:34, 9 November 2018 (UTC)
Good! Now the article looks good for me, only needing the ichnotaxa. I cropped it a bit more. Super Ψ Dro 21:27, 9 November 2018 (UTC)
Dunkleosteus77, pinging, the ichnogenera comments have been adressed, are there any more changes necessary? Ichthyovenator (talk) 13:36, 16 November 2018 (UTC)

When you say largest eurypterid trackway, do you mean longest or it has the biggest footprints or it’s the widest?   User:Dunkleosteus77 |push to talk  14:44, 16 November 2018 (UTC)
I'm a bit unsure, it's simply referred to as "the largest". It has the biggest footprints for sure and might be the longest (though as far as I can find a large portion of the original find is now lost). Ichthyovenator (talk) 11:42, 17 November 2018 (UTC)
”the largest eurypterid trackway known” seems to imply it’s the longest stretch of eurypterid tracks, so if you’re not 100% sure of that, you should change the wording to mean something you are 100% sure of   User:Dunkleosteus77 |push to talk  16:30, 17 November 2018 (UTC)
Done. Ichthyovenator (talk) 17:10, 18 November 2018 (UTC)

I think the title should be “Eurypterida” because “eurypterid” could refer to both Eurypterida or Eurypteridae, making it ambiguous   User:Dunkleosteus77 |push to talk  02:58, 17 February 2019 (UTC)

Absolutely. This is yet another case of a misinterpretation of WP:COMMONNAME run amok. Official "common names" work (more or less) as article titles for extant bird and mammal species. Scientific names work better as article titles for almost all other taxa. Over the history of Wikipedia, WP:COMMONNAME has been misinterpreted to mean "avoid scientific names at all costs", on the grounds that "common names" are more RECOGNIZABLE than scientific names. Scientific names often meet WP:COMMONNAME's specification of the "name that is commonly used in reliable sources". Eurypterid is jargony shorthand for two scientific names; it is not a COMMONNAME in the sense of a recognizable vernacular name. It offers no RECOGNIZABILity benefits for general audience readers over the relevant scientific names. Plantdrew (talk) 06:25, 17 February 2019 (UTC)
Members of the group Eurypterida are referred to as "Eurypterids" in virtually every paper I've read on the subject, I'd argue that it's more than a "jargony shorthand" but I can see that some confusion might arise as a result of the family Eurypteridae (although I think "Eurypterid" almost exclusively is used to refer to the order rather than the family), renaming the article might be a worthwhile idea to consider. There's also the ever present idea of maybe using the more famous COMMONNAME, "sea scorpion", though the papers that comment on this seem to dissuade use of that name on the basis of being phylogenetically incorrect and confusing. Ichthyovenator (talk) 11:29, 17 February 2019 (UTC)
The Eurypteridae family is not widely used today, although it has had much prominence in the past for harboring a large number of genera and species in the past. Perhaps this page could be renamed to "sea scorpion" for the same reason that xiphosurids are called "horseshoe crabs" despite not being crabs. However, I would prefer to keep the current name. Super Ψ Dro 16:02, 23 February 2019 (UTC)
I would personally be in favor of either "Eurypterid" as it is now or "Eurypterida". As a family of only two genera (up until recently only one), I don't think there's many that associate "Eurypterid" more with Eurypteridae than Eurypterida. Would be good with more viewpoints though. Ichthyovenator (talk) 16:41, 23 February 2019 (UTC)

On the “Origins” section of the page, it says “There are also reports of even earlier fossil eurypterids in the Fezouata Biota of Late Tremadocian (Early Ordovician) age in Morocco, but these have yet to be thoroughly studied.” I presume this is referring to the undescribed fossil nicknamed “The Meathook”, which has been re-identified as being a probable hurdiid radiodont, close to Hurdia itself. 2.219.19.241 (talk) 10:30, 9 August 2023 (UTC)

The Fezouata sea scorpion is ?Carcinosoma aurorae. Houcaris\Zhenghecaris^| Talk^ 19:09, 13 November 2025 (UTC)