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Edits
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.
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)reply
Chelicerae
Uncate (tong-like) chelicerae typical of harvestmen (200x magnification); these appendages are equivalent to a spider's fangs.
Pterygotus chelicera
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).
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♠nSoul23:48, 5 November 2010 (UTC)reply
The most fearsome swimming predators of the Palaeozoic?
"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." --
201.51.231.17620:28, 6 March 2007 (UTC)reply
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 Ninlil03:53, 7 March 2007 (UTC)reply
Largest arthropods
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.
PenguinJockey20:22, 13 May 2007 (UTC)reply
Largest Arthropod?
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.
Ammonight42300:50, 12 October 2007 (UTC)reply
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)reply
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)reply
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)reply
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)reply
Date of extinction
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)reply
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)reply
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)reply
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.--instantn00dle15:48, 15 November 2010 (UTC)reply
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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Articles for eurypterid taxonomy, morphology, etc.
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?
SuperΨDro16:33, 27 August 2018 (UTC)reply
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)reply
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?
SuperΨDro17:23, 29 August 2018 (UTC)reply
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)reply
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.
SuperΨDro17:56, 29 August 2018 (UTC)reply
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)reply
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 talk19:19, 16 October 2018 (UTC)reply
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)reply
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 talk03:09, 17 October 2018 (UTC)reply
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)reply
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)reply
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)reply
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)reply
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)reply
”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 talk15:48, 20 October 2018 (UTC)reply
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)reply
You say whether they were direct or hemianamorphic developers is controversial but then say point-blank they were direct developers
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)reply
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 talk20:36, 27 October 2018 (UTC)reply
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)reply
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)reply
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)reply
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)reply
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)reply
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)reply
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.
SuperΨDro21:34, 1 November 2018 (UTC)reply
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)reply
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)reply
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)reply
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)reply
”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 talk16:30, 17 November 2018 (UTC)reply
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)reply
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)reply
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.
SuperΨDro16:02, 23 February 2019 (UTC)reply
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)reply
Fezouata eurypterids?
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)reply