Hellow, BK, again!!!
Thank you very much for the question!!!
I want to ask, what do you think, who was the largest arthropod: pterygotus or jaekelopterus?
Also, I read in another text:
"Pterygotids constitute a monophyletic group of predatory eurypterids that have attracted attention as the largest arthropods known, attaining body lengths of more than 300cm, and even incomplete specimens are spectacular fossils."
"attaining body length of more than 300cm"- So it means length without claw extended, what do you think?
Hello again Alexander.
Even though the remains found of Jaekelopterus aren't complete, it has been estimated to exceed 8ft in length (without claws extended). That would make it slightly larger than Pterygotus. Until it's better established how large Jaekelopterus actually was, I have to say it's possible (but not definite).
In this particular article, the way the term "body length" is used, it seems to be indicating this length is without the claws extended, but it doesn't say for sure. In contrast, when stating the length of a tiger, most sources will specify "without the tail" or "including tail" or "total body length" to give the reader a more accurate idea of the actual dimensions. Because 300cm (almost 10 feet) is the current substantiated length of Pterygotus with claws extended, it's possible the article intended the term "body length" to mean the entire animal (with claws extended). It's a bit misleading. If I stated "a tiger is 9ft long" without including further details, it wouldn't be clear on whether or not I meant to include or exclude the tail. If this article means to say the body length of Pterygotus was 300cm without claws extended, that would make the entire creature almost 4 meters (13ft) long. It hasn't been established (so far) by any mainstream sources that it got that big, so the 300cm figure for the length with claws extended seems more reasonable.
In the same way sauropods are continually being found that exceed the sizes of previous ones (and establish a new largest land animal ever), it's certainly reasonable that new, complete fossils of Pterygotus & similar creatures will emerge and larger sizes will be established.