Jaekelopterus - The Biggest Arthropod That Ever Lived

millions and millions of years ago in the deep past of our planet life was very different unique environmental and ecological conditions enabled some absolutely extraordinary animals to evolve and relatives of organisms that today are generally very small were once capable of reaching and even exceeding the size of a person one of these beasts was Jacob for us a huge aquatic arthropod that's estimated to have grown to lengths of two and a half meters or 8 foot 2 inches J Kellogg Terrace was a member of a group known as the Europe turrets the so called sea scorpions though that name is a bit misleading as Europe turrets are not actually scorpions and only the earliest members of the lineage lived in the sea with many later taxa including our friends Jakob Taurus actually inhabiting brackish to freshwater Europe turrets were an incredibly successful and diverse group of arthropods that survived for well over 200 million years with quite a few different species managing to get to very large sizes however Jakob Taurus was the biggest of them all at least the recurrence beam though of so let's take a look at this magnificently terrifying creature to find out why it got so big how it lived and where it fits into the Great Tree of Life clearly the size of this author pod is one of the most significant things about it giant prehistoric arthropods from the Paleozoic have an understandable appeal to them from the huge millipede arthropleura which we've looked at on this channel before to the enormous dragonfly relatives such as Megan Errol but while those terrestrial and aerial species which live during the Carboniferous period and breathed with trachea were likely able to achieve the dimensions that got to thanks to greater levels of atmospheric oxygen at this time it has been noted that the widespread gigantism of aquatic arthropods such as in Europe turrets indicates that the mechanisms for enabling and selecting for gigantism in these animals is more complex than we had thought one now outdated idea for why Europe traits such as Jacob Taurus grew so large was that they were involved in an evolutionary arms race with the early vertebrates of the time and that in response to predation pressure from the Europe towards the vertebrates evolved their strong dermal Armour and then in return the sea scorpions got bigger in order to more effectively hunt them but this idea has been mostly dismissed as far too simplistic and as more of a narrative instead of it being solely due to an arms race with vertebrates it was probably a mix of many different environmental ecological and and cool factors that enabled these giants to rise though they were probably still the apex predators of their shallow marine and freshwater environments feeding on small early vertebrates and other arthropods the Jakob first specimen that led to the estimates of giant sizes in this taxon was described in 2007 and was composed of a claw technically known as a callus era from early devonian rocks in Germany this cloth specimen is actually missing a quarter of the total length and is thought to have been forty five and a half centimeters long when complete as such the researchers calculated based on the ratios of claw a total body length and other related Europe threads that this specimen of Jakob Turris would have reached about two and a half meters the largest size of any arthropod known to science this same paper also explains how certain basic points of arthropod anatomy generally restrict these animals from reaching enormous dimensions such as still maintaining the ability to move respire the amount of energy it would take to molt and the mechanical capabilities of their exoskeletons so Jakob Taurus and other huge Hewitt's would have had to find a way to overcome these issues one way they could have done this is also suggested in the study by having a very thin lightweight exoskeleton the claws of these creatures were very strong and heavily built however the rest of their exoskeleton seems to have had a very thin and unmanned er alized cuticle as you may remember if you've seen my arthropleura video this sort of thin exoskeleton was also noted in those giant millipedes and argued to be a reason for why they could get so big however it was then later argued by others that the thinness of the fossils could actually be due to the fact that the remains of malted exoskeletons nevertheless it would certainly have been physically much easier for your rep turrets to get as large as they did compared to arthur pleura since they display adaptations suggesting a fully aquatic lifestyle and would have had the support of water on their bodies so it doesn't seem like the giant sea scorpions would have been capable at all of moving about on land very well the proposed size estimate of two and a half metres in length based on the giant claw fossil was actually challenged in 2008 however with other researchers suggesting that it might have been overestimated these researchers pointed out that the way the claws increase in size as the animal grows could be different to the way the body as a whole grows and that sometimes appendages in arthropods can be oversized compared to the rest of the body meaning that finding such an appendage on its own could lead to an overestimation of the total body length however the authors of the publication describing the giant claw soon responded to these critiques stating that they had based their scaling on very closely related taxa in which the ratio of body length to callus array length is known for certain and so they can be fairly sure that the scaling is as accurate as possible in addition they say that the point about oversized growth of appendages in some arthropods a type of growth known as positive aloma tree is not known for the claws of any Europe turret so again the scaling estimate is fairly reliable the reply also hints at the existence of another giant claw specimen which could help in our understanding of Jacob Taurus scaling unfortunately it is now in a private collection and so cannot currently be studied as I mentioned earlier Jacob Taurus would have been a pretty formidable predator of his ancient watery habitats preying on all kinds of smaller animals there's actually some interesting direct evidence of the predation habits of Europe turrets with a species of jawless armored vertebrate from the Devonian that was named in 2011 lekker aspis actually preserving puncture wounds that seemed to have been inflicted by a Europe turrets such as Jacob Taurus other signs pointed to an active predatory lifestyle for this creature - such as the anatomy of the arthropods eyes the study from 2015 looked at the preserved eye lenses in several Europe to attack sir including Jacob Taurus finding that there was actually a good deal of difference between the apparent Ecology's of a few members of a Terry go to day family which Jacob versus a part of within Europe turrets by looking at the number of lenses and the angle between optical axes of adjacent lenses known as the IOA or inter a material angle it's possible to figure out the visual acuity of an arthropod and so this is what the researchers did with these Terry goated Europe turrets some such as the genus acuity ramas and a pretty low visual acuity and seems to have been a generalist feeder with relatively weak slicing adapted claws however moving to Jacob Taurus and a closely related to Terry gotas which had more robust crushing adapted callous array these taxa had very high visual acuity comparable to the vision in living arthropod predators so it would seem that somewhere along the Terry goated family there was a transition for more general feeders to specialized predators such as the giant Jackalope Taurus as I've just mentioned Jackalope Taurus is classified as a Terry goated Europe turret the Europe turret group as a whole includes about 250 different species and within the Terry goated family there are six general with many of these general containing a variety of species the Jaeckel Optimus genus itself actually includes two really quite different species the original type species Jackalope Taurus wren an EA and Jacob Taurus how early jaren an EA is the larger of the two species and the one that the giant claw belongs to being known from fossils found in Germany where as Jay Halle was much smaller reaching only 80 centimeters or 2 point 6 feet in length and coming from rocks in Wyoming the species are still similar in ways though such as an anatomical detail seen in identicals of the colossi and the shape of the telson the last segment of the abdomen as I also mentioned earlier Jacob Taurus is very closely related to the genus Terry gotas for which the whole family is named and an overall morphology they're very similar to one another in fact Jaeckel up Taurus was actually initially named as a species of Terry gotas by a german paleontologist Otto jcore in 1914 only in latest studies once more complete fossils of the animal had been discovered were various anatomical differences cited as indicating a generic level separation with a new genus Jackalope Taurus after Jaeckel being named in 1964 by Charles D Waterston then in 2007 the second american species was moved from the terry goatest genus to jacob tourist - recently there has also been some questioning as to whether Jacob Taurus Terry gotas and even a cutie ramas which was mentioned earlier do actually show enough distinctiveness from one another to be separated into three different genera with a being argued that the differences between denticulate and patterns of the Calissa is not a good indication of distinct general but for now at least they are still recognized as unique taxa so we know that Jacob to us was a Terry goated and that it was e-rep turret but what actually is a Europe turret well for a long time who thought this extinct group of organisms was very closely related to those life assurance horseshoe crabs various similarities between the members of both groups seemingly solidified this relationship for many years however in 2012 a reanalysis of the horseshoe cramp group revealed evidence that this clade was actually paraphyletic or an unnatural group in not including every of a common ancestor this study as well as later ones instead support a close relationship between you rep turrets and arachnids placing the groups along with others such as the Kaz matter spiders a strange extinct arthropod order in a group together called decant Reata research continues into the fascinating Europe turrets and their internal as well as external evolutionary relationships and as with many things in paleontology I'm sure we'll see changes in the specifics as new discoveries and analyses reveal insights that were unknown to us before so Jacob torus was a truly intriguing prehistoric creature a giant of its time well one of the species anyway it appears to have been an intimidating top predator of its shallow water environments using its acute vision to detect unfortunate small vertebrates or other arthropods and then employing its deadly robust callous array to crush them puncturing through their armor and exoskeletons it's a captivating organism and hopefully more specimens of some giant individuals will be uncovered in the future allowing us to discover more about this wonderful animal well I hope you enjoyed this video and learn something new and a big thank you to our patreon supporters especially our dinosaur tear supporters Dominic Buffy and slumbering giant if you would like to find out more about our world its history and the wonderful life that surrounds us all please feel free to subscribe to the channel if you think we deserve it and if you would like to see more from us [Music] you

Channel: Ben G Thomas

Views: 233,263

Rating: 4.9578013 out of 5

Keywords: Biology, Science, Paleontology, Palaeontology, Dinosaurs, Animals, Nature, Wildlife, Ben, Thomas, Prehistory, Anatomy, Fossil, Bones, News, 7Daysofscience, Days, of, sea scorpion, eurypterid, walking with monsters, devonian, arthropleura, meganeura, horseshoe crab

Id: EN2PhC4YZuk

Length: 10min 27sec (627 seconds)

Published: Sun Apr 05 2020