All pterosaur eurypterids (sea scorpions), giant aquatic arthropods with large claws, were considered apex predators, but some scientists believe that certain species are not predatory because their claws are weak. suggested. New research reveals that their claws were stronger and were only used to capture prey. Other appendages chewed it up. Fossils found in the pterosaur eurypterids show that some species specialized in lightly armored crustaceans and fishes, but most species specialized in heavily armored fishes.
Size of sea scorpions (Euripterids) over time.pterosaur eurypterid Jachelopterus (Background), the largest arthropod of all time, and a eurypterid of the Hibertopteridae family. Siltoctenus (Foreground) The size of a human (an average British male) compared to the silhouette of its eurypterid relatives. Image credit: Simon Powell.
Sea scorpions (family Eurypteridae) are ancient aquatic creepy crawlers (arthropods) that lived long before the dinosaurs, from 467 million to 253 million years ago.
These include the “pterygoids” (428 to 391 million years ago), which had large, fearsome claws. Grows up to 2.5 meters longthe biggest bug that ever existed.
An extinct millipede called Arthropleura was It is claimed that it is even largerHowever, if the length of 12 to 14 preserved body segments is 76 cm, the body length of an animal with 32 segments is (76/12 x 32), which is just over 2 m (excluding the head).
All pterosaurs, eurypterids, were thought to have been ferocious apex predators. tyrannosaurus About their time.
Later, some scientists believed that pterygoid claws acutiramus It could only catch and slice weak, soft-bodied prey, and its eyesight wasn't sharp enough Becoming a predator.It has been demoted from the top echelon of predators and even a label is attached “Pussycat”.
According to new research, nails acutiramus It was much more robust. Suggestions that they would snap were based on incorrect assumptions.
The apparent lack of an “elbow joint” doesn't hurt either. This was at the base of the nail. Also, the claws were used only for catching prey. If it had more powerful mouthparts in the groin, it would kill or chew it up.
It doesn't matter that their eyesight is poor either. Their prey is large, and some non-predatory insects (such as bees and butterflies) have eye indicators similar to arthropods that were considered predators.
Computer modeling and experiments with robotic swimming eurypterids also show that pterosaurs were slower swimmers than expected. They were so large that relatively small swim paddles could not provide sufficient propulsion, so a flat tail (telson) served both as a rudder and as propulsion.
Analysis of the types of fossils found with pterygomorphs also suggests that: acutiramus It specializes in lightly armored crustaceans (called foliaceans) and pterophytes. Eretopterus Therodont fish and pterigotus and Jachelopterus About the more heavily armored placoderm fish.
Evidence of predation (claw marks) and fossilized feces (coprolites) confirm that some eurypterids ate armored fish, trilobites, and even other eurypterids.
Previous studies have generally dismissed suggestions that Eurypteridae influenced the evolution of early vertebrates (fish) in a predator-prey arms race, but this new study This suggests that pterosaurs and other eurypterids probably had some influence on the evolution of early vertebrates.
The evolutionary relationships of pterygoids have also changed. Their shape, vision, fossil associations, ecology, and stratigraphic record all indicate that: acutiramus It was more basic Jachelopterus and pterigotus.
This is the largest arthropod in history (Jachelopterus lenaniae) It is now estimated to be about 2.6 meters long, 10 centimeters longer than previous estimates. The biggest bug is now a little bigger.
this paper will appear in Earth Science Bulletin.
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S. J. Brady. 2023. Paleoecology of the pterygoid eurypterids: Pladicnia and paleontological assemblages. Earth Science Bulletin 98(4); doi: 10.3140/bull.geosci.1891
Source: www.sci.news
