2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Reptile Eretmorhipis carrolldongi as seen by the artist. These marine vertebrates appear to have lived in shallow water and hunted by touch.
The ancient reptiles Eretmorhipis carrolldongi, which lived about 250 million years ago, hunted by touch. As Scientific Reports says, their eyes were too small to rely on. Scientists found no indication that the reptiles were looking for prey by smell or sound, and concluded that they most likely relied on tactile sensations.
The first carnivorous marine vertebrates appeared shortly after the massive Permian extinction, which occurred approximately 252 million years ago. Most of the oldest marine reptiles belonged to the Ichthyosauromorpha clade. This group included the fish-like ichthyosaurs, which appeared about 250 million years ago, and the Hupehsuchia, a group of reptiles with a long tail, webbed limbs and a number of armor-like bony plates on their backs. Apparently, they only existed for a few hundred thousand years, in the period 248-247, 2 million years ago.
The species Eretmorhipis carrolldongi belonged to the Hupesuchia. These reptiles had bony plates, like other chupezuchia, but, unlike them, they had toes on their front and hind legs. Previously, paleontologists found fossils of two Eretmorhipis in the Hubei province in central China, but the skulls were missing. In a new study, Chinese, American and Italian scientists led by Ryosuke Motani of the University of California, Davis describe the fossils of two skull-bearing erethmorhipis. The skeleton of one reptile was almost completely preserved, only a few bones of the limbs were missing, only the front part remained from the skeleton of the other. Fossils of both Eretmorhipis were found by paleontologists in Yuanyan county in Hubei province.
Fossils and drawings of the structure of the body of the Eretporkhipis
Judging by the structure of the skulls, these reptiles were a bit like modern platypuses. They also had an elongated muzzle and beak; an unpaired dumbbell-like bone that platypuses have and small eyes.
Eye size, at least in theory, affects visual acuity. Scientists have confirmed this relationship for mammals and ray-finned fish. In the Eretmorchipis, the size of the eyes in relation to the size of the body was approximately half that of the rest of the chupezuchia. Animals with small eyes see poorly and rely more on other senses. The authors made sure that this is indeed the case by comparing 13 modern animal species with the smallest eyes in relation to body size. Many of them are nocturnal, and all have more developed other senses - smell, hearing, the ability to electroreception, there are vibrissae.
Therefore, the researchers suggested that the eretmorhipis also used not sight, but other senses. Judging by the morphology of the skull, these were not scent or hearing, but tactile sensations. They may have used electroreception like modern platypuses, but that's just speculation. To date, no reptiles are known to use electroreception; it first appeared in mammals. But it is possible that ancient marine reptiles developed this ability.
Based on the results of the study of the fossils, the authors of the article described the structure and lifestyle of the Eretmorhipis. Supposedly they were slow but agile swimmers; they had large fan-shaped limbs. They probably hunted at dusk or in the dark. Based on the fossils found, eight more species of predatory marine reptiles lived in the lagoon where these reptiles lived at about the same time. Probably, in order to get along with each other, they had to share resources, for example, to hunt at different times of the day. It is not known exactly what the Eretmorhipis ate. But judging by finds in sediments in Yuanyan County, it could be shrimp-like arthropods.
Previously, paleontologists suggested that the distant relatives of the ichthyosaurs of the Eretmorchipis could be warm-blooded. In the fossils of one of the representatives of the order, they found the remains of subcutaneous fat, which is present in modern marine mammals. Among other functions, it allows animals to keep warm.