The history of life on our planet has some striking oddities. From the origin of life to the present day, millions of different species have populated this world. We know so many of them, and every year scientists continue to describe more and more different life forms. However, the percentage of species that we do not know is still much higher. Above all, it is overwhelming to look back over so many millions of years in which the main clues to knowing a species are the fossils of already extinct animals. Some of these fossils are from very famous species, such as Tyrannosaurus rex ; Others, like the ones we bring here, are from species that are so strange to modern humans that some were questioned as real creatures.
tully’s monster
Tullimonstrum gregarium is a rare bug that lived about 300 million years ago, during the Carboniferous period. It was discovered in 1958 and, for now, all the specimens have been found in North America, in present-day Illinois, where it is quite a celebrity.
Fossils have allowed us to reconstruct what it looked like, but it has taken us a while to clarify what this animal really was, which seems to be taken from an alien movie. It has a squid-like body without tentacles, with eyes located at the end of two antennae, and a proboscis topped with a pincer-like mouth full of teeth .
The four-legged snake
Tetrapodophis amplectus lived between 146 million and 100 million years ago and was a four-limbed snake that lived in burrows.
Although it may seem like a strange animal to us (it is, we are not going to deny it), it is a logical link in the chain of evolution that led to a transition from lizards to snakes, only no specimen with these characteristics was known. In 2015, a study led by David M. Martill described a fossil found in Brazil.
The body is like that of the snakes we know today, with a long throne, short tail and ventral scales that invite us to think that they moved making the characteristic “esses” of snakes. But the distinctive element of this species is that it conserves small extremities with fingers, two hind legs and two front legs . The fossil showed the presence of vertebrates in the guts, so this species hunted and fed on vertebrates.
Leptoceratops gracilis
It was discovered in 1910 by Barnum Brown in Alberta, Canada, although fossil remains have been found throughout the American West where it lived about 67 million years ago. It belongs to the family of the famous Triceratops , but in this case we are dealing with a small dinosaur, with short arms and long legs, which suggests that it could run upright and, although it has a robust skull, it does not have horns, as it is characteristic of the rest of its relatives. Rather, it has tall, sharp spines on its tail , possibly used for defense.
amargasaurus
This curious species of dinosaur, in addition to a long neck, had long bumps on the cervical vertebrae . It belonged to the sauropod family, among which are the famous long-necked dinosaurs like Brontosaurus .
Although the appearance and function of these vertebral spines are still being debated among scientists, the most weighty options defend that they would have the shape of spikes, although the latest studies speak of a sail: a membrane that would unite these bifid spines. As for their function, it has been said that they could serve to intimidate predators, to attack or even as an element to display during courtship.
Amargasaurus Cazaui lived in present-day South America around 130 million years ago.
References:
Cerda, I. et al. 2022. Osteohistology of the hyperelongate hemispinous processes of Amargasaurus Cazaui (Dinosauria: Sauropoda): Implications for soft tissue reconstruction and functional significance. Journal of Anatomy 240, 6, 1005-1019. DOI: 10.1111/joa.13659.
Martill, D. et al. 2015. A four-legged snake from the Early Cretaceous of Gondwana. Science 349, 6246, 416-419. DOI: 10.1126/science.aaa9208.
McCoy, V. et al. 2016. The ‘Tully monster’ is a vertebrate. Nature 532, 496-499. DOI: 10.1038/nature16992.
