In Depth Eopolycotylus is another example of one of the short necked/long jawed polycotylid plesiosaurs of the Cretaceous era. The genus name Eopolycotylus means ‘Dawn Polycotylus’ and is a reference to the earlier appearance of Eopolycotylus in the fossil record to Polycotylus, the type genus of the Polycotylidae. The type species name honours David O. … Read more
In Depth With remains that were found in Campanian age rocks Terminonatator was possibly one of the last elasmosaurid plesiosaurs to swim in the ocean. This is a far cry away from the Jurassic heyday of the plesiosaurs when they were one of the most common types of marine reptile in the ocean. In the … Read more
In Depth Fluvionectes is a genus of elasmosaurid plesiosaur that lived in North America during the late Cretaceous. The first fossils of this genus were recovered from the Dinosaur Park Formation in Canada, a location that has yielded numerous though fragmentary and scattered plesiosaur fossil for some time. Perhaps the most stand out fact about … Read more
In Depth Nakonanectes is a genus of elasmosaurid plesiosaur that would have hunted in the Western interior seaway during the late Cretaceous period. Nakonanectes is noted for having short cervical vertebrae and an estimated length of only about five and a half meters at most for the holotype individual. This is small for an elasmosaurid … Read more
In Depth Aphrosaurus seems to have been a middle sized lightweight elasmosaurid plesiosaur. Elasmosaurid plesiosaurs (those similar to Elasmosaurus) are known for having proportionately long legs, and like with others, half of the total length of Aphrosaurus was neck. This neck was one of the primary feeding adaptations that would have allowed it to reach … Read more
In Depth Dactylosaurus was one of the smallest known pachypleurosaurs, a group of marine reptiles with close associations to the nothosaurs, though opinions differ on if they should belong within the Nothosauroidea or be separate to them. Dactylosaurus may have been fed upon by other marine reptiles and large fish such as primitive sharks like … Read more
In Depth Callawayasaurus was originally known as a species of Alzadasaurus until Kenneth Carpenter studied the remains and found that they actually represented a new genus. On a related note the type specimen of Alzadasaurus today only exists as a synonym to Thalassomedon and Styxosaurus. Carpenter named the new genus in honour of fellow palaeontologist … Read more
In Depth Because the holotype specimen of Morenosaurus is incomplete, it is hard to establish a precise classification of his plesiosaur, especially since the skull is unknown. It is probable however that Morenosaurus is an elasmosaurid (similar to Elasmosaurus) since these were the dominant kinds of plesiosaurs during the late Cretaceous. Additionally if this is … Read more
In Depth Cryptoclidid plesiosaurs (those typified by Cryptoclidus) seem to have become very rare towards the end of the Cretaceous with Kaiwhekea being one of the few known members of this family present this late in the Mesozoic. Like with so many of the late surviving plesiosaurs, Kaiwhekea seems to have survived this long by … Read more
In Depth Although Alexeyisaurus was described from partial remains, it seems that further material was actually present at the site of its discovery. Still, the material recovered is enough to suggest that Alexeyisaurus is one of the earliest known elasmosaurid plesiosaurs, the group of plesiosaurs that had proportionately much longer necks than the more ‘standard’ … Read more