Cartorhynchus

Cartorhynchus is an extinct genus of basal ichthyosauriform marine reptile that lived during the early Triassic period.[1] Fossils have been found in eastern China and were unearthed from rocks in 2011. Those rocks were laid down as marine sediments about 248 million years ago. The only well-preserved fossil is quite complete, with only a portion of the tail missing. When alive, the creature was probably about 40 cm (16 in) long — about the size of a large lizard — and weighed about 2 kg (4.4 lb).

Etymology
The name of the only described species of the genus, Cartorhynchus lenticarpus, comes from the Greek words for “short snout” (a feature of the fossil) and Latin words for “flexible wrist.”

Description
The vertebrae and ribs are thick-walled and well mineralized, so the creature was probably an adult when it died. But most bones in the forelimbs were small and widely separated, a sign that the forelimbs were likely cartilage-filled flippers and not legs. The creature’s hindlimbs were reduced in size, another adaptation for life at sea. The creature’s heavy bones, like a scuba diver’s weight belt, counteracted natural buoyancy and probably enabled it to forage in shallow coastal waters. Yet Cartorhynchus could probably get around well on land using its flippers, just as seals and sea lions do today.