Trinacromerum was 3 meters (9.8 feet) long. Its teeth show that it fed on small fish.[1]
The long flippers of Trinacromerum enabled it to achieve high swimming speeds.[1] Its physical appearance was described by Richard Ellis as akin to a "four-flippered penguin."[2] Its name means "three tipped femur".
Classification
Below is a cladogram of polycotylid relationships from Ketchum & Benson, 2011.[3]
^Hilary F. Ketchum; Roger B. J. Benson (2011). "A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids". Special Papers in Palaeontology. 86: 109–129.