Temporal range: Late Cretaceous
Trinacromerum at Royal Ontario Museum
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Order: Plesiosauria
Suborder: Plesiosauroidea
Family: Polycotylidae
Genus: Trinacromerum
Profile view of Trinacromerum
Trinacromerum with a human to scale.
Trinacromerum bentonianum from the Late Cretaceous of Kansas

Trinacromerum is an extinct genus of sauropterygian reptile belonging to the plesiosaur suborder. It lived during the Late Cretaceous period in what is now Kansas. It was 3 meters (10 feet) long. Its teeth show it fed on small fish.

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]


  1. ^ Ellis, Richard (2003). Sea Dragons: Predators of the Prehistoric Oceans. University Press of Kansas. p. 189. ISBN 0-7006-1269-6. 
  2. ^ Ellis, 190

External links