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Trinacromerum
Temporal range: Late Cretaceous
Trinacromerum.jpg
Life restoration of Trinacromerum kirki
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Subclass: Sauropterygia
Order: Plesiosauria
Superfamily: Plesiosauroidea
Family: Polycotylidae
Genus: Trinacromerum
Cragin, 1888

Trinacromerum is an extinct genus of sauropterygian reptile, a member of the polycotylid plesiosaurs. It contains two species, T. bentonianum and T. kirki. Specimens have been discovered in the Late Cretaceous fossil deposits of what is now modern Kansas and Manitoba.[1]

Description

Trinacromerum was 3 meters 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]

Plesiosauroidea 

Cryptoclididae


 Leptocleidia 

Leptocleididae


 Polycotylidae 

Edgarosaurus





Plesiopleurodon



QM F18041






Eopolycotylus



Polycotylus



Thililua





Trinacromerum




Manemergus




"D. herschelensis"




Dolichorhynchops



Palmulasaurus











See also

References

  1. 1.0 1.1 1.2 Ellis, Richard (2003). Sea Dragons: Predators of the Prehistoric Oceans. University Press of Kansas. p. 189. ISBN 0-7006-1269-6. 
  2. Ellis, 190
  3. Hilary F. Ketchum and 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. doi:10.1111/j.1475-4983.2011.01083.x.