Trinacromerum was a plesiosaur, a type of marine reptile. It was not a dinosaur, though it coexisted with many dinosaurs. Trinacromerum lived during the Late Cretaceous.
All these Trinacromerum pictures were collected from the internet. Enjoy and explore:
- D. D. Gillette and M. C. Hayden. 1999. Occurrence and biostratigraphic framework of a plesiosaur from the Upper Cretaceous Tropic Shale of southwestern Utah. Utah Geological Survey Miscellaneous Publication 99-1:269-273
- K. Shimada and B. A. Schumacher. 2006. Fossil marine vertebrates from the lowermost Greenhorn Limestone (Upper Cretaceous: Middle Cenomanian) in southeastern Colorado. Journal of Paleontology 80(sp 63):1-45
- D. Bardack. 1968. Fossil vertebrates from the marine Cretaceous of Manitoba. Canadian Journal of Earth Sciences 5:145-153