Thalattosaurus

Thalattosaurus
Temporal range: Late Triassic,
Illustration of T. alexandrae holotype
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Thalattosauria
Family: Thalattosauridae
Genus: Thalattosaurus
Merriam, 1904
Type species
†Thalattosaurus alexandrae
Merriam, 1904
Species
  • T. alexandrae (Merriam, 1904) (type)
  • T. borealis (Nicholls and Brinkman, 1993)
  • T. perrini? (Merriam, 1905)
  • T. shastensis? (Merriam, 1905)

Thalattosaurus (pronounced: /θəˌlætəˈsɔːrəs/, tha-la-to-SORE-us from Ancient Greek: θάλαττα, romanized: thálatta, lit.'sea' and σαῦρος, saûros, 'lizard') is an extinct genus of marine reptile in the family Thalattosauroidea. Known exclusively from the Triassic period, it was a 2–3 metres (6.6–9.8 ft) long shellfish-eating diapsid with paddle-like limbs and a down-turned rostrum. Fossils were recovered in the Lower and Middle Triassic Sulphur Mountain Formation of British Columbia as well as the Upper Triassic Hosselkus Limestone of California. It has gained notoriety as a result of studies on general diapsid phylogeny.

Although originally described as four distinct species by Merriam in 1905, one was proven to be T. alexandrae upon further inspection and another has a missing type specimen. Currently it is believed to include two known species; Thalattosaurus alexandrae and T. borealis.