Thalattoarchon

Thalattoarchon; Temporal range: Middle Triassic, Late Anisian,
	Holotype skull (FMNH PR 3032)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Ichthyosauria
Node:	†Merriamosauria
Genus:	†Thalattoarchon; Fröbisch et al., 2013
Type species
	†Thalattoarchon saurophagis; Fröbisch et al., 2013

Thalattoarchon is a genus of large, Middle Triassic predatory ichthyosaur from North America, containing the single species T. saurophagis. The taxon was described in 2013 from a single specimen discovered in the Favret Formation in Nevada. The generic name, meaning "ruler of the seas", refers to its status as an apex predator, while the specific epithet, meaning "lizard eater", alludes to its carnivorous diet. The classification of this genus within the ichthyosaurs is much debated, being either classified within the clade Merriamosauria or in the more basal family Cymbospondylidae.

As an ichthyosaur, Thalattoarchon had flippers for limbs and a fin on the tail. The size of this large ichthyosaur is estimated around 8.6 meters (28 ft) long, although the authors are uncertain about the exact measurements. The animal has a long, slender body but with a proportionally large head and a straight, elongated tail. The jaws of Thalattoarchon feature large teeth with two cutting edges of up to 12 centimeters (0.39 ft), which would have been well suited for attacking large prey. Although the fossils are incomplete, it is estimated that the animal would have had a skeleton comprising at least 60 presacral vertebrae. Thalattoarchon would have been an apex predator, its sharp and cutting teeth suggesting that it would have mainly preyed on contemporary marine reptiles. Its position as a apex predator is generally comparable to that of orcas, which have a similar lifestyle.