Dakosaurus

Dakosaurus is an extinct genus within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially (flattened from side to side). The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named Geosaurus maximus by Plieninger. Dakosaurus was a carnivore that spent much, if not all, its life out at sea. The extent of its adaptation to a marine lifestyle means that it is most likely that it mated at sea, but since no eggs or nests have been discovered that have been referred to Dakosaurus, whether it gave birth to live young at sea like dolphins and ichthyosaurs or came ashore like turtles is not known. The name Dakosaurus means "tearing lizard", and is derived from the Greek Dakos- ("to tear") and -sauros ("lizard").

Discovery and species
When isolated Dakosaurus teeth were first discovered in Germany, they were mistaken for belonging to the theropod dinosaur Megalosaurus.[8]

Fossil specimens referrable to Dakosaurus are known from Late Jurassic deposits from England, France, Switzerland, Germany,[9]Poland,[10]Russia,[11]Argentina,[3] and Mexico.[12] Teeth referrable to Dakosaurus are known from Europe from the Oxfordian to the Valanginian

Valid species
The type species Dakosaurus maximus, meaning "greatest tearing lizard" is known from fossil discoveries in Western Europe (England, France, Switzerland and Germany) of the Late Jurassic (Late Kimmeridgian-Early Tithonian).[9][15]

Dakosaurus andiniensis, meaning "tearing lizard from the Andes", was first discovered in 1987 in the Neuquén Basin, a very rich fossil bed in Argentina. However, it was not until 1996 that the binomen Dakosaurus andiniensis was erected.[3] Two recently discovered skulls have indicated that D. andiniensis is unique among the metriorhynchids (the most specialised family of crocodylians to marine life) with its short, tall snout (which is why it was nicknamed Godzilla).This species has a fossil range from the End Jurassic-Beginning Cretaceous (Late Tithonian-Early Berriasian).[16]

Dakosaurus lapparenti, meaning "Lapparent's tearing lizard", was named in honour of French palaeontologist Albert-Félix de Lapparent. It is based upon isolated skull and post-cranial bones from the Early Cretaceous (Valanginian) of France.[4]

Dakosaurus carpenteri, meaning "Carpenter's tearing lizard" is known from fossils from England of the Late Jurassic (late Kimmeridgian).

Unnamed species
Incomplete skull specimens of Dakosaurus has been discovered in Kimmeridgian age rocks from Mexico.

Taxonomy and phylogeny
The genus Plesiosuchus is a junior synonym of Dakosaurus,[7] while Dacosaurus is a mis-spelling.[6] Recent phylogenetic analysis however, does not support the monophyly of Dakosaurus,[18] although the species D. maximus and D. andiniensis do constite a natural group.