Dyrosaurus Temporal range: Late Cretaceous to Eocene, 90–40 Ma |
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Restored skeleton | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Family: | †Dyrosauridae |
Genus: |
†Dyrosaurus Pomel, 1894 |
Species | |
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Dyrosaurus is a genus of extinct crocodylomorph that lived from the upper Cretaceous to the Eocene period, surviving the K-Pg extinction event.Dyrosaurus are linked to pholidosaurids as a clade and are defined as slender-snouted, fish-eating specialists adapted to near-shore marine habitats.
The Dyrosauridae are a group of mostly marine, long jawed, crocodile-like quadrupeds up to 6 metres (20 ft) long. Based on bone tissue evidence, it has been hypothesized that they were slow-growing near-shore marine animals with interlocking closed jaws, able to swim as well as walk on land. External nostrils at the posterior end of its snout and an internal naris in its pterygoid indicated a habit of hunting while swimming with the top of the head above the water, enabling it to breathe while stalking prey.
Fossils from this genus have been found in Africa, Europe, North and South America, Southern Asia and India. Although the family Dyrosauridae is quite diverse with many forms of crocodyliforms, the genus Dyrosaurus has only two described species: D. phosphaticus and D. maghribensis. D. phosphaticus was first discovered in Algeria and Tunsinia whereas D. maghribensis has only been found in Morocco.D. maghribensis differs from D. phosphaticus by several synapomorphies, most notably: a smooth dorsal margin of the parietal and widely opened choanae, interfenestral bar wide and strongly T shaped instead of moderately T shaped.
Dyrosaurids are known to have a very characteristic skull shape with a long and thin snout that is approximately 68% of the total skull length. The most anterior part of the skull and snout is the external naris followed posteriorly by two premaxillae bones until they reach two maxillae bones separated by a single nasal bone.
Typical in dyrosaurids is a single nasal element with a characteristic collection of small pits and a constant width until it widens to contact the lacrimal bones, then tapering off for a short distance until it meets the boundary of the frontals and prefrontals.