Nicrosaurus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of phytosaur

Phytosaur

Phytosaurs are an extinct group of large semi-aquatic Late Triassic archosaurs. Phytosaurs belong to the family Phytosauridae and the order Phytosauria. They were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodiles in size, appearance, and lifestyle, an example...

 reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

. Although it looked and probably lived like a crocodile

Crocodile

A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

, it was not closely related to these creatures, instead being a good example of parallel evolution

Parallel evolution

Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades.-Parallel vs...

. The main difference between Nicrosaurus (and all other phytosaurs) and real crocodiles was the position of the nostril

Nostril

A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation...

s - Nicrosauruss nostrils were placed directly in front of the forehead, whereas in crocodiles, the nostrils are positioned on the end of the snout.

A recent phylogenetic analysis found that the genera Pseudopalatus, Mystriosuchus

Mystriosuchus

Mystriosuchus is an extinct genus of phytosaur that lived in the Late Triassic in Europe. It was first named by Eberhard Fraas in 1896, and includes two species: M. westphali and the type species, M. planirostris...

, Redondasaurus

Redondasaurus

Redondasaurus is a genus of phytosaur from the Late Triassic of North America. Translated, the name Redondasaurus means "Redonda lizard," referring to the Redonda Formation of east-central New Mexico, USA. It was first named by Hunt & Lucas in 1993, and contains one species, R. gregorii...

and Nicrosaurus were pseudopalatines.