Saurolophus

Saurolophus Brown, 1912 is a herbivorous Dinosaure which lived with the higher Crétacé in Asia and North America.

A horn projected backwards

This dinosaur is typical of the family of the hadrosauridés , large dinosaurs with duck characteristics nozzle of the end of the Cretaceous. Like the others hadrosaurinés, it was equipped with powerful and lengthened posterior legs and a body rather massive traversed over the entire length of the back of a kind of low “veil” formed by a lengthening of the vertebrae. The principal characteristic of Saurolophus, however, made it possible to distinguish it from any other hadrosaure: it was equipped indeed with a kind of horn projected towards the back with the posterior part of cranium.

The horn consisted of a full bone, contrary to the structure of Parasaurolophus which was related for him, and it was a direct extension of the nasal bone. Its structure led some paleontologists to suppose that there was a particular fabric mass above the nasal area, which could be “inflated” to produce sounds, whom perhaps resembled particularly powerful mooings. The peak could act like a support of this “bag”, and it increased surface and the effectiveness of it. Of course there is no proof of the existence of such a structure, but as of moment that most probably these adrosaures lived in herds, the possibility of emitting a particular type of very powerful sounds could have been very effective intraspecific means of communication, even at long distances.

Two species out of two continents

Saurolophus was described for the first time in 1912 by Barnum Brown in the Alberta (Canada) with the species S. osborni. Well after, in 1952, Rozhdestvensky discovered a species similar to the other end of the world, in Mongolia, and called it S. angustirostris (owing to the fact that the horn was lengthened compared to North-American species). It is there a proof moreover than with the Cretaceous the higher Asia and the North America was connected and than there was between them an exchange of considerable fauna. Currently, however, some paleontologists insist on the fact that the two species of Saurolophus they belonged to two distinct kinds, even if they were narrowly related. Others support that S. angustirostris and S. osborni should be classified in same the Espèce.

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