Sunday, December 11, 2016

Mounted skeleton, Chicago Children's Museum.

Suchomimus (“crocodile mimic”) is a genus of large spinosaurid dinosaur with a crocodile-like skull that lived between 125–112 million years ago, during the Aptian to early Albian stage of the Cretaceous period in Niger, Africa. The only species named in the genus is Suchomimus tenerensis.

Size comparison of several species of spinosaurids and a human, Suchomimus in red. Author: Matt Martyniuk

Suchomimus was one of the largest known spinosaurid dinosaurs. It was discovered in Niger by a party led by Paul Sereno from the University of Chicago and was first described in 1998. Shortly before that, Dale Russell and Philippe Taquet announced the discovery of a very similar dinosaur from another part of Niger, but the fossils that were described by Sereno were much more complete and allowed for a more detailed reconstruction.

The length of the type specimen of Suchomimus, a subadult, was initially estimated at 10.3–11 m (34–36 ft). Its weight was estimated at between 2.7 and 5.2 tonnes (2.7 and 5.1 long tons; 3.0 and 5.7 short tons). In 2010, Gregory S. Paul gave lower estimations of 9.5 metres and 2.5 tonnes.

Like other spinosaurids, Suchomimus had a low and slender snout, much the same as that of a modern crocodile-hence the animal’s name. Suchomimus and other spinosaurids had a secondary palate. The nasal passages stretched all the way to the back of the mouth cavity, as they do in living mammals and crocodiles, and did not open within the mough, as they do in many living reptiles and most dinosaurs. This was possible because the nasal openings were set back from the tip of the snout. We do not know why these animals evolved these features, but the secondary palate may have strengthened the narrow snout or even allowed Suchomimus and its relatives to keep the tip of the snout submerged while they hunted for fish.

Skeletal restoration combining several specimens. By Jaime A. Headden

Like Baryonyx, Suchomimus had pointed teeth with very fine serrations. Also like Baryonyx, it had massively built forearms and a large sickle-like claw on each thumb. The nature of the teeth, together with its slender, gracile snout, suggests that Suchomimus may have been unable to catch large prey and so fed largely on fish-possibly either picking them up with its muzzle or grasping the slippery creatures with its blade-like claws.

The overall impression is of a massive and powerful creature that ate fish and presumably other sorts of meat — carrion — more than 113 million years ago, when what is today part of the Sahara was a lush, swampy habitat.