Leptostyrax is an extinct genus of mackerel sharks that lived during the Cretaceous. It contains two valid species, L. macrorhiza and L. stychi, found in North America, Europe, Africa, and Australia.
Vertebrae tentatively assigned to L. macrorhiza suggest lengths of, making it one of the largest Cretaceous sharks.[1]
Leptostyrax was a carnivorous large shark in the family Pseudoscapanorhynchidae that existed in Australia. It's diet presumably consisted on fish and any other animals it could snatch and eat, such as other sharks and bony fish.
Leptostyrax was mostly cold blooded just like other shark species, mostly in wide oceans and shallow waters or either freshwater areas close to the mainland.
Leptostyrax had gills just like other shark species, with females growing a lot larger than male specimens.