Ichthyosaurs Suck!!!

Galvasean

And not for the first time Galvasean starts athread witha misleading thread title...

Much like Shastasaurus, beaked whales have short skulls which, with the exception of one or two pairs of small teeth in the lower jaw, are functionally toothless. Rather than biting down on food, these whales rapidly retract their tongue, creating a small pocket of suction that draws in small prey. Since Shastasaurus has a generally similar skull anatomy, as well as equivalent sites for muscle attachments that would have allowed them to perform similar lingual maneuvers, Sander and colleagues propose that the ichthyosaur was adapted to be a suction feeder many, many millions of years before whales.

After revising the anatomy and habits of Shastasaurus, Sander and co-authors also suggest that the existence of multiple, suction-feeding ichthyosaur species over the course of millions of years during the Late Triassic indicates some underlying environmental cause. The scientists note that levels of atmospheric oxygen dropped during the time of Shastasaurus. Fish populations, strangled by the reduced oxygen in the seas, may have declined as a result, but cephalopods like squid—which are more tolerant of low-oxygen environments—may have proliferated. Since suction-feeding appears to be an adaptation to consuming small, quick prey, and soft-bodied cephalopods are known to have been an important part of the ichthyosaur diet, the scientists hint that the evolution of Shastasaurus might be attributable to a boom in squid which was itself caused by a decrease in ocean oxygen levels.

Read more here.


A modern day beaked whale, which had a similar skull to Shastasaurus

Capt'n Midnight

warm water holds less dissolved oxygen than cold water, could global warming affect cephlopod populations more than over fishing ?