Tag Archives: dinosaur

SuperCroc at Sternberg

The Sternberg Natural History Museum at Fort Hays State University is featuring a new exhibit, The Science of SuperCroc from now until August 5.

The star of the show is the African crocodilian species Sarcosuchus whose remains have been found in the modern Sahara, in the Elrhaz Formation. This Early Cretaceous (~112 million years ago) crocodile had a long, slender snout with a prominent down-turn or hook at the tip. When fully mature it is estimated to have been between 37-40 feet in length, and weighed as much as 17,000 pounds.

The largest living crocodile is the saltwater croc, and the largest confirmed individual was just over 20 feet in length and weighed a mere 2,600 pounds.

Restoration of Sarcosuchus, the SuperCroc

Restoration of Sarcosuchus, the SuperCroc

Sarcosuchus had its eyes placed high upon its skull suggesting that it spent most of its time submerged in the water. Like so many other things in paleontology, the question of what Sarcosuchus may have eaten is not agreed upon by researchers. Some suggested that the size of Sarcosuchus and its overhanging upper jaw made it able to wrestle large prey items, even massive long-necked sauropod dinosaurs. Others point to the slenderness of the muzzle and it not looking stout enough to withstand the forces that would be required to bring down large prey. There were plenty of lobe-finned fish in Sarcosuchus’s environment. I see a fish-eater in this skull myself.

Also on display with the large croc is Suchomimus, a theropod dinosaur whose remains have been found in the same geological formation as Sarcosuchus. Suchomimus, whose name means crocodile mimic, was a forty-foot long beast which also had a long slender muzzle. Its forelimbs were armed with very long sickle-curved claws. This animal is thought to have eaten fish and probably other sorts of meat, but its skull also does not appear equipped for biting and holding very large struggling prey.

Super Croc Sarcosuchus skeleton at Sternberg Museum

SuperCroc Sarcosuchus skeleton at Sternberg Museum

The presence of both of these animals, and many others found with them, show that the Sahara area of today was a lush, swampy habitat in the Early Cretaceous. The effect of climate change and plate movements over millions of years can turn a wet verdant habitat into a harsh, dry desert. My how times change.

Go see SuperCroc at the Sternberg Museum if you have a chance.

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The large consume the small

It is an interesting paradox of the natural world that some of the largest species alive survive by eating some of the smallest species.

Consider the largest animal ever known to have existed. No, it is not a dinosaur, but an animal alive today, the blue whale, Balaenoptera musculus. This behemoth can grow to over 100 feet long and weigh 380,000 pounds. And yet, this animal does not eat large fish, but tiny planktonic animals, those that float in the water.

The blue whale belongs to the suborder of baleen whales, or mysticets, that all make their living by filter feeding plankton—sucking water into their mouths and trapping the small, floating plankton to swallow. The toothed whales, or odontocets, do eat larger prey.

There are several other large vertebrate groups that also specialize in eating the very small, and they too grow to very large proportions. For example, the whale shark (Rhincodon typus), the largest living fish at about 40 feet long and weighing in at 47,000 pounds. And then there is the second largest fish, the basking shark (Cetorhinus maximus), also a filter feeder. Giant rays also feed this way.

Whale shark, the world's largest living fish

Whale shark, the world's largest living fish

So clearly, you can get very big eating small things. However, there has been a bit of a mystery in the fossil record. There has been a general lack of known filter feeding animals from the fossil record during the Mesozoic, the time of dinosaurs; clearly, that was a period in Earth’s history when things could get very large. So, where were the filter feeders?

An important piece of this puzzle has just fallen into place. Just published in Science is a paper outlining new discoveries of filter feeding fishes from the Mesozoic, and it turns out that they too were large (Friedman et al., 2010).

The fossils were mostly already in the collections of museums, having been collected in both Europe and North America. However, they were not well understood until this team began to look at them in more detail, and recognized their filter feeding adaptations. The fossils reported belong to the extinct pachycormid family, and include the new genus Bonnerichthys, named for the Bonner family of Kansas.

And in keeping with a theme, the pachycormid family of fish included the largest bony fish known, Leedsichthys, reaching over 30 feet in length in the Jurassic of Europe.

Leedsichthys, the largest spcies of fossil fish

Leedsichthys, the largest spcies of fossil fish

This latest work shows that in fact there were a number of filter feeding fish through about the last 100 million years of the Mesozoic, filling this lucrative niche held in modern times by rays, sharks, and whales. Another mystery from the past is closer to being solved.

FRIEDMAN, M., K. SHIMADA, L. MARTIN, M. J. EVERHART, J. LISTON, A. MALTESE, AND M. TRIEBOLD. 2010. 100-million-year dynasty of giant planktivorous bony fishes in the Mesozoic seas. Science, 327:990-993.

Many other interesting facts can be found here at Boneblogger. Look around and enjoy.

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