Thursday, October 24, 2013

Species that don't get publicity #2: Teratosaurus suevicus



The species for this week is one that seemed to be popular for a brief time only, and was misunderstood even then.  From around 1950 to 1990, dinosaur books featured this species; Never before, and never again. It has never appeared in a book in its real form. It has never been featured in films or documentaries.  Only one, cheap toy from the series Monsters In My Pocket has been made of it-nothing from Safari or Bullyland or Papo or even any model kits.  This is all too bad-this animal was the Tyrannosaurus of its time, and one of the three genera of giant predator that ruled central Europe in the late Triassic. The first large dinosaurs were its prey.



This is Teratosaurus.  It’s odd that the species had much coverage at all-it was based on the right maxilla (that is, half of the upper front of the mouth) and related teeth. It’s not much, but it’s enough to establish it as a large predator. It’s about the same size as Postosuchus, its American counterpart. Of course, since the United States has more media and paleontologists than Germany, more material has been found for Postosuchus and it has become the posterboy of the Rauisuchids. 

The history of this genus is an interesting one. Near the town of Stuttgart, a German army officer and natural historian, Sixt Friedrich von Kapff found and collected the teeth and skull from the Heslach quarries. The great paleontologist Christian von Meyer described it in the journal Palaeontographica in his article “Reptilien aus dem Stubensandstein des oberen Keupers” as a larger predator, grouping it with Megalosaurus, Streptospondylus,and “Laelaps” in his group Pachypodes.  In 1908, Friedrich von Huene attributed postcranial material from Trossingen to the genus.   And so a big-headed  Triassic superpredator was born .  Somehow (probably money), the material was sent to London, where is still resides today in the Museum of Natural History. 

Oddly enough, it was only during the 1960s that Teratosaurus started to sporadically appear in books. The most significant appearances of it were in 1977’s Dinosaur book by Peter Zallinger, and 1983’s Dinosaur Time by Peggy Paris as a sort of proto-Allosaur,. Anthony Rao’s 1980 Dinosaur Coloring book , John McLoughlin’s  1979 Archosauria ( see http://chasmosaurs.blogspot.com/2013/10/vintage-dinosaur-art-archosauria-part-1.html for more), and Dougal Dixon’s 1988 Macmillan illustrated encyclopedia of dinosaurs and prehistoric animals  are the most vivid and memorable examples. It’s possible the species only popped up in the 1970s revival of interest of dinosaurs. The only toy of the species was made in 1990’s Monsters In My Pocket series of small figures, very much in the same style as its other appearances as a “Carnosaur”

It was during this last burst of popularity when it suffered a fall from grace in the public eye.  In 1985 and 1986, Michael J Benton (http://palaeontology.palass-pubs.org/pdf/Vol%2029/Pages%20293-301.pdf) and Peter Galton  (http://biodiversitylibrary.org/page/30068837#page/317/mode/1up) both came to the conclusion that the postcranial material belonged to prosauropods (probably Efrassia and Plateosaurus), not the head. The Teratosaurus “Carnosaur” was a chimera with the head of a crocodilian relative and the body of a plant-eating dinosaur! 

Teratosaurus is a Rauisuchid, a name covering a group of near-crocodylomorphs (animals that diverged from the main crocodile stock after the dinosaurs but before true crocodilians) that were the top predators of the Triassic, dwarfing their sailbacked Poposaur cousins and more primitive bipedal Ornithosuchids . This group also includes the massive (30 feet long!) Fasolasuchus and slightly smaller Saurosuchus from South America and their ancestors Rauisuchus and Luperosuchus, the North Americans Heptosuchus and Postosuchus, Teratosaurus’ ancestor Ticinosuchus and its successor Polonosuchus, Tanzanian Stagonosuchus, and Indian Tikisuchus. Polonosuchus, Postosuchus, and Teratosaurus were very similar to each other, and fulfilled the same role in their ecosystem.  The recently discovered giant predator Smok might also be a rauisuchid, and might have been the top predator of the region over Teratosaurus.

The late Triassic (Carnian and Norian ages to be precise) of Europe was pretty diverse, and although the American contemporaries get far more press, finds in Germany, France, Poland, and Britain show a large, diverse Fauna.  Already herbivorous dinosaurs nicknamed prosauropods had diversified-the large derived Camelotia, the large gracile Efrassia, the archetypical, big, well-represented Plateosaurus and the more obscure Ruehleia and the small, bipedal primitive (and unfortunately named) Pantydraco and  Thecodontosaurus all munched on the tall trees of the Europeans river plains. Carnivorous dinosaurs included the large predators Liliensternus and Halticosaurus, the still-being-diagnosed Newtonsaurus, and the tiny Procompsognathus. 

Dinosaurs only formed a fraction of Teratosaurus’ world- tiny, furry cynodonts included herbivorous Habayia, Rosieria and Maubeugia, carnivorous Hahnia, Lepagia, and the advanced, almost mammalian Oligokyphus. The tusked herbivore dicynodonts, once a large, successful family, only had a few giant genera left in the world, with an as-of-now unnamed genus from Poland.  The other big plant eaters were the armored archosaurs Stagonelepis and Paratypothorax, distinguished from Mesozoic ankylosaurs by their plainer armor, flat bodies and piglike snouts. Small reptiles included the trilophosaurs Variodens and Tricuspiasaurus, the dinosauriforms herbivorous Silesaurus and carnivorous Saltopus, the piggish, beaked rhynchosaur Hyperadapodon, and the strange arboreal Depanosaurus. There were the first primitive pterosaurs-Peteinosaurus, Preondactylus, Eudimorphodon, Caviramus, Carinadactylus, Austriadactylus, all of which are uncertain in their affinities to each other and later pterosaurs.  Teratosaurus shared the large predator role with the sister genus Polonosuchus and the giant predatory archosaur Smok. Smaller predators included the more nimble Ornithosuchus, primitive Erpetosuchus and Apatosuchus, and very  small Dyoplax and Saltoposuchus. The first turtle with a carapace, Proganochelys swam the waterways with amphibians; the small pedomorphic Gerrothorax and giant fish-eating Cyclotosaurus and Metoposaurus.   The real kings of the rivers were another group of archosaurs, the phyosaurs. The European genera were Termatosaurus, Rileyasucuchus, Rutiodon, Paleorhinus and Mystriosuchus, and they competed with the amphibians in the rivers and streams of the Triassc.

All of these animals, except for the adult Plateosaurus, theropods,  aetosaurs and raisuchids most of the time, would have been prey for Teratosaurus.  The raiusuchid body plan has short front legs, long back legs, a long tail, armored back, and a large head with big, serrated teeth. This suggests that they were ambush predators, hiding in the dense bush or behind boulders, waiting for prey to get into range. The attack would be swift-their limbs suggest that bipedal locomotion might have been an option for short bursts, and brutal-their teeth evolved to carve large bloody wounds into prey.  The armored torso would defend from the claws, teeth, and tail of a struggling prey, as well as protect them from other predators’ attacks.  A fight between Teratosaurus and any of the dinosaurs of the day would be bloody and probably go the Teratosaurus’  way for their bulk, teeth, armor, and sheer brawn. 

Teratosaurus and most of the other Triassic archosaurs went extinct in at the end of the period. Some environmental catastrophe hit the world hard enough to wipe out most of these animals. Mammals, crocodiles, pterosaurs and dinosaurs survived, but the rauisuchids and all the large herbivores did not.  So the smaller, faster, more adaptable theropod dinosaurs took their place with species like Zupayosaurus, Sinosaurus and Dilophosaurus as the top predators of the day.  Teratosaurus was a flash in the pan evolutionarily-large animals are vulnerable to mass extinctions, and predators even more so.

I feel that the rauisuchids have been neglected for being so impressive and so unique. Postosuchus does show up in some books and has made a memorable appearance in the documentary Walking With Dinosaurs, and seems to have replaced its European cousin in the public eye. This is a shame, since Postosuchus is just one of these powerful predators that ruled the Triassic.  I just think it’s sad that this species lost its limelight just because it turned out not to be a dinosaur. Dinosaurs are awesome, of course, but they weren’t the only big scary animals in prehistory, or even the Mesozoic.  These animals ate dinosaurs and ruled their worlds as surely as any Tyrannosaurus.  After all, it could eat a Velociraptor if they weren’t separated by 150 million years. 

So anyway, Hollywood, give this guy a break. Museums, put him on display. Toy companies, here’s a new fresh face. Authors, think about the crap you’re writing and how this genus could perk up the place. And remember, shop Teratosaurus where you work or play.

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