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Gondwana South America   In the Late Triassic  From The Dinosaur Collector


 Late Triassic Carnian of Ischigualasto Argentina in South America has produced some of the first dinosaurs, only finds in Madagascar being older.  Herrerasaurids are the most common super predators.  Dinosaurs were not an immediate success when they first appear.  Rhyncosaurs and cynodonts are far more common than dinosaurs and in fact the rhyncosaur Scaphonix accounts for half of all tetrapod fossils  The older ornithosuchids and rauisuchids survive until the end of the Triassic.  The herbivore roles are filled by rhychosaurs, aetosaurs and the remaining dicynodonts.   update 070706

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Rhynchosaurs had beak-like mouths that they would have used to lop the tough plants of the Triassic, probably seed ferns. They were an important group of herbivores but died out during the Late Triassic mass extinction.  Staurikosaurus (Southern Cross reptile) was small and agile  with a slim body, a long, slender tail, sprinter's legs, and shins longer than its thighs. Its head was large for its size, with sharp flesh-eater's teeth. It probably had short arms with 5 fingered hands, and also 5 toes and is related to the larger Herrerasaurus.  Before the finding and the Madagascar prosauropods, Eoraptor, a small theropod was considered the most primitive dinosaur known.


Staurikosaurus and a rhychosaur.  Since neither of these animals is produced as a toy figure I used an anonymous dinosaur from the Rendition Cave woman figure for Staurikosaurus.  To be a Staurikosaurus it should have a five-toed foot instead of the normal theropod three-toed foot.  The Captorhinus (an Early Permian reptile) from a party favor set made in china most resembles the buck toothed rhychosaur Scaphonyx.

Scientists have debated where Herrerasaurus fits into the dinosaur family tree. Some have argued that it is too primitive to be considered either a saurischian or ornithischian. Currently the balance of opinion seems to be that it is an early side branch off the main theropod line.


The figures are from a vinyl set that shows up in dollars stores. The indeterminate theropods make a good custom project. Photo and painting from Fred Hinojosa.

Dinosaurs are neither the most numerous, nor the largest animals from Ischigualasto.  A top predator Herresaurus was the first big theropod at  10 feet.  Dinosaurs at this time only make up Only about 6% of all tetrapods and have few species.  They diversify in the following Norian after an extinction that clears out the top predators.


This not a very good reproduction from the Dinosaur Series of Toys from China.  It is supposed to light up and make sounds.  The only point of interest is that was labeled Herrerasaurus.

Herrerasaurus may have lived in upland forest areas with seasonal climate, preying on the early plant eating dinosaur Pisanosaurus and rhychosaurs.  Herrerasaurus is a very odd theropod and at one time was consider to be too primitive to be classified in the same family with later carnivores.  Now is is thought to an early side branch of the theropod family that died out.


Herrerasaurus from a set of DK paper dinosaur figures.       

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