Elaphrosaurus bambergi

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NameElaphrosaurus bambergi

Name Meaning: Lightweight lizard 

First Described: 1920 

Described By: Janensch 

ClassificationDinosauria, Saurischia, Theropoda, Neotheropoda, Averostra, Ceratosauria 

Elaphrosaurus was a rather strange theropod from the Late Jurassic period, in the Tithonian age (around 154 to 150 million years ago.) It was discovered in the Tendaguru Formation in Tanzania, and as such it lived in an area rich with dinosaurs. It lived with the sauropods Giraffatitan, Australodocus, Janenschia, Tornieria, and Dicraeosaurus, allosaurids and other ceratosaurs, the early carcharodontosaurid VeterupristisaurusKentrosaurus, and the iguanodontid Dysalotosaurus. It lived near the ocean, and as such shared its habitat with many pterosaurs. It is also known from possible (but inconclusive) footprints in Niger and Jerusalem. Elaphrosaurus was discovered before much of the theropod clades had been properly organized. As such, Elaphrosaurus has been shunted around between many groups, from the coelurids (which was a wastebasket taxon for small theropods), to the ornithomimids, and now it has been put in the Ceratosauria, with Limusaurus as its closest relative. It was a 6.2 meter long carnivore, with a shallow chest, and very short hindlimbs (much like the tyrannosaurids, though Elaphrosaurus was probably not in an ancestor clade group.)It also had a long neck and an elongate skull. Many other species have been described, however, they are all now considered dubious. 

Sources: 

http://www.prehistoric-wildlife.com/species/e/elaphrosaurus.html

http://en.wikipedia.org/wiki/Elaphrosaurus

Shout out goes to james-morietti! 

Sorry for the hiatus, guys. I had a bad week. Next week is going to be difficult too but I don’t have any tests so hopefully not as bad? I have a grant proposal due on the 1st though which is going to suck. 

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Elaphrosaurus bambergi: Jurassic Ostrich Mimics

Size: 20 feet (6 meters) long.

Time Period: The Kimmeridgian Stage of the Late Jurassic Period.
Locale:
The Tendaguru Beds of Tanzania, possibly the Morrison Formation of the United States.

Name: “Bamberg’s light lizard.”

Aside from the coelurosaurus and Spinosaurus, Carnotaurus is easily one of the more recognizable theropod dinosaurs. Still, it’s literally the only publically known ceratosaur, though some more well-studied kids may recognize Ceratosaurus as well. This is basically testament to our knowledge of ceratosaurs; we know abelisaurids from spectacular evidence and ceratosaurids from decent to scrappy evidence. Nevertheless, I doubt anyone in the general public has heard of a noasaurid or an “elaphrosaurid.” Why the quotes? “Elaphrosauridae” is an informal family. Anyway.

Our story starts with German expeditions into Tanzania in the early 20th century, at the time when the latter country was a colony of the former. Remains of many dinosaurs were excavated, such as Kentrosaurus, Brachiosaurus brancai (later Giraffatitan), and Dicraeosaurus. Elaphrosaurus was discovered there as well, and remains of Elaphrosaurus (or a relative of it) were found in the Morrison Formation. And was placed in the family Coeluridae, which was a wastebasket taxon into which any small theropod was dumped. At some point later on, it was thought of as a primitive ornithomimosaur and left that way for many years. More recently, a Chinese ceratosaur named Limusaurus was discovered. It had a beak, presumably showing that it had an herbivorous lifestyle. Though the skull of Elaphrosaurus was never found, it wouldn’t be too rash to assume that it and Limusaurus were both relatives of the ornithomimosaurs.

Still, that turned out to be wrong. They are both now found to be ceratosaurs, and they along with Spinostropheus of the Tiouraren Formation of Niger and the Morrison Formation relative of Elaphrosaurus constitute “Elaphrosauridae.” Note: North Africa’s Deltadromeus may be a gigantic, late-surviving elaphrosaur, but until this is proven, the range of the group is limited to the Jurassic period. Anyway, if Limusaurus shows the general trend for the group, then all “elaphrosaurids” were plant-eaters that didn’t fall into the micropredatory roles of other small theropods.

Like with many poorly known fossil groups, “elaphrosaurids” were probably far more widespread than our current myopic knowledge suggests. If they were indeed widespread, their moderately expansive distribution was cut short by some climate change or inability to cope with other kinds of stimuli, like competition with coelurosaurs. Maybe the extinction of this group of herbivorous theropods is what opened up a large amount of space for the ornithomimosaurs to evolve. They looked very similar, after all, which explains the title of this post. On a different note, both groups not only resembled the modern flightless ratites, but also the more distantly related shuvosaurid crurotarsans of the Late Triassic, like the weird Effigia. Like ostriches, it can be presumed that plant-eating theropods weren’t all herbivorous, and supplemented their diets with small vertebrates whenever they needed to. It’s what ostriches do now.

So, this is a very poorly known group, but one that may have been a fairly important component of Late Jurassic ecosystems. Maybe “elaphrosaurids” lived in areas where they wouldn’t fossilize, or were uncommon in some areas but not in others. Only further research will shed light on these mysterious dinosaurs.

The lightweight lizard, Elaphrosaurus (1920)

Phylum : Chordata
Class : Reptilia
Order : Saurischia
Infraorder : Ceratosauria
Genus : Elaphrosaurus
Species : E. bambergi

  • Late Jurassic (154 - 150 Ma)
  • 6 m long and 210 kg (size)
  • Tanzania (map)

The type specimen for Elaphrosaurus bambergi was discovered in the Middle Saurian member of the Tendaguru Formation of Tanzania. A related animal, perhaps the same genus, was found in stratigraphic zones 2-4 of the Morrison Formation. Few theropod skeletons have been found, most discoveries being fragments.

The Tendaguru Formation of Tanzania also yielded Giraffatitan, Allosaurus, and Kentrosaurus. Paul (1988) noted that Elaphrosaurus babamergi was too small to prey on the sauropods and stegosaurs present in its paleoenvironment, and instead, it likely hunted the small and swift ornithopod herbivores.

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I’m a Dinosaur - Elaphrosaurus