Lophostropheus airelensis

Late Triassic – Early Jurassic (200 Ma)

Things are scary lately, but I hope everyone is doing well. In these stressful times I've taken to drawing dinosaurs on my computer to ease my nerves. Originally, I set out to draw a dromaeosaur, but it somehow ended up a Lophostropheus. But don't worry, I'll do some dromaeosaurs once I'm confident I can draw them as beautifully as they deserve.

Lophostropheus was found in the Triassic-Jurassic boundary in France. Few animals are known to have lived from the end of the Triassic and into the early Jurassic, because this transition was marked by a mass extinction  caused, at least in part, by the breaking up of Pangea. Mass extinctions are often recognized because of sudden, dramatic turnovers in the fossil record. We don't expect to see individual genera or species surviving the events, and this is especially true for dinosaurs of the T-J Extinction, which disproportionately impacted terrestrial life. Of course, we know species had to survive these times of hardship, but thanks to the spottiness of the fossil record it's not often we get to see it. I'm realizing this is starting to sound kind of doom and gloom in today's context, so let's talk more about Lophostropheus.

This is a member of the coelophysoids, one of the first prolific groups of theropods. Coelophysoids were, despite being relatively short-lived, a sign of things to come. They were lankier and had smaller heads compared to the more robust earlier theropods, like Herrerasaurids. They also have a lot of traits we associate with later theropods, showing that these features appeared quickly once dinosaurs established themselves. Many were small and slender like the group's namesake, Coelophysis, but some later members, like this one here, got bigger. Lophostropheus isn't known from the best remains, but could have been up to 3 meters (10 feet) long. That may not sound like much, but this put it among the largest carnivorous dinosaurs of the time.

Because Lophostropheus is known from fragmentary remains, it's difficult to say much definitively about its behavior or ecology, and I'll admittedly be inferring based on similar features in related dinosaurs. So, take the next section as you will, but know I'm trying to avoid speculating too hard. As a science communicator, the last thing I want to do is mislead.

Lophostropheus probably preyed on large herbivores, including early sauropodomorphs like Plateosaurus, and may have chased down smaller, more agile animals as well. The function of its crest is unclear. It was too fragile to be used as a weapon or armor, which, to be fair, would be kind of far-fetched anyway. It may have been used for intraspecies interactions, as a mating display or as an intimidation tool against rivals.

It was originally considered a species of the closely-related Liliensternus, but was assigned to its own genus in 2007. In fact, after deciding not to draw a dromaeosaur, I wanted to draw Liliensternus, but found out it didn't have that Dilophosaurus-like crest it's always depicted with. BUT I learned a very similar dinosaur who did have a crest existed, and thus, Lophostropheus. I'm wondering if the trend of Liliensternus being depicted with a crest was caused by this dinosaur being associated with it, but I haven't found anything confirming it.

That's about what I have to say about Lophostropheus. I didn't really know it existed until I drew it, but the Triassic/early Jurassic is one of my favorite time periods of the Mesozoic. It's fascinating how quickly dinosaurs established a foothold, and then how quickly they flourished once they had the space. Even when they looked kind of the same, dinosaurs were starting to show the traits that would become markers of their diversity.

SOURCES

Ezcurra & Cuny 2007 – The coelophysoid Lophostropheus airelensis (Abstract only, I couldn’t access the full paper)

Olsen, Shubin, & Anders 1987 –  New Early Jurassic Tetrapod Assemblages Constrain Triassic-Jurassic Tetrapod Extinction Event

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Name: Lophostropheus airelensis 

Name Meaning: Crest vertebrae from the Airel Quarry 

First Described: 2007 (formerly 1993) 

Described by: Ezcurra & Cuny (previously, Cuny & Galton) 

Classification: Dinosauria, Saurischia, Theropoda, Coelophysoidea 

Lophostropheus is a later Coelophysoid that lived about 200 million years ago, which was the boundary line between the Late Triassic and Early Jurassic Period, in the Rhaetian stage of the former and the Hettangian stage of the latter. It is one of the few dinosaurs known from good remains at that boundary (most likely due to the mass extinction occurring at that time.) It was discovered in the Moon-Airel Formation in Normandy, France, and is based on a partial skeleton. It was about the size (and probably had similar behavior as) the Coelophysoid Liliensternus,making it a medium sized bipedal carnivore, but still probably one of the larger dinosaurs of the time. It is one of the few dinosaurs that survived the extinction at the time, and if better remains are found it could demonstrate the intermediate step between late Triassic ceratosaurs such as Coelophysis and early Jurassic ones such as Dilophosaurus 

Sources: 

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

http://dinosaurs.wikia.com/wiki/Lophostropheus