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Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Coelophysoidea
Genus: Lophostropheus
The Lophostropheus Dinosaur
The Lophostropheus is a western European, carnivorous dinosaur that existed approximately 200-201 million years ago (mya.), near the end of the Triassic and the advent of the Jurassic Period. Its remains were found in present-day Normandy, France. It was a small, moderately-built dinosaur and was a bipedal carnivore.
The Discovery and Recognition of Fossils
A partial theropod dinosaur fossil was found in the Moon-Airel quarry of Basse-Normandy, France by Pareyn in 1959. The skeletal remains consisted of a tooth, two back vertebrae, five neck vertebrae, four sacral vertebrae, and portions of the pelvic bones, tail vertebrae and an unrecognized bone fragment. Having been confused with Halticosaurus and Liliensternus, the dinosaur was categorized as a new genus in 2007 by paleontologist Martin Ezcurra from Argentina, and French Gilles Cuny.
The new genus was named Lophostropheus. Lophostropheus translates to ‘Crest vertebra’ - a reference to the creature’s peculiar characteristics observed in the cranial cervical vertebrae. The sole identified species is Lophostropheus airelensis, referring to the Airel quarry where the specimen was found. The remains are preserved at Normandy’s Caen University and the holotype specimen has not been numbered or classified yet.
Martin Ezcurra is an Argentine paleontologist and has been credited for his research and various theories about dinosaurs. He has co-discovered, identified or reclassified several species of dinosaurs including the Archeopelta, Guabisauridea, Herrerasauridea, Coelophysoidea, and several aetosaurs. He is a curator at the Argentine Museum of Natural Sciences. Gilles Cuny is a French paleontologist. He is curator of University of Pierre-and-Marie-Curie (UPMC) in Paris, France.
The Triassic-Jurassic boundary
The remains of the Lophostropheus were found in lenticular limestone and sandy claystone that date back to the boundary of the Rhaetian stage of the Upper Triassic Period and the early Hettangian of the Lower Jurassic period. The Rhaetian stage is the last of three stages of the final epoch of the Triassic period, known as the upper or the Late Triassic.
The Hettangian is the earliest or lowest of the stages from the Jurassic period. It is followed by the Sinemurian stage. It spans the period of approximately 199.3 to 201.3 million years ago.
At the Triassic-Jurassic boundary a catastrophic event took place that is estimated to have put an end to half the living species on the planet at that time. This is known as the Triassic-Jurassic extinction event.
Anatomical features and Physical Characteristics
The Lophostropheus was a slender dinosaur of moderate build. It is estimated to have been somewhere between 3-5 meters long (i.e. 10 to 15 feet) and weighed as much as 200 kilograms. The Lophostropheus inhabits characteristics from more derived theropods like a ball-socket connection in the anterior neck vertebrae and a socket joint in the tail vertebra’s front end. It also showcases a vertical ridge on its illium.
The most striking feature about this dinosaur is the presence of prominent crest-like structures both above and below the neck vertebrae, which is why the creature has been so-named. The neck vertebrae housed a couple of extra cavities.
An automorphy is a peculiar and distinctive anatomical feature or characteristic that is unique to a given group of organisms or a species. The following are some of the automorphies that the Lophostrosternus dinosaur displayed (Ezcurra and Cuny, 2007):
- The convex frontal articular surface of the ventral postaxial cervical vertebrae has a medium radius of curvature.
- A large and elliptical lateral fossa is observed on the last dorsal vertebral column.
- An elongated hyposphere extends from the front to the back of the last dorsal vertebra.
- The length of the caudal vertebrae is constant throughout the entire tail length.
- An incipient concave curve manifests itself on the articular surface of the cranial caudal vertebra.
About the Lophostropheus dinosaur
The Lophostropheus was a carnivorous dinosaur i.e. it was a flesh eating creature. It belonged to the theropod family. It was a coelophysoid dinosaur being a part of the Coelophysoidea superfamily. It exhibited more coelophysoid characteristics than theropod ones. Its habits and size are not unlike those of the Liliensternus.
It was a bipedal creature meaning it could walk on its two lower forelimbs. The feet i.e. the lower limbs ha well developed claws. It was a ground dwelling carnivore that lived in the swamps and marshes of the western part of present-day Europe.
The dinosaur is known only from the set of partial remains of the skeletal remains found in Normandy. Therefore not much data can be estimated about this dinosaur. Owing to this there were many incorrect guesses in the context of this creature’s classification.
French paleontologists Albert-Felix de Lapparent and C. Larsonneur classified the remains as a species of Halticosaurus in 1966. In 1993, Gilles and Peter Galton listed it under the newly formed species of Liliensternus and this creature was named L. airelensis. Finally after much analysis, that included the identification of differences from the other Liliensternus dinosaurs like the pleurocels of the cervical vertebrae, enabled Gilles n Guny to reclassify it as a separate genus in 2007.
The dinosaur was a part of the period when the dinosaurs increased exponentially in size from lizard sized creatures to humongous giants. It might benefit us to know more about this dinosaur as we may learn more about the evolution of other dinosaurs through the study of that time through the Lophostropheus.
Another makes the Lophostropheus such an important dinosaur is that it is one of few rare species, whose fossils have been formed that lived near the end of Triassic period. In fact, the specimens are the only good known remains of theropods from that period. The Lophostropheus is also special in the respect that it survived the Triassic-Jurassic extinction event, while the majority of the planet’s then living population perished.
Detailed study of the creature might help us understand what ecological calamity caused such massive destruction. This is an important event from the prehistoric time frame of earth and one that we should strive to understand. Also, we might understand why the Lophostropheus managed to survive what caused so many other species to perish.
Index
Extinct Profiles
- Triassic Dinosaurs
- Jurassic Dinosaurs
- Cretaceous Dinosaurs
- Pterosaurs
- Marine Reptiles
- Dinosaur Extinction