Lophostropheus
Encyclopedia
Lophostropheus was a genus
of coelophysoid
dinosaur
from the Rhaetian
-Hettangian
stage border (about 200 Ma) Moon-Airel Formation
of Normandy
, France
. It is based on a partial skeleton first described in 1966 as a specimen of Halticosaurus
. It is one of the few dinosaurs known from rocks near the Triassic-Jurassic boundary.
The type species
, Lophostropheus airelensis, was named by Argentine
paleontologist
Martin Ezcurra of the Museo Argentino de Ciencias Naturales in Buenos Aires
and French paleontologist Gilles Cuny of the Université Pierre et Marie Curie in Paris. Cuny had previously helped describe the specimen in 1993 as a species of Liliensternus
(L. airelensis).
in several ways. It has features reminiscent of more derived
theropods, such as having a ball connection
to the front of its neck vertebrae, a socket connection to the front of its tail vertebrae, and a vertical ridge on the ilium
. These are all interpreted as convergences
, however. It also has prominent crests on the tops and bottoms of its neck vertebrae (for which it was named), and an extra pair of cavities in its neck vertebrae, unlike Liliensternus. It was closer to the coelophysid
s, including the well-known Coelophysis
, than to Liliensternus.
described a partial theropod skeleton from the Triassic-Jurassic boundary of Normandy as Halticosaurus sp. This specimen, now held at the University of Caen, consisted of a tooth
, five neck
vertebrae, two vertebrae from the back, four sacral
vertebrae, tail
vertebrae, portions of all the pelvic
bones, and an unidentified fragment. It was reinterpreted in 1993 by Gilles Cuny and Peter Galton
as belonging to a new species
, assigned to Liliensternus
and named L. airelensis. Other researchers began to notice differences between L. airelensis and the type species
, L. liliensterni, and in 2007, Martin Ezcurra and Cuny assigned it to its own genus, Lophostropheus.
, probably comparable in size and habits to Liliensternus (best specimen estimated at 5.15 meters long, or 16.9 feet). Very few dinosaurs are known from its time period; in fact, it is the only theropod genus known from good remains at the Triassic-Jurassic boundary.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of coelophysoid
Coelophysoidea
Coelophysoids were common dinosaurs of the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to the coelurosaurs, with which they were formerly...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from the Rhaetian
Rhaetian
The Rhaetian is in geochronology the latest age of the Triassic period or in chronostratigraphy the uppermost stage of the Triassic system. It lasted from 203.6 ± 1.5 to 199.6 ± 0.6 million years ago...
-Hettangian
Hettangian
The Hettangian is the earliest age or lowest stage of the Jurassic period of the geologic timescale. It spans the time between 199.6 ± 0.6 Ma and 196.5 ± 1 Ma . The Hettangian follows the Rhaetian and is followed by the Sinemurian.In Europe stratigraphy the Hettangian is a part of the time span in...
stage border (about 200 Ma) Moon-Airel Formation
Moon-Airel Formation
The Moon-Airel Formation is a geological formation in France. It dates back to the early Hettangian.-Vertebrate fauna:-References:* Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka : The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2....
of Normandy
Normandy
Normandy is a geographical region corresponding to the former Duchy of Normandy. It is in France.The continental territory covers 30,627 km² and forms the preponderant part of Normandy and roughly 5% of the territory of France. It is divided for administrative purposes into two régions:...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. It is based on a partial skeleton first described in 1966 as a specimen of Halticosaurus
Halticosaurus
Halticosaurus is a genus of theropod dinosaur from the Late Triassic period . It was a coelophysoid found in the Middle Stubensandstein formation of what is present-day Germany...
. It is one of the few dinosaurs known from rocks near the Triassic-Jurassic boundary.
The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Lophostropheus airelensis, was named by Argentine
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
paleontologist
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
Martin Ezcurra of the Museo Argentino de Ciencias Naturales in Buenos Aires
Buenos Aires
Buenos Aires is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent...
and French paleontologist Gilles Cuny of the Université Pierre et Marie Curie in Paris. Cuny had previously helped describe the specimen in 1993 as a species of Liliensternus
Liliensternus
Liliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
(L. airelensis).
Description
Lophostropheus differs from other theropodsTheropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...
in several ways. It has features reminiscent of more derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
theropods, such as having a ball connection
Ball and socket joint
A ball and socket joint is a joint in which the distal bone is capable of motion around an indefinite number of axes, which have one common center...
to the front of its neck vertebrae, a socket connection to the front of its tail vertebrae, and a vertical ridge on the ilium
Ilium (bone)
The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
. These are all interpreted as convergences
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
, however. It also has prominent crests on the tops and bottoms of its neck vertebrae (for which it was named), and an extra pair of cavities in its neck vertebrae, unlike Liliensternus. It was closer to the coelophysid
Coelophysidae
The Coelophysidae are a family of primitive carnivorous theropod dinosaurs. Most species were relatively small in size. The family flourished in the Late Triassic and Early Jurassic periods....
s, including the well-known Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
, than to Liliensternus.
History of discovery
In 1966, the French paleontologists C. Larsonneur and Albert-Félix de LapparentAlbert-Félix de Lapparent
Albert-Félix de Lapparent was a French palaeontologist. He was also a Sulpician priest. He undertook a number of fossil-hunting explorations in the Sahara desert. He contributed greatly to our knowledge of dinosaurs and other prehistoric creatures...
described a partial theropod skeleton from the Triassic-Jurassic boundary of Normandy as Halticosaurus sp. This specimen, now held at the University of Caen, consisted of a tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
, five neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...
vertebrae, two vertebrae from the back, four sacral
Sacrum
In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...
vertebrae, tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
vertebrae, portions of all the pelvic
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
bones, and an unidentified fragment. It was reinterpreted in 1993 by Gilles Cuny and Peter Galton
Peter Galton
Peter M. Galton is a British vertebrate paleontologist working in America, who has to date written or co-written about a hundred papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosauropod dinosaurs.With Robert Bakker in a joint article...
as belonging to a new species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, assigned to Liliensternus
Liliensternus
Liliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
and named L. airelensis. Other researchers began to notice differences between L. airelensis and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, L. liliensterni, and in 2007, Martin Ezcurra and Cuny assigned it to its own genus, Lophostropheus.
Paleobiology
Lophostropheus, as a coelophysoid, would have been a small- to medium-sized bipedal carnivoreCarnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
, probably comparable in size and habits to Liliensternus (best specimen estimated at 5.15 meters long, or 16.9 feet). Very few dinosaurs are known from its time period; in fact, it is the only theropod genus known from good remains at the Triassic-Jurassic boundary.