Lophostropheus

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Lophostropheus
Temporal range: Late Triassic-Early Jurassic, 205.6–196.5  Ma
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Genus:† Lophostropheus
Ezcurra & Cuny, 2007
Species:
†L. airelensis
Binomial name
†Lophostropheus airelensis
(Cuny & Galton, 1993)
Synonyms

Lophostropheus (pronounced: "LOAF-oh-STRO-fee-us") is an extinct genus of coelophysoid theropod dinosaur that lived approximately 205.6 to 196.5 million years ago during the boundary between the Late Triassic Period and the Early Jurassic Period, in what is now Normandy, France. Lophostropheus is one of the few dinosaurs that may have survived the Triassic–Jurassic extinction event.

Contents

Lophostropheus was a small to medium-sized, moderately-built, ground-dwelling, bipedal carnivore, that could grow up to 3 m (9.8 ft) long. Over the years it had been incorrectly classified as Halticosaurus and Liliensternus , but was later recognized as a new genus and was reassigned to Lophostropheus in 2007.

Etymology

Lophostropheus was described and named by Argentine paleontologist Martin Ezcurra (Museo Argentino de Ciencias Naturales) and French paleontologist Gilles Cuny of the Université Pierre et Marie Curie in 2007, and the type species is Lophostropheus airelensis. The composite term Lophostropheus is derived from the Greek words "lophè" (λόφη) meaning "crest" and the word "stropheus" (στροφεύς) meaning "pertaining to the vertebrae"; [1] thus, "crest vertebrae". This naming is a reference to the prominent dorsal and ventral laminae observed in the cranial cervical vertebrae. The specific name, "airelensis" is a reference to the locality where the specimen was discovered, the Airel Quarry.

Description

Estimates suggest that Lophostropheus was at best 3 m (10 ft) long and weighed 100 kilograms (220 pounds) at most. [2] In 2016 Molina-Pérez and Larramendi gave a higher estimation of 5.2 meters (17 ft) and 136 kg (300 lbs). [3] It is based on a partial skeleton first described in 1966 as a specimen of Halticosaurus .

Classification

Lophostropheus differs from other theropods 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 characteristics have all been interpreted as convergences, however. [4] It also has prominent crests on the tops and bottoms of its neck vertebrae (for which it was named), [4] and an extra pair of cavities in its neck vertebrae, unlike Liliensternus. [5] It was closer to the coelophysids, including the well-known Coelophysis , than to Liliensternus. [4] It has been assigned to the superfamily Coelophysoidea. An analysis of early dinosaurs by Baron, Norman and Barrett (2017) placed Lophostropheus in a position close to the derived theropods Sinosaurus and Cryolophosaurus . [6]

Distinguishing anatomical features

A diagnosis is a statement of the anatomical features of an organism (or group) that collectively distinguish it from all other organisms. Some, but not all, of the features in a diagnosis are also autapomorphies. An autapomorphy is a distinctive anatomical feature that is unique to a given organism or group.

According to Ezcurra and Cuny (2007), Lophostropheus can be distinguished based on the following characteristics:

History of discovery

In 1966, the French paleontologists Claude Larsonneur and Albert-Félix de Lapparent described a partial theropod skeleton from the Triassic-Jurassic boundary of Normandy, found in 1959 by Claude Pareyn, as Halticosaurus sp. [7] This specimen 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. [4] It was reinterpreted in 1993 by Gilles Cuny and Peter Galton as belonging to a new species, assigned to Liliensternus and named L. airelensis. [8] Other researchers began to notice differences between L. airelensis and the type species, L. liliensterni, [5] [9] such as those observed in the pleurocoels of the cervical vertebrae, [5] and in 2007, Martin Ezcurra and Gilles Cuny assigned it to its own genus, Lophostropheus. [4]

Paleobiology

Lophostropheus, as a coelophysoid, would have been a small to medium-sized bipedal carnivore, [10] probably comparable in size and habits to Liliensternus (best specimen estimated at 5.15 meters long, or 16.9 feet). [11] 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. [4]

Paleoecology

Provenance and occurrence

The remains of the type specimen of Lophostropheus airelensis was recovered in the Airel Quarry locality of the Moon-Airel Formation, in Basse-Normandie, France. The specimen was collected by Pareyn in 1959 in sandy claystone and lenticular, sandy limestone that was deposited on the boundary of the Rhaetian stage of the Triassic period and the Hettangian stage of the Jurassic period, approximately 205.6 to 196.5 million years ago. It is one of the few dinosaurs known to have lived during the Triassic-Jurassic boundary. Lophostropheus is one of the few dinosaurs that may have survived the Triassic–Jurassic extinction event when at least half of the known species living on Earth became extinct. This specimen is housed in the collection of Caen University in Normandy, France, and has not been assigned a collection number.

Related Research Articles

<i>Dilophosaurus</i> Genus of theropod dinosaur from Early Jurassic

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<i>Coelophysis</i> Genus of theropod dinosaurs from the late Triassic and early Jurassic

Coelophysis is an extinct genus of coelophysid theropod dinosaur that lived approximately 204 to 201.6 million years ago during the latter part of the Triassic Period in what is now the southwestern United States and a specmen possibly belonging to the second species, C. rhodesiensis, has been found in South Africa and Zimbabwe, though this interpretation has been challenged since 2017.

Ceratosauria Extinct clade of dinosaurs

Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with Ceratosaurus than with birds. The oldest known ceratosaur, Saltriovenator, dates to the earliest part of the Jurassic, around 199 million years ago. According to the majority of the latest research, Ceratosauria includes three major clades: Ceratosauridae, Noasauridae, and Abelisauridae, found primarily in the Southern Hemisphere. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea and Dilophosauridae, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group with other ceratosaurs, and are excluded from this group.

Coelophysoidea Extinct superfamily of dinosaurs

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<i>Procompsognathus</i> Extinct genus of dinosaurs

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<i>Liliensternus</i> Extinct genus of dinosaurs

Liliensternus is an extinct genus of basal neotheropod dinosaur that lived approximately 210 million years ago during the latter part of the Triassic Period in what is now Germany. Liliensternus was a moderate-sized, bipedal, ground-dwelling carnivore, that could grow up to 5.15 m (16.9 ft) long. It is the best represented Triassic theropod from Europe and one of the largest known.

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<i>Gojirasaurus</i> Extinct genus of dinosaurs

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Podokesaurus is a genus of coelophysoid dinosaur that lived in what is now the eastern United States during the Early Jurassic Period. The first fossil was discovered by the geologist Mignon Talbot near Mount Holyoke, Massachusetts, in 1910. The specimen was fragmentary, preserving much of the body, limbs, and tail. In 1911, Talbot described and named the new genus and species Podokesaurus holyokensis based on it. The full name can be translated as "swift-footed lizard of Holyoke". This discovery made Talbot the first woman to find and describe a non-bird dinosaur. The holotype fossil was recognized as significant and was studied by other researchers, but was lost when the building it was kept in burned down in 1917; no unequivocal Podokesaurus specimens have since been discovered. It was nominated as state dinosaur of Massachusetts in 2021.

Coelophysidae Extinct family of dinosaurs

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<i>Zupaysaurus</i> Extinct genus of dinosaurs

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Halticosaurus (pron.:"HAL-tick-oh-SORE-us") is a dubious genus of theropod dinosaur from the late Triassic period. It is known from a single fragmentary fossil specimen of the species H. longotarsus, found in the Middle Stubensandstein formation of what is present-day Germany The only known specimen was poorly preserved and may have been put together from bones of unrelated animals. Further research would be required to determine which of the bones belonged together, and what kind of theropod Halticosaurus was. However, most of the bones have been lost. For these reasons, Halticosaurus is considered to be a nomen dubium.

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<i>Berberosaurus</i> Extinct genus of dinosaurs

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Neotheropoda Clade of theropods

Neotheropoda is a clade that includes coelophysoids and more advanced theropod dinosaurs, and is the only group of theropods that survived the Triassic–Jurassic extinction event. All neotheropods became extinct by the end of the Early Jurassic period except for Averostra.

<i>Tawa hallae</i> Extinct species of dinosaur

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Averostra Clade of dinosaurs

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs, namely Ceratosauria and Tetanurae, and represent the only group of post-Early Jurassic theropods. Both survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians, megaraptorans an incertae sedis group within Tetanurae, and two groups of tetanurans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of Maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

<i>Megapnosaurus</i> Extinct genus of dinosaur

Megapnosaurus is an extinct genus of coelophysid theropod dinosaur that lived approximately 188 million years ago during the early part of the Jurassic Period in what is now Africa. The species was a small to medium-sized, lightly built, ground-dwelling, bipedal carnivore, that could grow up to 3 m (9.8 ft) long. It was originally given the genus name Syntarsus, but that name was later determined to be preoccupied by a beetle. The species was subsequently given a new genus name, Megapnosaurus, by Ivie, Ślipiński & Węgrzynowicz in 2001. Many subsequent studies have classified it as a species within the genus Coelophysis.

Timeline of coelophysoid research

This timeline of coelophysoid research is a chronological listing of events in the history of paleontology focused on the coelophysoids, a group of primitive theropod dinosaurs that were among Earth's dominant predators during the Late Triassic and Early Jurassic epochs. Although formally trained scientists didn't discover coelophysoid fossils until the late 19th century, Native Americans of the modern southwestern United States may have already encountered their fossils. Navajo creation mythology describes the early Earth as being inhabited by a variety of different kinds of monsters who hunted humans for food. These monsters were killed by storms and the heroic Monster Slayers, leaving behind their bones. As these tales were told in New Mexico not far from bonebeds of Coelophysis, this dinosaur's remains may have been among the fossil remains that inspired the story.

Martin Dario Ezcurra is an Argentinian born palaeontologist naming many extinct genera such as Aerotitan, Lophostropheus and Powellvenator.

References

  1. ↑ Liddell, Henry George and Robert Scott (1980). A Greek-English Lexicon (Abridged Edition). United Kingdom: Oxford University Press. ISBN   0-19-910207-4.
  2. ↑ "LOPHOSTROPHEUS". Dinochecker.com. Retrieved 5 May 2013.
  3. ↑ Molina-Pérez & Larramendi (2016). Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos. Spain: Larousse. p. 253.
  4. 1 2 3 4 5 6 Ezcurra, Martin D.; Cuny, Gilles (2007). "The coelophysoid Lophostropheus airelensis, gen. nov.: a review of the systematics of "Liliensternus" airelensis from the Triassic-Jurassic boundary outcrops of Normandy (France)". Journal of Vertebrate Paleontology. 27 (1): 73–86. doi:10.1671/0272-4634(2007)27[73:TCLAGN]2.0.CO;2.
  5. 1 2 3 Rauhut, Oliver W.M.; Hungerbühler, A. (2002). "A review of European Triassic theropods". Gaia. 15: 75–88.
  6. ↑ Baron, M.G., Norman, D.B., and Barrett, P.M. (2017). A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature, 543: 501–506. doi : 10.1038/nature21700
  7. ↑ C., Larsonneur; and de Lapparent, Albert-Félix (1966). "Un dinosaurien carnivore, Halticosaurus, dans le Rhétien d'Airel (Manche)". Bulletin de la Société Linnéenne de Normandie (in French). 7: 108–117.
  8. ↑ Cuny, Gilles; Galton, Peter M. (1993). "Revision of the Airel theropod dinosaur from the Triassic-Jurassic boundary (Normandy, France)". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 187 (3): 261–288.
  9. ↑ Carrano, M. T., and Sampson, S. D., 2004, A review of coelophysoids (Dinosauria: theropoda) from the Early Jurassic of Europe, with comments on the late history of the coelophysoidea: Neues Jahrbuch für Geologie und Paläontologie, Monatschefte, 2004, n. 9, p. 537-558.
  10. ↑ Tykoski, Ronald S.; Rowe, Timothy (2004). "Ceratosauria". In Weishampel, David B.; Dodson, Peter; Osmólska Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 47–70. ISBN   0-520-24209-2.
  11. ↑ Paul, Gregory S. (1988). Predatory Dinosaurs of the World. New York: Simon & Schuster. pp.  267. ISBN   0-671-61946-2.
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