Aristosuchus

Aristosuchus was a small coelurosaurian dinosaur whose name was derived from the Greek ἄριστος (meaning bravest, best, noblest) and σουχος (the Ancient Greek corruption of the name of the Egyptian crocodile-headed god Sobek). It shared many characteristics with birds.

Aristosuchus
Temporal range: Barremian
~130–123 Ma
Aristosuchus
Assigned elements as figured by Owen
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Compsognathidae
Genus: Aristosuchus
Owen 1876
Species:
A. pusillus
Binomial name
Aristosuchus pusillus
Owen 1876

Description

Aristosuchus restoration
Hypothetical restoration

Aristosuchus was a bipedal, meat-eating (carnivorous) theropod dinosaur. This predator is thought to have been about 2 metres (6.6 ft) and is estimated to have weighed about 30 kilograms (66 lb). According to Gregory S. Paul, its weight was 7 kilograms (15 lb).[1]

The femur of Aristosuchus has a wing-like anterior trochanter and a markedly reduced fourth trochanter.

Classification

It was similar to its close relative Compsognathus in appearance and size and some authors have argued that it belongs to that genus. It has also been confused with Calamospondylus, including when Richard Lydekker assumed that Reverend William D. Fox had named it Calamospondylus oweni in 1866. However, on the basis of the pubis, it is considered by Darren Naish to be a valid compsognathid. Since some species are only represented by a few skeletal fragments, this sort of discussion is not uncommon in dinosaur palaeontology. Aristosuchus is known from holotype BMNH R178: a sacrum, a pubis, a femur and a few vertebrae. Two ungual phalanges were found nearby, which may have been from the same animal and would suggest long claws.

Discovery

Aristosuchus pusillus
Sacrum and pubes as figured by Seeley

The type species, Aristosuchus pusillus, was described in 1876 by Richard Owen and named Poekilopleuron pusillus.[2] The specific epithet means "small" in Latin. Harry Govier Seeley (1839–1909) gave it the name Aristosuchus in 1887.[3]

It was found in the Wealden Group dating to the Early Cretaceous (Barremian) in England, on the Isle of Wight, i.e. from about 125 million years ago.

References

  1. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 122
  2. ^ Owen, R. (1876). "Supplement (No. VII) to the Monograph on the Fossil Reptilia of the Wealden and Purbeck Formations. (Poikilopleuron and Chondrosteosaurus)". Palaeontographical Society Monograph. 30: 1–7.
  3. ^ Seeley, H. G. (1887). "On Aristosuchus pusillus (Owen), being further notes on the fossils described by Sir R. Owen as Poikilopleuron pusillus, Owen". Quarterly Journal of the Geological Society of London. 43: 221–228. doi:10.1144/GSL.JGS.1887.043.01-04.22.

Further reading

  • Naish, D. (2011). "Theropod dinosaurs". In Batten, D. J. (ed.). English Wealden Fossils. London: The Palaeontological Association. pp. 526–559.
  • Naish, D. (2001). "The historical taxonomy of the Lower Cretaceous theropods (Dinosauria) Calamospondylus and Aristosuchus from the Isle of Wight". Proceedings of the Geologists' Association. 113: 153–163.
1887 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1887.

Barremian

The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch (or Lower Cretaceous series). It is preceded by the Hauterivian and followed by the Aptian stage.

Baryonyx

Baryonyx () is a genus of theropod dinosaur which lived in the Barremian stage of the Early Cretaceous Period, about 130–125 million years ago. The first skeleton was discovered in 1983 in the Weald Clay Formation of Surrey, England, and became the holotype specimen of B. walkeri, named by palaeontologists Alan J. Charig and Angela C. Milner in 1986. The generic name, Baryonyx, means "heavy claw" and alludes to the animal's very large claw on the first finger; the specific name, walkeri, refers to its discoverer, amateur fossil collector William J. Walker. The holotype specimen is one of the most complete theropod skeletons from the UK (and remains the most complete spinosaurid), and its discovery attracted media attention. Specimens later discovered in other parts of the United Kingdom and Iberia have also been assigned to the genus.

The holotype specimen, which may not have been fully grown, was estimated to have been between 7.5 and 10 m (25 and 33 ft) long and to have weighed between 1.2 and 1.7 t (1.3 and 1.9 short tons). Baryonyx had a long, low, and narrow snout, which has been compared to that of a gharial. The tip of the snout expanded to the sides in the shape of a rosette. Behind this, the upper jaw had a notch which fitted into the lower jaw (which curved upwards in the same area). It had a triangular crest on the top of its nasal bones. Baryonyx had a large number of finely serrated, conical teeth, with the largest teeth in front. The neck formed an S-shape, and the neural spines of its dorsal vertebrae increased in height from front to back. One elongated neural spine indicates it may have had a hump or ridge along the centre of its back. It had robust forelimbs, with the eponymous first-finger claw measuring about 31 cm (12 in) long.

Now recognised as a member of the family Spinosauridae, Baryonyx's affinities were obscure when it was discovered. Some researchers have suggested that Suchosaurus cultridens is a senior synonym (being an older name), and that Suchomimus tenerensis belongs in the same genus; subsequent authors have kept them separate. Baryonyx was the first theropod dinosaur demonstrated to have been piscivorous (fish-eating), as evidenced by fish scales in the stomach region of the holotype specimen. It may also have been an active predator of larger prey and a scavenger, since it also contained bones of a juvenile Iguanodon. The creature would have caught and processed its prey primarily with its forelimbs and large claws. Baryonyx may have had semiaquatic habits, and coexisted with other theropod, ornithopod, and sauropod dinosaurs, as well as pterosaurs, crocodiles, turtles and fishes, in a fluvial environment.

Bauxite of Cornet

The Bauxite of Cornet is a geological formation in Romania whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

Calamospondylus

Calamospondylus (meaning "quill vertebrae") was a theropod dinosaur genus. It lived during the Early Cretaceous, and its fossils were found in England. The type species, Calamospondylus oweni, was described anonymously by amateur paleontologist William D. Fox in 1866, but is based on fragmentary material. It has been part of a confusing taxonomic issue also involving Aristosuchus and Calamosaurus (which was also named "Calamospondylus", but then renamed). It may have been a primitive oviraptorosaurian.

Compsognathidae

Compsognathidae is a family of coelurosaurian theropod dinosaurs. They were small carnivores, generally conservative in form, hailing from the Jurassic and Cretaceous Periods. The bird-like features of these species, along with other dinosaurs such as Archaeopteryx inspired the idea for the connection between dinosaur reptiles and modern-day avian species. Compsognathid fossils preserve diverse integument — skin impressions are known from four genera commonly placed in the group, Compsognathus, Sinosauropteryx, Sinocalliopteryx, and Juravenator. While the latter three show evidence of a covering of some of the earliest primitive feathers over much of the body, Juravenator and Compsognathus also show evidence of scales on the tail or hind legs.

The first member of the group, Compsognathus, was discovered in 1861, after Johann A. Wagner published his description of the taxon. The family it was created by Edward Drinker Cope in 1875. This classification was accepted by Othniel Charles Marsh in 1882, and added to the Coelurosauria clade by Friedrich von Huene in 1914 after additional fossils had been found. With further discoveries, fossils have been uncovered across three different continents, in the countries of China, France, Germany, Italy, and Brazil. Assignment to Compsognathidae is usually determined through examination of the metacarpal, which is used to separate Compsognathidae from other dinosaurs. However, classification is still complicated due to similarities to the body of several other theropod dinosaurs, as well as the lack of unifying, diagnostic features that are shared by all compsognathids.

Compsognathus

Compsognathus (; Greek kompsos/κομψός; "elegant", "refined" or "dainty", and gnathos/γνάθος; "jaw") is a genus of small, bipedal, carnivorous theropod dinosaur. Members of its single species Compsognathus longipes could grow to around the size of a turkey. They lived about 150 million years ago, during the Tithonian age of the late Jurassic period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Today, C. longipes is the only recognized species, although the larger specimen discovered in France in the 1970s was once thought to belong to a separate species and named C. corallestris.

Many presentations still describe Compsognathus as "chicken-sized" dinosaurs because of the size of the German specimen, which is now believed to be a juvenile. Compsognathus longipes is one of the few dinosaur species whose diet is known with certainty: the remains of small, agile lizards are preserved in the bellies of both specimens. Teeth discovered in Portugal may be further fossil remains of the genus.

Although not recognized as such at the time of its discovery, Compsognathus is the first theropod dinosaur known from a reasonably complete fossil skeleton. Until the 1990s, it was the smallest-known non-avialan dinosaur, with the preceding centuries incorrectly labelling them as the closest relative of Archaeopteryx.

Compsognathus was the first dinosaur genus to be portrayed with feathers, by Thomas Henry Huxley in 1876.

Darren Naish

Darren Naish is a British vertebrate palaeontologist and science writer. He obtained a geology degree at the University of Southampton and later studied vertebrate palaeontology under British palaeontologist David Martill at the University of Portsmouth, where he obtained both an M. Phil. and PhD. He is founder of the blog Tetrapod Zoology, created in 2006.

Dinosaur Isle

Dinosaur Isle is a purpose-built dinosaur museum located in Sandown on the Isle of Wight in southern England.The museum was designed by Isle of Wight architects Rainey Petrie Johns in the shape of a giant pterosaur. It claims to be the first custom-built dinosaur museum in Europe.

Eotyrannus

Eotyrannus (meaning "dawn tyrant") is a genus of tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom. The remains (MIWG1997.550), consisting of assorted skull, axial skeleton and appendicular skeleton elements, from a juvenile or subadult, found in a plant debris clay bed, were described by Hutt et al. in early 2001. The etymology of the generic name refers to the animals classification as an early tyrannosaur or "tyrant lizard", while the specific name honors the discoverer of the fossil.

Iguanodon

Iguanodon ( i-GWAH-nə-don; meaning "iguana-tooth") is a genus of ornithopod dinosaur that existed roughly halfway between the first of the swift bipedal hypsilophodontids of the mid-Jurassic and the duck-billed dinosaurs of the late Cretaceous. While many species have been classified in the genus Iguanodon, dating from the late Jurassic Period to the early Cretaceous Period of Asia, Europe, and North America, research in the first decade of the 21st century suggests that there is only one well-substantiated species: I. bernissartensis, which lived from the late Barremian to the earliest Aptian ages (Early Cretaceous) in Belgium, Spain, England and possibly elsewhere in Europe, between about 126 and 113 million years ago. Iguanodon were large, bulky herbivores. Distinctive features include large thumb spikes, which were possibly used for defense against predators, combined with long prehensile fifth fingers able to forage for food.

The genus was named in 1825 by English geologist Gideon Mantell but discovered by William Harding Bensted, based on fossil specimens found in England, some of which were subsequently assigned to Mantellodon. Iguanodon was the second type of dinosaur formally named based on fossil specimens, after Megalosaurus. Together with Megalosaurus and Hylaeosaurus, it was one of the three genera originally used to define Dinosauria. The genus Iguanodon belongs to the larger group Iguanodontia, along with the duck-billed hadrosaurs. The taxonomy of this genus continues to be a topic of study as new species are named or long-standing ones reassigned to other genera.

Scientific understanding of Iguanodon has evolved over time as new information has been obtained from fossils. The numerous specimens of this genus, including nearly complete skeletons from two well-known bone beds, have allowed researchers to make informed hypotheses regarding many aspects of the living animal, including feeding, movement, and social behaviour. As one of the first scientifically well-known dinosaurs, Iguanodon has occupied a small but notable place in the public's perception of dinosaurs, its artistic representation changing significantly in response to new interpretations of its remains.

Istiodactylus

Istiodactylus is a genus of pterosaur that lived during the Early Cretaceous period, about 120 million years ago. The first fossil was discovered on the English Isle of Wight in 1887, and in 1901 became the holotype specimen of a new species, O. latidens (Latin for "wide tooth"), in the genus Ornithodesmus. This species was moved to its own genus, Istiodactylus, in 2001; this name is Greek for "sail finger". More specimens were described in 1913, and Istiodactylus was the only pterosaur known from three-dimensionally preserved fossils for much of the 20th century. In 2006, a species from China, I. sinensis, was assigned to Istiodactylus, but it has since been found to belong to a different genus.

Istiodactylus was a large pterosaur; estimates of its wingspan range from 4.3 to 5 metres (14 to 16 ft). Its skull was about 45 centimetres (18 in) long, and was relatively short and broad for a pterosaur. The front of the snout was low and blunt, and bore a semicircle of 48 teeth. The triangular teeth were closely spaced, interlocked, and formed a "razor-edged" outline. The lower jaw also had a tooth-like projection that occluded with the teeth. The skull had a very large naso-antorbital opening (which combined the antorbital fenestra and the opening for the bony nostril) and a slender eye socket. Some of the vertebrae were fused into a notarium, to which the shoulder blades connected. It had very large forelimbs, with a wing-membrane distended by a long wing-finger, but the hindlimbs were very short.

Until the 21st century, Istiodactylus was the only known pterosaur of its kind, and was placed in its own family, Istiodactylidae, within the group Ornithocheiroidea. Istiodactylus differed from other istiodactylids in having a proportionally shorter skull. The distinctive teeth of Istiodactylus indicate that it was a scavenger that may have used its teeth to sever morsels from large carcasses in the manner of a cookie cutter. The wings of Istiodactylus may have been adapted for soaring, which would have helped it find carcasses before terrestrial carnivores. Istiodactylus is known from the Wessex Formation and the younger Vectis Formation, which represent river and coastal environments that were shared with various pterosaurs, dinosaurs, and other animals.

Laevisuchus

Laevisuchus (, "light crocodile") is a genus of abelisauroid theropod dinosaur from the Late Cretaceous. Its remains were discovered by Charles Alfred Matley near Jabalpur in Maastrichtian deposits in the Lameta Formation in India, and were named and described by paleontologists Friedrich von Huene and Matley in 1933. The type species is Laevisuchus indicus. The generic name is derived from Latin laevis, "light" and the Greek name for the Egyptian crocodile god, Soukhos. The specific name means "Indian" in Latin. It is known only from three cervical vertebrae (GSI K20/613, GSI K20/614 and GSI K27/696) and a dorsal vertebra (GSI K27/588). A holotype was not assigned by Huene and Matley and a lectotype has never been chosen from the syntypes. All remains except GSI K27/696 were lost; GSI K20/613 was rediscovered in 2012.

List of European dinosaurs

Dinosaurs evolved partway through the Triassic period of the Mesozoic era, around 230 Ma (million years ago). At that time, the earth had one supercontinental landmass, called Pangaea, of which Europe was a part. So it remained throughout the Triassic. By the start of the Jurassic period, some 30 million years later, the supercontinent began to split into Laurasia and Gondwana. The largest inlet from Panthalassa, the superocean that surrounded Pangaea, was called the Tethys Ocean, and as this inlet cut deeper into the supercontinent, much of Europe was flooded.

By the Cretaceous, from 145 to 66 million years ago, the continents were beginning to approach their present shapes, but not their present positions, and Europe remained tropical. At times, it was a chain of island-microcontinents including Baltica and Iberia.

Europe is relatively rich in fossils from the Jurassic-Cretaceous boundary, and much of what is known about European dinosaurs dates from this time. As the timeline below illustrates, there are substantial gaps in our knowledge from the rest of the Mesozoic. The absence of dinosaur genera from this time is because few fossils have been discovered, and almost certainly not because Europe contained few types of dinosaur—except, perhaps, immediately after the Triassic–Jurassic extinction event.

List of dinosaur genera

This list of dinosaurs is a comprehensive listing of all genera that have ever been included in the superorder Dinosauria, excluding class Aves (birds, both living and those known only from fossils) and purely vernacular terms.

The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered dinosaurs. Many listed names have been reclassified as everything from birds to crocodilians to petrified wood. The list contains 1559 names, of which approximately 1192 are considered either valid dinosaur genera or nomina dubia.

Mirischia

Mirischia is a small (two meter-long) genus of compsognathid theropod dinosaur from the Albian stage (Early Cretaceous Period) of Brazil.

Poekilopleuron

Poekilopleuron (meaning "varied ribs") is an extinct genus of megalosauroid tetanuran theropod dinosaur, which lived during the middle Bathonian of the Jurassic, about 168 to 166 million years ago. The genus has been used under many different spelling variants, although only one, Poekilopleuron, is valid. The type species is P. bucklandii, named after William Buckland, and many junior synonyms of it have also been erected. Few material is currently known, as the holotype was destroyed in World War II, although many casts of the material still exist.

Wessex Formation

The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages (about 145–125 million years ago) of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vectis Formation and overlies the Durlston Formation. The dominant lithology of this unit is mudstone with some interbedded sandstones.

William Fox (palaeontologist)

William D. Fox (9 August 1813 – 1881) was an English clergyman and palaeontologist who worked on the Isle of Wight and made some significant discoveries of dinosaur fossils.

The Reverend William D. Fox was born in Cumberland. He moved to the Isle of Wight in 1862 to take up the post of curate at the Parish church of St Mary the Virgin in Brixton (now known as Brighstone). He resigned his post in 1867 but continued to live in the area to carry on his collecting. In 1875, he became curate of nearby Kingston, near Shorwell.Although lacking formal scientific training Fox was remarkably astute and discussed his findings with eminent palaeontologists of the day including John Hulke (1830-1895) and Sir Richard Owen. Fox had easy access to Brighstone Bay from his home, Myrtle Cottage in Brighstone, and so spent many an hour collecting fossils, much to the detriment of his pastoral work; in fact, it was said of him at the time, by the wife of the vicar, that it was "always bones first and the parish next". He is also quoted as having written in a letter to Owen "I cannot leave this place while I have any money left to live on, I take such deep [sic] in hunting for old dragons".In 1882 Fox's collection of more than 500 specimens was acquired by the Natural History Museum after his death.Fox is credited with the finding of several species, most described by his friend Owen, and named by him after their finder. These include Polacanthus foxii, Hypsilophodon foxii, Eucamerotus foxi, Iguanodon foxii, Calamosaurus foxii (formerly Calamospondylus) and Aristosuchus.

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