| Mirischia Temporal range: Early Cretaceous, | |
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| Hypothetical Model | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Family: | † Compsognathidae |
| Genus: | † Mirischia Naish et al., 2004 |
| Species: | †M. asymmetrica |
| Binomial name | |
| †Mirischia asymmetrica Naish et al., 2004 | |
Mirischia is a small (two meter-long) genus of compsognathid theropod dinosaur from the Albian stage (Early Cretaceous Period) of Brazil.
In 2000 David Martill and Eberhard Frey reported the find of a small dinosaur fossil present in a chalk nodule, illegally acquired by the German Staatliches Museum für Naturkunde Karlsruhe from an illegal Brazilian fossil dealer who had indicated the piece had been uncovered in the Chapada do Araripe, specifically at Araripina, Pernambuco. [1] In 2004 the type species Mirischia asymmetrica was named and described by Martill, Frey and Darren Naish. The generic name combines the Latin mirus, 'wonderful', with "ischia", the Latinised plural of Greek ἴσχιον, ischion, 'hip joint'. The specific name asymmetrica refers to the fact that in the specimen the left ischium differs from its right counterpart. [2]
The holotype, SMNK 2349 PAL, has its probable provenance in the Romualdo Formation of the Santana Group, dating from the Albian. It consists of a partial articulated skeleton, largely consisting of the pelvis and incomplete hind limbs, including two posterior dorsal vertebrae, a rib, gastralia, partial ilia, pubes and ischia, partial thigh bones and the upper parts of the right tibia and fibula. In front of the pubes, a piece of a petrified intestine is present. The specimen represents a subadult individual. [2]
Mirischia was a small bipedal predator. Its length was in 2004 estimated at 2.1 metres. [2] In 2010 Gregory S. Paul estimated the weight at seven kilogrammes. [3] The holotype of Mirischia is notable for having asymmetrical ischia. Quoting from Naish et al. (2004): "The ischia of Mirischia are asymmetrical, that on the left being perforated by an oval foramen while that on the right has an open notch in the same position." The specimen is also unusual in that it preserves some soft tissue remains: apart from the intestine, what the describers interpreted to have been an air sac was preserved between its pubic and ischial bones in the form of a vacuity. Previous workers had suggested that non-avian theropods might — like birds — possess post-cranial air sacs, and Mirischia seems to confirm that. Another notable trait is the exceptional thinness of the bone wall of all skeletal elements. [2]
In 2004 Mirischia was assigned to the Compsognathidae, as closely related to Compsognathus from the Upper Jurassic of Europe and Aristosuchus from the Lower Cretaceous of England. It would then be the only compsognathid known from the Americas. [2] In 2010 Naish suggested it may have instead been a basal member of the Tyrannosauroidea. [4] In 2024, Andrea Cau published a study on the phylogenetics of compsognathids that recovered Mirischia, along with four other proposed Compsognathids in a polytomy within basal Coelurosauria. This polytomy notably did not include Composognathus proper, which would make none of these species Compsognathids. [5]
This is a simplified version of the phylogeny in Cau (2024), with Mirischia in bold.
| Tetanurae |
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Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the Albian stage of the Early Cretaceous Period, about 113 to 110 million years ago. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. Fossil dealers had acquired this skull and sold it to the State Museum of Natural History Stuttgart. In 1996, the specimen became the holotype of the type species Irritator challengeri. The genus name comes from the word "irritation", reflecting the feelings of paleontologists who found the skull had been heavily damaged and altered by the collectors. The species name is a homage to the fictional character Professor Challenger from Arthur Conan Doyle's novels.
The Isle of Wight is one of the richest dinosaur localities in Europe, with over 20 species of dinosaur having been recognised from the early Cretaceous Period, some of which were first identified on the island, as well as the contemporary non-dinosaurian species of crocodile, turtle and pterosaur.
Neovenator is a genus of carcharodontosaurian theropod dinosaur. It is known from several skeletons found in the Early Cretaceous (Hauterivian-Barremian) Wessex Formation on the south coast of the Isle of Wight, southern England. It is one of the best known theropod dinosaurs from the Early Cretaceous of Europe.
Eotyrannus 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 animal's classification as an early tyrannosaur or "tyrant lizard", while the specific name honors the discoverer of the fossil.
Darren William Naish is a British vertebrate palaeontologist, author and science communicator.
Scipionyx was a genus of theropod dinosaur from the Early Cretaceous Pietraroja Formation of Italy, around 113 million years ago.
Calamospondylus is a genus of theropod dinosaur. It lived during the Early Cretaceous and its fossils were found on the Isle of Wight in southern England. The type species is C. oweni.
Calamosaurus was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae, collected by Reverend William Fox.
Huaxiagnathus is a genus of theropod dinosaur from the Lower Cretaceous of China. It was a compsognathid, large for that group at about half a meter longer than Compsognathus and larger specimens of Sinosauropteryx, with the largest specimen about 1.8 meters in length.
Tupuxuara is a genus of large, crested, and toothless pterodactyloid pterosaur from the Early Cretaceous period of what is now the Romualdo Formation of the Santana Group, Brazil, about 125 to 112 million years ago. Tupuxuara is a close relative of Thalassodromeus, and both form a group that is either called Thalassodrominae or Thalassodromidae.
Santanaraptor is a genus of tyrannosauroid theropod dinosaur that lived in South America during the Early Cretaceous, about 112 million years ago.
Thalassodromeus is a genus of pterosaur that lived in what is now Brazil during the Early Cretaceous period, about a hundred million years ago. The original skull, discovered in 1983 in the Araripe Basin of northeastern Brazil, was collected in several pieces. In 2002, the skull was made the holotype specimen of Thalassodromeus sethi by palaeontologists Alexander Kellner and Diogenes de Almeida Campos. The generic name means "sea runner", and the specific name refers to the Egyptian god Seth due to its crest being supposedly reminiscent of Seth's crown. Other scholars have pointed out that the crest was instead similar to the crown of Amon. A jaw tip was assigned to T. sethi in 2005, became the basis of the new genus Banguela in 2015, and assigned back to Thalassodromeus as the species T. oberlii in 2018, though other researchers consider it a valid genus. Another species was described in 2015 based on a supposed crest fragment, but this was later shown to be part of a turtle shell.
Compsognathidae is a family of coelurosaurian theropod dinosaurs. Compsognathids 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. "Ubirajara jubatus", informally described in 2020, had elaborate integumentary structures on its back and shoulders superficially similar to the display feathers of a standardwing bird-of-paradise, and unlike any other non-avian dinosaur currently described.
Sinocalliopteryx is a genus of carnivorous compsognathid theropod dinosaurs from the Lower Cretaceous Yixian Formation of China.
Samrukia is a genus of large Cretaceous pterosaurs known only from a single lower jaw discovered in Kazakhstan. The holotype and only known specimen was collected from the Santonian-Campanian age Bostobynskaya Formation in Kyzylorda District. It was described by Darren Naish, Gareth Dyke, Andrea Cau, François Escuillié, and Pascal Godefroit in 2012, and the type species is named Samrukia nessovi. The species is named after Lev Nessov, a paleontologist, and the genus is named after Samruk, a magical bird of Kazakh folklore.
Siats (/see-ats/) is an extinct genus of large theropod dinosaur known from the Late Cretaceous Cedar Mountain Formation of Utah, United States. It contains a single species, Siats meekerorum. It was initially classified as a megaraptoran, a clade of large theropods with very controversial relationships. Siats may be a neovenatorid allosauroid, a coelurosaur of uncertain phylogenetic position, or a tyrannosauroid.
Aratasaurus is an extinct genus of basal coelurosaurian theropod dinosaur from the Early Cretaceous (Aptian) Romualdo Formation of Brazil. The genus contains a single species, A. museunacionali, known from a partial right leg. Aratasaurus represents the only tetrapod fossil known from the lower levels of the Romualdo Formation.
"Ubirajara" is an informal genus of compsognathid theropod that lived during the early Cretaceous period in what is now Brazil. The manuscript describing it was available online pre-publication but was never formally published and, as a consequence, both genus and species name are considered invalid and unavailable. It is known by a single species, "Ubirajara jubatus", recovered from the Crato Formation. It was described as the first Gondwanan non-avian theropod dinosaur discovered with preserved integumentary structures. Such proto-feathers, most likely used for display, include slender monofilaments associated with the base of the neck, increasing in length along the dorsal thoracic region, where they would form a mane, as well as a pair of elongate, ribbon-like structures likely emerging from its shoulders. The taxon was informally named in 2020 in a now-withdrawn in-press academic paper. The description caused controversy due to the fossil having been apparently illegally smuggled from Brazil. In July 2022, Germany agreed to return the fossil to Brazil after a legitimate export permit could not be found. The name "Ubirajara jubatus" was removed from ZooBank in November 2022, which means it no longer has any nomenclatural significance.
Riparovenator is a genus of baryonychine spinosaurid dinosaur from the Early Cretaceous (Barremian) period of Britain. The genus contains a single species, Riparovenator milnerae.
Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. The clade was named by Charig & Milner in 1986 and defined by Sereno et al. in 1998 and Holtz et al. in 2004 as all taxa more closely related to Baryonyx walkeri than to Spinosaurus aegyptiacus.
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