Chenanisaurus Temporal range: Late Cretaceous | |
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Holotype partial dentary of Chenanisaurus barbaricus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Abelisauridae |
Genus: | † Chenanisaurus Longrich et al., 2017 |
Type species | |
†Chenanisaurus barbaricus Longrich et al., 2017 |
Chenanisaurus is a genus of predatory abelisaurid dinosaur, with a single known species C. barbaricus. It comes from the upper Maastrichtian phosphates of the Ouled Abdoun Basin in Morocco, North Africa. The animal is known from a holotype, consisting of a partial jaw bone, and several isolated teeth found in the same beds. Chenanisaurus is one of the largest members of the Abelisauridae, and one of the last, being a contemporary of the North American Tyrannosaurus . It would have been among the dinosaur species wiped out by the Chicxulub asteroid impact and the Cretaceous-Paleogene mass extinction that followed. [1]
Chenanisaurus is quite a large abelisaurid, measuring 7–8 m (23–26 ft), based on measurements of the holotype dentary. Its size is comparable to that of large abelisaurids such as Carnotaurus and Pycnonemosaurus . [1]
Nicholas R. Longrich and colleagues, the describers of Chenanisaurus, identified distinctive features distinguishing the animal from other abelisaurid species. The lower jaw is high, while the dentary is bent in side view. The lateral groove and associated foramina are located high on the outer surface of the dentary. The anterodorsal margin of the dentary is curved downward. The symphysis of the lower jaws is heavily built while the leading edge is vertical in side view. The front jaw points are wide in plan view, encountering each other at an obtuse angle. [1]
The most striking feature of the mandible is the extreme height, especially when compared with the relatively short teeth. This seems to indicate that the jaw is also very short, with a build even more extreme than seen in the related Carnotaurus . This suggests the jaws were built to withstand a high bite force. The jaw flexes forwardly downwards to terminate in a deep blunt point. At the back there is a deep high furrow above it with a row of foramina that open towards the top in a series of vertical grooves. The high position is a basal characteristic. The outer lower side shows an ornamentation of pits and interweaved ridges. The front interdental plates are very high but they quickly lower towards the rear of the jaw. The tooth sockets are rectangular in upper view. The jaw carries at least ten teeth. These are relatively slender, but the front teeth have a D-shaped cross section with the convexity facing outward; the rear teeth are dagger-shaped and more flattened. The cutting edges are convex and show up to thirteen denticles per five millimetres at the crown base, and up to eight denticles near the apex. They have small blood grooves. The enamel has an irregular structure without clear ornamentation. [1]
The holotype is labelled as OCP DEK-GE 772. Individual teeth collected from the surrounding area, two premaxillary teeth labelled as OCP DEK-GE 457 and DEK-GE 458 and the maxillary tooth WDC-CCPM-005 already described in 2005, [2] were referred to Chenanisaurus due to their similarity to the teeth of the holotype. Chenanisaurus is named after the Sidi Chennane mines where it was discovered and its specific name of barbaricus translates as "barbaric" and refers to Barbary. [1] Its discovery came as a surprise, because the rocks that produced the jaw were marine and primarily produced marine reptiles, not dinosaurs. [3]
In 2017, Chenanisaurus was placed in Abelisauridae in a basal position outside the Abelisaurinae and Carnotaurinae. Though it resembles carnotaurine abelisaurids in aspects of its jaw morphology, Chenanisaurus may belong to an as-yet undescribed group of abelisaurids unique to Africa. Only further research will determine the true relations of this species. [1]
Chenanisaurus was a predator, like other abelisaurids. Given its size, it could have hunted relatively large prey. The lower jaw suggests a relatively short powerfully built head and jaws. [1] Along with the large size of the animal, the proportions of the jaws would have given it a powerful bite force, suggesting the ability to prey on relatively large dinosaurs.
Titanosaurian sauropods have been found in the same beds, along with the small hadrosaurids Ajnabia odysseus and Minqaria Bata were likely prey for Chenanisaurus. [4]
The presence of Chenanisaurus in the phosphates is unusual because the phosphates represent a marine environment. Most of the fossils known from these beds are therefore marine animals, such as sharks, fish, mosasaurs, and plesiosaurs. [1] The presence of Chenanisaurus in these beds is therefore surprising. It is possible that some animals died and were washed out to sea by rivers; it is also possible that Chenanisaurus sometimes entered the ocean to swim.
Other Gondwanan continents, such as South America, India, and Madagascar show a similar combination of titanosaurians and abelisaurids in the latest Cretaceous, suggesting a distinct evolutionary history from the Laurasian continents of Asia and North America.
The finding of Chenanisaurus and these fragments of titanosaurids also indicate that in Africa, an abelisaurid/titanosaur fauna existed just prior to the Cretaceous–Paleogene extinction event, suggesting that the faunal assemblage of Gondwana was relatively stable until that point in time. [1] Chenanisaurus' remains were found in marine deposits that comprise most of the Sidi Chennane phosphate mines, indicating that post-mortem, the theropod had washed out to sea, where the holotype specimen became fossilized. [5]
Carnotaurus is a genus of theropod dinosaur that lived in South America during the Late Cretaceous period, probably sometime between 72 and 69 million years ago. The only species is Carnotaurus sastrei. Known from a single well-preserved skeleton, it is one of the best-understood theropods from the Southern Hemisphere. The skeleton, found in 1984, was uncovered in the Chubut Province of Argentina from rocks of the La Colonia Formation. Carnotaurus is a derived member of the Abelisauridae, a group of large theropods that occupied the large predatorial niche in the southern landmasses of Gondwana during the late Cretaceous. Within the Abelisauridae, the genus is often considered a member of the Brachyrostra, a clade of short-snouted forms restricted to South America.
Rajasaurus is a genus of carnivorous abelisaurid theropod dinosaur from the Late Cretaceous of India, containing one species: Rajasaurus narmadensis. The bones were excavated from the Lameta Formation in the Gujarat state of Western India, probably inhabiting what is now the Narmada River Valley. It was formally described by palaeontologist Jeffrey A. Wilson and colleagues in 2003 based on a partial skeleton comprising the braincase, spine, hip bone, legs, and tail–a first for an Indian theropod. The dinosaur likely measured 6.6 metres (22 ft), and had a single horn on the forehead which was probably used for display and head-butting. Like other abelisaurids, Rajasaurus was probably an ambush predator.
Abelisauridae is a family of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian subcontinent and the island of Madagascar. Isolated teeth were found in the Late Jurassic of Portugal, and the Late Cretaceous genera Tarascosaurus, Arcovenator and Caletodraco have been described in France. Abelisaurids possibly first appeared during the Jurassic period based on fossil records, and some genera survived until the end of the Mesozoic era, around 66 million years ago.
Majungasaurus is a genus of abelisaurid theropod dinosaur that lived in Madagascar from 70 to 66 million years ago, at the end of the Cretaceous Period, making it one of the last-known non-avian dinosaurs that went extinct during the Cretaceous–Paleogene extinction event. The genus contains a single species, Majungasaurus crenatissimus. This dinosaur is also called Majungatholus, a name which is considered a junior synonym of Majungasaurus.
Ekrixinatosaurus is a genus of abelisaurid theropod which lived approximately 100 to 97 million years ago during the Late Cretaceous period. Its fossils have been found in Argentina. Only one species is currently recognized, Ekrixinatosaurus novasi, from which the specific name honors of Dr. Fernando Novas for his contributions to the study of abelisaurid theropods, while the genus name refers to the dynamiting of the holotype specimen. It was a large abelisaur, measuring between 6.5 and 8 m in length and weighing 800 kg (1,800 lb).
Koutalisaurus is a potentially dubious genus of extinct hadrosaurid dinosaur from the Arenysaurini. It is based on a mostly complete dentary from the Maastrichtian-age Upper Cretaceous Tremp Formation near the town of Abella de la Conca, Lleida, Spain.
Phosphatodraco is a genus of azhdarchid pterosaur that lived during the Late Cretaceous of what is now Morocco. In 2000, a pterosaur specimen consisting of five cervical (neck) vertebrae was discovered in the Ouled Abdoun Phosphatic Basin. The specimen was made the holotype of the new genus and species Phosphatodraco mauritanicus in 2003; the genus name means "dragon from the phosphates", and the specific name refers to the region of Mauretania. Phosphatodraco was the first Late Cretaceous pterosaur known from North Africa, and the second pterosaur genus described from Morocco. It is one of the only known azhdarchids preserving a relatively complete neck, and was one of the last known pterosaurs. Additional cervical vertebrae have since been assigned to the genus, and it has been suggested that fossils of the pterosaur Tethydraco represent wing elements of Phosphatodraco.
Pluridens is an extinct genus of marine lizard belonging to the Mosasauridae. Pluridens is placed in the subfamily Halisaurinae with the genera Phosphorosaurus, Eonatator and Halisaurus. Compared to related halisaurines, Pluridens had longer jaws with more teeth, and smaller eyes. It also grew large size, measuring 5–6 m (16–20 ft) long and perhaps over 9 m (30 ft) in some individuals. The jaws in some specimens are robust, and sometimes show injuries suggestive of combat. The jaws may have been used for fighting over mates or territories.
Arambourgisuchus is an extinct genus of dyrosaurid crocodylomorph from the late Palaeocene of Morocco, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by palaeontologist Stéphane Jouve. Arambourgisuchus was a large animal with an elongated skull 1 meter in length.
Canardia is an extinct genus of lambeosaurine dinosaur known from the Late Cretaceous Marnes d'Auzas Formation of Haute-Garonne department, in Occitanie region, southwestern France. The type species Canardia garonnensis was first described and named by Albert Prieto-Márquez, Fabio M. Dalla Vecchia, Rodrigo Gaete and Àngel Galobart in 2013. It is only known from juvenile specimens. The name of the genus comes from “canard”, the French word for “duck”, an allusion to the fact that this animal belongs to the hadrosaurids which are also known as duck-billed dinosaurs. The specific epithet garonnensis refers to the Haute-Garonne department where this dinosaur has been found. Although universally recognized as a lambeosaurine, its precise position within them is debated. Some authors consider it as a close relative of the genus Aralosaurus from Central Asia with which it would form the tribe Aralosaurini, while others include it in a more derived clade, the Arenysaurini in which all lambeosaurines from Europe and North Africa are placed. Canardia was one of the last non-avian dinosaurs and lived between 67,5 and 66 my on the former Ibero-Armorican Island, which included much of France and Spain.
Arcovenator is an extinct genus of abelisaurid theropod dinosaurs hailing from the Late Cretaceous of France and possibly Spain. The type and only described species is Arcovenator escotae.
Majungasaurinae is a subfamily of large carnivorous theropods from the Upper Cretaceous, found in Madagascar, India, and France. It is a subgroup within the theropod family Abelisauridae, a Gondwanan clade known for their thick and often horned skulls and vestigial arms. The two subfamilies of Abelisauridae are Carnotaurinae, best known from the South American Carnotaurus, and Majungasaurinae, consisting of Madagascar’s Majungasaurus and its closest relatives. Their ancestors emerged in the Middle Jurassic, and the clade lasted until the Upper Cretaceous.
The Oulad Abdoun Basin is a phosphate sedimentary basin located in Morocco, near the city of Khouribga. It is the largest in Morocco, comprising 44% of Morocco's phosphate reserves, and at least 26.8 billion tons of phosphate. It is also known as an important site for vertebrate fossils, with deposits ranging from the Late Cretaceous (Cenomanian-Turonian) to the Eocene epoch (Ypresian), a period of about 25 million years.
Tethydraco is a genus of pterodactyloid pterosaur that lived during the Late Cretaceous period of what is now the area of present Morocco, about 66 million years ago. Tethydraco was originally assigned to the family Pteranodontidae. Some researchers argued that subsequently described material suggests that it may have been an azhdarchid, and possibly synonymous with Phosphatodraco, though this has been disputed. The type and only species is T. regalis.
Niebla is a genus of abelisaurid theropod dinosaur from the Late Cretaceous Period (Campanian-Maastrichtian) of Río Negro province, Argentina. The genus contains a single species, Niebla antiqua, and is known from a partial, non-articulated skeleton. The holotype, found in the Allen Formation, represents an adult individual about nine years old in minimum age.
Ajnabia is a genus of lambeosaurine hadrosaur from the Late Cretaceous (Maastrichtian) of Morocco. It is the first definitive hadrosaur from Africa, and is thought to be related to European dinosaurs like Arenysaurus. The discovery of Ajnabia came as a surprise to the paleontologists who found it, because Africa was isolated by water from the rest of the world during the Cretaceous, such that hadrosaurs were assumed to have been unable to reach the continent. Ajnabia is relatively small and similar in size to its contemporary relative Minqaria, which is estimated to have reached 3.5 metres (11 ft) in total body length. Assuming that the holotype represents an adult, Ajnabia would be one of the smallest if not the smallest known hadrosaurids.
Xenodens is an extinct genus of marine lizard belonging to the mosasaur family. It currently contains a single species, X. calminechari, which is known from Late Maastrichtian phosphate deposits in the Ouled Abdoun Basin, Morocco. Its closest known relative is believed to be the durophagous Carinodens.
Thalassotitan is an extinct genus of large mosasaurs that lived during the late Maastrichtian of the Cretaceous period in what is now Morocco, around 66 million years ago. The only known species is T. atrox, described in 2022 from fossils discovered in the Ouled Abdoun Basin, where many other mosasaurs have been found. It was assigned to the tribe Prognathodontini alongside other mosasaurs like Prognathodon and Gnathomortis. The prognathodontines are separated from other mosasaurs based on their massive jaws and robust teeth.
Minqaria is a genus of arenysaurinin lambeosaurine hadrosaur from the Late Cretaceous (Maastrichtian) Ouled Abdoun Basin of Morocco. The genus contains a single species, M. bata, known from a partial skull.
Khinjaria is an extinct genus of plioplatecarpine mosasaurid from the Late Cretaceous Ouled Abdoun Basin of Morocco. The genus contains a single species, K. acuta, known from a partial skull and vertebra. Khinjaria was likely an apex predator in its environment, as its large body size, blade-like teeth, and unusual skull morphology would have allowed it to attack large prey animals.