Ajnabia

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Ajnabia
Temporal range: Late Maastrichtian, 68–66  Ma
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Ajnabia odysseus maxilla by Nick Longrich.jpg
Maxilla of Ajnabia odysseus from the late Maastrichtian of Morocco
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Ornithopoda
Family: Hadrosauridae
Subfamily: Lambeosaurinae
Tribe: Arenysaurini
Genus: Ajnabia
Longrich et al., 2021
Type species
Ajnabia odysseus
Longrich et al., 2021

Ajnabia (meaning "stranger" or "foreigner") 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 . [1] 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. [2] [3] 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. [4] Assuming that the holotype represents an adult, Ajnabia would be one of the smallest if not the smallest known hadrosaurids.

Contents

Discovery and naming

Life restoration Life reconstruction of Ajnabia odysseus.png
Life restoration

Ajnabia was recovered from the Late Maastrichtian strata of the phosphate mines at Sidi Chennane, in Khouribga Province, Morocco. Recovered elements include most of the left maxilla and part of the right, and a fragment of the right dentary. The name Ajnabia derives from the Arabic أجنبي (ajnabi), meaning "strange" or "foreign", referring to the animal as part of a dinosaur lineage that immigrated to Africa from elsewhere. The type and only species is A. odysseus, referring to the Greek hero and legendary sea voyager Odysseus. [1]

Arenysaurini

Arenysaurus

Pararhabdodon

Koutalisaurus

Basturs lambeosaurine

Canardia

Adynomosaurus

Serrat del Rostiar lambeosaurine

Blasisaurus

Ajnabia

Palaeoecology

Late Maastrichtian dinosaurs of Morocco, including Ajnabia odysseus, Chenanisaurus barbaricus Maastrichtian Dinosaur Fauna of Morocco by Nick Longrich.jpg
Late Maastrichtian dinosaurs of Morocco, including Ajnabia odysseus, Chenanisaurus barbaricus

The holotype specimen, MHNM KHG 222, was recovered from the phosphates of the Ouled Abdoun Basin of north-central Morocco. The phosphates are a nearshore marine environment, dominated by sharks, fish, mosasaurs, and other marine reptiles. Dinosaurs are rare, however, including the large abelisaurid Chenanisaurus barbaricus , two other potentially distinct abelisaurids of smaller size, and an unnamed titanosaurian. [5] [6] [7] Moroccan lambeosaurine fossils belonging to individuals of various sizes, including the holotype of Minqaria , indicate that hadrosaurs were diverse and abundant within the ecosystem. [4] These dinosaurs would have lived in the very latest Cretaceous (Late Maastrichtian) approximately 1 million years before the K-Pg boundary and the Chicxulub asteroid impact that wiped out the dinosaurs. [1]

Palaeobiogeography

Restoration of Chenanisaurus hunting Ajnabia Chase on the beach.jpg
Restoration of Chenanisaurus hunting Ajnabia

Hadrosaurs, the taxonomic group Ajnabia is assigned to, had not been documented from Africa until its discovery; specifically, its close relatives within Lambeosaurinae are all known from Europe. Given this taxonomic position and reconstructions of Late Cretaceous continents and seas, oceanic dispersal between Europe and North Africa is considered the only viable explanation for the presence of Ajnabia in Africa. While oceanic dispersal had previously been considered for the distribution of European hadrosaurs, intermittent land connections as means of dispersal could not be ruled out. The much more prominent oceanic barrier between Europe and Africa, characterized by deep waters, makes Ajnabia far stronger evidence of this phenomenon, as the gap could be narrowed by varying conditions but not conceivably bridge entirely. The possibility Ajnabia was a carcassed or fossil that had floated from Europe was also considered highly unlikely due to the fossil's taphonomy and the inability to assign it to any known European species. Further evidence for the oceanic dispersal as the model for lambeosaur dispersal also exists from the lack of more complete interchange of fauna between locations, expected from land bridge dispersal. [1] In turn, Ajnabia has been used as an important datapoint to support the possibility of oceanic dispersal between European islands. [8] Possible means of dispersal include swimming, drifting, or rafting (wherein animals are transported on top of floating debris or vegetation). Rafting is considered unlikely for a large animal, but it's considered possible young hadrosaurs could be transported in this way. [1]

Map of the continents in the Late Cretaceous, the southern "Gondwanan" continents were diverging and Northern Africa was an island LateCretaceousMap.jpg
Map of the continents in the Late Cretaceous, the southern "Gondwanan" continents were diverging and Northern Africa was an island

More broadly speaking, the Maastrichtian fauna of the Northe African ecosystem Ajnabia inhabited seems biogeographically linked more to Gondwanan faunas - that is, those of the southern continents - then that of Europe and the other Laurasian continents of the Northern Hemisphere. Whilst Laurasia is characterized by tyrannosaurids, ornithischians and herbivorous coelurosaurs, Gondwana is dominated by titanosaurs and abelisaurs, as seen in Morocco. Despite this, a degree of endemism is noted, similar to that of other Gondwanan continents. A small abelisaur from the Sidi Daoui region is unlike those from South America or India, but may be related to North African forms from earlier in the Cretaceous or similarly sized abelisaurs in Europe; [6] likewise, Chenanisaurus may represent a distinct lineage from other known abelisaurs. [5] [6] Inversely, other Gondwanan animals from South America such as ankylosaurs, unenlagiinaes, elasmarians, and megaraptorids aren't documented in Africa. This endemism is explained by the fragmentation of the former Gondwanan supercontinent into increasingly distant landmasses, leading to the ancestrally linked faunas of different southern continents becoming distinct. Even within the African continent, the presence of a Trans-Saharan seaway connecting the Tethys Ocean of Europe to the Gulf of Guinea may have isolated the fauna of Northern Africa from more southern portions of the continent, such as fossil bearing sites in Kenya, and Morocco itself may have been an isolated island. [6]

Related Research Articles

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

Pararhabdodon is a genus of tsintaosaurin hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Group of Spain. The first remains were discovered from the Sant Romà d’Abella fossil locality and assigned to the genus Rhabdodon, and later named as the distinct species Pararhabdodon isonensis in 1993. Known material includes assorted postcranial remains, mostly vertebrae, as well as maxillae from the skull. Specimens from other sites, including remains from France, a maxilla previously considered the distinct taxon Koutalisaurus kohlerorum, an additional maxilla from another locality, the material assigned to the genera Blasisaurus and Arenysaurus, and the extensive Basturs Poble bonebed have been considered at different times to belong to the species, but all of these assignments have more recently been questioned. It was one of the last non-avian dinosaurs known from the fossil record that went extinct during the Cretaceous-Paleogene extinction event.

<span class="mw-page-title-main">Mosasaurinae</span> Subfamily of reptiles

The Mosasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "mosasaurines" and their fossils have been recovered from every continent except for South America.

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

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.

<i>Phosphatodraco</i> Late Cretaceous genus of pterosaur

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.

<i>Brachysaurana</i> Extinct genus of lizards

Brachysaurana is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Clidastes. Although traditionally synonymized with Prognathodon, recent cladistic studies do not find it closely related to the Prognathodon type species to the exclusion of other prognathodontin mosasaurines.

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

Blasisaurus is a genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous. It is known from a partial skull and skeleton found in late Maastrichtian-age rocks of Spain. The type species is Blasisaurus canudoi, described in 2010 by Penélope Cruzado-Caballero, Xabier Pereda-Suberbiola and José Ignacio Ruiz-Omeñaca, a group of researchers from Spain.

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

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.

<span class="mw-page-title-main">Aralosaurini</span>

Aralosaurini is a proposed tribe of hadrosaurid dinosaurs belonging to the subfamily Lambeosaurinae. The members of this group lived in Asia and Europe during the end of the Late Cretaceous about 83.6 to 66.0 million years ago. The clade may not be monophyletic, with Canardia and Aralosaurus potentially instead being unrelated primitive members of the subfamily.

<span class="mw-page-title-main">Tsintaosaurini</span> Extinct tribe of dinosaurs

Tsintaosaurini is a tribe of basal lambeosaurine hadrosaurs native to Eurasia. It is thought to contains the genera Tsintaosaurus, Pararhabdodon and Koutalisaurus, though some studies have questioned its existence as a natural grouping.

<span class="mw-page-title-main">Ouled Abdoun Basin</span> Phosphate basin in Morocco

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.

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

Adelolophus is a genus of lambeosaurine dinosaur from Upper Cretaceous rocks in the U.S. state of Utah. The type and only known species is A. hutchisoni; the type specimen consists only of a broken maxilla. It constitutes the oldest known lambeosaur remains from North America, as well as the only known lambeosaur species from the Wahweap Formation, of which it pertains to the Upper Member. Among its relatives, it seems to be particularly similar to Parasaurolophus, rather than animals like Lambeosaurus; phylogenetic analysis confirms this, finding it in Parasaurolophini. It would have lived in a wet environment, bordering on the sea but with a more arid season during some times of the year. This environment would have been shared with a diverse variety of fish and turtles, as well as other dinosaurs like ceratopsids and tyrannosaurids.

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

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.

<i>Tethydraco</i> Genus of ornithocheiroid pterosaur from the Late Cretaceous

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.

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

Adynomosaurus is a genus of lambeosaurine dinosaur from the Late Cretaceous of what is now Catalonia, Spain. First discovered in 2012, it was named in 2019 with the type and only species being Adynomosaurus arcanus. It is only known from scant material, but is distinguished from other hadrosaurs by its weakly developed shoulder blade which would have had underdeveloped musculature, which lends it its scientific name, partially from the Greek word for "weak". Its exact relationships with other hadrosaurs remain unresolved, with it not consistently being recovered as a relative of any other specific genera, though some studies have allied it with Tsintaosaurini or even found it outside of Hadrosauridae. It would have lived as part of a diverse coastal estuary ecosystem, made up of meandering rivers and mud flats. The discovery of Adynomosaurus adds to the very incomplete fossil record of hadrosaurid dinosaurs in the Late Cretaceous of Europe, and it fits into a picture of major ecological turnover that was occurring during the Maastrichtian stage in the region.

<span class="mw-page-title-main">Arenysaurini</span> Extinct tribe of dinosaurs

Arenysaurini is a proposed tribe of primitive lambeosaurine hadrosaurs. It is composed of genera found in Europe and North Africa during the end of the Cretaceous period, and has been suggested to unite all lambeosaurs from the former continent into a singular monophyletic group.

<i>Gavialimimus</i> Extinct genus of lizards

Gavialimimus is an extinct genus of plioplatecarpine mosasaur from the Maastrichtian of Morocco. The holotype MHNM.KHG.1231, an articulated skull and associated fragmentary postcrania, was found in the Ouled Abdoun Basin.

<i>Thalassotitan</i> Large bodied African mosasaur

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.

Patagopelta is an extinct genus of nodosaurine dinosaur from the Late Cretaceous Allen Formation of Argentina. The genus contains a single species, P. cristata, known from a partial skeleton. Patagopelta is a very small ankylosaur, comparable in size to the dwarf nodosaurid Struthiosaurus, about 2 m (6.6 ft) long.

<i>Stelladens</i> Extinct genus of mosasaurine

Stelladens is an extinct genus of mosasaurine. Fossils of Stelladens have been recovered from the Late Cretaceous Ouled Abdoun Basin of Morocco. The genus contains a single species, S. mysteriosus. It was a medium-sized mosasaur, measuring about 5 metres (16 ft) long.

<i>Minqaria</i> Extinct genus of hadrosaurid dinosaurs

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.

References

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  2. Southworth, Phoebe (November 5, 2020). "Dinosaurs swam across oceans, landmark study reveals" via www.telegraph.co.uk.
  3. "New fossil discovery suggests dinosaurs traveled across oceans". www.msn.com.
  4. 1 2 Longrich, N. R.; Pereda-Suberbiola, X.; Bardet, N.; Jalil, N.-E. (2024). "A new small duckbilled dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and dinosaur diversity in the late Maastrichtian of North Africa". Scientific Reports. 14. 3665. doi: 10.1038/s41598-024-53447-9 . PMC   10864364 .
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  8. Nikolov, Vladimir; Dochev, Docho; Brusatte, Stephen L. (2024). "The ontogenetic status of a small hadrosauroid dinosaur from the uppermost Cretaceous of Bulgaria, and implications for the paleobiogeography and assembly of European island faunas". Cretaceous Research. In Press. doi:10.1016/j.cretres.2023.105819.