Abelisauroidea

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Abelisauroids
Temporal range: Middle Jurassic - Late Cretaceous, 179–66  Ma
Majungasaurus SBU right.jpg
Majungasaurus crenatissimus skeleton, Stony Brook University
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Ceratosauria
Clade: Neoceratosauria
Superfamily: Abelisauroidea
Bonaparte & Novas, 1985
Families

Abelisauroidea is a diverse superfamily of ceratosaurian dinosaurs, typically regarded as a Cretaceous group, though the earliest abelisaurid remains are known from the Middle Jurassic of Argentina (classified as the species Eoabelisaurus mefi ) and possibly Madagascar (fragmentary remains of an unnamed species). Possible Abelisauridae remains (an isolated left tibia, right femur, and right tibia) were also discovered in Late Jurassic Tendaguru Beds in Tanzania.

Contents

Abelisauroids flourished in the Southern hemisphere during the Cretaceous period, but their origins can be traced back to at least the Middle Jurassic, when they had a more global distribution (the earliest known abelisauroid remains come from Australian and South American deposits dated to about 170 million years ago). [1] By the Cretaceous period, abelisauroids had apparently become extinct in Asia and North America, possibly due to competition from tyrannosauroids. However, advanced abelisauroids of the family Abelisauridae persisted in the southern continents until the Cretaceous–Paleogene extinction event 66 million years ago. [2]

Diversity

In an assessment of the phylogenetic position of Eoabelisaurus, the analysis found it as the most basal member of the Abelisauridae. Abelisaurid synapomorphies include the laterally covered lacrimal antorbital fossa, broad cervical prespinal fossae, anteroposteriorly short anterior caudal neural spines, absence of a ventral groove in the anterior caudals, presence of rudimentary centrodiapophyseal laminae in the anterior mid-caudals, reduced distal ginglymus in the manual phalanges, and the presence of a flexor depression in the pedal unguals. Alternative phylogenetic placements of Eoabelisaurus are significantly suboptimal, except for a slightly more basal position. [3] Noasaurids had longer arms than their relatives the abelisaurids, whose arms were tiny and diminished. Although by no means as large or specialized as the arms of advfanced bird-like theropods, noasaurid arms were nevertheless capable of movement and use, possibly even for hunting in large-clawed genera such as Noasaurus . Some genera such as Limusaurus did have somewhat reduced arms and hands, but far from the extent that abelisaurids acquired. Noasaurids were also nimble and lightly built, with feet showing adaptations for running such as a long central foot bone. Noasaurids varied in size, from the small Velocisaurus which was under 5 feet (1.5 meters) long, to much larger genera such as Elaphrosaurus and Deltadromeus , which were more than 20 feet (6.1 meters) in length. [4]

Classification

Abelisauroidea is a superfamily which contains the family Noasauridae and Abelisauridae. Noasauridae was a very diverse group, with the two most complete members, Masiakasaurus and Limusaurus, showing unusual features very different from each other. Masiakasaurus had an unusually downturned jaw, with long and sharply pointed spoon-shaped teeth. Some of these teeth were nearly horizontal in orientation. Limusaurus, on the other hand, was completely toothless as an adult and likely possessed a horny beak. This large disparity means that it is difficult to find any skull features shared by members of Noasauridae as a whole. Abelisauridae remains are mainly known in the southern continents, which once made up the supercontinent of Gondwana. It has had several definitions in phylogenetic taxonomy. It was originally defined as a node-based taxon including Abelisaurus, Carnotaurus, and all of its descendants. Later, it was redefined as a stem-based taxon, including all animals more closely related to Abelisaurus (or the more complete Carnotaurus) than to Noasaurus.

 Abelisauroidea 
  Noasauridae  

Laevisuchus

Masiakasaurus Masiakasaurus BW (flipped).jpg

Noasaurus

Velocisaurus

 Abelisauridae 

Eoabelisaurus

Rugops

Abelisaurus Abelisaurus.JPG

  Carnotaurinae  

Majungasaurus Majungasaurus BW (flipped).jpg

Indosaurus

Rajasaurus Rajasaurus restoration.jpg

  Brachyrostra  

Ilokelesia Ilokelesia (flipped).jpg

Ekrixinatosaurus Ekrixinatosaurus novasi by Henrique Paes.png

Skorpiovenator Skorpiovenator bustingorryi by D-Juan.jpg

  Carnotaurini  

Carnotaurus Carnotaurus DB 2 white background.jpg

Aucasaurus Aucasaurus garridoi by Paleocolour.jpg

Shared characteristics

Complete skeletons have been described only for the most advanced abelisauridae (such as Carnotaurus and Aucasaurus), making the establishment of defining features of the skeleton for the family as a whole more difficult. However, most are known from at least some skull bones, so known shared features come mainly from the skull. Many abelisaurid skull features are shared with carcharodontosaurids. [5] These shared features, along with the fact that abelisauridae seem to have replaced carcharodontosauridae in South America, has led to suggestions that the two groups were related. Noasaurids were considered to be distinctive Abelisauroidea with a peculiar "sickle claw" on the second toe of the foot, convergently developed with that of Deinonychosaurians. Among Noasaurids, the Argentinean species Noasaurus leali (Later Cretaceous) and Ligabueino(Early Cretaceous) are known from incomplete specimens, including disarticulated non-ungual phalanges and in Noasaurus, a claw. A detailed overview of these elements indicates that the supposed raptorial claw of the second pedal digit actually belongs to the first or second finger of the manus, and the putative pedal non-ungual phalanges or both genera also pertain to the manus. [6]

Discovery

Most abelisauroid were found in Madagascar, Asia, or sometimes in Africa. Abelisauridae 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. In Madagascar, what are known as "Majungasaurus" were discovered by French paleontologist Charles Depéret. Majungasaurus was the most common abelisauroid which we know. Studies of the abelisauridae Majungasaurus indicate that it was a much slower-growing dinosaur than other theropods, taking nearly 20 years to reach adult size. Not only Majungasaurus was found in Madagascar but also Masiakasaurus which was the most complete fossil noasauridae found. Similar studies on other abelisaurid genera indicate that this slow maturation may have been a common trait to the whole of the Abelisauridae. Noasaurines are Late Cretaceous noasaurids known exclusively from southern continents and islands such as South America, Madagascar, and India which was an island near Madagascar during the Cretaceous. Elaphrosaurines were lightly built theropods, with small skulls and long necks and legs. If Limusaurus is any indication, adult elaphrosaurines were completely toothless, and their mouths were probably edged with a horny beak. It is likely that Limusaurus and other elaphrosaurines were primarily herbivorous as adults, due to mature Limusaurus specimens preserving gastroliths and chemical signatures resembling those of herbivorous dinosaurs. In South America, many abelisauroids were discovered such as Skorpiovenator, Tarasscosaurus, Erikasaurus, Quilmesaurus, Aucasarus, Ilokelesia, Pycnonemosaurus etc. In Africa, we can find many abelisauroid which were Rugops, Kryptops, etc. Many abelisauroid can grow in South America, because they can evolve in a fruitful place. Kurupi itaata represents the first formally named vertebrate of the Marília Formation (Bauru Group, Bauru Basin) and one of the few theropod records for the Maastrichtian of the Bauru Basin. Its abelisauridae affinities are well established based on the anatomy of the pelvis and anterior caudal vertebrae; however, closer relationships with other abelisauridae are still unclear. The specimens provide new information on abelisauroids which are still poorly known in the Brazilian fossil record, and on the distribution of this diverse group of theropod dinosaurs in South America. [7] These discoveries indicate that abelisauroids were the most common large predatory dinosaurs in the outcrops where they come from. [8]

Paleobiology

Behavior

Using three methods, namely a cladistic analysis performed on a dentition-based data matrix, and discriminant and cluster analyses conducted on a large dataset of theropod teeth measurements, we identify three dental morphotypes which are confidently referred to abelisaurid theropods. Whether the morphotypes represent different abelisaurid subclades or different positional entities within the jaw of the same abelisaurid species, is unknown. Such an identification, nevertheless, provides additional evidence of abelisaurids feeding on sauropod carcasses. [9]

See also

Related Research Articles

<i>Carnotaurus</i> Abelisaurid theropod dinosaur from the Late Cretaceous period

Carnotaurus is a genus of theropod dinosaur that lived in South America during the Late Cretaceous period, probably sometime between 71 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.

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

<i>Rajasaurus</i> Abelisaurid dinosaur genus from Late Cretaceous India

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.

<i>Masiakasaurus</i> Noasaurid theropod dinosaur genus from the Late Cretaceous period

Masiakasaurus is a genus of small predatory noasaurid theropod dinosaurs from the Late Cretaceous of Madagascar. In Malagasy, masiaka means "vicious"; thus, the genus name means "vicious lizard". The type species, Masiakasaurus knopfleri, was named after the musician Mark Knopfler, whose music inspired the expedition crew. It was named in 2001 by Scott D. Sampson, Matthew Carrano, and Catherine A. Forster. Unlike most theropods, the front teeth of M. knopfleri projected forward instead of straight down. This unique dentition suggests that they had a specialized diet, perhaps including fish and other small prey. Other bones of the skeleton indicate that Masiakasaurus were bipedal, with much shorter forelimbs than hindlimbs. M. knopfleri was a small theropod, reaching 1.8–2.1 m (5.9–6.9 ft) long and weighing 20 kg (44 lb).

<span class="mw-page-title-main">Abelisauridae</span> Extinct family of dinosaurs

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 and Arcovenator have been described in France. Abelisaurids first appear in the fossil record of the early middle Jurassic period, and at least three genera survived until the end of the Mesozoic era 66 million years ago.

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

Aucasaurus is a genus of medium-sized abelisaurid theropod dinosaur from Argentina that lived during the Late Cretaceous of the Anacleto Formation. It was smaller than the related Carnotaurus, although more derived in some ways, such as its extremely reduced arms and almost total lack of fingers. The type skeleton is complete to the thirteenth caudal vertebra, and so is relatively well understood, and is the most complete abelisaurid yet described. However, the skull is damaged, causing some paleontologists to speculate that it was involved in a fight prior to death.

<i>Majungasaurus</i> Abelisaurid theropod dinosaur from the Late Cretaceous period

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.

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

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).

Genusaurus is a genus of abelisauroid dinosaur from the Early Cretaceous. Its fossils were found in France. Genusaurus is believed to have lived during the Albian stage, around 112-100 million years ago.

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

Noasaurus is a genus of ceratosaurian theropod dinosaur genus from the late Campanian-Maastrichtian of Argentina. The type and only species is N. leali.

<span class="mw-page-title-main">Noasauridae</span> Extinct family of dinosaurs

Noasauridae is an extinct family of theropod dinosaurs belonging to the group Ceratosauria. They were closely related to the short-armed abelisaurids, although most noasaurids had much more traditional body types generally similar to other theropods. Their heads, on the other hand, had unusual adaptations depending on the subfamily. 'Traditional' noasaurids, sometimes grouped in the subfamily Noasaurinae, had sharp teeth which splayed outwards from a downturned lower jaw.

<i>Limusaurus</i> Genus of theropod dinosaur

Limusaurus is a genus of theropod dinosaur that lived in what is now China during the Late Jurassic, around 161 to 157 million years ago. The type and only species Limusaurus inextricabilis was described in 2009 from specimens found in the Upper Shishugou Formation in the Junggar Basin of China. The genus name consists of the Latin words for "mud" and "lizard", and the species name means "impossible to extricate", both referring to these specimens possibly dying after being mired. Limusaurus was a small, slender animal, about 1.7 m in length and 15 kg (33 lb) in weight, which had a long neck and legs but very small forelimbs. It underwent a drastic morphological transformation as it aged: while juveniles were toothed, these teeth were completely lost and replaced by a beak with age. Several of these features were convergently similar to the later ornithomimid theropods as well as the earlier non-dinosaurian shuvosaurids.

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

Eoabelisaurus is a genus of abelisaurid theropod dinosaur from the Lower Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Argentina, South America. The generic name combines a Greek ἠώς, (eos), "dawn", with the name Abelisaurus, in reference to the fact it represents an early relative of the latter. Only one species is currently recognized, E. mefi; the specific name honours the MEF, the Museo Paleontológico "Egidio Feruglio", where discoverer Diego Pol is active. It is characterized by reduced forelimb proportions that show primitive characteristics of the Abelisauridae family.

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

Dahalokely is an extinct genus of carnivorous abelisauroid theropod dinosaur from the Late Cretaceous (Turonian) of Madagascar.

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

Arcovenator is an extinct genus of abelisaurid theropod dinosaurs hailing from the Late Cretaceous of France. The type and only described species is Arcovenator escotae.

<span class="mw-page-title-main">Majungasaurinae</span> Extinct subfamily of reptiles

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.

<span class="mw-page-title-main">Timeline of ceratosaur research</span>

This timeline of ceratosaur research is a chronological listing of events in the history of paleontology focused on the ceratosaurs, a group of relatively primitive, often horned, predatory theropod dinosaurs that became the apex predators of the southern hemisphere during the Late Cretaceous. The nature and taxonomic composition of the Ceratosauria has been controversial since the group was first distinguished in the late 19th century. In 1884 Othniel Charles Marsh described the new genus and species Ceratosaurus nasicornis from the Late Jurassic Morrison Formation of the western United States. He felt that it belonged in a new family that he called the Ceratosauridae. He created the new taxon Ceratosauria to include both the Ceratosauridae and the ostrich-like ornithomimids. The idea of the Ceratosauria was soon contested, however. Later that same decade both Lydekker and Marsh's hated rival Edward Drinker Cope argued that the taxon was invalid.

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

Afromimus is a genus of theropod dinosaur from the Early Cretaceous Elrhaz Formation of Niger. It contains a single species, A. tenerensis, named in 2017 by Paul Sereno from parts of the right leg, vertebrae, and ribs found in the Ténéré Desert. It was originally classified as an ornithomimosaurian, but subsequently it was argued to be an abelisauroid.

<span class="mw-page-title-main">Furileusauria</span> Clade of abelisaurid theropod dinosaurs

Furileusauria is an extinct clade of derived abelisaurid dinosaurs only known from South American fossil remains. They represent some of the largest members of the Abelisauridae, with an average length of 7.1 ± 2.1 m (23.3 ± 6.9 ft). The clade is defined as the most inclusive clade containing Carnotaurus sastrei but not Ilokelesia aguadagrandensis, Skorpiovenator bustingorryi, or Majungasaurus crenatissimus.

Tralkasaurus is a genus of abelisaurid dinosaur from the Huincul Formation from Río Negro Province in Argentina. The type and only species is Tralkasaurus cuyi, named in 2020 by Mauricio Cerroni and colleagues based on an incomplete skeleton. A medium-sized abelisaurid, Tralkasaurus exhibits a conflicting blend of characteristics found among the early-diverging abelisauroids with others that characterize the highly specialized clade Brachyrostra, and thus its position within the clade is poorly-resolved.

References

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  6. Agnolin, Federico; Chiarelli, Pablo. "The position of the claws in Noasauridae (Dinosauria: Abelisauroidea) and its implications for abelisauroid manus evolution". ResearchGate.
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  8. Méndez, Ariel; E Novas, Fernando; Vidoi Iori, Fabiano. "New records of abelisauroid theropods from the Bauru Basin (Upper Cretaceous), Sao Paulo State, Brazil". ResearchGate.
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Creative Commons by small.svg  This article incorporates text from this source, which isby Jorge G. Meso, Christophe Hendrickx, Mattia A. Baiano, Juan I. Canale, Leonardo Salgado, and Ignacio Diaz Martinez available under the CC BY 4.0 license.