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41-528: Abelisauridae (meaning "Abel's lizards") is a family (or clade ) 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
82-758: A ceratosaurid, an abelisauroid or its sister taxon outside abelisaurids. Indeterminate remains are also known from the Jurassic period of Madagascar and Tanzania . Abelisaurid remains are mainly known in the southern continents, which once made up the supercontinent of Gondwana . When first described in 1985, only Carnotaurus and Abelisaurus were known, both from the Late Cretaceous of South America . Abelisaurids were then located in Late Cretaceous India ( Indosuchus and Rajasaurus ) and Madagascar ( Majungasaurus ), which were closely connected for much of
123-554: A lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching a consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called
164-613: A noasaurid or an abelisaurid. With the description of Skorpiovenator in 2008, Canale et al. published another phylogenetic analysis focusing on the South American abelisaurids. In their results, they found that all South American forms, including Ilokelesia (except Abelisaurus ), grouped together as a subclade of carnotaurines, which they named the Brachyrostra . In the same year Matthew T. Carrano and Scott D. Sampson published new large phylogenetic analysis of ceratosaurian. With
205-606: Is a genus of abelisauroid 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
246-437: Is about half the length of metacarpal II and considerably more slender. The arm also bears a stout phalanx that is slightly longer than the metacarpal. The non-terminal manual phalanges are about as long as wide and lack any constriction between the articular ends, and manual unguals are reduced. It is these reduced limb proportions that demonstrate Eoabelisaurus was indeed a primitive abelisaurid. The exact number of vertebrae
287-841: Is adopted. Ekrixinatosaurus was also published in 2004, so it was not included in Sereno's analysis. However, an independent analysis, performed by Jorge Calvo and colleagues, shows it to be an abelisaurid. Some scientists include Xenotarsosaurus from Argentina and Compsosuchus from India as basal abelisaurids, while others consider them to be outside the Abelisauroidea. The French Genusaurus and Tarascosaurus have also been called abelisaurids but both are fragmentary and may be more basal ceratosaurians, though Tortosa et al. (2014) considered both to be distinct abelisaurids. Subsequent phylogenetic analyses recover Xenotarsosaurus and Tarascosaurus as an abelisaurid, but Genusaurus as either
328-499: Is commonly referred to as the "walnut family". The delineation of what constitutes a family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to
369-526: Is derived from the Greek suffix -ιδαι ( - idai ) meaning 'descendants'. Abelisauridae is a family in rank-based Linnaean taxonomy , within the infraorder Ceratosauria and the superfamily Abelisauroidea , which also contains the family Noasauridae . It has had several definitions in phylogenetic taxonomy . It was originally defined as a node-based taxon including Abelisaurus , Carnotaurus , their common ancestor, and all of its descendants. Later, it
410-448: Is not notably thickened and no cranial ornamentation is present. Both humeri from the known material are poorly preserved, but show primitive characters. The articular head is slightly rounded, but not a globular shape that is commonly seen in noasaurids and abelisaurids . The radius and ulna are short and the ulna has a large olecranon process. The manus is very foreshortened, retains four digits, and has short metacarpals. Metacarpal I
451-480: Is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family
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#1732859375386492-544: Is placed in a series of fine beds of mudstone, marlstone, and limestone in the Cañadón Asfalto Formation . In 2012, based on these remains, the type species Eoabelisaurus mefi was named and described by Pol and his German colleague Oliver Rauhut. Before discovery, the oldest known abelisaurids were represented only by fragmentary remains from the late Early Cretaceous of South America and Africa and older records of abelisauroids in general were questionable. With
533-469: Is unknown due to several gaps in the holotype's spine, but its cervical vertebrae are short and have two pneumatic foramina on either side of the centra. The length of vertebral centra remains constant over the preserved portion of the tail, but middle and posterior caudals are considerably lower. Eoabelisaurus was assigned to the basalmost position in Abelisauridae by its describers. It would, then, be
574-501: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Eoabelisaurus Eoabelisaurus ( / ˈ i oʊ ə ˌ b ɛ l ɪ ˈ s ɔː r ə s / )
615-560: The Aalenian - Bajocian , roughly 170 million years old, yet a recent advanced zircon datation constrained its age to the Middle-Late Toarcian (179-178 million years). It consists of a nearly complete skeleton with skull, of a subadult or adult individual. The posterior half of the skeleton was found in articulation and the anterior dorsal and cervical vertebrae and forelimbs were found partially disarticulated prior to burial. The skull
656-472: The astragalus and calcaneum (upper ankle bones) fused to each other and to the tibia , forming a tibiotarsus. The tibia was shorter than the femur , giving the hind limb stocky proportions. Three functional digits were on the foot (the second, third, and fourth), while the first digit, or hallux , did not contact the ground. Although skull proportions varied, abelisaurid skulls were generally very tall and very short in length. In Carnotaurus , for example,
697-694: The skull bones, with grooves and pits. In many abelisaurids, such as Carnotaurus , the forelimbs are vestigial , the skull is shorter, and bony crests grow above the eyes. Most of the known abelisaurids would have been between 5 and 9 m (17 to 30 ft) in length, from snout to tip of tail, with a new and as yet unnamed specimen from northwestern Turkana in Kenya, Africa reaching a possible length of 11–12 m (36 to 39 ft). Before becoming well known, fragmentary abelisaurid remains were occasionally misidentified as possible South American tyrannosaurids . Abelisaurid hind limbs were more typical of ceratosaurs, with
738-484: The Cretaceous. It was thought that the absence of abelisaurids from continental Africa indicated that the group evolved after the separation of Africa from Gondwana, around 100 million years ago . However, the discovery of Rugops and other abelisaurid material from the middle of the Cretaceous in northern Africa disproved this hypothesis. Mid-Cretaceous abelisaurids are now known from South America as well, showing that
779-693: 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 . Like most theropods, abelisaurids were carnivorous bipeds . They were characterized by stocky hind limbs and extensive ornamentation of
820-628: 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. In 2009, Argentinian paleontologist Diego Pol discovered the skeleton of a theropod near the village of Cerro Cóndor in Chubut Province . The remains were found in the Jugo Loco locality that
861-475: The description of Eoabelisaurus , Diego Pol and Oliver W. M. Rauhut (2012) combined these analyses and added 10n new characters. The following cladogram follows their analysis. Berberosaurus Deltadromeus Spinostropheus Limusaurus [REDACTED] Elaphrosaurus [REDACTED] Ceratosaurus [REDACTED] Genyodectes Laevisuchus Family (biology) Family ( Latin : familia , pl. : familiae )
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#1732859375386902-467: The discovery of Eoabelisaurus , the temporal range of the clade was extended for more than 40 million years into the Toarcian . The existence of a derived ceratosaur at that time indicated a rapid diversification of ceratosaurs during that time period, as all the major ceratosaurian lineages (ceratosaurids, noasaurids, and abelisaurids) had already been established. It was a bipedal carnivore that
943-458: The evolution towards vestigial fore limbs in the group was because of a genetic defect; the loss of function in HOXA11 and HOXD11 , two genes that regulate the fore limbs' development. Abelisaurids are typically regarded as a Cretaceous period group. The earliest possible abelisaurid taxon is Eoabelisaurus mefi from the Jurassic period of Argentina, though other researchers either consider it as
984-441: The eye socket, to form a ridge or brow above the eye. Sculpturing is seen on many of the skull bones, in the form of long grooves, pits, and protrusions. Like other ceratosaurs , the frontal bones of the skull roof were fused together. Carnotaurines commonly had bony projections from the skull. Carnotaurus had two pronounced horns, projecting outward above the eyes, while its close relative Aucasaurus had smaller projections in
1025-530: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and
1066-467: The first or fourth digits, only one on the second digit and two on the third digit. These two external fingers were extremely short and immobile. Manual claws were very small in Eoabelisaurus , and totally absent in carnotaurines. More primitive relatives such as Noasaurus and Ceratosaurus had longer, mobile arms with fingers and claws. Paleobiologist Alexander O. Vargas suggested a major reason for
1107-533: The group existed prior to the breakup of Gondwana. In 2014, the description of Arcovenator escotae from southern France provided the first indisputable evidence of the presence of Abelisaurids in Europe . Arcovenator presents strong similarities with the Madagascan Majungasaurus and Indian abelisaurids, but not with the South American forms. Arcovenator , Majungasaurus , and Indian forms are united in
1148-504: The length of the upper arm ( humerus ) in Carnotaurus and 33% in Aucasaurus . The entire arm was held straight, and the elbow joint was immobile. As is typical for ceratosaurs, the abelisaurid hand had four basic digits, but any similarity ends there. No wrist bones existed, with the four palm bones ( metacarpals ) attaching directly to the forearm. No phalanges (finger bones) were on
1189-402: The level of the skull roof. Possibly, this rugose brow ridge supported a keratinous or scaly structure for displays. Data for the abelisaurid fore limbs are known from Eoabelisaurus and the carnotaurines Aucasaurus , Carnotaurus , and Majungasaurus . All had small fore limbs, which seem to have been vestigial. The bones of the forearm ( radius and ulna ) were extremely short, only 25% of
1230-564: The most advanced abelisaurids (such as Carnotaurus and Aucasaurus ), making 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 . These shared features, along with the fact that abelisaurids seem to have replaced carcharodontosaurids in South America, have led to suggestions that
1271-464: The new clade Majungasaurinae . Paleontologists Jose Bonaparte and Fernando Novas coined the name Abelisauridae in 1985 when they described the eponymous Abelisaurus . The name is formed from the family name of Roberto Abel, who discovered Abelisaurus , and from the Greek word σαυρος ( sauros ) meaning lizard. The very common suffix -idae is usually applied to zoological family names and
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1312-1024: The oldest abelisaurid species known by forty (40) million years. The describers indicated that in the cladistic analysis a difference of only a single trait would have resulted in a position lower in the evolutionary tree, basal in the Abelisauroidea . The following cladogram follows their analysis. Berberosaurus Deltadromeus Spinostropheus Limusaurus [REDACTED] Elaphrosaurus [REDACTED] Ceratosaurus [REDACTED] Genyodectes Laevisuchus Masiakasaurus [REDACTED] Noasaurus Velocisaurus Eoabelisaurus [REDACTED] Rugops Abelisaurus Majungasaurus [REDACTED] Indosaurus Rajasaurus [REDACTED] Ilokelesia [REDACTED] Ekrixinatosaurus [REDACTED] Skorpiovenator [REDACTED] Carnotaurus [REDACTED] Aucasaurus [REDACTED] In 2018, Rafael Delcourt placed Eoabelisaurus at
1353-421: The same area. Majungasaurus and Rajasaurus had a single bony horn or dome, projecting upwards from the skull. These projections, like the horns of many modern animals, might have been displayed for species recognition or intimidation. In Arcovenator , the dorsal margin of the postorbital (and probably also the lacrimal) is thickened dorsolaterally, forming a strong and rugose bony brow ridge rising above
1394-567: The seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted
1435-540: The skull was nearly as tall as it was long. The premaxilla in abelisaurids was very tall, so the front of the snout was blunt, not tapered as seen in many other theropods. Two skull bones, the lacrimal and postorbital bones, projected into the eye socket from the front and back, nearly dividing it into two compartments. The eye would have been located in the upper compartment, which was tilted slightly outwards in Carnotaurus , perhaps providing some degree of binocular vision . The lacrimal and postorbital also met above
1476-970: The two groups were related. However, no cladistic analysis has ever found such a relationship, and aside from the skull, abelisaurids and carcharodontosaurids are very different, more similar to ceratosaurs and allosauroids , respectively. Below is a cladogram generated by Tortosa et al. (2014) in the description of Arcovenator and creation of a new subfamily Majungasaurinae. Kryptops Rugops Genusaurus MCF-PVPH-237 abelisaurid Xenotarsosaurus Tarascosaurus La Boucharde abelisaurid Pourcieux abelisaurid Arcovenator [REDACTED] Majungasaurus [REDACTED] Indosaurus Rahiolisaurus Rajasaurus [REDACTED] Ilokelesia [REDACTED] Ekrixinatosaurus [REDACTED] Skorpiovenator [REDACTED] Abelisaurus Aucasaurus [REDACTED] Pycnonemosaurus Quilmesaurus [REDACTED] Carnotaurus [REDACTED] Ilokelesia
1517-541: The use of this term solely within the book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,
1558-507: Was discovered slightly separated from the vertebral column. The skull and anterior presacrals were also exposed at the time of discovery and had been partially been destroyed by erosion. From the material known of the snout, only a small fragment of the right maxilla has been recovered and shows that the interdental plates are fused, but not striated. The known posterior part of the skull is high, with an oval orbit and an enlarged infratemporal fenestra, similar to other ceratosaurs . The skull roof
1599-424: Was estimated to have reached 6–6.5 metres (19.7–21.3 ft) in length, although a comprehensive analysis of abelisaur size conducted in 2016 yielded a size estimate of 5.8 metres (19 ft). It is estimated to have weighed up to 730–800 kilograms (1,610–1,760 lb). The holotype specimen, MPEF PV 3990 , was uncovered in a layer of the Cañadón Asfalto Formation , a lacustrine deposit dating originally from
1640-476: Was originally described as a sister group to the Abelisauroidea. However, Sereno tentatively places it closer to Abelisaurus than to noasaurids, a result which agrees with several other recent analyses. If a stem-based definition is used, Ilokelesia and Rugops are therefore basal abelisaurids. However, as they are more basal than Abelisaurus , they are outside of the Abelisauridae if the node-based definition
1681-598: Was redefined as a stem-based taxon, including all animals more closely related to Abelisaurus (or the more complete Carnotaurus ) than to Noasaurus . The node-based definition would not include animals such as Rugops or Ilokelesia , which are thought to be more basal than Abelisaurus and would be included by a stem-based definition. Within the Abelisauridae is the subgroup Carnotaurinae , and among carnotaurines, Aucasaurus and Carnotaurus are united in Carnotaurini . Complete skeletons have been described only for