Deltadromeus (meaning "delta runner") is a genus of theropod dinosaur from Northern Africa. It had long, unusually slender hind limbs for its size, suggesting that it was a swift runner. The skull is not known. One fossil specimen of a single species (D. agilis, or "agile delta runner") has been described, found in the Kem Kem Beds, which date to the mid Cretaceous Period (mid Cenomanian age), about 95 million years ago. It may be a junior synonym of the contemporary Bahariasaurus. Deltadromeus has often been considered a ceratosaurian, more specifically a member of the family Noasauridae. In 2016, a South American theropod known as Gualicho shinyae was found to possess many similarities with Deltadromeus. Depending on the phylogenetic position of Gualicho, Deltadromeus may have been a neovenatorid carnosaur, a tyrannosauroid, or a basal coelurosaur if its close relation to Gualicho is legitimate.
|Mounted skeleton cast with reconstructed skull|
Sereno et al., 1996
Sereno et al., 1996
The holotype of Deltadromeus agilis (museum catalogue number SGM-Din2) is a partial skeleton of an animal which is estimated to have measured 8 meters (26.24 feet) long. The weight of the living animal was estimated to have been around 1050 kilograms, slightly more than an imperial ton.
A number of specimens (catalogued under IPHG 1912 VIII) were originally considered by Ernst Stromer to be conspecific with Bahariasaurus, but were referred to Deltadromeus by Paul Sereno in 1996. They were thought to come from a much larger individual, with a femur (upper leg bone) length of 1.22 meters (4 feet), compared to the 0.74 meter (2.46 foot) long femur of the holotype. These referred specimens, if legitimately assigned to Deltadromeus, would have indicated that members of the genus could grow up to 12.2 meters (40 feet) in length, approximately the size of a Tyrannosaurus rex. However, the referral of the coracoid, pubes, and hindlimb material catalogued under IPHG 1912 VIII to Deltadromeus has been questioned because the remains came from different horizons and localities in the Bahariya Formation, and actually exhibit notable differences from the holotype of Deltadromeus.
The Deltadromeus skeleton has been found in the same formation as those of the giant theropods Carcharodontosaurus, Spinosaurus, and Bahariasaurus, which may be synonymous with Deltadromeus. No skull material has been found for either Deltadromeus or Bahariasaurus, and though carnivore teeth labelled as "Deltadromeus" are commonly sold in rock shops, there is no way of knowing if they actually come from this animal.
Many studies published since the original description of Deltadromeus have considered it to be a ceratosaur, although different studies disagree on what kind of ceratosaur. One 2003 study suggested it was a member of the Noasauridae, though others have found it to be more primitive, possibly related to the primitive ceratosaurs Elaphrosaurus and Limusaurus. A more comprehensive study of noasaurid relationships published in 2016 found that both of these interpretations were essentially correct, with Deltadromeus, Limusaurus, and Elaphrosaurus all found to be within the Noasauridae. A 2017 paper describing ontogenetic changes in Limusaurus and the affect of juvenile taxa on phylogenetic analyses placed Deltadromeus as a noasaurid in every analysis regardless of which Limusaurus specimen was used, although the analyses did not include Gualicho or Aoniraptor. According to the writers of the paper, resolving the phylogenetic positions of Gualicho, Aoniraptor, Deltadromeus, and megaraptorans is one of the most critical issues presently facing theropod systematics.
The original description of Deltadromeus in 1996 found that it was a fairly basal coelurosaur, only slightly more advanced than the Late Jurassic genus Ornitholestes. In 2016, an analysis of Gualicho, a South American theropod considered to belong to the allosauroid family Neovenatoridae, finds Deltadromeus to be Gualicho's probable sister taxon. However, the analysis also noted that Deltadromeus shared many features with ceratosaurs and that if Gualicho was removed from the analysis, Deltadromeus would resolve to a member of Ceratosauria. In an analysis of Aoniraptor, which may be the same animal as Gualicho, Deltadromeus was found along with Aoniraptor and Bahariasaurus to probably form a still poorly known clade of megaraptoran tyrannosauroids different from the Megaraptoridae. A 2018 study by Porfiri et al. has supported the idea that Gualicho and megaraptorans were basal coelurosaurs, outside of both Neovenatoridae and Tyrannosauroidea. However, this study did not include Deltadromeus.
The cladogram below follows the 2016 Gualicho analysis by Sebastián Apesteguía, Nathan D. Smith, Rubén Juarez Valieri, and Peter J. Makovicky.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1996.Bahariasaurus
Bahariasaurus (meaning "Bahariya lizard") is a genus of theropod dinosaur found in the Bahariya Formation in El-Waha el-Bahariya or Bahariya (Arabic: الواحة البحرية meaning the "northern oasis") oasis in Egypt, the Farak Formation of Niger, and Kem Kem Beds of North Africa, which date to the late Cretaceous Period, (Cenomanian age), about 95 million years ago. It was a huge theropod, in the same size range as Tyrannosaurus and the contemporary genus Carcharodontosaurus.The type species, B. ingens, was described by Ernst Stromer in 1934, though the type specimen was destroyed during World War II. The exact placement of Bahariasaurus is uncertain, although it has been variously assigned to several theropod groups, including Carcharodontosauridae (by Rauhut in 1995) and Tyrannosauroidea (by Chure in 2000). It is potentially synonymous with Deltadromeus, another theropod from the early Late Cretaceous of North Africa, this would possibly make it the largest ceratosaur. More specimens would be needed to more accurately classify it, and to determine its relationship to Deltadromeus.In 2016 the description and analysis of Aoniraptor, Bahariasaurus was found along with Aoniraptor and Deltadromeus to probably form a still poorly known clade of megaraptoran tyrannosauroids different from the Megaraptoridae.Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name.
As a unit of geologic time measure, the Cenomanian age spans the time between 100.5 ± 0.9 Ma and 93.9 ± 0.8 Ma (million years ago). In the geologic timescale it is preceded by the Albian and is followed by the Turonian. The Upper Cenomanian starts approximately at 95 M.a.
The Cenomanian is coeval with the Woodbinian of the regional timescale of the Gulf of Mexico and the early part of the Eaglefordian of the regional timescale of the East Coast of the United States.
At the end of the Cenomanian an anoxic event took place, called the Cenomanian-Turonian boundary event or the "Bonarelli Event", that is associated with a minor extinction event for marine species.Ceratosauria
Ceratosaurs are members of a group of theropod dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than with birds. Ceratosaurs are believed to have diverged from the rest of Theropoda by the early Jurassic, however, the oldest confirmed discovered specimens date to the Late Jurassic. According to the majority of the latest research, Ceratosauria includes the Late Jurassic to Late Cretaceous theropods Ceratosaurus, Elaphrosaurus, and Abelisaurus, found primarily (though not exclusively) 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.Ceratosauria derives its names from the type species, Ceratosaurus nasicornis, described by O.C. Marsh in 1884. A moderately large predator from the Late Jurassic, Ceratosaurus nasicornis, was the first ceratosaur to be discovered. Ceratosaurs are generally moderately large in size, with some exceptions like the larger Carnotaurus and the significantly smaller noasaurs. The major defining characteristics of Ceratosauria include a robust skull with increased ornamentation or height and a shortening of the arms. Both of these characteristics are generally accentuated in later members of the group, such as the abelisaurs, whereas more basal species such as C. nasicornis appear more similar to other basal theropods. The highly fragmented nature of the ceratosaur fossil record, means that the characteristics, relationships, and early history of Ceratosauria remain mysterious and highly debated.Eoabelisaurus
Eoabelisaurus () is a genus of abelisaurid theropod dinosaur from the Middle 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, from which 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.Fossils of Egypt
Egypt has many fossil-bearing geologic formations, in which many dinosaurs have been discovered.Gualicho
Gualicho (named in reference to the gualichu) is a genus of theropod dinosaur. The type species is Gualicho shinyae. Gualicho lived in what is now northern Patagonia, on what was then a South American island continent split off from the supercontinent Gondwana. The fossils were found in the Huincul Formation, dating to the late Cenomanian-early Turonian age of the upper Cretaceous Period, around 93 million years ago.Jeffrey A. Wilson
Jeffrey A. Wilson also known as "JAW" is a professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan.
His doctoral dissertation was on sauropod evolution and phylogeny, and he has continued this work in cladistic analysis and revision of the group (see e.g. Wilson and Sereno 1994, 1998, Wilson 2005b, and especially Wilson 2002). With Paul Sereno, he defined the clades Macronaria and Somphospondyli (Wilson & Sereno 1998).
Wilson was also involved in the discovery and description of Pabwehshi pakistanensis, the first discovery of decent (diagnostic) Cretaceous crocodylian fossil remains from the Indian subcontinent, in the discovery of Rajasaurus narmadensis, the most completely known theropod dinosaur from India and a member of the family Abelisauridae, description of a number of North African dinosaurs (theropods and sauropods) from Niger, and rediscriptions of the Cretaceous sauropods Titanosaurus colberti (as Isisaurus) and Nemegtosaurus (previously thought to be a diplodocoid, but now recognised as a titanosaur).
His younger brother, Dr. Gregory P. Wilson, studies Mesozoic mammals and is currently an assistant professor in the Department of Biology at the University of Washington, and adjunct curator of vertebrate paleontology at the Burke Museum of Natural History and Culture.Kem Kem Beds
The Kem Kem Beds (also referred to by various names including the Continental Red Beds and Continental intercalaire) is a geological formation along the border between Morocco and Algeria in southeastern Morocco, whose strata date back to the Late Cretaceous.Dinosaur remains are among the fossils that have been recovered from the formation. Recent fossil evidence in the form of isolated large abelisaurid bones and comparisons with other similarly aged deposits elsewhere in Africa indicates that the fauna of the Kem Kem Beds (specifically in regard to the numerous predatory theropod dinosaurs) may have been mixed together due to the harsh and changing geology of the region when in reality they would likely have preferred separate habitats and likely would be separated by millions of years.Kemkemia
Kemkemia is a genus of crocodyliforms living in the Cretaceous, described from a single fossil in 1999 recovered from Morocco by an Italian team searching for fossil invertebrates.
The type species, Kemkemia auditorei, was named and described in 2009 by Italian paleontologists Andrea Cau and Simone Maganuco and is based on a single distal caudal vertebra, MSNM V6408. This vertebra measures 60.48 mm in length and 33.81 mm in height. The genus name refers to the Kem Kem Beds and the specific name honours Italian paleontological illustrator Marco Auditore. The fossil dates from the Cenomanian.
The describers, because of the general morphology of the vertebra, especially the strongly developed neural spine, originally considered it likely that K. auditorei was a theropod dinosaur belonging to the group Neoceratosauria, but in view of the limited remains cautiously assigned it to a more general Neotheropoda incertae sedis. However, the authors later discovered it to be a typical crocodyliform, rather than an unusual theropod.Kemkemia was a predator with a body length of about four to five metres and, given that the vertebra is not very robust, possibly lightly built. The species length could be extrapolated because the specimen is that of an adult. The fossil is one of the few known crocodyliform caudal vertebrae and comes from the Kem Kem Beds that have produced the fossils of very large predatory dinosaur species: Spinosaurus, Carcharodontosaurus and Deltadromeus.List of African dinosaurs
This is a list of dinosaurs whose remains have been recovered from Africa. Africa has a rich fossil record, but it is patchy and incomplete. It is rich in Triassic and Early Jurassic dinosaurs. African dinosaurs from these time periods include Coelophysis, Dracovenator, Melanorosaurus, Massospondylus, Euskelosaurus, Heterodontosaurus, Abrictosaurus, and Lesothosaurus. In the Middle Jurassic, the sauropods Atlasaurus, Chebsaurus, Jobaria, and Spinophorosaurus, flourished, as well as the theropod Afrovenator. The Late Jurassic is well represented in Africa, mainly thanks to the spectacular Tendaguru Formation. Veterupristisaurus, Ostafrikasaurus, Elaphrosaurus, Giraffatitan, Dicraeosaurus, Janenschia, Tornieria, Tendaguria, Kentrosaurus, and Dysalotosaurus are among the dinosaurs whose remains have been recovered from Tendaguru. This fauna seems to show strong similarities to that of the Morrison Formation in the United States and the Lourinha Formation in Portugal. For example, similar theropods, ornithopods and sauropods have been found in both the Tendaguru and the Morrison. This has important biogeographical implications.
The Early Cretaceous in Africa is known primarily from the northern part of the continent, particularly Niger. Suchomimus, Elrhazosaurus, Rebbachisaurus, Nigersaurus, Kryptops, Nqwebasaurus, and Paranthodon are some of the Early Cretaceous dinosaurs known from Africa. The Early Cretaceous was an important time for the dinosaurs of Africa because it was when Africa finally separated from South America, forming the South Atlantic Ocean. This was an important event because now the dinosaurs of Africa started developing endemism because of isolation.
The Late Cretaceous of Africa is known mainly from North Africa. During the early part of the Late Cretaceous, North Africa was home to a rich dinosaur fauna. It includes Spinosaurus, Carcharodontosaurus, Rugops, Bahariasaurus, Deltadromeus, Paralititan, Aegyptosaurus, and Ouranosaurus.Megaraptora
Megaraptora is a clade of carnivorous theropod dinosaurs with elongated hand claws and controversial relations to other theropods.Megaraptorans are incompletely known, and no complete megaraptoran skeleton has been found. However, they still possessed a number of unique features. Their forelimbs were large and strongly built, and the ulna bone had a unique shape in members of the family Megaraptoridae, a subset of megaraptorans which excludes Fukuiraptor. The first two fingers were elongated, with massive curved claws, while the third finger was small. Megaraptoran skull material is very incomplete, but a juvenile Megaraptor described in 2014 preserved a portion of the snout, which was long and slender. Leg bones referred to megaraptorans were also quite slender and similar to those of coelurosaurs adapted for running. Although megaraptorans were thick-bodied theropods, their bones were heavily pneumatized, or filled with air pockets. The vertebrae, ribs, and the ilium bone of the hip were pneumatized to an extent which was very rare among theropods, only seen elsewhere in taxa such as Neovenator. Other characteristic features include opisthocoelous neck vertebrae and compsognathid-like teeth.The clade was originally named in 2010 as a subset of the family Neovenatoridae, a group of lightly-built allosauroids related to the massive carcharodontosaurids such as Giganotosaurus and Carcharodontosaurus. A 2013 phylogenetic analysis by Fernando Novas and his colleagues disagreed with this classification scheme, and instead argued that the megaraptorans evolved deep within Tyrannosauroidea, a superfamily of basal coelurosaurs including the famous Tyrannosaurus. Subsequent refinements to Novas's data and methodologies have supported a third position for the group, at the base of Coelurosauria among other controversial theropods such as Gualicho, but not within the Tyrannosauroidea. Regardless of their position, it is clear that megaraptorans experienced a large amount of convergent evolution with either Neovenator-like allosauroids or basal coelurosaurs.Megaraptorans were most diverse in the early Late Cretaceous of South America, particularly Patagonia. However, they had a widespread distribution. Fukuiraptor, the most basal ("primitive") known member of the group, lived in Japan. Megaraptoran material is also common in Australia, and the largest known predatory dinosaur from the continent, Australovenator, was a megaraptoran.Neovenatoridae
Neovenatoridae is a family of large carnivorous dinosaurs representing a branch of the allosauroids, a large group of carnosaurs that also includes the sinraptorids, carcharodontosaurids, and allosaurids. Compared to other allosauroids, neovenatorids had short, wide shoulder blades, and their ilia (upper hip bones) had many cavities.. They lived in Africa, Asia, Europe, South America and North America.Noasauridae
Noasauridae was a group of diverse theropod dinosaurs from the group Ceratosauria. They were closely related to the short-armed abelisaurids, although most noasaurids had a much more conservative body type 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. The most complete and well-known example of these kinds of noasaurids was Masiakasaurus knopfleri from Madagascar. Another group, Elaphrosaurinae, has also been placed within Noasauridae by some studies. Elaphrosaurines developed toothless jaws and herbivorous diets, at least as adults. The most complete and well known elaphrosaurine was Limusaurus inextricabilis. At least some noasaurids had pneumatised cervical vertebrae.Some are considered to have had cursorial habits. Noasauridae is defined as all theropods closer to Noasaurus than to Carnotaurus.Noasaurus
Noasaurus ("Northwestern Argentina lizard") is a genus of ceratosaurian theropod dinosaur genus from the late Campanian-Maastrichtian (Late Cretaceous) of Argentina. The type and only species is N. leali.Paleoworld (season 2)
Paleoworld (Season 2) is the second season of Paleoworld.Paleoworld (season 3)
Paleoworld (Season 3) is the third season of Paleoworld.Paul Sereno
Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites in Inner Mongolia, Argentina, Morocco and Niger. One of his most widely publicized discoveries is that of a nearly complete specimen of Sarcosuchus imperator — popularly known as SuperCroc — at Gadoufaoua in the Tenere desert of Niger.Rugops
Rugops (meaning "wrinkle face") is a genus of abelisaurid theropod dinosaur that inhabited what is now Africa approximately 95 million years ago, during the Cenomanian stage of the Late Cretaceous.