Rajiformes is one of the four orders in the superorder Batoidea, flattened cartilaginous fishes related to sharks. Rajiforms are distinguished by the presence of greatly enlarged pectoral fins, which reach as far forward as the sides of the head, with a generally flattened body. The undulatory pectoral fin motion diagnostic to this taxon is known as rajiform locomotion. The eyes and spiracles are located on the upper surface of the head and the gill slits are on the underside of the body. Most species give birth to live young, although some lay eggs enclosed in a horny capsule.
Hyposaurus is a genus of extinct marine dyrosaurid crocodyliform. Fossils have been found in Paleocene aged rocks of the Iullemmeden Basin in West Africa, Campanian–Maastrichtian Shendi Formation of Sudan and Maastrichtian through Danian strata in New Jersey, Alabama and South Carolina. Isolated teeth comparable to Hyposaurus have also been found in Thanetian strata of Virginia. It was related to Dyrosaurus. The priority of the species H. rogersii has been debated, however there is no sound basis for the recognition of more than one species from North America. The other North American species are therefore considered nomina vanum.
Dalpiazia is an extinct genus of sclerorhynchid sawfish whose fossils are found in rocks dating from the Maastrichtian stage in mines in Jordan, Libya, Morocco and Syria. The type species D. stromeri was named by Checchia-Rispoli (1933) in honor of Ernst Stromer, and the holotype, a rostral tooth, was found in Tripolitania, Libya.
Madtsoia is an extinct genus of madtsoiid snakes. It is known from the Eocene of Argentina, the Paleocene of Brazil, the Late Cretaceous (Maastrichtian) of India, and the Late Cretaceous (Maastrichtian) of Madagascar. The type species was the largest with an estimated length of 9–10 m (30–33 ft), and the other three species were smaller. A 5.1 m (17 ft) long M. madagascariensis would have weighed 50 kg (110 lb), but an isolated specimen suggests that this species reached 8 m (26 ft) in maximum length.
Toxochelys is an extinct genus of marine turtle from the Late Cretaceous period. It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas.
The Dukamaje Formation is a geological formation in Niger and Nigeria whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. A wealth of Mosasaur fossils have also been recovered from this formation, particularly from the area around Mt. Igdaman.
Araripichthys is an extinct genus of ray-finned fish that lived from the Aptian to Coniacian stages of the Cretaceous period. The genus is named after the Araripe Basin, where it was found in the Crato and Santana Formations. Other fossils of the genus have been found at Goulmima in Morocco, the Tlayua Formation of Mexico and the Apón Formation of Venezuela.
Charactosuchus is an extinct genus of crocodilian. It was assigned to the family Crocodylidae in 1988. Specimens have been found in Colombia, Brazil, Jamaica, and possibly Florida and South Carolina. It was gharial-like in appearance with its long narrow snout but bore no relation to them, being more closely related to modern crocodiles than to gharials.
Ptychoceratodus is an extinct genus of lungfish living from Early Triassic to Middle Jurassic. It was established by Otto Jaekel for one species, transferred from Ceratodus genus. Type species is P. serratus from the Middle Triassic of Switzerland and Germany. Ptychoceratodus had two pairs of massive dental plates, bearing 4-6 acute ridges. Its skull roof was composed from massive, plate-like bones. In the central part of skull roof was localized an unossified fenestra. Most of the Ptychoceratodus findings are isolated dental plates, some associated with jaws. Other parts of skull or postcranial skeleton are relatively rarely found as fossils. The anatomy of skull is the best recognized in P. serratus, whereas less complete cranial material is available also for P. concinuus, P. phillipsi, and P. rectangulus. Although Ptychoceratodus is known exclusively from the Triassic and Jurassic, there were also Cretaceous specimens referred to this genus. However, they are more often regarded as representants of Metaceratodus. Ptychoceratodus is the only member of the family Ptychoceratodontidae. The first named species is P. phillipsi by Louis Agassiz in 1837 as a species of Ceratodus and later moved to Ptychoceratodus genus. Occurrences of Ptychoceratodus come mainly from Europe. However, occurrences from other continents suggest it was dispersed globally during the Triassic. After 2010, the new fossil material behind the Europe was reported from South America, India, and Greenland
Cylindracanthus is an extinct genus of Cretaceous to Eocene aged ray-finned fish. It is almost exclusively known from bony rostrum fragments as well as some associated teeth, with the rest of the skeleton being cartilaginous. While originally considered to be closely related to billfish, the structure of its rostrum is dissimilar, and is unlikely to be closely related, some later studies suggested closer affinities to the Acipenseriformes. However, this was later rejected due to the lack of osteocytes in histologically examined specimens, which resembles the condition of derived teleosts. A close relation to Blochius has been suggested.
Pristis is a genus of sawfish of the family Pristidae. These large fish are found worldwide in tropical and subtropical regions in coastal marine waters, estuaries, and freshwater lakes and rivers. Sawfish have declined drastically and all species are considered critically endangered today.
Onchopristis is an extinct genus of sclerorhynchoid from the Cretaceous of North Africa, Europe, and North America. Its name is derived from the Ancient Greek ónkos and prístis. It contains two valid species, O. numida and O. dunklei, though some researchers argue that both may be considered a single taxon with variation in morphology caused by a wide geographical range. Specimens of Onchopristis have been discovered in coastal and fluvial deposits dated from the Barremian to the Cenomanian age, making this genus one of the oldest and longest-lived sclerorhynchoid genera.
Ptychotrygon is a genus of sawfish-like Late Cretaceous ray whose fossils have been found worldwide. It, Ptychotrygonoides, Texatrygon, and Asflapristis are members of the family Ptychotrygonidae within the suborder Sclerorhynchoidei.
Onchosaurus is an extinct genus of sclerorhynchid sawskate from the Late Cretaceous. Its fossils have been found in the Cretaceous sediments of Egypt, Brazil, Congo, Morocco, France, Niger, Japan, Chile, Peru and the United States.
Coniophis is an extinct genus of snakes from the late Cretaceous period. The type species, Coniophis precedes, was about 7 cm long and had snake-like teeth and body form, with a skull and a largely lizard-like bone structure. It probably ate small vertebrates. The fossil remains of Coniophis were first discovered at the end of the 19th century in the Lance Formation of the US state of Wyoming, and were described in 1892 by Othniel Charles Marsh. For the genus Coniophis, a number of other species have been described. Their affiliation is, however, poorly secured, mostly based on vertebrae descriptions from only a few fossils.
Atlanticopristis is an extinct genus of sclerorhynchid that lived during the Middle Cretaceous (Cenomanian) of what is now the Northeast Region of Brazil, between 100.5 and 93.9 million years ago. Fourteen fossil teeth from Atlanticopristis were found in the Alcântara Formation, and referred to the closely related Onchopristis in 2007; a redescription in 2008 by Brazilian paleontologists Manuel Medeiros and Agostinha Pereira assigned it to a new genus containing one species, Atlanticopristis equatorialis.
Ankistrorhynchus is an extinct genus of sawfish-like ray from the Cretaceous Period. It is known only isolated rostral teeth from two species. A. lonzeensis is named for its type locality of Lonzée, Belgium. It is from the lower Santonian stage. A. washakiensis was described from the Campanian-aged Mesaverde Formation of Wyoming, USA. The species A. major was named from Campanian/Santonian of New Jersey, USA off of fragmentary material, thus making its validity questionable.
Biropristis is an extinct genus of sawfish-like shark from the Late Cretaceous epoch of the Cretaceous period. The genus is named in honor of Dr. Lajos Biró-Bagózcky who studied the formation in which it was found. It is known from a single species, B. landbecki. It is known solely from isolated oral teeth found in the Maastrichtian-aged Quiriquina Formation of central Chile. The species is named for Luis Landbeck who found the first fossils at the locality in which it was found.
