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29-638: The unit unconformably overlies Paleozoic marine units of Cambrian , Silurian and Devonian ages and is itself capped by limestone platform rock of Cenomanian- Turonian age. It primarily consists of freshwater and estuarine deltaic deposits. The lower Gara Sbaa Formation primarily consists of fine and medium grained sandstone , while the Douira Formation consists of fining-upward, coarse-to-fine grained sandstones intercalated with siltstones , variegated mudstones , and occasional thin gypsiferous evaporites . Dinosaur remains are among

58-566: A few, fragmentary jaw elements, reside at the Museum National d'Histoire Naturelle in Paris . The holotype's fragmentary nature meant that its placement in the genus was disputed until more remains were found in 2009 by Sereno and Larsson; these, along with the specimens of A. tsangatsangana, confirmed its place. Araripesuchus patagonicus was described from a patagonian specimen (MUC-PV 269) in 2000. Another species to be assigned to

87-734: A fossil material of a member of the genus Uromastyx . Lapparentophis L. ragei Two isolated trunk vertebrae An early snake. Madtsoiidae indet. Indeterminate Vertebrae An early snake. ? Nigerophiidae indet. Indeterminate Dorsal vertebrae An early snake. Norisophis N. begaa One posterior and two mid-trunk vertebrae A stem -snake. Indeterminate A mid-trunk vertebra Simoliophis cf. S. libycus Vertebrae An early snake. Dirqadim D. schaefferi A Euraxemydid Galianemys G. emringeri A Cearachelyin Hamadachelys H. escuilliei A tooth enamel identified as cf. Sarcosuchus

116-534: A freshwater habitat located near a river delta (with some estuarine influence that increased over time as the sea level rose), the Kem Kem deposits were quickly submerged by the sea during the Cenomanian-Turonian boundary event , and are thus overlaid by the marine deposits of the younger latest Cenomanian and early-mid Turonian -aged Akrabou Formation , which was formerly also considered a member of

145-584: A lower jaw. A more complete specimen, AMNH 24450 is held by the American Museum of Natural History . A second species, A. wegeneri was described in 1981. This species was discovered from Early Cretaceous deposits of Niger on the African continent, as opposed to the South American paleodistribution of the other species in the genus. The type specimen for the species, GDF-700 consisting of

174-534: A sister taxon of Anatosuchus , questioning the monophyly of the genus. Lumping all species into one genus would lead to Uruguaysuchus taking priority, rendering Araripesuchus a junior synonym of Uruguaysuchus . Araripesuchus remains have been recovered from the continents of South America and Africa suggesting a Gondwanan origin for the evolution of the genus. At around the time of Araripesuchus' existence, South America and Africa were physically adjacent to each other. The various species evolved from

203-421: Is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record . The significance of angular unconformity (see below)

232-478: Is deposited against older strata thus influencing its bedding structure. A blended unconformity is a type of disconformity or nonconformity with no distinct separation plane or contact, sometimes consisting of soils, paleosols , or beds of pebbles derived from the underlying rock. Araripesuchus Araripesuchus is a genus of extinct crocodyliform that existed during the Cretaceous period of

261-431: Is required. A. wegeneri is estimated to reach 81 centimetres (32 in) long while A. rattoides is estimated to reach up to 1 metre (3.3 ft). Araripesuchus can be distinguished by their laterally bulged edges of the snout, with the bulge being the most prominent around the area of an enlarged maxillary tooth. The snout and premaxilla are also smoother than that of most crocodyliforms, without foramina or

290-588: The African island of Madagascar . Analysis of this specimen solidifies the position of A. wegneri as a member of the genus. A. tsangatsangana is the geologically youngest known of this genus. The sixth species, A. rattoides , was found in the Kem Kem Beds of the Sahara in a similar location to the specimens of A. wegeneri found by Sereno and Larsson, and is known only from parts of dentary bones, up to

319-418: The African species support the inclusion of all five first described species into the same genus. The genus was originally assigned by Price to the family Uruguaysuchidae in the original 1959 description. This classification was followed by Buffetaut in 1981 with the description of A. wegeneri also within the same family. However, in their 2000 description of A. patagonicus , Ortega et al. avoided placing

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348-494: The Kem Kem Group, but has been differentiated from it in more recent studies due to their differing paleoenvironments. Bicuspidon B. hogreli A polyglyphanodontid lizard. J. aleadonta Partial mandible with teeth. An iguanian belonging to the group Acrodonta , possibly a relative of the uromastycine agamids . Argued by Vullo et al. (2022) to actually come from Quaternary beds, and to be based on

377-432: The back and paired dorsal ones along the tail. Each side of the tail also had a single row of osteoderms, and there were paired ventral osteoderms across most of the belly and underside as well. The osteoderms were not strongly keeled, which, along with the long limb bones and shoulder, hip and ankle joints that suggest upright posture, indicate that Araripesuchus was probably more active on land than on water. The name of

406-405: The case. A. rattoides also had the distinctive feature of a highly enlarged and forward-pointing first dentary tooth referred to as an incisiform, resembling the elongated incisors found in rodents (hence the specific epithet). All species of Araripesuchus had relatively large orbits and hence eyes . They also had thin osteoderms that covered the entire body, multiple rows of them across

435-518: The family Uruguaysuchidae. This family was found to be the most basal group of Notosuchia. Below is a cladogram from the analysis: Uruguaysuchus A. wegeneri A. buitreraensis A. gomesii A. patagonicus Libycosuchus Simosuchus Malawisuchus Candidodon Chimaerasuchus Sphagesaurus Baurusuchus Bretesuchus Iberosuchus Notosuchus Comahuesuchus Mariliasuchus However, recent phylogenetic analyses placed A. wegeneri as

464-402: The first African species discovered, A. wegeneri , was questioned for a while by various authors. Ortega et al. argued for the assignment of the errant species to another genus based on phylogenetic analysis Further analysis, combined with the discovery of the second African species A. tsangatsangana has shed more light on the placement of A. wegeneri within the genus. When analyzed together,

493-595: The fossils that have been recovered from the group. 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 Group (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 have been separated by millions of years. Although preserving

522-476: The fourteenth alveolus. It was described in the same paper as Kaprosuchus , Laganosuchus and Anatosuchus ; the four were therefore popularized by the authors as 'RatCroc', 'BoarCroc', 'PancakeCroc' and 'DuckCroc' respectively. As of 2024, seven species were recognized within the genus Araripesuchus : A. gomesii ( type species ), A. buitreraensis , A. manzanensis , A. patagonicus , A. rattoides , A. tsangatsangana and A. wegeneri . The placement of

551-648: The genus was coined in 1959 with the description of the type species Araripesuchus gomesii , a notosuchian crocodylian from the famed Santana Group of the Araripe Basin in Brazil . The holotype used to describe the genus, 423-R is currently in the care of the Divisão de Mineralogia e Geologia do Departamento Nacional da Produção Mineral in Rio de Janeiro . 423-R consists of a single skull articulating with part of

580-444: The genus, was Araripesuchus buitreraensis , described in 2005. This species was described from a single skull (MPCA-PV 235) retrieved from Late Cretaceous deposits in what is now Argentina . At 130 millimeters, the skull is the largest Araripesuchus specimen discovered to date. A fifth species, Araripesuchus tsangatsangana was described in 2006. This species' type specimen was discovered from latest Late Cretaceous deposits from

609-404: The late Mesozoic era some 125 to 66 million years ago. Araripesuchus is generally considered to be a notosuchian (belonging to the clade Mesoeucrocodylia ), characterized by the varied teeth types and distinct skull elements. Seven species have been referred to Araripesuchus , though it has been argued that the phylogenetic position of this genus is uncertain, and that taxonomic revision

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638-538: The next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is called a hiatus . It is a kind of relative dating . A disconformity is an unconformity between parallel layers of sedimentary rocks which represents a period of erosion or non-deposition. Disconformities are marked by features of subaerial erosion. This type of erosion can leave channels and paleosols in

667-534: The overlying horizontal layers. The whole sequence may later be deformed and tilted by further orogenic activity. A typical case history is presented by the Briançonnais realm (Swiss and French Prealps) during the Jurassic. Angular unconformities can occur in ash fall layers of pyroclastic rock deposited by volcanoes during explosive eruptions . In these cases, the hiatus in deposition represented by

696-543: The rock record. A nonconformity exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock. Namely, if the rock below the break is igneous or has lost its bedding due to metamorphism, then the plane of juncture is a nonconformity. An angular unconformity is an unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with

725-515: The species within the family. Instead, it was simply noted that Uruguaysuchus was a possible close relative of the genus. Ortega et al. and several other studies place Araripesuchus outside Notosuchia. In some phylogenetic analyses, it is placed closer to the clade Neosuchia , which includes modern crocodilians. In most recent analyses, however, Araripesuchus is placed as a basal notosuchian. The phylogenetic analysis of Soto et al. (2011) joined Araripesuchus with Uruguaysuchus , reinstating

754-432: The typical rugose texture. There are seven valid species within this genus, all with slightly differing maxillary or dentary structure. A. gomesii, A. wegeneri and A. tsangatsangana all have a mild concavity of the external alveolar margin of the premaxilla as viewed from the ventral surface; A. rattoides may also have this feature, although this part of its skull is not known, as the dentary suggests that this would be

783-526: The unconformity may be geologically very short – hours, days or weeks. A paraconformity is a type of unconformity in which the sedimentary layers above and below the unconformity are parallel, but there is no obvious erosional break between them. A break in sedimentation is indicated, for example, by fossil evidence. It is also called nondepositional unconformity or pseudoconformity. Short paraconformities are called diastems . A buttress unconformity also known as onlap unconformity, occurs when younger bedding

812-469: Was discovered from the Ifezouane Formation. Aegisuchus A. witmeri "Partial braincase of a large individual with skull roof, temporal, and occipital regions." An aegyptosuchid that may be a synonym of Laganosuchus. Antaeusuchus A. taouzensis Paired mandibles and a partial right mandible A peirosaurid . Araripesuchus Unconformity An unconformity

841-517: Was shown by James Hutton , who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in Berwickshire in 1788, both in Scotland. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before

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