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''Arambourgisuchus'' ("Prof. Camille Arambourg's crocodile") is an
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
dyrosaurid Dyrosauridae is a family (biology), family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. ...
crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably mor ...
from the late Palaeocene of
Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...
, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by
palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
Stéphane Jouve. ''Arambourgisuchus'' was a large animal with an elongated skull 1 meter in length.


History and naming

The fossils of ''Arambourgisuchus'' were unearthed in the Spring of 2000 thanks to the collaboration of French (
French National Centre for Scientific Research The French National Centre for Scientific Research (, , CNRS) is the French state research organisation and is the largest fundamental science agency in Europe. In 2016, it employed 31,637 staff, including 11,137 tenured researchers, 13,415 engi ...
,
National Museum of Natural History, France The French National Museum of Natural History ( ; abbr. MNHN) is the national natural history museum of France and a of higher education part of Sorbonne University. The main museum, with four galleries, is located in Paris, France, within the ...
) and Moroccan (
Office Chérifien des Phosphates The OCP Group (OCP S.A.) (formerly Office Chérifien des Phosphates) is a Moroccan state-owned phosphate rock miner, phosphoric acid manufacturer and fertilizer producer. Founded in 1920, the company has grown to become the world's largest prod ...
, Ministére de l’Energie et des Mines, Morocco) researchers in the phosphatic deposits of the
Ouled Abdoun Basin The Oulad Abdoun Basin (also known as the Ouled Abdoun Basin or Khouribga Basin) is a phosphate sedimentary basin located in Morocco, near the city of Khouribga. It is the largest in Morocco, comprising 44% of Morocco's phosphate reserves, and at ...
,
Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...
. The deposits of the basin range from the latest Cretaceous (
Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...
) to the middle Eocene (
Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...
), with the deposits yielding ''Arambourgisuchus'' dating to the
Thanetian The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...
age of the
Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
, ca. 59 to 56 Ma. Four specimens have been described by Stéphane Jouve and colleagues. All of them stem from the Sidi Chenane phosphate mine, the holotype OCP DEK−GE 300, a nearly complete but heavily crushed skull, OCP DEK−GE 18 (a crushed skull and mandible) as well as two mandibular elements from two different specimens (OCP DEK−GE 1200 & OCP DEK−GE 269). Although heavily crushed and missing the tip of the rostrum, the holotype specimen can easily be reconstituted and is accessible from all sides. The referred skull OCP DEK−GE 18 does preserve the tip of the snout, however does not allow for the examination of several details of the bones. ''Arambourgisuchus'' is named after French paleontologist
Camille Arambourg Camille Arambourg (February 3, 1885 – November 19, 1969) was a French vertebrate paleontologist. He conducted extensive field work in North Africa. In the 1950s, he argued against the prevailing model of Neanderthals as brutish and simian. Du ...
for his research on the fossil fauna of Morocco's phosphate mines. The species name alludes to the town of
Khouribga Khouribga (Moroccan , ) is the capital of Khouribga Province in the Béni Mellal-Khénifra region, Morocco. With a population of 342,125 (2024 census), Khouribga owes its growth to the phosphate deposits nearby. Geography Located at 107 km ...
north of the type locality.


Description

The skull of ''Arambourgisuchus'' measures up to in length, most of which being made up by the elongated rostrum. The nares are poorly preserved but large, the
orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...
are rounded and bordered by a prominent process of the
postorbital bone The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ...
as seen in other dyrosaurs. In ''Arambourgisuchus'' the
supratemporal fenestrae Temporal fenestrae are openings in the Temple (anatomy), temporal region of the skull of some Amniote, amniotes, behind the Orbit (anatomy), orbit (eye socket). These openings have historically been used to track the evolution and affinities of re ...
are very large and elongated, nearly three times longer than they are wide and only separated by a narrow interfenestral bar. The premaxilla is almost circular at the front of the skull and extends back to approximately the level of the third tooth of the maxilla, preventing the
nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Eac ...
from contacting the nares. The
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...
likely contained four teeth. A small first tooth is followed by a small concavity (receiving the robust first mandibular tooth), in turn followed by the larger second and third tooth, the later of which appearing to be the largest based on a prominent gap in the toothrow of the
mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...
. Although the fourth tooth is not preserved, the absence of a large gap between the mandibular teeth suggests that it would have been small. The transition between premaxillary and maxillary teeth is marked by an enlarged toothless area (diastema) receiving an enlarged fourth dentary tooth. Estimates suggest that the maxillae each contained seventeen additional teeth, which are widely spaced up to the thirteenth tooth (at which point the distance between teeth decreases). The teeth of ''Arambourgisuchus'' are generally robust and sharp. The maxilla is long and narrow, making up the majority of the rostrum and gives the dyrosaur its longirostrine appearance. The
nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Eac ...
consists of a single fused bone with only very little ornamentation compared to the maxilla, which are laterally sculpted by deep ridges and furrows. Both the lacrimal and
prefrontal bone The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most modern and ...
are longer than they are wide and make up the majority of the anterior border of the orbits. Most of the
frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...
is located in the area between the orbits and the nasal, which it bifurcates. The frontal contributes very little to the interfenestral bar, but lightly overhangs the supratemporal fenestrae. Three ridges can be seen between the eyes, however aside from these the bone shows no ornamentation. The parietal contributes the vast majority of the interfenestral bar and shows a more developed overhang than the frontal. The back margin of the bone tapers and forms an acute process that overhangs the
occipital condyle The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the Atlas (anatomy), atlas vertebra. The condyles are oval or reniform (kidney-shaped) in shape ...
. The
postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ve ...
contacts the
jugal The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy ...
to form the postorbital bar and the
squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestra ...
to form the lateral margin of the supratemporal fenestra. Based on the skull length ''Arambourgisuchus'' was a large dyrosaur. It may be among the most longirostrine dyrosaurs, differing from '' Dyrosaurus phosphaticus'' by being more robust with fewer teeth. However, the teeth are sharper and more slender than those of the Eocene '' Phosphatosaurus''.


Phylogeny

Initial phylogenetic analysis were heavily restricted in terms of available taxa, only including species known from cranial material (and subsequently excluding '' Hyposaurus derbianus'' and ''Hyposaurus'' specimens from Mali). The resulting tree was consequently poorly resolved and while indicating a dispersal of the clade from Africa, did not match well with the stratigraphic range of the individual taxa. Following more intensive research on dyrosaurids during the 2000s and 2010s, including the description of several additional taxa, Jouve and colleagues published a comprehensive phylogenetic analysis on the internal relationships of the family. In this analysis ''Arambourgisuchus'' was recovered as a hyposaurine dyrosaurid, most closely related to the two species of ''Dyrosaurus'' and the then newly described '' Luciasuchus'' from
Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
.


References

{{Taxonbar, from=Q988132 Prehistoric pseudosuchian genera Prehistoric marine crocodylomorphs Paleocene crocodylomorphs Fossils of Morocco Dyrosauridae Fossil taxa described in 2005