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 least 26.8 billion tons of phosphate.^[1][2] It is also known as an important site for vertebrate fossils, with deposits ranging from the Late Cretaceous (Maastrichtian) to the Eocene epoch (Ypresian), a period of about 25 million years.^[3]

Ouled Abdoun Basin
Stratigraphic range: Maastrichtian-Ypresian ~70.6–47.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
The Oulad Abdoun and other major phosphate basins (in yellow) of Morocco
Type	Geological formation
Unit of	Sedimentary Basins
Lithology
Primary	Phosphorite
Other	Clay, Limestone, Sandstone
Location
Coordinates	32°53′N 6°55′W
Approximate paleocoordinates	24°2′N 6°8′W
Region	Béni Mellal-Khénifra, Khouribga
Country	Morocco
Ouled Abdoun Basin (Morocco)

Geography

The Oulad Abdoun is located west of the Atlas Mountains, near the city of Khouribga. The Oulad Abdoun phosphate deposits encompass some 100 by 45 kilometres (62 by 28 mi), an area of 4,500 square kilometres (1,700 sq mi).^[2] The Oulad Abdoun is the largest and northernmost of Morocco's major phosphate basins, which from northeast to southwest, include the Ganntour, Meskala, and Oued Eddahab (Laayoune-Baa) basins.^[1][2]

Paleobiota

Life restoration of Ouled Abdoun Basin paleoenvironments during the late Cretaceous: dinosaurs of Sidi Chennae (left) and numerous aquatic animals of Sidi Daoui (right).

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

The Oulad Abdoun Basin stretches from the late Cretaceous to the Eocene and contains abundant marine vertebrate fossils, including sharks, bony fish, turtles, crocodilians, and other reptiles, as well as sea birds and a small number of terrestrial mammals.^[3][4]

Molluscs

Mollusca from the Khouribga Phosphates[5]
Genus	Species	Location	Time	Material	Notes	Images
Cucullaea (Idonearca)	C. (I.) thevestensis				A false ark shell.
Heligmopsis	H. wegmanianus		Maastrichtian		A feather oyster also present in Ganntour basin.
Venericardia	V. coquandi		Danian		A carditid clam also present in Ganntour basin.
Baculites	B. sp.		Maastrichtian		A straight-shelled ammonite, also present in Ganntour basin.
Cimomia	C. aff. sudanensis		Ypresian		A nautiloid also present in Ganntour basin.
Ampullinopsis	A. crassatina				An ampullinid gastropod.
Hemithersitea	H. chouberti		Lutetian		A thersiteid gastropod.

Fish

Bony fish

Bony fish from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Acipenseridae[6]	Indeterminate		Maastrichtian		First record of a sturgeon on the continent of Africa.
Enchodus	E. libycus		Maastrichtian		An enchodontid aulopiform.
	E. bursauxi		Maastrichtian
	E. elegans		Maastrichtian
Eoserrasalmimus[7]	E. cattoi		Maastrichtian		A pycnodontiform.
Mawsoniidae[8]	Indeterminate		Maastrichtian		A giant mawsoniid coelacanth measuring 3.65–5.52 metres (12.0–18.1 ft) long.
Phacodus[9]	P. punctatus var. africanus		Maastrichtian		A pycnodontiform.
Plethodidae[10]	Indeterminate		Maastrichtian		Youngest occurrence of plethodid fish.
Pycnodontidae	Indeterminate		Maastrichtian
Pseudoegertonia	P. sp.		Maastrichtian
Serrasalmimus[7]	S. secans		Thanetian		A carnivorous pycnodontiform.
Stephanodus	S. libycus		Maastrichtian		A pycnodontid
Stratodus	S. apicalis		Maastrichtian		An alepisauroform.
Macroprosopon	M. hiltoni[11]		Ypresian		A marine osteoglossid.

Sharks

Sharks from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Abdounia[12]	A. africana		Selandian		A requiem shark.
Brachycarcharias	B. atlasi[11]		Ypresian
Casieria	C. maghrebiana		Selandian
Chiloscyllium	C. salvani.		Selandian		A carpet shark.
Cretalamna	C. appendiculata		Maastrichtian		An otodontid shark
	C. maroccana		Maastrichtian
Delpitoscyllium	D. africanum		Selandian
Eostegostoma	E. sp.		Selandian		A carpet shark.
Foumtizia	F. abdouni		Selandian
Galeorhinus	G. mesetaensis		Selandian		A houndshark
Ginglymostoma	G. chenanei		Selandian		An early relative of nurse shark
	G. khouribgaense		Selandian
Hologinglymostoma	H. jaegeri		Selandian
Khouribgaleus	K. gomphorhiza		Selandian
Metlaouia	M. delpiti		Selandian
Microscyliorhinus	M. simplex		Selandian
Palaeogaleus	P. larachei		Selandian
Palaeorhincodon	P. daouii		Selandian		A carpet shark.
Porodermoides	P. spanios		Selandian
Premontreia	P. peypouqueti		Selandian
	P. subulidens		Selandian
Pseudocorax[13]	P. heteroserratus		Maastrichtian		A pseudocoracid mackerel shark
Scyliorhinus	S. ptychtus		Selandian		A catshark
	S. entomodon		Selandian
	S. sulcidens		Selandian
Serratolamna	S. serrata		Maastrichtian		A mackerel shark
	S. khderii		Maastrichtian
Squalicorax	S. pristodontus		Maastrichtian		A crow shark
	S. bassanii		Maastrichtian
	S. africanus		Maastrichtian
	S. microserratus		Maastrichtian
	S. benguerirensis		Maastrichtian
Triakis	T. antunesi		Selandian		A houndshark

Other cartilaginous fish

Other cartilaginous fish from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Archaemanta	A. priemi		Selandian		A ray.
Burnhamia	B. cf. davisi		Selandian		A devil ray
Coupatezia	C. larivei		Selandian		A ray.
	C. fallax		Maastrichtian
	C. elevata		Maastrichtian
Dasyatis	D. ponsi		Selandian		A stingray. An indeterminate species found in Maastrichtian deposits of Ganntour Basin.
Delpitia	D. reticulata		Selandian		A ray.
Gymnura	G. delpiti		Selandian		A ray.
Heterobatis	H. talbaouii		Selandian		A ray.
Heterotorpedo	H. brahimi		Selandian		A ray.
Hypolophodon	H. sp.		Selandian		A ray.
Rhombodus	R. binkhorsti		Maastrichtian		A ray.
	R. microdus		Maastrichtian
	R. meridionalis		Maastrichtian
Schizorhiza	S. stromeri		Maastrichtian		A sclerorhynchoid skate which resembled a sawfish.

Dinosaurs

Late Maastrichtian dinosaurs of Ouled Abdoun Basin, including Minqaria, Ajnabia, Chenanisaurus, and several unnamed specimens

Ornithischians

Ornithischians from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Ajnabia[14]	A. odysseus	Office Cherifien des Phosphates mines at Sidi Chennane	Maastrichtian	partial left maxilla with teeth fragments of right maxilla partial right dentary	A small lambeosaurine hadrosaur; the first known from Africa
Lambeosaurinae[15]	Indeterminate	Mrah Lahrach	Maastrichtian	right femur	A lambeosaurine larger than Ajnabia and Minqaria
Lambeosaurinae[15]	Indeterminate	Sidi Daoui	Maastrichtian	left humerus	A lambeosaurine larger than Ajnabia and Minqaria
Minqaria[15]	M. bata	Sidi Chennane	Maastrichtian	right maxilla left dentary braincase	A lambeosaurine hadrosaur
Taleta[16]	T. Taleta	Sidi Chennane	Maastrichtian	partial left and right maxilla with teeth	A lambeosaurine hadrosaur

Sauropods

Sauropods from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Titanosauria[17]	Indeterminate	Sidi Daoui[18]	Maastrichtian	right femur, tibia, and fibula undescribed material	A new titanosaurian taxon, currently unnamed.

Theropods

Abelisaurs

Abelisaurs from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Abelisauridae[19]	Indeterminate	Sidi Chennane	Maastrichtian	right tibia	Probably distinct from Chenanisaurus due to its smaller size (about 5 m (16 ft) long) despite being mature. Similar to South American abelisaurids. Possibly a member of Furileusauria.[20]	Chenanisaurus
Abelisauridae[19]	Indeterminate	Sidi Daoui	Maastrichtian	right metatarsal II	A mature specimen but very small for an abelisaurid, about 2.6 m (8.5 ft) long
Chenanisaurus[17]	C. barbaricus	Sidi Chennane Sidi Daoui	Maastrichtian	anterior end of left dentary 2 premaxillary teeth a maxillary tooth	A large abelisaurid theropod.

Birds

Bird fossils are common in the Basin, which includes the oldest birds in Africa.^[4] At least three orders and several families of sea birds are represented, including Procellariiformes (albatrosses and petrels, fossils assignable to Diomedeidae and Procellariidae), Pelecaniformes (pelicans and allies, fossils assignable to Phaethontidae, Prophaethontidae, Fregatidae and Pelagornithidae), and Anseriformes (waterfowl, including fossil Presbyornithidae).^[4]

Birds from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Dasornis[21]	D. abdoun	Sidi Daoui	Ypresian	A holotype specimens consists of carpometacarpus, ulna, radius, tibiotarsus, and humerus.	A pelagornithid, or pseudotooth bird.
	D. emuinus	Sidi Daoui	Ypresian	A partial skeleton with incomplete cranium.
	D. tolapica		Selandian	A parital skeleton.
Lithoptila[22]	L. abdounensis	Sidi Daoui	Thanetian	A neurocranium.	A seabird related to modern tropicbirds.

Pterosaurs

Pterosaurs from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Alcione	A. elainus[23]	Sidi Daoui	Maastrichtian		A nyctosaurid which shows possible adaptations towards diving behaviour.
Barbaridactylus	B. grandis[23]	Sidi Daoui	Maastrichtian		A nyctosaurid.
Simurghia	S. robusta[23]	Sidi Daoui	Maastrichtian		A nyctosaurid related to Alcione.
Phosphatodraco	P. mauritanicus[24]	Sidi Daoui	Maastrichtian		An azhdarchid.
cf Arambourgiania[23]	A. sp?	Sidi Chennane	Maastrichtian		A giant azhdarchid, may belong to the Jordanian taxon Arambourgiania.
aff. Quetzalcoatlus[23]	indet.		Maastrichtian
Tethydraco	T. regalis[23]	Sidi Daoui	Maastrichtian		A pterosaur of debated affinity; may be an azhdarchid[25] or a pteranodontid.[23]

Crocodylomorphs

Crocodylomorphs from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Arambourgisuchus[26]	A. khouribgaensis		Thanetian		A dyrosaurid.
Atlantosuchus	A. coupatezi		Danian		A dyrosaurid.
Chenanisuchus	C. lateroculi		Thanetian		The most basal known dyrosaurid.
Dyrosaurus	D. maghribensis		Ypresian		A dyrosaur.
Maroccosuchus[27]	M. zennaroi		Ypresian		A tomistomine crocodylian.
Ocepesuchus[28]	O. eoafricanus		Maastrichtian		A gavialoid crocodylian.

Squamates

Mosasaurs

The late Maastrichtian deposits of the Khouribga Phosphates preserve abundant mosasaur fossils, especially isolated teeth. At least fifteen species are represented, covering the majority of ecological niches the group is known to have occupied.^[29] The Ouled Abdoun Basin is one of the richest known mosasaur fossil sites in the world.^[29]

Mosasaurs from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Carinodens[30][29]	C. acrodon		Maastrichtian	Dentaries[29] Isolated teeth[29]	A small mosasaurine mosasaur with crushing teeth.[31] Fossils of all reported Carinodens species are very rare in Khouribga.[31] The dentition differs slightly between species, suggesting marginally different diets.[31] More fossil material is required to determine if both C. minalmamar and C. belgicus are present in the Khouribga Phosphates, as the present material is difficult to differentiate.[29]
	C. belgicus			Dentaries[31] Isolated teeth[31]
	C. minalmamar			Dentaries[31] Isolated teeth[31]
Eremiasaurus	E. heterodontus		Maastrichtian	Partial and subcomplete skeletons[31] Isolated teeth[31]	A mosasaurine mosasaur with unusually heterodont teeth, including straight and conical anterior teeth, blade-like median teeth, and recurved posterior teeth.[31] A medium-sized (4.5–5 metres) predator and one of the more commonly found fossil mosasaurs in the Khouribga Phosphates.[31]
Gavialimimus[32]	G. almaghribensis		Maastrichtian	A complete skull[31] Isolated teeth[31]	An unusual longirostrine plioplatecarpine mosasaur, measuring about 6 metres long.[31] Fossils of G. almaghribensis are very common in the Khouribga Phosphates.[31]
Globidens	G. phosphaticus		Maastrichtian	Isolated teeth[31]	A durophagous mosasaurine mosasaur with specialized crushing teeth.[31] G. phosphaticus is known from Morocco only in the form of isolated teeth but more complete material from the species is known from Angola.[31] G. phosphaticus and G. simplex were of similar size but had slightly different teeth, suggesting marginally different diets.[31]
	G. simplex		Maastrichtian	A partial skull[31] Isolated teeth[31]
Halisaurus	H. arambourgi		Maastrichtian	Several skeletons[31] Isolated teeth[31]	A halisaurine mosasaur, measuring about 3–4 metres long.[31] One of the most commonly found mosasaurs in Morocco.[31]
Igdamanosaurus	I. aegyptiacus		Maastrichtian		"Globidens aegyptiacus" was previously reported as present in the Khouribga Phosphates on the basis of isolated teeth. G. aegyptiacus was reclassified as Igdamanosaurus aegyptiacus in 1991 and differs from the globidensin material known from Morocco.[33] Moroccan fossils previously referred to G. aegyptiacus are now referred to G. phosphaticus.[33]
Khinjaria[34]	K. acuta	Sidi Chennane	Maastrichtian	A partial skull and vertebra[34]	A plioplatecarpine mosasaur, known only from a single specimen.[31] Khinjaria possessed a unique skull and teeth morphology and might have been an ambush predator.[31]
Liodon	L. anceps		Maastrichtian		"Mosasaurus (Leiodon) cf. anceps" was reported as present in Khouribga by Camille Arambourg (1952) based on isolated teeth.[35] Liodon anceps is now considered a nomen dubium.[31] Teeth previously referred to Liodon likely belong to Eremiasaurus heterodontus (small and slender specimens) and Thalassotitan atrox (other specimens).[31]
Mosasaurus	M. beaugei		Maastrichtian	Skulls and mandibles[31] Isolated teeth[31]	A large mosasaurine mosasaur, measuring about 8–10 metres long.[31] Relatively scarce compared to other mosasaurs of comparable size. Likely a local apex predator.[31]
Platecarpus	P. ptychodon		Maastrichtian	Isolated teeth and vertebrae[31]	Platecarpus ptychodon is known only from isolated material. The fossils referred to P. ptychodon are treated either as non-diagnostic (in which case P. ptychodon is a nomen dubium) or as belonging to Gavialimimus almaghribensis (in which case G. almaghribensis is considered a junior synonym of the new combination Gavialimimus ptychodon).[31]
Pluridens[36]	P. serpentis		Maastrichtian	Complete skulls with associated vertebrae[31] Isolated teeth[31]	A large halisaurine mosasaur, also known from Niger and Nigeria. Measured about 5–6 metres long.[31] Pluridens is relatively uncommon in Morocco and distinguished from the closely related Halisaurus based on features in the skull and its larger size.[31] The teeth of Pluridens are identical to those of Halisaurus, only larger, and the two are thus difficult to differentiate in samples of isolated teeth.[31]
Prognathodon	P. currii		Maastrichtian	Isolated teeth[31]	A large mosasaurine mosasaur. Prognathodon curii is known in Morocco only from isolated teeth and is comparably rare, with only about a dozen teeth identified.[31] The related species Prognathodon giganteus is also known from Morocco, though only from earlier lower Maastrichtian deposits in the Gantour Basin to the southwest of the Ouled Abdoun Basin.[31][35]
Stelladens[37]	S. mysteriosus		Maastrichtian	A dentary fragment[31] Isolated teeth[31]	A medium-sized mosasaurine with distinct, unique teeth structure with prominent serrated ridges.[31] Stelladens is a very scarce taxon in the Khouribga Phosphates.[31] Stelladens would have measured about 5 metres long and was probably a highly specialized predator.[31]
Thalassotitan[38]	T. atrox		Maastrichtian	Several skeletons[31] Isolated teeth[31]	A large-bodied mosasaurine with powerful jaws and massive teeth, closely related to Prognathodon.[31] Fossils of Thalassotitan are comparably very common and it likely represented the largest local apex predator.[31] Fossils now referred to Thalassotitan were before its description often referred to as "Prognathodon nov. sp."[31]
Xenodens[39]	X. calminechari		Maastrichtian	A left maxilla with four teeth[31] A left maxilla with eight teeth[40]	A small mosasaurine mosasaur with unusual, shark-like teeth.[31] The holotype of Xenodons was suggested to potentially be a forged specimen by Sharpe et al. (2024),[41] but Longrich et al. (2025) published a rebuttal based on CT scans of the holotype and another referred specimen, arguing for the validity of the genus.[40]

Snakes

Snakes from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Palaeophis[42]	P. maghrebianus		Maastrichtian?–Ypresian	Multiple fossilized vertebrae.	A palaeophiid marine snake.

Varanoids

Varanoids from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Pachyvaranus	P. crassispondylus		Maastrichtian	Vertebrae and ribs[43]	A near-shore marine lizard.[43] Originally described based only on a small number of isolated vertebrae. Discovery of further vertebrae and ribs in Morocco and Syria allowed in 2011 for classification in the Varanoidea, in a new family Pachyvaranidae.[43] Osteoderms were originally referred to this taxon but likely come from fish instead, perhaps Stratodus.[43]

Plesiosaurs

Plesiosaur material found in the Ouled Abdoun Basin has been referred to one valid species, Zarafasaura oceanis. Isolated elasmosaurid fossils may all belong to this species but comparison is difficult.^[44][45]

Plesiosaurs from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Elasmosauridae	indet.	Sidi Daoui	Maastrichtian	Articulated and isolated vertebrae[45] Pelvic elements[45]	Elasmosaurid fossils without cranial elements. Could represent the same taxon as Zarafasaura oceanis but comparison impossible at the time of discovery due to no overlap in the fossil material.[45] Comparison may be possible after the discovery of postcranial Zarafasaura elements in 2013.[44]
Plesiosaurus	P. mauritanicus		Maastrichtian	Isolated teeth and vertebrae[44]	Named by Camille Arambourg (1952) based on isolated fossils. Plesiosaurus mauritanicus is regarded as a nomen dubium since the fossils are non-diagnostic beyond being elasmosaurid, and because the holotype and paratypes are from different individuals found at different localities.[44] Potentially the same taxon as Zarafasaura oceanis.[44]
Zarafasaura	Z. oceanis	Sidi Daoui	Maastrichtian	Holotype specimen, a crushed skull and partial mandible[44] Paratype specimen, complete skull with many postcranial elements[44]	A relatively small elasmosaurid plesiosaur, closely related to plesiosaurs known from North America and Japan.[46]

Turtles

Turtles from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Alienochelys[47]	A. selloumi	Sidi Daoui	Maastrichtian		A sea turtle with crushing jaws.
Araiochelys[48]	A. hirayamai	Sidi Daoui	Maastrichtian	A skull, lower jaws, partial disarticulated shell, including a few carapace fragments (left first and fifth costals, left third, seventh, and eighth peripherals and other fragments), nearly complete plastron and limb bones.	A bothremydid pleurodiran turtle.
Argillochelys[49]	A. africana		Ypresian		A pancheloniid sea turtle.
Bothremys[48]	B. kellyi		Danian-Thanetian		A bothremydid pleurodiran turtle.
	B. maghrebiana
Brachyopsemys	B. tingitana		Danian		A sandownid sea turtle
Euclastes	E. acutirostris		Danian-Thanetian		A pancheloniid sea turtle. An indeterminate species also present in the Maastrichtian deposits of Ganntour Basin.[50]
	E. wielandi		Danian
Labrostochelys[48]	L. galkini	Oued Zem	Danian	A nearly complete skull.	A bothremydid pleurodiran turtle
Ocepechelon[51]	O. bouyai	Sidi Chennane	Maastrichtian	A complete but isolated 70-cm-long skull.	A giant protostegid sea turtle with an unusual pipette-like snout.
Puppigerus	P. camperi		Ypresian		A Pancheloniid sea turtle.
Rhothonemys[48]	R. brinkmani		Danian		A bothremydid pleurodiran turtle.
Tasbacka	T. ouledabdounensis		Danian		A Cheloniidae sea turtle.
Taphrosphys	T. ippolitoi		Danian		A bothremydid pleurodiran turtle.
Ummulisani	U. rutgersensis	Mrah Iaresh	Ypresian	A skull without a palate.	A bothremydid pleurodiran turtle.

Mammals

Afrotheres

Afrotheres from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Abdounodus[52]	A. hamdii		Thanetian-Ypresian	A lower jaw.	An early afrotherian mammal.
Daouitherium[53]	D. rebouli		Ypresian	lower jaws and associated cheek teeth	An early proboscidean.
Eritherium[54]	E. azzouzorum	Sidi Chennane	Thanetian	An upper jaw (with approaches of the zygomatic bone and two maxillary branches, each of the two posterior premolars (P3 and 4) and three molars (M1-3))	An early proboscidean.
Hadrogeneios[55]	H. phosphaticus		Selandian-Thanetian	A mandibular symphysis with some partial left dentary, two sockets for the incisors, the first lower canine, and the first to third premolars	An early afrotherian mammal.
Ocepeia[52]	O. daouiensis	Grand Daoui, Meraa El Arech, and Sidi Chennane	Selandian	Partial skull consists of an upper jaw and dental fragments	An early afrotherian mammal.
	O. grandis		Thanetian	Lower jaw and teeth.
Phosphatherium	P. escuilliei		Selandian		An early proboscidean.
Stylolophus[56]	S. minor		Ypresian		An embrithopod.
	S. major		Ypresian

Hyaenodonts

Hyaenodonts from the Khouribga Phosphates
Genus	Species	Location	Time	Material	Notes	Images
Boualitomus	B. marocanensis		Selandian		A hyaenodont.
Lahimia[57]	L. selloumi		Selandian		A hyaenodont.

See also

• Paleontology portal
• Earth sciences portal
• Morocco portal

• Cretaceous–Paleogene extinction event
• Fauna of Africa
• List of dinosaur bearing rock formations