Kem Kem Group
Geological group in eastern Morocco
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The Kem Kem Group (commonly known as the Kem Kem beds)[1] is a geological group in the Kem Kem region of eastern Morocco, whose strata date back to the Cenomanian stage of the Late Cretaceous.
| Kem Kem Group | |
|---|---|
| Stratigraphic range: Cenomanian[1] ~ | |
| |
| Type | Geological group |
| Sub-units | Douira Formation, Gara Sbaa Formation |
| Underlies | Cenomanian-Turonian limestone platform (Akrabou Formation) |
| Lithology | |
| Primary | Sandstone |
| Location | |
| Coordinates | 32°50′N 4°50′W |
| Approximate paleocoordinates | 18.8°N 4.1°W |
| Region | Er Rachidia, Tafilalt |
| Country | Morocco |
| Extent | central and eastern Morocco north and south of the Pre-African Trough |
  Kem Kem Group (Morocco) | |
Dinosaur remains are among the fossils that have been recovered from the group.[2] 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.[3]
Stratigraphy and paleoenvironment
Although preserving 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 the Kem Kem Group, but has been differentiated from it in more recent studies due to their differing paleoenvironments.[1][4]
Its strata are subdivided into two geological formations, with the lower Ifezouane Formation and the upper Aoufous Formation used for the strata on the eastern side of the Atlas Mountains (Tinghir), with the Gara Sbaa Formation and Douira Formation used in the southern Tafilalt region.[5] It is exposed on an escarpment along the Algeria–Morocco border. According to Ibrahim, the Lower Kem Kem consists of the Ifezouane & Gara Sbaa Formations, while the Upper Kem Kem is consisted of The Douira & Aufous Formations. [1]
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.[1]
The Kem Kem is interpreted as being deposited in a tropical semi-arid climate, with brief monsoon rains.[6][7] It is believed to Span the Lower to Middle Cenomanian, a span of roughly 100-95 mya. [1]
Vertebrate paleofauna
Cartilaginous fish
| Cartilaginous fish | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Acrodontidae indet.[1] | Indeterminate | Members of Hybodontoidea | ||||
| Bahariyodon[1] | B. bartheli | A member of Hybodontoidea | ||||
| Cenocarcharias[1] | C. tenuiplicatus | One tooth[1] | A member of the family Cretoxyrhinidae | |||
| Distobatus[1] | D. nutiae | A member of Hybodontoidea | ||||
| Haimirichia[1] | H. amonensis | One tooth[1] | A mackerel shark | |||
| Marckgrafia[1] | M. lybica | 13 teeth[1] | A member of Batoidea | |||
| Onchopristis | O. numida[8] | A rajiform sawskate[9] |  | |||
| Peyeria[1] | P. libyca | Three teeth[1] | A sawskate. Might be a junior synonym of Onchopristis numida. | |||
| Tribodus[1] | T. sp. | A member of Hybodontoidea | ||||
Ray-finned fish
| Ray-finned fish | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Adrianaichthys[1] | A. pankowskii | Isolated scales[10] and two skulls[11] | A member of Lepisosteiformes. Originally described as a species of Lepidotes, but subsequently transferred to a separate genus.[12] |
   .jpg)  | |
| Afrocascudo[13] | A. saharaensis | A neopterygiian fish, either an ancient loricariid catfish or a juvenile obaichthyid lepisosteiform.[14] | |||
| Agassizilia[15] | A. erfoudina | Possibly a member of the family Pycnodontidae. | |||
| Agoultichthys[1] | A. chattertoni | A long-bodied member of Actinopterygii of uncertain phylogenetic placement. Might be a member of the family Macrosemiidae[16] or Ophiopsiellidae.[17] | |||
| Aidachar | A. pankowskii | A member of Ichthyodectiformes | |||
| Bartschichthys[1] | B. sp. | Isolated pinnulae (spines that support each dorsal finlet)[1] | A cladistian | ||
| Bawitius | cf. B. sp. | Isolated scales and jaw fragments[10] | A cladistian | ||
| Calamopleurus[1] | C. africanus | A partial skull[1] | A member of Amiiformes | ||
| Concavotectum[1] | C. moroccensis | A member of Tselfatiiformes | |||
| Dentilepisosteus[1] | D. kemkemensis | A member of Lepisosteiformes | |||
| Diplomystus[1] | D. sp. | A deep-bodied teleost belonging to the group Clupeomorpha | |||
| Diplospondichthys[1] | D. moreaui | A member of Actinopterygii of uncertain phylogenetic placement, possibly a teleost | |||
| Erfoudichthys[1] | E. rosae | Isolated skull[1] | A small-bodied teleost of unknown affinity | ||
| Neoproscinetes[15] | N. africanus | A member of the family Pycnodontidae | |||
| Obaichthys | O. africanus | Isolated scales[10] | A member of Lepisosteiformes | ||
| Oniichthys | O. falipoui | Near complete skeleton including skull[10] | A member of Lepisosteiformes | ||
| Palaeonotopterus[1] | P. greenwoodi | A member of Osteoglossomorpha | |||
| Serenoichthys[1] | S. kemkemensis | Several articulated skeletons[1] | A small cladistian | ||
| Spinocaudichthys[1] | S. oumtkoutensis | An elongate freshwater acanthomorph | |||
| Stromerichthys | S. aethiopicus | ||||
| Sudania[1] | S. sp. | An isolated pinnula[1] | A cladistian | ||
Lobe-finned fish
| Lobe-finned fish | |||||
|---|---|---|---|---|---|
| Genus | Species | Location | Material | Notes | Images |
| Arganodus | A. tiguidiensis | A lungfish |
 .jpg) | ||
| Axelrodichthys[18] | A.? lavocati | A mawsoniid coelacanth; this species was previously assigned to Mawsonia, and its generic assignment is still not certain[19] | |||
| Neoceratodus | N. africanus | A lungfish | |||
Amphibians
| Amphibians | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Anura indet.[20] | Indeterminate | Douira Formation | Incomplete left ilium | |||
| Cretadhefdaa[20] | C. taouzensis | Douira Formation | Posterior portion of the skull, incomplete squamosal, incomplete maxilla, three incomplete presacral vertebrae, one incomplete sacral vertebra | A neobatrachian frog with possible hyloid affinities. | ||
| cf. Kababisha[21] | Indeterminate | A salamander belonging to the family Sirenidae | ||||
| ?Neobatrachia indet.[20] | Indeterminate | Douira Formation | Incomplete humerus | A frog, possibly a member of Ranoidea. | ||
| Oumtkoutia[21] | O. anae | A frog belonging to the family Pipidae | ||||
Lizards and snakes
Color key
|
Notes Uncertain or tentative taxa are in small text; |
| Lizards and snakes reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
B. hogreli[22] |
A polyglyphanodontid lizard. |
|||||
| Jeddaherdan[23] |
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 a fossil material of a member of the genus Uromastyx.[24] |
|||
|
L. ragei[25] |
Two isolated trunk vertebrae |
An early snake. |
||||
|
Madtsoiidae indet.[21] |
Indeterminate |
Vertebrae[1] |
An early snake. |
|||
|
?Nigerophiidae indet.[21] |
Indeterminate |
Dorsal vertebrae[1] |
An early snake. |
|||
|
Norisophis[26] |
N. begaa[26] |
One posterior and two mid-trunk vertebrae |
A stem-snake. |
|||
|
Indeterminate[26] |
A mid-trunk vertebra | |||||
|
cf. S. libycus |
Vertebrae[1] |
An early snake. |
||||
Plesiosaurs
| Plesiosaurs | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Leptocleididae cf. Leptocleidus[27] | indeterminate | Isolated teeth, a humerus and vertebrae |  | |||
Turtles
| Turtles reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
Dirqadim |
D. schaefferi |
A Euraxemydid | ||||
|
G. emringeri |
A Cearachelyin | |||||
| G. whitei | ||||||
|
Hamadachelys |
H. escuilliei |
|||||
Crocodylomorphs
A tooth enamel identified as cf. Sarcosuchus was discovered from the Ifezouane Formation.[28]
| Crocodylomorphs reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
A. witmeri |
"Partial braincase of a large individual with skull roof, temporal, and occipital regions."[29] |
An aegyptosuchid that may be a synonym of Laganosuchus.[1] |
     | |||
|
A. taouzensis |
Paired mandibles and a partial right mandible |
A peirosaurid. | ||||
|
A. rattoides |
Douira Formation | |||||
|
E. cherifiensis |
|
A pholidosaurid. The material may represent two different species.[1] | ||||
|
H. rebouli |
|
A peirosaurid. | ||||
|
K. auditorei |
Errachidia Province, Morocco[31] |
Known from an isolated caudal vertebra.[31] |
Initially thought to be a neotheropod,[31] but subsequently discovered to be an indeterminate crocodyliform.[32] | |||
| L. maghrebensis | ||||||
|
L. sigogneaurusselae |
Anterior portion of a rostrum with mandible, with an almost complete dentition[33] |
|||||
Dinosaurs
Indeterminate lithostrotian remains once misattributed to the Titanosauridae are present in the province of Ksar-es-Souk, Morocco.[2]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Ornithischians
| Ornithischians reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
Indeterminate |
Douira Formation |
An isolated tooth.[1] |
A probable ankylosaur[34] |
|||
|
Indeterminate |
Douira Formation |
A large, clover-shaped, three-toed footprint.[1] A smaller print is known as well.[1] |
Comparable in size and shape to tracks typically attributed to Iguanodon.[35] Smaller possible ornithopod track is known as well. | |||
Sauropods
| Sauropods reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
R. garasbae |
Ksar-es-Souk province, Morocco.[2] |
Gara Sbaa Formation |  | |||
|
Indeterminate |
The vertebra might belong to a basal titanosaurian, possibly distinct from Aegyptosaurus and Paralititan.[36] The ischium is not identifiable beyond Somphospondyli; it preserves numerous grooves and pits which might be feeding traces left by a very large non-avian theropod.[36] | |||||
|
Indeterminate |
|
Isolated teeth, caudal vertebrae, a partial humerus, a tarsal bone and the proximal end of an ulna.[1] |
Fossil material of one or more titanosaurian sauropods. Some fossils are indicative of large body size comparable to Paralititan stromeri.[1] The largest specimens hail from the Douira Formation.[1] An ulna from Doira has a width of 51 cm.[1] | |||
| Rebbachisauridae Indet. | Indeterminate |
|
Teeth | Teeth referred to an indeterminate rebbachisaurid.[1] | ||
Theropods
| Theropods reported from the Continental Red Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
Indeterminate |
Isolated teeth.[38][39] |
Abelisaurid material belonging to one or two distinct taxa.[1] Some of the material has been noted as similar to Rugops, but the diagnostic features in that genus are on the orbital bones;not preserved in the Kem Kem material. Preventing definitive referral.[1] |
    | |||
|
C. saharicus[2] |
Ksar-es-Souk province, Morocco.[2] | Douira Formation | Partial skull, including braincase, nasals, postorbitals, jugals, left lacrimal and right maxilla with most teeth.[41] |
A carcharodontosaurid theropod. | ||
| Carcharodontosauridae[42] | Indeterminate | Southeast of Taouz, Errachidia Province | Ifezouane Formation | partial maxilla and partial jugal | A carcharodontosaurid theropod different from C. saharicus | |
|
D. agilis |
Gara Sbaa Formation |
"Partial skeleton, isolated limb elements."[43] |
A noasaurid ceratosaurian, May be synonymous with Bahariasaurus. | |||
|
Indeterminate |
Isolated teeth.[38] |
Originally described as teeth of indeterminate dromaeosaurids. Hendrickx et al. (2024) reinterpreted this fossil material as teeth of abelisauroid theropods, including noasaurids and juvenile abelisaurids.[39] | ||||
|
cf. Elaphrosaurus |
Indeterminate |
Ksar-es-Souk province, Morocco.[2] |
Fossils previously referred to cf. Elaphrosaurus are actually indeterminate theropod remains. | |||
|
Indeterminate |
||||||
| "Osteoporosia"[44] | "O. gigantea"[44] | A tooth and a possible neural arch from another specimen.[44] | A theropod, possibly synonymous with Sauroniops.[45] | |||
|
Indeterminate |
An isolated cervical vertebra.[46] |
An indeterminate saurischian. | ||||
|
S. pachytholus |
Ifezouane Formation |
"An isolated and almost complete left frontal,[48] and a possible tooth and neural arch from two other specimens."[45] |
A carcharodontosaurid thought to be distinct from Carcharodontosaurus,[47][48] considered a nomen dubium by Kellerman et al.[49] | |||
| Sigilmassasaurus | S. brevicollis | Tafilalt Oasis region, Morocco. | Kem Kem Formation | A single neck vertebrae. | A controversial spinosaurid theropod. | |
|
S. aegyptiacus |
Ksar-es-Souk province, Morocco.[2] | Douira Formation | Partial skeleton, including parts of the skull, neck, torso, and most of the tail and hind limbs.[50]
Numerous isolated bones. |
A spinosaurid theropod. | ||
| Averostra indet | Indeterminate | Tooth | Said to belong to either a non-abelisaurid ceratosaur or a megaraptoran.[39] | |||
| Abelisauroidea indet. | Indeterminate | Douira Formation[51] | Pedal ungual[52] | An indeterminate abelisauroid, known from a 7 cm long pedal ungual. Likely an abelisaurid or noasaurid. | ||
Pterosaurs
| Pterosaurs of the Kem Kem Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
A. zouhri[53] |
Takmout | Ifezouane Formation |
A fragment of bone interpreted as a fragment of anterior mandibular symphysis,[54] and additional jaw fragments that pertain to the rostrum as well as indeterminate jaw fragments.[5] |
A tapejarid pterosaur. Originally believed to belong to either the family Thalassodromidae[55] or an additional specimen of Alanqa saharica.[56] |
 .jpg)      | |
| Akharhynchus[57] | A. martilli | Tafilalt | Ifezouane Formation | A fragment of the anterior part of the premaxillae | A tropeognathine anhanguerian. | |
|
A. saharica[55] |
Ifezouane Formation | The holotype is a mandibular symphysis, of different parts of the jaw | A pterosaur of uncertain phylogenetic placement, probably an azhdarchid.[5] | |||
|
A. cf. piscator[58] |
upper Ifezouane Formation |
Partial mandibular symphysis[58] |
||||
|
A. gyrostega[59] |
Ifezouane Formation |
Partial rostrum and mandible, with additional referred jaw fragments[5] |
A possible chaoyangopterid azhdarchoid pterosaur.[59] Originally believed to be a possible pteranodontid,[55] a possible dsungaripterid,[60] a possible non-azhdarchid azhdarchoid or nyctosaurid,[60] or a specimen of Alanqa saharica.[56] | |||
|
Azhdarchidae indet.[60][5] |
Indicative of multiple taxa.[60] Some of these vertebrae may pertain to Alanqa saharica.[56][61] | |||||
|
Azhdarchoidea indet. |
"Jaw morphotype A"[5] | Two jaw fragments[5] | Different from all named Kem Kem pterosaur taxa[5] | |||
| "Jaw morphotype B"[5] | Partial mandible fragment[5] | Probably had a similarly long jaw to Leptostomia[5] | ||||
| "Jaw morphotype C"[5] | Partial jaw fragments[5] | May belong to Apatorhamphus or Xericeps[5] | ||||
|
Indeterminate[5] |
Five cervical vertebrae, a scapulocoracoid, two humeri, two ulnae, a metacarpal IV, and a tibiotarsus[5] | |||||
| Coloborhynchus[58] | C. sp. A.[58] | Hassi El Begaa | Premaxillae fragment[58] | Possibly a specimen of Nicorhynchus fluviferox.[62] | ||
|
L. begaaensis[63] |
Aferdou N' Chaft |
upper Ifezouane Formation |
Partial rostrum and partial mandibular synthesis[63] |
A small, long-beaked pterosaur, likely a member of Azhdarchoidea.[63] | ||
|
Possibly Aferdou N'Chaft, Hassi El Begaa[62] |
Ifezouane Formation |
An anterior portion of the rostrum.[62] |
Originally described as a species of Coloborhynchus[64] but subsequently transferred to the genus Nicorhynchus. | |||
|
O. cf. simus.[58] |
upper Ifezouane Formation |
Premaxillae fragment[58] |
||||
|
S. moroccensis[65] |
Anterior part of a rostrum |
Classified by some authors as a species belonging to the genus Coloborhynchus.[55] | ||||
| Xericeps | X. curvirostra | Aferdou N'Chaft | Douira Formation | Mandibular symphysis and partial mandible[5] | An indeterminate azhdarchoid, possibly a chaoyangopterid.[5] | |
Non-vertebrate paleofauna
The formation contains fossils of various insects, crustaceans, mollusks, and sea urchins.[1][66] There are also traces of insect and priapulid activity.[35][67]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Unicellular organisms
| Genus | Species | Stratigraphic position | Material | Notes | Image |
|---|---|---|---|---|---|
| Eukaryote | Indeterminate | Douira Formation | Biofilm of bacteria or fungi.[1] |  | |
| Foraminifera | Douira Formation, Aoufous Formation | Foraminiferal tests | Various foraminifera.[66] |  |
Mollusc
Gastropods and ammonites were found in the upper units.[66]
| Genus | Species | Stratigraphic position | Material | Notes |
|---|---|---|---|---|
| ?Margaritifera[68] | Ifezouane Formation | Shell | A freshwater bivalve. | |
| Goumardonaia[68] | G. radieri | Shell | A large (83 mm) freshwater bivalve. | |
| Kemkemnaia[68] | K. parvum | Shell with preserved gill structures. | A freshwater bivalve. | |
| Monginella[68] | M. cf. flattersensis | Shell | A freshwater bivalve. | |
| Trigonioidoidea[68] | Indeterminate | Shell | A freshwater bivalve. | |
| Unio[68] | U. radleyi | Shell | A freshwater bivalve. | |
| Unionidae[68] | Indeterminate | Shell | A freshwater bivalve. |
Arthropods
| Genus | Species | Stratigraphic position | Material | Notes | Image |
|---|---|---|---|---|---|
| Cretapenaeus | C. berberus | A freshwater prawn.[1] | |||
| Cubiculum | C. ornatus | Traces of bone borings on dead animals. | A terrestrial necrophagous insect.[35] |  | |
| Odonata | Indeterminate | A dragonfly larva.[1] | |||
| Ostracoda | Different types of ostracods.[66] | ||||
| Troponoma | T. constricta | Feeding traces on a leaf. | A herbivorous insect.[67] |  |
Paleoflora
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Based primarily on Krassilov & Bacchia.[67]
| Genus | Species | Stratigraphic position | Material | Notes | Image |
|---|---|---|---|---|---|
| Abietites | A. (Tritaenia) cf. linkii | Gara Sbaa Formation | Needles | A conifer. |    |
| Barykovia | B. cf. tschuckotika | Leaf | A potentially fagalean angiosperm. | ||
| Cocculophyllum | C. cf. fucinerve | Leaf | A climbing angiosperm. | ||
| Coniopteris | C. cf. Dicksonia mamiyai | Leaflet | A fern. | ||
| Dryophyllum | D. cf. subcretaceum | Leaf | A potentially fagalean angiosperm. | ||
| Frenelopsis | F. cf. teixeirae | Shoot | A cheirolepidiacean conifer. | ||
| Garasbahia | G. flexuosa | Branching shoot with leaves | A cabombacean angiosperm. | ||
| Pseudotorellia | P. cf. ensiformis | Leaf | A ginkgoalean. | ||
| Sulcatocladus | S. cf. robustus | Shoot | A conifer. | ||
| Weichselia[1] | W. reticulata | Shoot | A tree fern. | ||
| Welwitschiophyllum | W. sp. | Leaf | A possible welwitschialean. |
See also
- Aoufous Formation, which lies within the Kem Kem Beds
- List of dinosaur-bearing rock formations