| Berberosaurus | |
|---|---|
 | |
| Liferestoration and size comparison | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Averostra |
| Clade: | †Ceratosauria |
| Genus: | †Berberosaurus |
| Species: | †B. liassicus |
| Binomial name | |
| †Berberosaurus liassicus Allainet al., 2007 | |
| Synonyms | |
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Berberosaurus (meaning "Berber lizard", in reference to the Berbers ofMorocco) is agenus ofneotheropoddinosaur, possibly aceratosaur, from theToarcian-age (Lower Jurassic) "Toundoute Continental Series" (Azilal Formation) found in the CentralHigh Atlas of Toundoute,Ouarzazate, Morocco. Thetype species of the genusBerberosaurus isB. liassicus, in reference to theLiasepoch.Berberosaurus might be the oldest known ceratosaur, and is based on partialpostcranial remains. This genus represents the oldest formally identified theropod from the North of Africa, as well one of the few from the region in the Early Jurassic.[2]
The remains ofBerberosaurus were discovered during a series of expeditions to the High Atlas beginning in the early 2000s, where over 6 years, they dug in the local redbeds. It isbased on an associated partial postcranial skeleton of a subadult individual cataloged in theMuséum d'Histoire Naturelle de Marrakech; bones from this skeleton includeMHNM-Pt9 a neck vertebra;MHNM-Pt23, an anterior part of thesacrum;MHNM-Pt22, a metacarpal;MHNM-Pt19, afemur;MHNM-Pt21, proximal end of the lefttibia;MHNM-Pt16, distal end of the righttibia;MHNM-Pt20, leftfibula;MHNM-To1–218, part of anotherfemur, has been assigned to the genus as well. Its remains were found alongside those ofTazoudasaurus and an indeterminate large-bodiedtheropod withinbone beds inmudflow deposits. Latertectonic activity has affected the bones.[2] Recent papers have quoted that new material of this genus was recovered on the same area, namely the axis, a postorbital, the cranium and teeth, that are currently being studied.[3] Berberosaurus is characterized by the following features: the cervical vertebra is highly pneumatic, with short cervical centra and holes in the neural arch, with low and short neural spine, unlikeElaphrosaurus andCeratosaurus. It has anteroposteriorly short centra and neural spine; the sacral series markedly arched; the central sacrum narrow transversely; the metacarpal with a very grooved proximal end; anterior femoral trochanter reaches proximally to the midpoint of the femoral head, unlikeCeratosaurus; large femoral trochanteric platform; tibia with subtriangular distal profile; presence of an oblique ridge that covers proximally the medial sulcus of the fibula.[2]
Ronan Allain and colleagues, who describedBerberosaurus, performed aphylogenetic analysis and found their new genus to be the mostbasal knownabelisauroid, more derived thanElaphrosaurus,Ceratosaurus, andSpinostropheus, but less so thanXenotarsosaurus andabelisaurians.Berberosaurus is distinguished from other theropods by anatomical details found in itsvertebrae,metacarpals, and hindlimb bones. Its assignment as an abelisauroid pushes back the record of this group and shows that it had diversified by the Early Jurassic.[2] However, Carrano and Sampson (2008) found it to be a basal ceratosaur outsideNeoceratosauria instead.[4] Subsequently, the analysis of Xuet al. (2009) recovered it as adilophosaurid in unresolved polytomy withDilophosaurus wetherilli,"Dilophosaurus" sinensis,Dracovenator andCryolophosaurus.[5] The phylogenetic analysis performed by Ezcurra, Agnolin and Novas (2010) recoveredBerberosaurus in unresolvedpolytomy withCeratosaurus and Abelisauroidea,[6] while the 2018 description of the basal ceratosaurSaltriovenator placesBerberosaurus as the sister taxon to that genus.[7] Same year, a paper found Berberosaurus in different positions: considered as a basal ceratosaurian, a neoceratosaurian or a basal abelisauroid.[8] The paper which described Berberosaurus was the last one to find a monophyletic Ceratosauria that contained both Coelophysoids and Neoceratosaurs, most papers have since excluded Coelophysoidea from Ceratosauria and instead have favored the idea that Tetanurae and Ceratosauria are both part of a monophyletic group calledAverostra, a classification which was already gaining popularity at around that time.[9]
The classification of Berberosaurus based on Delcourt et al. (2018):
| Ceratosauroidea |
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Berberosaurus is estimated to have been approximately 4.58–5 m (15.0–16.4 ft) long and weighed 300 kg (660 lb).[10][11] Like other ceratosaurians, it was abipedalcarnivore.[12]
The "Toundoute Continental Series" is unlike other members of theAzilal Formation due to the presence of volcanic material of coeval age. The Azilal Formation recovers a Terrestrial progradation that happened in the Central High Atlas Basin towards the Toarcian, where the older Pliensbachian Carbonate Platform retreated to the east. The lithology of this unit at Tundoute is divided in 5 units from D to H, (A-C represent the units of the underlying marine dolomite, C representing a transition to a terrestrial environment).[13] These layers have been referred to a Pliensbachian-Toarcian age, as the underliying Carbonates belong to the Sinemurian-agedImi-n-Ifri Formation, with a small transitional layer similar to the Sin-Pliensbachian atTodhra.[14] The section including the bones ofBerberosaurus was likely deposited on a channel/floodplain type fluvial system, with sand-filled channels abundant in plant roots (mostly located in fine limestone, probably from the channel margins), developed in the near E-W direction of transit. These layers also recover the presence of thick (up to 6 m) gypsium facies, which suggest the presence of a localChott, indicating a succession of humid and dry seasons.[13] Based on mesofossils, local vegetation was apparently dominated by ferns, cycads and conifers.[13] Apart fromBerberosaurus,Tazoudasaurus and a large-bodied theropod of uncertain affinities, a possibleCoelophysidae with juvenile & adult specimens and a small sauropod have been recovered from Acforcid, E ofDemnate, as well Gravisaurian (Tazoudasaurus?[15]) remains at the E of Azilal village, Medium-Sized Sauropod remains at Mizaguène Hill (SW Azilal) and indeterminate Dinosaur remains from other locations around Azilal and Demnate.[16]
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