Genus: Berberosaurus Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007

Classification: Dinosauria - Saurischia - Theropoda - Ceratosauria - Abelisauroidea

Etymology: Generic name is from the Berbers who live mainly in Morocco; “ sauros” is Greek for lizard.

Synonyms: none

Type species: B. liassicus Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007

Other Species: none

Diagnosis: as for the type species

Species: Berberosaurus liassicus Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007

Etymology: Specific name from Lias, referring to the statigraphic epoch of the specimen.

Synonyms: none

Holotype: Associated postcranial material housed in the Museum d’Histoire Naturelle de Marrakech, including a cervical vertebra (MHNM-Pt9); anterior part of the sacrum (MHNMPt23); the second left metacarpal (MHNM-Pt22); a right femur (MHNM-Pt19); the proximal end of the left tibia (MHNM-Pt21); the distal end of the right tibia (MHNM-Pt16); and the left fibula (MHNM-Pt20).

Referred Specimens: MHNM-To1– 218, the proximal end of a right femur.

Time: middle to late Early Jurassic (Pliensbachian-Toarcian).

Horizon: Upper bone-bed (“ Fossil locality B” of Allain et al., 2004) of the Toundoute continental series.

Location: Douar of Tazouda, near the village of Toundoute in the Province of Ouarzazate, High Atlas of Morocco.

Total length: ~ 5 m (subadult) and 6-7 m (adult).

Mass: 300-600 kg.

Diagnosis: Berberosaurus is characterized by the following unique combination of characters that nests the taxon among the abelisauroid ceratosaurs: highly pneumatic cervical vertebrae; anteroposteriorly short cervical vertebral centra with camerate internal structure; cervical neural spine anteroposteriorly short; ventral margin of sacral series strongly arched dorsally; transversely narrow sacral centra; proximal end of the second metacarpal deeply grooved ventrally; femoral anterior trochanter reaches proximally to mid-point of femoral head; large femoral trochanteric shelf; tibia with subtriangular distal profile; presence of an oblique ridge that proximally caps the medial sulcus of the fibula. Berberosaurus differs from Elaphrosaurus in: short cervical centra, pneumatic foramina on the cervical neural arch; from Ceratosaurus in: camerate structure of cervical vertebra, low and short neural spine of the cervical vertebra, femoral anterior trochanter reaches proximally to mid-point of femoral head; from Spinostropheus in: absence of the epipophysealprezygapophyseal lamina on the cervical neural arches, short cervical neural spine; from Abelisauria in: distal end of metacarpal with deep extensor pits; pronounced femoral trochanteric shelf (Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

Comments: The fossil record of abelisauroid carnivorous dinosaurs was previously restricted to Cretaceous sediments of Gondwana and probably Europe. The discovery of an incomplete specimen of a new basal abelisauroid, Berberosaurus liassicus, is reported from the late Early Jurassic of Moroccan High Atlas Mountains. Phylogenetic analysis recovers Ceratosauroidea and Coelophysoidea as sister lineages within Ceratosauria, and Berberosaurus as a basal abelisauroid. Berberosaurus is the oldest known abelisauroid and extends the first appearance datum of this lineage by about 50 million years. The taxon bridges temporal, morphological, and phylogenetic gaps that have hitherto separated Triassic to Early Jurassic coelophysoids from Late Jurassic through Cretaceous ceratosauroids. The discovery of an African abelisauroid in the Early Jurassic confirms at least a Gondwanan distribution of this group long before the Cretaceous (Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

The balance of these observations suggests that the holotypic specimen ofn Berberosaurus is a subadult that died prior to reaching skeletal maturity (Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

Berberosaurus is the oldest known abelisauroid, and it represents a considerable temporal range extension for a lineage whose other members are Neocomian or younger , except if the material from
Tendaguru, recently described by Rauhut (2005), is proved by a future phylogenetic analysis to be an abelisauroid. Its presence implies a previously unrecognized diversification of ceratosauroids by the Early Jurassic (Fig. 9). Berberosaurus essentially closes the stratigraphic gap separating coelophysoids and ceratosauroids, as predicted by cladistic phylogenetic hypothesis. Abelisauroids, and more especially Abelisauridae were used as key evidence for faunal exchanges between Gondwanan landmasses and between Gondwana and Europe, because their record was restricted to Late Cretaceous strata of the southern continents and probably Europe. Berberosaurus reveals that basal abelisauroids were already diversified by the Early Jurassic, and they were probably distributed between Africa, South America, Madagascar, India and Europe long before the Cretaceous and the fragmentation of Gondwana. This scenario is consistent with the pan-Gondwanan hypothesis suggested by previous authors, but with faunal exchanges among Gondwanan landmasses occurring between the Early Jurassic and the Early Cretaceous. It also suggests that fossils of basal abelisauroids should be present in Early Jurassic sediments across Pangea, given that Laurasia and Gondwana were still connected through that time. This discovery emphasizes how poorly known is the origin and early evolution of ceratosauroids, and highlights the importance of finding and describing new Early and Middle Jurassic theropod remains in order to document the evolutionary history of Theropoda across the Triassic-Jurassic faunal transition.(Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

Illustrations:
Right femur of Berberosaurus liassicus (MHNM-Pt19) in anterior (A), medial (B), posterior (C), and lateral (D) views. Abbreviations: atr, anterior trochanter; fh, femoral head; gtr, great trochanter; mep, medial epicondyle; sul, sulcus; tfc, tibiofibular crest; ts, trochanteric shelf; 4tr, fourth trochanter. Scale bar equals 5 cm (modified from Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

Phylogenetic relationships of Berberosaurus liassicus within Theropoda. Clade numbers: 1, Theropoda; 2, Neotheropoda; 3, Tetanurae; 4, Avetheropoda; 5, Spinosauroidea; 6, Ceratosauria; 7, Coelophysoidea; 8, Coelophysidae; 9, Ceratosauroidea; 10, Neoceratosauria; 11, Abelisauroidea (modified from Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

Stratigraphically calibrated phylogeny of Ceratosauria and basal Theropoda, based on the strict consensus tree of the current study. Clade numbers: 1, Theropoda; 2, Neotheropoda; 3, Tetanurae; 4, Ceratosauria; 5, Ceratosauroidea; 6, Neoceratosauria; 7, Abelisauroidea; 8, Abelisauria. Arcs indicate stem-names, solid circles indicate node-names. Black lines indicate known stratigraphic ranges and grey lines indicate inferred ghost lineages (modified from Allain, Tykoski, Aquesbi, Jalil, Monbaron, Russell, and Taquet, 2007).

References:
Allain, R., Tykoski, R., Aquesbi, N., Jalil, N.-E., Monbaron, M., Russell, D., and Taquet, P., 2007, An abelisauroid (Dinosauria: Theropoda) from the Early Jurassic of the High Atlas Mountains, Morocco, and the radiation of ceratosaurs: Journal of Vertebrate Paleontology, v. 27, n. 3, p. 610-624.

© Tetrapoda Database Roman Ulansky roman.ulansky@gmail.com or adios85@mail.ru