Italian Journal of Geosciences - Vol. 142 (2023) f.3

Redescription of Schizobrissus mauritanicus Pomel, 1885, on the basis of new topotypic material from the Lower Miocene of the Oran region (northwestern Algeria)

Mohamed Belkercha1, Fadila Yacef1, Bruno Ferré2, Mohamed Bendella3, Mustapha Bensalah4, Loïc Villier5 & Mansour Zaagane6
1Département des Sciences de la Terre et de l’Univers, Université Hassiba Benbouali de Chlef. Faculté de Génie civil et d’Architecture, Pôle Universitaire Ouled Fares, DZ-2010 Chlef, Algeria.
2Rue Guy de Maupassant, F-76800 Saint Étienne du Rouvray, France.
3Mohamed Ben Ahmed Oran 2 University, Laboratory of Basin Geodynamics and Sedimentary Balance, P.O. Box 1524, El M’Naouer, DZ-31000 Oran, Algeria.
4Laboratoire de Recherche n° 25, Université Abou-Bekr Belkaid, DZ-13000 Tlemcen, Algeria.
5Université Pierre & Marie Curie Paris VI, Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), F-75252 Paris CEDEX 05, France.
6University of Mascara, Mustapha Stambouli, Mascara, 29000 Algeria.
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Volume: 142 (2023) f.3
Pages: 411-425


Schizobrissus mauritanicus Pomel, 1885, is an extinct species of echinoids from the Lower Miocene of Algeria, indicated by Pomel (1885) as the type species of the genus Schizobrissus Pomel, 1869, but subsequent authors established Brissus cruciatus (Agassiz in Agassiz & Desor, 1847a) as type species. New collections within the type locality (Ben Abdelmalek Ramdane, formerly named Ouillis) allowed a careful redescription of S. mauritanicus by means of biometric measurements and thorough analysis of the oral plate architecture of these topotypical samples. Two morphological types differing by the elongation of the test and the dimensions of the plastronal area are documented. Synonymy of nominal Schizobrissus species are discussed. Since Schizobrissus mauritanicus is well defined, as well as its type locality, and given the ambiguities and disagreement of the scientific community on S. cruciatus, it is now appropriate to restore S. mauritanicus as the type species of the genus.


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