|mhorn||Дата: Wednesday, 31.07.2013, 21:44 | Сообщение # 1|
|Quereilhac P. (2013) Étude de l'espèce Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1830 ) (Oxfordien moyen, Zone à Transversarium) // Carnets de Géologie [Notebooks on Geology], Brest, Article 2013/05 (CG2013_A05), P.209-235. |
The species Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1830 ), discussed here, is certainly the most representative of the Transversarium Zone (Middle Oxfordian) in the Tethyan domain (Mediterranean Province). It appears in the Parandieri Subzone and seems to go extinct in the Stenocycloides Subzone (Late Oxfordian, base of the Bifurcatus Zone). It is abundantly represented in the ammonite populations and has a wide geographical range and has a wide geographical spread. Analysis shows that it is always associated with species referred to Ochetoceras (Ochetoceras) hispidum [M] (Oppel, 1863) and Glochiceras (Glochiceras) subclausum [m] (Oppel, 1863) ; many authors have long thought that it was a single species. A reading of I.C.Z.N. (4th edition, 1999) makes it clear that the publication date of the case and the author's name were incorrect: here they are corrected. These three "species" are thus here united under the name Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1830 ): macroconchs corresponding to the "morphs" canaliculatum and hispidum are polymorphic evolving from a narrow to a wide whorl cross section whereas the "morph" subclausum is a sexual dimorphic microconch.
Middle Jurassic - Lower Cretaceous ammonites & aptychi