|mhorn||Дата: Friday, 12.10.2012, 23:17 | Сообщение # 1|
|Quereilhac P. (2012) Creniceras crenatum (Bruguière, 1789) (Oxfordien inférieur) versus Creniceras crenatum (Bruguière, 1789) (Oxfordien moyen) // Revue de Paléobiologie, Genève, Vol.31. no.1. P.51-61. |
There are two species of Creniceras crenatum (Bruguière, 1789) with the same name both recognized in the Oxfordian (Jurassic) genus Creniceras (Ammonoidea, Ammonitinae, Oppeliidae, Taramelliceratinae). The first one is from the Lower Oxfordian (Cordatum Subzone) and the second one is from the Middle Oxfordian (Luciaeformis Subzone of the Transversarium Zone). After studying the various publications dealing with these species, it appeared many inconsistencies: imprecision in the stratigraphic position of the type-specimen which have disappeared, erroneous introduction date of the species (1789), imperfectly understood diagnosis and approximate assigning to one or the other species by the authors. It appeared that one of these species have to be necessary renamed (here Creniceras boreki nov. sp., Cordatum Subzone of the Cordatum Zone, Lower Oxfordian) and the second one (from the Luciaeformis Subzone of the Transversarium Zone), which is also usually named C. crenatum should be attributed to the author who has provided reliable information regarding this ammonite (Oppel, 1863).
Middle Jurassic - Lower Cretaceous ammonites & aptychi