|mhorn||Дата: Saturday, 09.02.2013, 22:24 | Сообщение # 1|
|Pandey D.K., Alberti M., Fürsich F.T. (2012) Ammonites of the genus Perisphinctes Waagen, 1869 from the Oxfordian of Kachchh, western India // Revue de Paléobiologie, Vol.31. no.2. P.483-587. |
The majority of ammonites occurring in the Oxfordian rocks of the Kachchh Basin in western India belong to the genus Perisphinctes Waagen, 1869. Although these ammonites are closely related and share an overall similar morphology, they can be divided into several morphospecies based, for example, on their proportional dimensions, whorl section, and ornamentation. Most of these taxa have short stratigraphic ranges and therefore serve as excellent index fossils. In this publication more than 300 ammonites, collected from the Oxfordian succession of the Kachchh Basin, have been assigned to 43 taxa of the genus Perisphinctes. The material considerably refines the existing knowledge on ammonite taxonomy and biostratigraphy in the basin and promotes intercontinental correlation e.g., with the ammonite zonation of Europe. Nine ammonite levels have been identified, representing Early (Cordatum Zone), Middle (Plicatilis, Transversarium zones), and Late (Bifurcatus Zone) Oxfordian.
Middle Jurassic - Lower Cretaceous ammonites & aptychi