Record details

    On the Turonian origin of the Goniocamax-Belemnitella stock (Cephalopoda, Coleoidea)
    Košťák, Martin
Publication type
    článek v periodiku
Source title - serial
    Roč. 45, č. 1
Thesaurus term
    evolutionary lineage
    Upper Cretaceous
Abstract (in english)
   A new subgenus within the genus Goniocamax, Progoniocamax nov. subgen., is described. It includes the Late Turonian-Early Coniacian species "Actinocamax" surensis Naidin and Actinocamax intermedius Arkhangelsky. The new subgenus represents a transition between the genera Praeactinocamax and Goniocamax. It occurs in the Central Russian Subprovince. From a geographical point of view, it indicates the origin of the Goniocamax-Belemnitella stock to be situated in the Russian Platform (Central Russian Subprovince, East European Province) during the Late Turonian. The origin of the Upper Cretaceous belemnitellid Goniocamax Naidin, and consequently the Belemnitella-stock, is explained herein by the deepening of the pseudoalveolus and the gradual calcification of the anterior part of the rostrum. The occurrence of the so-called "bottom [base] of ventral fissure", a major morphological feature known in the later belemnitellids (Goniocamax, Gonioteuthis, Belemnitella), the enlarging of the ventr
   al fissure, and the calcification of its surrounding area, enabled a gradualistic increase of the rostra within the Progoniocamax-Goniocamax-Belemnitella evolutionary lineage.
    UK Praha, Přírodovědecká fakulta
Contributor code
    UK, PřF
Source format
Import date
    27. 4. 2014