Article: Lower Cretaceous diplobelinid belemnites from the Anglo-Paris Basin
Re-evaluation of belemnites belonging to the suborder Diplobelina Jeletzky, 1965 has resulted in erection of the new genera Vectibelus (based on Conoteuthis vectensis Spath, 1939) and Chalalabelus (based on Conoteuthis renniei Spath, 1939). A specifically indeterminate representative of Chalalabelus is described from the Barremian of Speeton, England. The genera Vectibelus gen. nov. and Conoteuthis d'Orbigny, 1842 are characterized by thin, skin-like guards, which are different from the stout, adapically rounded guards of Chalalabelus gen. nov. and Diplobelus Zittel, 1868. C. dupiniana d'Orbigny, 1842 is redescribed on the basis of new material from the French and English Aptian. 'Conoteuthis' cantiana Spath, 1939 from the Albian of Folkestone, England is redescribed and assigned to the Central Russian genus Pavloviteuthis Shimansky, 1957. This genus is redescribed and interpreted as a morphologically conservative descendant of the unknown, early Late or Mid-Jurassic rootstock of the Diplobelina. This hypothetical rootstock is assumed to be derived from Coeloteuthis? ex gr. palliatus (Dumortier, 1869). Diplobelus is interpreted as an early offshoot of this rootstock and the direct ancestor of Chalalabelus. Conoteuthis and Vectibelus are interpreted as direct descendants of Pavloviteuthis, which are not directly related to other diplobeline genera.