Some new and rare upper cretaceous ammonites from north-eastern Nigeria

Abstract

The following ammonites are described from north-eastern Nigeria: Placenticeras (Karamaites) cumminsi Cragin (Upper Cenomanian), Watinoceras aff. coloradoense (Henderson) (basal Turonian), Fikaites varicostatus gen. et sp. nov. (Upper Cenomanian), Rubroceras sp. (Upper Cenomanian), Kamerunoceras turoniense (d'Orbigny) (Lower-Middle Turonian boundary) and Eotissotia simplex Barber (Lower to? Middle Turonian). The genus Fikaites is probably derived from Eucalycoceras Spath and is one of a number of ammonites independently acquiring a vascoceratid type suture pattern during Late Cenomanian and Early Turonian times.