Crioceratites (Balearites) balearis

Hoedemaeker, Philip, 2013, Genus Pseudothurmannia Spath, 1923 and related subgenera Crioceratites (Balearites) Sarkar, 1954 and C. (Binelliceras) Sarkar, 1977 (Lower Cretaceous Ammonoidea), Revue de Paléobiologie 32 (1), pp. 1-209 : 25

ancestor of C. (B.) balearis . Crioceratites (Binelliceras)

begins close to, or at the base of, the Balearis Zone , and has its roots in the large group of species of Crioceratites with trituberculate main ribs on the inner whorls, especially in the group of C. sornayi Sarkar, 1955 , C. sornayi var. tuberculata Sarkar, 1955 and C. majoricensis Nolan, 1894 . Vermeulen (2004) introduced the name Davouxiceras for the group of Crioceratites with trituberculate main ribs, type species C. nolani Kilian, 1910 , but the present author hesitates to use this name, because he cannot yet judge whether this group of completely or partly trituberculate Crioceratites constitutes a monophyletic or a polyphyletic group (iterative origination). He suspects it to be an artificial species. Within Crioceratites (Binelliceras) , there also seems to be a gradual reduction of the fine uniform ribbing of the young stage in the course of the phylogeny of the subgenus.