Branneroceras PLUMMER et SCOTT, 1937

Dernov, Vitaly, 2022, Late Bashkirian Ammonoids From The Mospyne Formation Of The Donets Basin, Ukraine, Fossil Imprint 78 (2), pp. 489-512 : 506

Genus Branneroceras PLUMMER et SCOTT, 1937

T y p e s p e c i e s. Gastrioceras branneri SMITH, 1896 ; by original designation.

D i a g n o s i s. Genus of the family Schistoceratidae with subdiscoidal, evolute conch with moderate to wide umbilicus. Ornamented with prominent ribs on or adjacent to the umbilical shoulder. In widely umbilicate forms the ribs are long and more strongly developed than in the narrowly umbilicate forms; these ribs decrease in size and robustness until they become more like nodes. Ventral region ornamented by prominent sinuous transverse lirae with wider interspaces, forming rounded prominent ventral and lateral sinuses and corresponding salients between, crossed by finer longitudinal lirae, giving a cancellate appearance and commonly beaded where two sets of lirae cross. Suture line with narrow, inflated and attenuate ventral prongs that are separated from each other by a relatively broad secondary ventral saddle; the ventral saddle is more than half the height of the first lateral saddle. The first lateral saddle is broad and evenly rounded and the first lateral lobe is comparatively narrow, asymmetric and attenuate (after Gordon 1965, McCaleb 1968, Nassichuk 1975).

S p e c i e s i n c l u d e d. Br. branneri ( SMITH, 1896) , Texas ( USA); Br. hillsi NASSICHUK, 1975 , Canadian Arctic Archipelago ( Canada); Br. nicholasi NASSICHUK, 1975 , Canadian Arctic Archipelago ( Canada); Br. perornatum ( YIN, 1935) , Guangxi ( China); Br. reticulatum ( YIN, 1935) , Guangxi; Br. termierorum (KULLMANN in STEVANOVICH et KULLMANN, 1962), Kenadza Region ( Algeria); Br. triangularum SHENG, 1987 , Gansu ( China); Br. yohi ( YIN, 1935) , Guangxi ( China).

R e m a r k s. Branneroceras differs from Inzeroceras RUZHENCEV, 1974 by the more pronounced relief on the umbilical nodes, narrower ventral lobe and low median saddle; in addition, the umbilical lobe of Inzeroceras is displaced to the lateral face. Branneroceras is distinguished from Retites in long and narrow (longer than half the height of the first lateral saddle) ventral prongs. Branneroceras differs from Diadoloceras by the lack of triangular coiling of early whorls.

S t r a t i g r a p h i c r a n g e. Late Bashkirian (Gastrioceras-Branneroceras Genozone).