Koninckioceratidae Hyatt 1900

Family Koninckioceratidae Hyatt, 1900 Fig. 14 Diagnosis Family of the superfamily Koninckioceratoidea with discoidal, subevolute to evolute conch. Whorl profile depressed oval without ventrolateral shoulder or umbilical margin. Dorsal whorl zone always very small. Shell surface usually not sculptured. Suture line is almost straight or with small lobes and saddles on the outer side of the whorl, with a rounded or funnel-shaped internal lobe. Siphuncle subcentral. Included genera Lophoceras Hyatt, 1893 (Viséan to Serpukhovian; 8 species). Koninckioceras Hyatt, 1884 [nomen dubium]. Koninckoceras Hyatt, 1900 [nomen nullum]. Millkoninckioceras Kummel, 1963 (Viséan to Kasimovian; 9 species). Remarks Nomenclatural problems within the Koninckioceratidae were discussed in detail by Kummel (1963). The simple morphology of the conch in the Koninckioceratidae is an obstacle to analysing the origin of the group. Based on the conch morphology, an origin from genera such as Thrincoceras seems possible. An alternative would be an origin from a gyroconic or an advolute ancestor.