Article: Origin, evolution and systematics of the Cretaceous ammonoid Spathites

Spathites Kummel and Decker, 1954. a predominantly early to mid-Turonian genus common in Tethyan regions of both the Old and New Worlds, is a key genus in the early radiation of the Mammitinae (of which the Metoicoceratinae and Fallotitinae are shown to be synonyms). Spathitoides Wiedmann, I960 is a strict synonym and Jeanrogericeras Wiedmann, 1960 (of which Faltotites Wiedmann, i960 is a synonym) no more than subgenerically distinct. The genus evolved from Metoicoceras; a succession is demonstrated from S. (Jeanrogericeras) to S. (Spathites). Mammites is an early offshoot from the former subgenus, whilst the Coniacian Buchiceras, previously referred to the Tissotiidae, is a direct descendant of the S. (S.)rioensis Powell to S. (S.) chispaensis Kummel and Decker to S. (5.) puercoensis (Herrick and Johnson) lineage.