Species. This rare genus was long considered monospecific, with Umsinenoceras linguatuberculatum discovered at the Lower-Middle Albian boundary in Zululand (South Africa), near the Mzinene or Umsinene River, from which it takes its name. Specimens from Kennedy et al. (1979) range from 20 to 46.5 mm in diameter. In 2005, Medina and Riccardi defined Umsinenoceras cardielense in the Middle Albian of Patagonia (left image), a species initially described by Piatnitzky in 1938 as Kossmaticeras meseticum. According to them, the collected specimens, with diameters ranging from 17.6 to 53 mm, are distinct from U. linguatuberculatum by a less compressed section and less marked constrictions. In my opinion, these ammonites are very similar and maybe conspecific.
Distribution and age. This genus is found in South Africa and Argentina according to Wright (1996), which is not surprising since the southern extremities of America and Africa were contiguous during the Albian. In South Africa, all specimens come from the Mzinene Formation, for which Kennedy & Klinger (1975) provide a list of ammonites including Lyelliceras pseudo-lyelli and lyelli. These species indicate the equivalent of the Hoplites benettianus zone of the Anglo-Paris Basin, which covers the upper part of Lower Albian and the base of Middle Albian.