A taxonomic correction after 140 years

Abstract

Abstract.-Waagen (1875) was the first who dealt with the Jurassic ammonites of Kutch based on detailed taxonomic work. In his monograph, he described among many species Perisphinctes spirorbis Neumayr, 1870 and P. aberrans Waagen, 1875 from the Callovian of Kutch, but the figures mentioned in the description did not correspond to the actual species. For P. spirorbis, the plate illustrated the holotype of an entirely different species (P. aberrans). On the other hand, P. spirorbis was illustrated as the lectotype of P. aberrans. Later, Spath (1924) introduced a new genus, Subgrossouvria, based on Waagen's P. aberrans as type species. He also erected another genus, Indosphinctes, and included P. spirorbis Waagen, 1875 within the synonymy of I. indicus (Siemiradzki, 1899). Spath (1931) was aware of wrong numbering of plates of Waagen's two species. But subsequent workers were ignorant of these taxonomic errors and continued to refer Waagen's wrong plate numbers. We have here described both the type specimens and provided diagnoses for Spath's two genera. We plead for this taxonomic correction in the incoming revised Treatise on Jurassic ammonites.

The taxonomic status of the genus Hubertoceras Spath: A new light on sexual dimorphism from the Callovian ammonites of Kutch, India

“…Spath (1931) only described Indosphinctes from the lower Callovian beds, and we recently discovered a distinct middle Callovian species. Indosphinctes is a large genus with evolute and compressed shell and smooth body chamber (Spath, 1931;Dutta and Bardhan, 2017;Figure 4.7). Thus Indosphinctes may be a contender for the macroconchiate counterpart of Hubertoceras.…”

“…Moreover, furcation of ribs takes place at the higher flank in Indosphinctes whereas secondaries originate nearly at the midflank in Hubertoceras. Septal suture of Hubertoceras is very simple while it is highly complex and ramified in the genus Indosphinctes (see Dutta and Bardhan, 2017, figure 2.2). Stratigraphically, Indosphinctes spans from the lower to middle Callovian where as Hubertoceras is from the middle to upper Callovian.…”