Acamptodaphne Shuto 1971

Genus Acamptodaphne Shuto, 1971

Type species: Pleurotomella biconica Schepman, 1913

Remarks: Shuto (1971) proposed Acamptodaphne as a subgenus of Cryptodaphne to allocate the Recent Indonesian Pleurotomella biconica Schepman, 1913, a peculiar species which differs from Cryptodaphne species in having a more broadly biconic shell with gradually tapering base and relatively well developed axial sculpture on all teleoconch whorls. Furthermore, both Schepman (1913) and Shuto (1971) reported the presence in P. biconica of a conspicuous ornamentation of numerous collabral growth lines particularly evident on sutural ramp (“ rather strong, nearly rib-like, much curved, raised striae in the excavation ” Schepman 1913: p. 444). The discovery of two undescribed species that appear to be congeneric with P. biconica and are morphologically divergent from Cryptodaphne pseudodrillia, type species of the genus Cryptodaphne, suggests that Acamptodaphne be considered worthy of full generic rank. According to Shuto (1971) the anal sinus of P. biconica is deeper and narrower than that of “typical” Cryptodaphne species but his statement is in obvious contrast with the original description of the species provided by Schepman (1913). Furthermore, the anal sinus features of both species here discussed basically conform to those of Cryptodaphne (figs. 1K and 1R). In shell outline, Acamptodaphne species may resemble miniature members of fossil genera Austrotoma Finlay, 1926 or Pseudotoma Bellardi, 1875 (=Acamptogenotia Rovereto, 1899) but species belonging to the latter genera have very different protoconch features (large and conical consisting of 3–5 whorls initially smooth, subsequently sculptured by spiral cords).