Parvanachis Radwin, 1968

Maintenon, Marta J., 2014, Taxonomic revision of the species of Parvanachis Radwin, 1968 (Gastropoda: Columbellidae) from the Gulf of Panama, Zootaxa 3753 (3), pp. 201-225 : 209

Parvanachis Radwin, 1968

Anachis (Parvanachis) Radwin, 1968: 145 –147 (type by original designation Buccinum obesum C.B. Adams, 1845 ).

Diagnosis. Shell small (3–8 mm long), globose fusiform, with dominant axial ridges and underlying spiral grooves. Spire generally flat-sided with incised sutures. Aperture edge thickened and denticulate, with a shallow posterior notch anterior to the suture. The radula is typical for columbellids, with sigmoid lateral teeth, having a triangular basal secondary lateral cusp with a strong hook toward the radular membrane. The female gonoduct has a short thin-walled vestibule, lacks a bursa copulatrix, has a single gland mass, and has a coiled gonopericardial duct and gonopericardial-pallial duct, both encased in muscle. The male gonoduct is typical for columbellids, but lacks the secondary seminal vesicle found in many species. The penis is simple in form with a long or short filament-like tip.

Remarks. Parvanachis has been usually considered either as a genus or as a subgenus of Anachis since its description. Keen (1971) still gave it subgeneric status. Radwin (1977a, 1977b) raised Parvanachis to a full genus in his papers on Western Atlantic columbellids, though was apparently thinking about this earlier, as he lists Parvanachis as a genus in a Festivus paper in 1974 but does not discuss it. His justification (1977b) was based on Parvanachis’ distinct shell and radular morphology. Lopes et al. (1971) referred Anachis obesa to Zafra A. Adams, 1860 , an Indo-Pacific taxon, and Faber (2004) similarly regarded Parvanachis as a subgenus of Zafra .