Pincerna thompsoni (Godwin-Austen, 1914)
Alycaeus (Cycloryx) thompsoni Godwin-Austen, 1914: 404, pl. 146, figs 3, 3a.
Alycaeus (Cycloryx) thompsoni - Gude 1921: 285.
Cycloryx thompsoni - Ramakrishna et al. 2010: 74.
Type locality.
“Munipur” .
Material examined.
Munipur, coll. Godwin-Austen, NHMUK 1903.7.1.2550 (1 syntype).
Remarks.
Entire shell somewhat weathered; protoconch matte; R1 regularly, densely ribbed, spiral striation not visible, but additional, lower radial lines present between the ribs; R2 very short, ca. five ribs, similar to those on R1 in density.
This species may be conspecific with P. graphicus var. dihingensis because there is only a slight difference in the density of ribbing (coarser and more oblique in thompsoni ). Pincerna thompsoni has a completely closed umbilicus, but due to the lack of large shell material we are unable to determine whether this represents individual variability or a stable character. Alternatively, the closed umbilicus may be a feature of more mature (more developed) specimens.