9. Serina soluta, synonymous name Serina soluta stenochila (Möllendorff, 1901)

Figs. 5 J–K, 7; Tables 1, 3

Buliminus (Serina) solutus stenochilus Möllendorff, 1901: 362.

Buliminus (Serina) solutus stenochilus—Kobelt, 1902: 863.

Ena (Serina) solutus stenochilus—Yen, 1938: 442.

Serina soluta stenochila— Yen, 1939: 87, pl. 8, fig. 22; Chen, Zhou, Luo & Zhang, 2003: 442.

Type locality. Tal des Tung (Sichuan).

Material examined. SMF-42048: Lectotype. SMF-42049: 3 paralectotypes (Yen, 1939: 87) (All lectotypes / paralectotypes in this study were defined by Yen, 1939. It should be noticed that the “ paralectotype ” were written as “paratypoide” by Yen, 1939).

Distribution. Sichuan (type locality).

Diagnosis. Shell fusiform; with the most swollen part occurred at penultimate whorl. Suture simple. Last whorl gradually ascending towards aperture; rounded at periphery. Aperture separated from body whorl; not armed; not duplicate.

Shell. Fusiform; with apex not abruptly pointed; dextral; with the most swollen part occurred at penultimate whorl. Growth lines fine and clear. Whorls convex. Postnuclear whorls smooth. Suture simple. Last whorl gradually ascending towards aperture; rounded at periphery; abaperturally indistinctly with a rugate region with crowded and/or thickened growthline-like folds. Aperture wavy; subcircular; vertical; completely separated from body whorl; not armed. Aperture not duplicate. Peristome and parietal callus almost completely fusing except for a channel at upper insertion of peristome. Reflexed part of peristome straight and not curved backward. Columellar margin reflexed. Columella arched. Umbilicus narrowly open. Shell uniformly brown. Aperture brownish white. Measured specimens: SMF-42048, SMF-42049: 4 shells.

Taxonomic remarks. S. soluta stenochila does not differ from the S. soluta soluta and S. soluta inflata by the less stretched out lip as diagnosed in the original description (Möllendorff, 1901). The analysis of the measurements suggests, based mostly on the type specimens, the three subspecies are very weakly conchologically distinguishable (Fig. 7). Considering both the resemblance among the “subspecies” and their insufficient distribution information, we suggest that at the current state of knowledge the subspecies in this species are not tenable, the taxa should be regarded as synonyms of S. soluta.