Taxon classification Animalia Stylommatophora Trochomorphidae

Genus Trochomorpha Albers, 1850

Trochomorpha Albers, 1850: 116; Albers in Albers & Von Martens, 1860: 60.

Diagnosis for the Sabah species.

Shell rather small to medium-sized, (pale) yellowish green to (yellowish) brown, without any colour patterns, or with lighter or darker streaks following the growth lines; low-conical with flat or slightly convex sides, apex protruding or not. Radial sculpture above the periphery distinct, consisting of riblets or irregularly spaced, raised growth lines locally causing a coarse, irregular wrinkling. Spiral sculpture distinct, consisting of threads which are highest or nodular where crossing the radial sculpture, lower or even absent elsewhere. Umbilicus closed, entirely covered by an extension of the parietal callus of the peristome.

Cross diagnosis.

Shares the closed umbilicus with Borneo Geotrochus . We keep the two separate, although the Sabah representatives of both genera have very similar shells. Sabah Trochomorpha is characterized by a coarser radial sculpture on the upper surface of the shell. The spiral sculpture overlies the radial sculpture, forming nodes where the two cross.

Remarks.

Possibly, the protoconch with radial riblets can be added to the diagnostic set distinguishing between Borneo Geotrochus and Trochomorpha . Unfortunately, we could not check this for all Borneo Trochomorpha species.

We provide a review of the Sabah species of Trochomorpha .