Japonia barbata (L. Pfeiffer, 1855) Figures 4A-B, 46A

Cyclostoma (Leptopoma) barbatum L. Pfeiffer, 1855: 104-105.

Type locality.

"Borneo, Sarawak".

Material examined.

Gunung Doya: ME 0817, ME 8903, ME 9092, ME 9668. Gunung Kapor: ME 0737, ME 0780, ME 0784, ME 2949, ME 8069, ME 8490, ME 8768, ME 8783, ME 9047, ME 9609, ME 9841. Lobang Angin: ME 0791, ME 9083, ME 9134, ME 9275. Gunung Batu: ME 0783, ME 0796, ME 0800, ME 8808. Gunung Sebayat: ME 8008. Kampung Bunga Rampai: ME 0833, ME 0834. Kampung Padang Pan: ME 6668.

Distribution in Borneo.

Sarawak: Kuching, Samarahan, Serian, Sibu, and Mukah divisions. Endemic to Borneo.

Remarks.

It differs from other Bornean Japonia species by the following combination of characters: more depressed medium-sized shell with wide umbilicus, last whorl with distinctly keeled periphery, with long, deciduous, slender, feather-like periostracal hairs along the first peripheral ridge and below the periphery. Shells of different local populations may vary: shells from near Jambusan have a smooth surface with very faint lirae; shells from near Lobang Angin have a distinctly keeled periphery (Fig. 4B); shells from non-limestone areas usually have a somewhat rounded periphery (Fig. 4A). Japonia similis (E. A. Smith, 1893) differs by having a larger, high spired shell with moderately wide umbilicus. Living snails were observed foraging among leaf litter and plant debris near the cliff in lowland limestone forest.