Microcystina sinica Von Moellendorff, 1885

Vermeulen, Jaap J., Liew, Thor-Seng & Schilthuizen, Menno, 2015, Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species, ZooKeys 531, pp. 1-139 : 33-37

Taxon classification Animalia Stylommatophora Ariophantidae

Microcystina sinica Von Moellendorff, 1885 Figure 27, 31

Microcystina sinica Von Moellendorff, 1885: 386; Clements et al. 2008: 2761-2762; Liew et al., 2010: Appendix S1 in online Supporting Information; Schilthuizen et al., 2011: 5; Schilthuizen et al. 2013: online supplementary data. Type from China, Guangdong Province, Shiu Heng Hap.

Examined material from Sabah.

Interior Province. Upper Padas valley, Matang River South of Long Pasia (leg. J.J. Vermeulen, V 9813). Tenom (leg. M. Schilthuizen, BOR/MOL 3349). Crocker Range N.P., West of the km 10 marker on the road Tambunan-Ranau, Mahua Waterfall (leg. J.J. Vermeulen & M. Schilthuizen, V 9745). Sepulut valley, Gua Pungiton (leg. J.J. Vermeulen & M. Schilthuizen, V 7549); Gua Sanaron (leg. J.J. Vermeulen & M. Schilthuizen, V 8071). Kudat Province. Balambangan Island, Kok Simpul (leg. J.J. Vermeulen & M. Schilthuizen, V 9527, V 9515); South end, Batu Sireh (leg. J.J. Vermeulen & M. Schilthuizen, V 9565; leg. T.H. Liew, Sazilin & Ramlan, BOR/MOL 3690). Banggi Island, South end, Karakit Hill (leg. J.J. Vermeulen, V 1465; leg. J.J. Vermeulen & M. Schilthuizen, V 9501, V 9466; leg. M.A. Rahman, BOR/MOL 1127). Sandakan Province. Kinabatangan valley, Batu Batangan (leg. M. Schilthuizen, BOR/MOL 2347, BOR/MOL 2348); Batu Tai (not Bod Tai) near Gomantong (leg. J.J. Vermeulen & M. Schilthuizen, V 9579). Tawau Province. Gua Madai c. 40 km S.S.W. of Lahad Datu (leg. J.J. Vermeulen & H. Duistermaat, V 13457); N.E. End (leg. J.J. Vermeulen, V 7699; leg. M. Schilthuizen & A.S. Cabanban, BOR/MOL 3574). Segama valley, ‘Kirk’s Cave’ 8 km North of Lahad Datu (leg. J.J. Vermeulen, V 1220). Semporna area, Segarong Hills, Batu Tengar, 25 km E.S.E. of Kunak (leg. J.J. Vermeulen & H. Duistermaat, V 13460); Bukit Pababola, 25 km E.S.E. of Kunak (leg. J.J. Vermeulen & H. Duistermaat, V 1769). Semporna Islands Park: Pulau Bod Gaya (leg. M. Schilthuizen & A.S. Cabanban, V 12744) (leg. T.S. Liew, Abdul & Ladja, BOR/MOL 4723, BOR/MOL 4741, BOR/MOL 4751, BOR/MOL 4762, BOR/MOL 4776, BOR/MOL 4790, BOR/MOL 4803, BOR/MOL 4816, BOR/MOL 4841, BOR/MOL 4857, BOR/MOL 4876, BOR/MOL 4886, BOR/MOL 4898, BOR/MOL 4927, BOR /MOL 4937, BOR/MOL 4949, BOR/MOL 4958); Pulau Bohay Dulang (leg. M. Schilthuizen & A.S. Cabanban, V 12743, BOR/MOL 3535; leg. T.S. Liew, BOR/MOL 4608, BOR/MOL 4621, BOR/MOL 4645, BOR/MOL 4656, BOR/MOL 4669; leg. T.S. Liew & M. Ruf, BOR/MOL 4696, BOR/MOL 4710); Sebangkat Island (leg. T.S. Liew, Abdul & Ladja, BOR/MOL 4993); Selakan Island (leg. T.S. Liew, BOR/MOL 5005, BOR/MOL 5340); Tetagan Island (leg. T.S. Liew, Abdul & Ladja, BOR/MOL 5021, BOR/MOL 5029). West Coast Province. Kinabalu N.P., Poring Hot Springs, along path to waterfall (leg. J.J. Vermeulen, V 13005); Serinsim (leg. M. Schilthuizen, BOR/MOL 3102). Pulau Tiga in Kimanis Bay (leg. J.J. Vermeulen, V 11347). Mantanani Kecil Island (leg. T.H. Liew, BOR/MOL 3734).

Description.

Shell minute, thin, somewhat translucent, pale yellowish to pale corneous, lenticular; spire moderately elevated, conical with a rounded apex. Surface moderately glossy, or with a silky shine. Whorls moderately convex. Protoconch with a fine, moderately spaced spiral striation consisting of rows of minute pits (barely visible at 40 times magnification) which are arranged in a reticulate pattern, sometimes traces of radial riblets (barely visible at 40 times magnification). Teleoconch: Spiral sculpture sometimes approx. absent or very fine (just visible at 40 times magnification), rather widely spaced, continuous, shallow, rather sharply outlined grooves present locally or over the entire shell. Radial sculpture teleoconch: inconspicuous growth lines, next to these inconspicuous to distinct, well-spaced to densely placed shallow grooves, often at irregular intervals. Umbilicus closed, or open and very narrow; columellar side of the peristome somewhat thickened but not covering the umbilicus; umbilical region slightly concave. Dimensions: Height up to 1.1 mm; width up to 1.7 mm; diameters of the first three whorls 0.3-0.5 mm, 0.5-0.8 mm, 0.8-1.3 mm respectively; number of whorls up to 4 18; height aperture up to 0.9 mm; width aperture up to 0.9 mm.

Habitat in Sabah and distribution.

Primary and secondary forest, coastal woodland on limestone, sandstone and volcanic bedrock, up to 1100 m alt. Elsewhere also in more severely degraded environments such as Imperata grass fields. Sabah: rather common in East Sabah, scattered localities in West Sabah. Also in Sarawak; Kalimantan. Distribution: widespread, from South China to Java; Eastwards to Irian Jaya.

Cross diagnosis.

Shares the small size, slowly expanding whorls, and pitted protoconch with Microcystina muscorum ; it differs by having a continuous spiral striation on the teleoconch. Shells entirely without spiral striation can be distinguished by the colour, as well as by the absence of shallow, widely spaced radial grooves, as occur in Microcystina muscorum .

Microcystina striatula and Microcystina gratilla have more rapidly expanding whorls, and have a flatter shell; Microcystina striatula also has a white shell.