Microcystina appendiculata (Von Moellendorff, 1893)

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 : 37-40

Taxon classification Animalia Stylommatophora Ariophantidae

Microcystina appendiculata (Von Moellendorff, 1893) Figure 34

Lamprocystis appendiculata Von Moellendorff, 1893: 72. Type from Philippines, Leyte.

Microcystina lissa nomen nudum, Clements et al. 2008: 2761-2762; Schilthuizen et al. 2013: online supplementary data.

Microcystina sp. “BO-03”, Schilthuizen et al. 2002 a: 257-258; Schilthuizen et al. 2002b: 37, 41-42; Schilthuizen and Vermeulen 2003: 96.

Examined material from Sabah.

Interior Province. Sepulut valley, Batu Punggul (leg. J.J. Vermeulen, V 1972); Batu Temurung (leg. J.J. Vermeulen, V 8042); Bukit Tinagas, East end of Batu Punggul limestone (leg. J.J. Vermeulen & M. Schilthuizen, V 7628; leg. M. Schilthuizen, BOR/MOL 1102). Sandakan Province. Kinabatangan valley, Batu Keruak 2 near Sukau (leg. J.J. Vermeulen & M. Schilthuizen, V 9789; leg. M. Salverda & H. van Oosten, BOR/MOL 1348); Batu Mawas (leg. M. Schilthuizen, BOR/MOL 1333; leg. T.S. Liew & M. Schilthuizen, BOR/MOL 1970, BOR/MOL 2006); Batu Materis (leg. M. Schilthuizen, BOR/MOL 1330; leg. T.S. Liew & B. Elahan, BOR/MOL 2095, BOR/MOL 2127); Batu Pangi (leg. J.J. Vermeulen & M. Schilthuizen, V 9669); Batu Tai (not Bod Tai) near Gomantong (leg. J.J. Vermeulen & M. Schilthuizen, V 9596; leg. T.S. Liew & B. Elahan, BOR/MOL 1927); Batu Tomanggong Besar (leg. M. Schilthuizen, BOR/MOL 1125, BOR/MOL 1332; leg. T.S. Liew & B. Elahan, BOR/MOL 2264, BOR/MOL 2295); Batu Tomanggong Kecil (leg. J.J. Vermeulen & M. Schilthuizen, V 9687; leg. T.S. Liew & B. Elahan, BOR/ MOL 2037, BOR/MOL 2065); Gomantong Hill 30 km South of Sandakan (leg. J.J. Vermeulen & H. Duistermaat, V 1630; leg. A. van Til, BOR/MOL 3267, BOR/MOL 3282; leg. T.S. Liew & J.P. King, BOR/MOL 3648); Hill Sg. Resang (leg. M. Schilthuizen, BOR/MOL 1335, BOR/MOL 3612); Unnamed hill near Sukau Police Station (leg. T.S. Liew & B. Elahan, BOR/MOL 2198). Segama valley, North end of limestone ridge on East bank Tabin River (leg. J.J. Vermeulen & M. Schilthuizen, V 7781). Tawau Province. Batu Baturong c. 50 km W.S.W. Lahad Datu (leg. J.J. Vermeulen & H. Duistermaat, V 1856); North slope (leg. J.J. Vermeulen, V 7599). Danum Valley (leg. H.A. Rutjes, BOR/MOL 1105; leg. M. Schilthuizen, BOR/MOL 1103, BOR/MOL 1110; leg. UMS students, BOR/MOL 1108; leg. T. Kimsin & H.N. Chai, BOR/MOL 1212). Gua Madai c. 40 km S.S.W. of Lahad Datu (leg. J.J. Vermeulen & H. Duistermaat, V 1722); N.E. End (leg. J.J. Vermeulen, V 7698). Segama valley, hill N.W. of crossing road Sandakan-Lahad Datu with the Segama River (leg. J.J. Vermeulen & H. Duistermaat, V 1695); ‘Kirk’s Cave’ 8 km North of Lahad Datu (leg. J.J. Vermeulen, V 1221); limestone hill on North bank Segama River, near bridge of road Sandakan to Lahad Datu (leg. J.J. Vermeulen, V 7502); Sabahmas Cave (leg. J.J. Vermeulen, V 7457, BOR/MOL 1109); Tabin Wildlife Reserve (leg. M. Schilthuizen, BOR/MOL 1106; leg. J.J. Vermeulen & M. Schilthuizen, BOR/MOL 1104). Semporna area, Bukit Tengkorak, 5 km South of Semporna (leg. M. Schilthuizen & A.S. Cabanban, V 12745, BOR/MOL 3563); Segarong Hills, Batu Tengar, 25 km E.S.E. of Kunak (leg. J.J. Vermeulen & H. Duistermaat, V 1821); Segarong Hills, Bukit Pababola, 25 km E.S.E. of Kunak (leg. J.J. Vermeulen & H. Duistermaat, V 1766). Tawau Hills N.P., path up to Bukit Bombalai (leg. J.J. Vermeulen, V 13163). West Coast Province. Crocker Range N.P., km 54 marker on the road Kota Kinabalu-Tambunan, Gunung Mas (leg. J.J. Vermeulen & M. Schilthuizen, V 9760).

Description.

Shell very small, thin, somewhat translucent, brown, lenticular; spire slightly to moderately elevated, conical with a rounded apex. Surface glossy. Whorls slightly convex. Protoconch with 6-10 very fine, well-spaced, continuous, shallow spiral grooves. Teleoconch: very fine, moderately to widely spaced, continuous, shallow, rather vaguely outlined spiral grooves on the top whorls, in adults usually absent on the last whorl above the periphery, but more frequently present, more densely placed, below the periphery. Spiral sculpture rarely entirely absent. Radial sculpture teleoconch: inconspicuous growth lines, a few irregularly spaced, very slight grooves. Umbilicus partly or entirely covered by a minute, semi-elliptic to triangular spur protruding from the columellar corner of the peristome; this spur often less conspicuous in juveniles. Dimensions: Height up to 1.9 mm; width up to 3.3 mm; diameters of the first three whorls 0.5-0.6 mm, 0.9-1.2 mm, 1.5-1.9 mm respectively; number of whorls up to 4 3/4; height aperture up to 1.3 mm; width aperture up to 1.9 mm.

Habitat in Sabah and distribution.

Primary and secondary forest on limestone and sandstone soil, up to 1400 m alt. Sabah: common in East Sabah, scattered localities in West Sabah. Distribution: Philippines (Palawan, Leyte).

Cross diagnosis.

The only Sabah species within group 2 of Microcystina with a peristome extension covering the umbilicus. Similar to Microcystina planiuscula , but with less rapidly expanding whorls, and with a finer spiral striation. Juveniles with an inconspicuous spur on the columellar side of the peristome can be distinguished from Microcystina physotrochus by the lack of radial riblets on the protoconch and by with the flat, not convex, sides of the spire.

Microcystina cavernae Godwin Austen, 1891, from Sarawak, has a shell of similar shape and colour; it differs in lacking the columellar spur.