Microcystina Moerch , 1872

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: 27

publication ID

http://dx.doi.org/10.3897/zookeys.531.6097

publication LSID

lsid:zoobank.org:pub:C845838E-C912-4BD8-AB4E-07980F91959E

persistent identifier

http://treatment.plazi.org/id/50D9CF5F-68F5-12D0-133D-228C2B84BDF9

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ZooKeys by Pensoft

scientific name

Microcystina Moerch , 1872
status

 

Taxon classification Animalia Stylommatophora Ariophantidae

Genus Microcystina Moerch, 1872 

Nanina  subgenus Microcystina  Mörch, 1872: 311. Microcystina  ( Mörch) Godwin Austen, 1882 (1882-1888): 11.

Diagnosis for the Sabah species.

Shell minute or very small, thin, lenticular, inflated-lenticular to depressed-ovoid; spire almost flat to moderately elevated. Surface shiny or glossy. Sculpture very fine, hardly prominent. Umbilicus open but very narrow, to closed, often partly or entirely covered by a minute, triangular spur protruding from the columellar corner of the peristome; this spur lacking or inconspicuous in juveniles. Dimensions: Width of adult shells 1.7-3.6 mm.

Remarks.

The genus Microcystina  includes small (up to 3.6 mm wide) species with lenticular (depressed ovoid in Microcystina physotrochus  ) shells. Invariably, the shell surface seems smooth at a first impression, any sculpture present on the shells is very fine and inconspicuous. This distinguishes the smaller species of Microcystina  (particularly Microcystina sinica  ) from sympatric, yet undescribed Charopa  species ( Charopidae  ), which have lenticular, minute shells (width of adult shells 0.9-1.9 mm) with a much more conspicuous sculpture. In several Microcystina  species the umbilicus is partly or entirely covered by a minute, triangular spur protruding from the columellar corner of the peristome.

Borneo Macrochlamys  and Everettia  ( Ariophantidae  ), and Helicarion  ( Helicarionidae  ) may have similarly shaped shells, including the inconspicuous sculpture, but they are larger (width of adult shells 8 mm or more).

Placement of Microcystina  into the family Ariophantidae  follows Schileyko (2003).

We provide a review of the Sabah species of Microcystina  . We divide the genus into two informal groups.