Cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra & Indochina

The Tropical micro-landsnail of the genus Plectostoma exhibits a greater diversity in shell forms, largely due to the last whorl, which, in some species is coiled irregularly. The genus counts 79 species and occurs in Vietnam, Thailand, Peninsular Malaysia, Sumatra, and Borneo. Plectostoma can only be found in limestone outcrops, where the rock face is its major habitat. This work revises non-Borneo Plectostoma species, which are more diverse in their shell form than Bornean Plectostoma. As a result, 10 new Plectostoma species are described together with the existing 21 species, based on the redefined shell characters and genetic data. In addition, all the data of 31 species, namely, 62 references, 214 collections, 290 pictures, and 155 3D models, were simultaneously tagged and linked to each other. All the synthesised, semantic-tagged, and linked taxonomic information is made freely and publicly available online.

Contents:

Introduction.............................................................................................................. 4
Current issues in taxonomy................................................................................. 4
An overview of genus Plectostoma’s taxonomy history.......................................... 6
Current taxonomic status of Plectostoma from Indochina, Sumatra and Peninsular
Malaysia.............................................................................................................. 8
Materials and methods.............................................................................................. 8
Taxonomic data mining, storing and tagging (Appendix 1)................................. 8
Specimen repositories........................................................................................ 10
Establishing identity and revising the collection data......................................... 10
Species delimitation.......................................................................................... 12
Morphological analysis...................................................................................... 13
Conservation status assessment......................................................................... 28
Molecular phylogeny and COI barcoding......................................................... 28
Data resources......................................................................................................... 35
Results and discussion............................................................................................. 35
Taxonomic data depository and cybertaxonomy................................................ 35
Morphological analysis...................................................................................... 38
Conservation status assessment......................................................................... 38
Molecular phylogeny and COI barcoding......................................................... 38
Key to Peninsular Malaysia Plectostoma............................................................. 43
Taxonomy............................................................................................................... 45
Genus Plectostoma............................................................................................. 45
Plectostoma dindingensis sp. n...................................................................... 49
Plectostoma mengaburensis sp. n................................................................... 51
Plectostoma sinyumensis (Maassen, 2001)..................................................... 51
Plectostoma umbilicatum (van Benthem Jutting, 1952)................................ 53
Plectostoma siphonostomum (van Benthem Jutting, 1952)............................. 55
Plectostoma panhai (Maassen, 2001)............................................................ 56
Plectostoma christae (Maassen, 2001)........................................................... 57
Plectostoma crassipupa (van Benthem Jutting, 1952).................................... 60
Plectostoma tonkinianum (Dautzenberg & Fischer, 1905)............................ 61
Plectostoma whitteni sp. n............................................................................ 63
Plectostoma sciaphilum (van Benthem Jutting, 1952)................................... 64
Plectostoma senex (van Benthem Jutting, 1952)............................................ 65
Plectostoma turriforme (van Benthem Jutting, 1952).................................... 66
Plectostoma palinhelix (van Benthem Jutting, 1952)..................................... 68
Plectostoma retrovertens (Tomlin, 1938)....................................................... 69
Plectostoma ikanensis sp. n........................................................................... 71
Plectostoma kayiani sp. n.............................................................................. 73
Plectostoma davisoni sp. n............................................................................ 75
Plectostoma relauensis sp. n........................................................................... 76
Plectostoma kakiense (Tomlin, 1948)............................................................ 78
Plectostoma kubuensis sp. n.......................................................................... 79
Plectostoma laemodes (van Benthem Jutting, 1961)...................................... 80
Plectostoma salpidomon (van Benthem Jutting, 1952).................................. 82
Plectostoma kitteli (Maassen, 2002).............................................................. 83
Plectostoma klongsangensis (Panha, 1997)..................................................... 85
Plectostoma charasense (Tomlin, 1948)......................................................... 86
Plectostoma tohchinyawi sp. n....................................................................... 87
Plectostoma annandalei (Sykes, 1903).......................................................... 89
Plectostoma praeco (van Benthem Jutting, 1961).......................................... 90
Plectostoma tenggekensis sp. n....................................................................... 91
Plectostoma laidlawi (Sykes, 1902)............................................................... 93
Author contributions............................................................................................... 95
Acknowledgements.................................................................................................. 95
References............................................................................................................... 96
Appendix.............................................................................................................. 105