Biodiversity Data Journal : Taxonomy & Inventories
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Taxonomy & Inventories
The land snail fauna of Batu Kudik, isolated limestone outcrop near Simunjan, Sarawak, Malaysian Borneo (Mollusca, Gastropoda)
expand article infoJie Ying Lee‡,§, Nurul Syafiqah Nasir‡,§, Mohammad Effendi Marzuki§, Jaap J. Vermeulen|, Mohd Zacaery Khalik‡,§
‡ Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
§ Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| JK art and science, Lauwerbes 8 2318 AT, Leiden, Netherlands
Open Access

Abstract

Background

The present study provides a checklist of land snails collected from Batu Kudik, a small and isolated limestone outcrop in Simunjan, Sarawak. A total of 24 species of land snails, representing 18 genera and 14 families were recorded, including one newly-described subspecies. The most species-rich of the families in Batu Kudik are Diplommatinidae (17%) and Chronidae (17%) with four recorded species from each of the families. Based on our analysis, Plectostoma wallacei kudikense subsp. nov., Opisthostoma javanica and Georissa pyrrhoderma were identified as the most abundant land snails at this isolated outcrop, whereas Diplommatina onyx and Everettia minuta were recorded as the least abundant. All of the land snails at Batu Kudik were exclusively found sheltered between limestone boulders, underscoring the critical role of this outcrop as their refuge for survival. Consequently, conserving this biodiversity-rich limestone area becomes paramount to prevent the local extinction of these land snail species and possibly other organisms that depend on the unique attributes of the limestone for their survival. We also provide detailed descriptions of Plectostoma wallacei kudikense, a new subspecies of the genus Plectostoma which is endemic to Batu Kudik.

New information

A description of a new subspecies Plectostoma wallacei kudikense subsp. nov.

Keywords

land snails, limestone, Sarawak, species abundance

Introduction

Karst areas (areas on limestone bedrock) of Borneo are well-known for their rich and varied biodiversity (Clement et al. 2006), including site-endemic and local-endemic species (Vermeulen and Whitten 1999). Liew et al. (2021) has charted the majority of all known limestone outcrops in Sabah and Sarawak (Malaysian Borneo) to facilitate land-use planning that minimises the impact of limestone quarrying.

Batu Kudik (1°12'35.38"N, 110°51'38.23"E) (see Fig. 1) is a cluster of two small limestone outcrops which are 5835 m2 and 497 m2, respectively. It is an isolated limestone outcrop which is similar to Bukit Sarang. Unfortunately, Batu Kudik limestone outcrops are not documented in the recent publication of Liew et al. (2021). Therefore, it has come to our attention after the publication of Vermeulen and Junau (2007) and Liew et al. (2021). We investigated its biodiversity making use of land snails (Mollusca Gastropoda) as an indicator group, since the recent publications have provided overviews of the local fauna (Vermeulen and Junau 2007, Marzuki et al. 2021, Vermeulen and Liew 2022) and, also, the land snails are often considered as limestone-bound endemic organisms.

Figure 1.

Batu Kudik limestone outcrop surrounded by oil palm plantation.

aEast side of the outcrop;  
bWest side of the outcrop;  
cThe remaining limestone inhabitants in between limestone boulders;  
dDried, exposed outer limestone wall surfaces.  

Batu Kudik is of interest because it is approximately 49 km distant from the nearest limestone outcrop, Gunung Silabur and such spatial isolation is a driver of speciation amongst limestone-bound fauna. Additionally, Batu Kudik lies in between the limestone ranges south of Kuching (to the West) and Bukit Sarang (to the East) (see Fig. 2). Marzuki et al. (2021) found that the land snail fauna of a small part of the Kuching ranges (south of Bau) includes 47 out of 122 (38.5%) species, endemic to the Kuching ranges; the fauna of Bukit Sarang includes 26 out of ca. 83 (31.3%) species, endemic to the hill.

Figure 2.  

Limestone outcrops in the State of Sarawak, Malaysian Borneo. The red polygon represents the individual limestone outcrops, while the blue polygons around the limestone outcrop are background to emphasise outcrops that are too small to be seen on the map. The map is adapted from Liew et al. (2021). The green-coloured dot signifies the limestone outcrops of Bukit Sarang, the purple dot represents the limestone outcrops of Batu Kudik and the orange dot indicates the Gunung Silabur limestone outcrops.

Therefore, this study presents the first checklist of the faunistic composition of land snails at Batu Kudik. Through this study, we elucidated the species richness and species abundance of the surrounding area. In addition, we describe a new subspecies namely, Plectostoma wallacei kudikense.

Materials and methods

Two separate surveys were conducted in October 2021 and April 2022 at Batu Kudik. The surveys were conducted around the limestone outcrops by a team of four individuals, with each survey taking a duration of at least four hours. Batu Kudik limestone outcrop is surrounded by an oil-palm plantation. During the surveys, live and empty shells were searched and collected, which consisted of sifting through leaf litter, scanning rock and wood surfaces and the surrounding karst vegetation. Top soils and leaf litters were collected to extract snails and empty shells via floatation methods. Then, shells were extracted from soil samples by manually picking up the shells and identifying them under a stereomicroscope. All specimens were identified to species level and the collected materials were deposited at Universiti Malaysia Sarawak (MZU.MOL) and the private collection (ME) of the third author. The identification of the species was based on the original description or a more recent publication of the respective species. The shell size classification were based on Vermeulen and Whitten (1998), which indicates the size of the microsnails are less than 5 mm, medium-sized snails range between 5 and 20 mm and the large snails are more than 20 mm in size.

Then, representatives of each of the species were photographed using a modified digital camera. For the setup and photoshoot, Capture One 15.0.0 was used for stack imaging. After that, the images were uploaded to Helicon 8.2.0 to create a composite image of the representative shell. The final images were scaled and cropped by using Adobe Photoshop 24.1 before importing into GIMP 2.10.32 to remove the background, sharpened and the images arranged onto a plate. The shell surfaces of representative paratype of Plectostoma wallacei kudikense were coated with platinum for detailed examination in scanning electron microscope (SEM). For the analysis, species abundance was computed using RStudio (Team 2015) with R version 3.3.0. Species abundance percentage was calculated by dividing the number of individuals of a particular species by the total number of individuals and then converting the result to a percentage.

Taxon treatment

Plectostoma wallacei kudikense Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023 ssp. nov.

Materials   Download as CSV 
Holotype:
  1. family:
    Diplommatinidae
    ; genus:
    Plectostoma
    ; scientificNameAuthorship:
    Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023
    ; country:
    Malaysia, Sarawak
    ; stateProvince:
    Samarahan
    ; locality:
    Batu Kudik, small isolated limestone outcrop near Sungai Simunjan Kiri, approx. 14 miles SE Simunjan
    ; individualCount:
    1
    ; catalogNumber:
    MZU.MOL.21.17
    ; occurrenceID:
    23E34535-FC8A-593B-942E-A4366A7F872C
Paratypes:
  1. family:
    Diplommatinidae
    ; genus:
    Plectostoma
    ; scientificNameAuthorship:
    Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023
    ; country:
    Malaysia, Sarawak
    ; stateProvince:
    Samarahan
    ; locality:
    Batu Kudik, small isolated limestone outcrop near Sungai Simunjan Kiri, approx. 14 miles SE Simunjan
    ; individualCount:
    18
    ; catalogNumber:
    MZU.MOL.22.05
    ; occurrenceID:
    87105945-FEFE-53DE-A2C7-BDF2C6134ED9
  2. family:
    Diplommatinidae
    ; genus:
    Plectostoma
    ; scientificNameAuthorship:
    Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023
    ; country:
    Malaysia, Sarawak
    ; stateProvince:
    Samarahan
    ; locality:
    Batu Kudik, small isolated limestone outcrop near Sungai Simunjan Kiri, approx. 14 miles SE Simunjan
    ; individualCount:
    13
    ; catalogNumber:
    ME 13360
    ; occurrenceID:
    97B4820E-0338-5337-83C4-050FE8F15112
  3. family:
    Diplommatinidae
    ; genus:
    Plectostoma
    ; scientificNameAuthorship:
    Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023
    ; country:
    Malaysia, Sarawak
    ; stateProvince:
    Samarahan
    ; locality:
    Batu Kudik, small isolated limestone outcrop near Sungai Simunjan Kiri, approx. 14 miles SE Simunjan
    ; individualCount:
    23
    ; catalogNumber:
    ME 13895
    ; occurrenceID:
    1942E36B-DD50-5CB5-817F-E4C206B5B5C1
Other material:
  1. family:
    Diplommatinidae
    ; genus:
    Plectostoma
    ; scientificNameAuthorship:
    Lee, Nasir, Marzuki, Vermeulen & Khalik, 2023
    ; country:
    Malaysia, Sarawak
    ; stateProvince:
    Samarahan
    ; locality:
    Batu Kudik, small isolated limestone outcrop near Sungai Simunjan Kiri, approx. 14 miles SE Simunjan
    ; individualCount:
    1773
    ; catalogNumber:
    MZU.MOL.21.20
    ; occurrenceID:
    EA7B72FA-229B-5865-ADCB-C420F3C288B7

Description

Shell: spire conical with slightly convex sides. Apex is not or slightly oblique. Whorls 6 ½, convex; last whorl rounded or slightly angular at the periphery. Tuba free from the spire, abruptly narrowed towards the constriction, rounded below. Teleoconch: radial ribs on the spire are rather closely spaced (6 ribs/0.5 mm on penultimate whorl), slightly sinuous, often with a shallowly concave projection halfway, abrading to a not or slightly sinuous scar; those on the tuba widely spaced (6-12 ribs/0.5 mm half-way), not or hardly sinuous below (Fig. 3). Spiral striation present, distinct. Aperture: hardly tilted with regard to the coiling axis, circular to elliptic peristome simple or inconspicuous double, distant from the spire; outer peristome hardly spreading beyond the inner; inner peristome not protruding from the outer, widely spreading. Umbilicus: open, narrow, deep, 0.14-0.17 mm across. Dimensions: spire height 2.39-2.63 mm; spire width 1.49-1.64 mm, shell width (including tuba) 2.49-2.99 mm; aperture height 1.19-1.37 mm and aperture width 1.05-1.29 mm. Holotype dimensions: spire height 2.55 mm; spire width 1.57 mm, shell width (including tuba) 2.89 mm; aperture height 1.37 mm and aperture width 1.29 mm.

Figure 3.

Plectostoma wallacei kudikense subsp. nov. Paratypes (ME 13360). a-f showing the shell variation amongst the population. Scale = 1 mm.

Diagnosis

Plectostoma wallacei kudikense (Figs 4, 5), is different from the type subspecies together with other two known subspecies by having a shell with tuba free from the spire, simple or inconspicuous double peristome and constriction with a transverse palatalis, an oblique palatalis and a knob-shaped parietalis without longitudinal palatalis. Interestingly, the oblique palatalis is absent in most Bornean diplommatinids species and observed only in Plectostoma wallacei kudikense and Moussonia isseli (Godwin-Austen 1889).

Figure 4.

Plectostoma wallacei kudikense subsp. nov. Paratype (ME 13360). Scanning Electron Microscope images showing detailed characters of the shell.

aPosterior view at 30x magnification;  
bThe shell tuba at 55x magnification;  
cThe shell tuba at 100x magnification;  
dThe shell tuba at 600x magnification.  
Figure 5.

Plectostoma wallacei kudikense subsp. nov. Paratype (ME 13360). Scanning Electron Microscope images showing detailed characters of the shell.

aApertural view at 30x magnification;  
bEnlargement of apertural view at 90x magnification;  
cApical view at 30x magnification;  
dBasal view at 30x magnification.  

Etymology

The specific epithet kudikense is in reference to the type locality, Batu Kudik.

Distribution

Known to be only endemic to Batu Kudik.

Ecology

Living snails were observed on the wet limestone wall surfaces covered with mosses and lichens inside the collapsed cave. The representative is shown in Fig. 6.

Figure 6.  

Apertural, posterial, umbilical and apical views of Plectostoma wallacei kudikense subsp. nov. Holotype (MZU.MOL.21.17). Scale = 1 mm.

Checklists of land snails at Batu Kudik, Simunjan, Sarawak (Malaysia)

Acmella cyrtoglyphe Vermeulen, Liew & Schilthuizen, 2015

Materials   Download as CSV 
  1. family:
    Assimineidae
    ; genus:
    Acmella
    ; scientificNameAuthorship:
    Vermeulen, Liew & Schilthuizen, 2015
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    ME 13355
    ; occurrenceID:
    8872ABBA-9006-5389-A479-3AC539C478F6
  2. family:
    Assimineidae
    ; genus:
    Acmella
    ; scientificNameAuthorship:
    Vermeulen, Liew & Schilthuizen, 2015
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    ME 13890
    ; occurrenceID:
    CF201FC2-21CD-59D1-91C1-39AD69E54E86
Distribution: 

Sarawak: Samarahan and Kuching Divisions (Vermeulen et al. 2015; Marzuki et al. 2021). Sabah: Interior, Sandakan and Tawau Divisions. Distribution elsewhere: Indonesia: Kalimantan (Vermeulen and Liew 2022). Endemic to Borneo.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 7. The identification of the species was based on the original description by Vermeulen et al. (2015) and species description by Marzuki et al. (2021). Holotype, not seen (RMNH.5003948).

Figure 7.  

Apertural, posterial, umbilical and apical views of Acmella cyrtoglyphe (ME 13355). Scale = 1 mm.

Japonia bellula (E. von Martens, 1865)

Materials   Download as CSV 
  1. family:
    Cyclophoridae
    ; genus:
    Japonia
    ; scientificNameAuthorship:
    (E. von Martens, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    MZU.MOL.22.12
    ; occurrenceID:
    1D92B0AD-0AC3-54E9-91F3-06828A34B5A2
  2. family:
    Cyclophoridae
    ; genus:
    Japonia
    ; scientificNameAuthorship:
    (E. von Martens, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    10
    ; catalogNumber:
    ME 13356
    ; occurrenceID:
    9046639D-277B-5C96-AC1C-6B218FFE63F6
  3. family:
    Cyclophoridae
    ; genus:
    Japonia
    ; scientificNameAuthorship:
    (E. von Martens, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    16
    ; catalogNumber:
    ME 13891
    ; occurrenceID:
    41018002-D7E2-5CC7-B77C-9A1B8336EDBF
Distribution: 

Sarawak: Kuching Division. Distribution elsewhere: Indonesia: Kalimantan, Western Region (Martens 1865).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 8. The identification of the species was based on the original description by Martens (1865). Type specimen, not seen.

Figure 8.  

Apertural, posterial, umbilical and apical views of Japonia bellula (ME 13356). Scale = 5 mm.

Stomacosmethis jagori (E. von Martens, 1860)

Materials   Download as CSV 
  1. family:
    Alycaeidae
    ; genus:
    Stomacosmethis
    ; scientificNameAuthorship:
    (E. von Martens, 1860)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    54
    ; catalogNumber:
    MZU.MOL.22.07
    ; occurrenceID:
    CAEE2A19-A99C-5DCF-BFDF-D9A922AE23BB
  2. family:
    Alycaeidae
    ; genus:
    Stomacosmethis
    ; scientificNameAuthorship:
    (E. von Martens, 1860)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    68
    ; catalogNumber:
    ME 13357
    ; occurrenceID:
    06A0FCD4-9311-5503-A53C-72E50536895F
  3. family:
    Alycaeidae
    ; genus:
    Stomacosmethis
    ; scientificNameAuthorship:
    (E. von Martens, 1860)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    64
    ; catalogNumber:
    ME 13892
    ; occurrenceID:
    D0F206B2-8A2F-5E1B-BDEB-5C7982BB61DF
Distribution: 

Widely distributed in Sarawak, Sabah: Sapulut and lower Kinabatangan. Distribution elsewhere: Indonesia: Kalimantan, Sumatra, Java and Bali (Martens 1860; Vermeulen and Liew 2022).

Notes: 

Living snails were observed on the wet limestone wall surfaces covered with mosses and lichens. The representative is shown in Fig. 9. The identification of the species was based on the original description by Martens (1860). Type specimen, not seen.

Figure 9.  

Apertural, posterial, umbilical and apical views of Stomacosmethis jagori (ME 13357). Scale = 5 mm.

Diplommatina concinna H. Adams, 1872

Materials   Download as CSV 
  1. family:
    Diplommatinidae
    ; genus:
    Diplommatina
    ; scientificNameAuthorship:
    H. Adams, 1872
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    150
    ; catalogNumber:
    MZU.MOL.22.06
    ; occurrenceID:
    3981DB7C-6B58-55A5-B6C0-1FE473EC2B32
  2. family:
    Diplommatinidae
    ; genus:
    Diplommatina
    ; scientificNameAuthorship:
    H. Adams, 1872
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    213
    ; catalogNumber:
    ME 13358
    ; occurrenceID:
    4D0570FC-6043-520A-8A36-E2194622B1B9
  3. family:
    Diplommatinidae
    ; genus:
    Diplommatina
    ; scientificNameAuthorship:
    H. Adams, 1872
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    189
    ; catalogNumber:
    ME 13893
    ; occurrenceID:
    15002878-9609-5177-A96F-D7701F8BC1AD
Distribution: 

Sarawak: Kuching, Serian and Miri Divisions (Adams 1872; Marzuki et al. 2021). Distribution elsewhere: Indonesia: Bunguran Island.

Notes: 

Living snails were observed amongst the leaf litter and plant debris at the base of the limestone cliff. The representative is shown in Fig. 10. The identification of the species was based on the original description by Adams (1872), species description by Vermeulen (1993) and Marzuki et al. (2021). Holotype, not seen (BMNH 78.1.28.266.).

Figure 10.  

Apertural, posterial, umbilical and apical views of Diplommatina concinna (ME 13358). Scale = 1 mm.

Diplommatina onyx Fulton, 1901

Material   Download as CSV 
  1. family:
    Diplommatinidae
    ; genus:
    Diplommatina
    ; scientificNameAuthorship:
    Fulton, 1901
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    MZU.MOL.22.193
    ; occurrenceID:
    1810A537-0BF5-5E71-848D-F06FCC9DE7E1
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Fulton 1901; Vermeulen 1993; Marzuki et al. 2021). Endemic to Sarawak.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 11. The identification of the species was based on the original description by Fulton (1901), species description by Vermeulen (1993) and Marzuki et al. (2021). Holotype, not seen (BMNH 1901.12.9.93.).

Figure 11.  

Apertural, posterial, umbilical and apical views of Diplommatina onyx (MZU.MOL.22.193). Scale = 1 mm.

Opisthostoma javanica Benthem-Jutting, 1932

Materials   Download as CSV 
  1. family:
    Diplommatinidae
    ; genus:
    Opisthostoma
    ; scientificNameAuthorship:
    Benthem-Jutting, 1932
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1138
    ; catalogNumber:
    MZU.MOL.22.192
    ; occurrenceID:
    DA3F927F-4ACA-5977-AAFD-7ACE5900A225
  2. family:
    Diplommatinidae
    ; genus:
    Opisthostoma
    ; scientificNameAuthorship:
    Benthem-Jutting, 1932
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    974
    ; catalogNumber:
    ME 13359
    ; occurrenceID:
    9D969EE8-F9F9-53E4-B938-59538C239EC9
  3. family:
    Diplommatinidae
    ; genus:
    Opisthostoma
    ; scientificNameAuthorship:
    Benthem-Jutting, 1932
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1410
    ; catalogNumber:
    ME13894
    ; occurrenceID:
    9F31BD45-A97D-53F8-B5F4-F3818B50CAB7
Distribution: 

Sarawak: Samarahan Division. Distribution elsewhere: Indonesia: Kalimantan, Java, Madura and Celebes (Vermeulen 1991).

Notes: 

Living snails were observed amongst the leaf litter and plant debris inside the collapsed cave. Bornean Opisthostoma javanica Benthem-Jutting, 1932 has constriction with transverse palatalis together with infracolumellaris. Nurinsiyah and Hausdorf (2017) mentioned that the infracolumellaris was not observed in the Javan population. However, the shell radial ribs are widely spaced (4-6 ribs/0.5 mm on the penultimate whorl) and with distinctly elevated top whorls compared to Javan Opisthostoma javanica. Some specimens characterised by the rather upward-turned aperture similar to some Opisthostoma occurring in Peninsular Malaysia. The representative is shown in Fig. 12. The identification of the species was based on the original description of the species by van Benthem-Jutting (1932) and species description by Vermeulen (1991). Syntype, not seen (ZMA 136008).

Figure 12.  

Apertural, posterial, umbilical and apical views of Opisthostoma javanica (MZU.MOL.22.192). Scale = 1 mm.

Georissa hungerfordi Godwin-Austen, 1889

Materials   Download as CSV 
  1. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Godwin-Austen, 1889
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.11
    ; occurrenceID:
    B902587F-2AB8-5AD8-822F-2EF73710611E
  2. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Godwin-Austen, 1889
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    9
    ; catalogNumber:
    ME 13353
    ; occurrenceID:
    9601FC42-39C3-56EA-BB3C-B906CE915A07
  3. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Godwin-Austen, 1889
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    33
    ; catalogNumber:
    ME 13888
    ; occurrenceID:
    0D0459EB-BA81-5DEF-B5E4-052F21C30F73
Distribution: 

Sarawak: Kuching, Serian and Samarahan Divisions (Godwin-Austen 1889; Khalik et al. 2019; Marzuki et al. 2021). Endemic to western Sarawak.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 13. The identification of the species was based on the original description by Godwin-Austen (1889), species description by Khalik et al. (2019) and Marzuki et al. (2021). Lectotype, seen (NHMUK 1891.3.17.864).

Figure 13.  

Apertural, posterial, umbilical and apical views of Georissa hungerfordi (ME 13353). Scale = 1 mm.

Georissa pyrrhoderma Thompson & Dance, 1983

Materials   Download as CSV 
  1. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Thompson & Dance, 1983
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    987
    ; catalogNumber:
    MZU.MOL.22.08
    ; occurrenceID:
    699683AF-EE08-5CAD-8523-63D16C81639C
  2. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Thompson & Dance, 1983
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1050
    ; catalogNumber:
    ME 13354
    ; occurrenceID:
    597B12A2-1DFC-50A8-A418-63EDFAA91D95
  3. family:
    Hydrocenidae
    ; genus:
    Georissa
    ; scientificNameAuthorship:
    Thompson & Dance, 1983
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1033
    ; catalogNumber:
    ME 13889
    ; occurrenceID:
    70EA2F8C-D1B0-52A3-8596-7158FFE37797
Distribution: 

Sarawak: Serian and Samarahan Divisions (Thompson and Dance 1983; Khalik et al. 2018). Endemic to western Sarawak.

Notes: 

Living snails were observed on the wet limestone wall surfaces covered with mosses and lichens. This marked the second locality record of this species after the type locality. The representative is shown in Fig. 14. The identification of the species was based on the original description by Thompson and Dance (1983), species description by Beron (2015) and Khalik et al. (2018). Paratype, not seen (NHMUK1984005).

Figure 14.  

Apertural, posterial, umbilical and apical views of Georissa pyrrhoderma (ME 13354). Scale = 1 mm.

Allopeas gracile (Hutton, 1834)

Materials   Download as CSV 
  1. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Hutton, 1834)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    MZU.MOL.22.09
    ; occurrenceID:
    19B635C9-85D4-5EC7-B2C5-474C84D48304
  2. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Hutton, 1834)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    20
    ; catalogNumber:
    ME 13365
    ; occurrenceID:
    7D699A5D-067F-5650-A3C0-DB24A587E7CE
  3. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Hutton, 1834)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    25
    ; catalogNumber:
    ME 13900
    ; occurrenceID:
    12B5C88E-AD84-586A-95F2-3AF5C8EBCF05
Distribution: 

Sarawak: Kuching, Serian, Samarahan, Mukah and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Kudat, Sandakan, Tawau and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: West Kalimantan Provinces and circumtropical (Hutton 1834; Vermeulen and Whitten 1998; Vermeulen and Liew 2022).

Notes: 

Widespread through­out Borneo. Living snails were observed amongst the leaf litter and plant debris near the cliff in a lowland limestone forest. The representative is shown in Fig. 15. The identification of the species was based on the original description by Hutton (1834) and species description by Marzuki et al. (2021). Syntype, not seen (NHMUK1856.9.15.68).

Figure 15.  

Apertural, posterial, umbilical and apical views of Allopeas gracile (MZU.MOL.22.09). Scale = 5 mm.

Allopeas clavulinum (Potiez & Michaud, 1838)

Materials   Download as CSV 
  1. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Potiez & Michaud, 1838)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    MZU.MOL.22.10
    ; occurrenceID:
    FB3CED1F-8D21-5413-A53E-0C3C6C5AEA6D
  2. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Potiez & Michaud, 1838)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    23
    ; catalogNumber:
    ME 13366
    ; occurrenceID:
    D39E9F60-49E2-5C84-87C9-F3FECD06316A
  3. family:
    Achatinidae
    ; genus:
    Allopeas
    ; scientificNameAuthorship:
    (Potiez & Michaud, 1838)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    ME 13901
    ; occurrenceID:
    70E85BA3-FF59-52E4-8085-DBF9A21F6691
Distribution: 

Sarawak: Kuching, Serian, Samarahan, Sibu and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Sandakan, Tawau, Kudat and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Africa, Asia, Australia and Pacific Islands. (Potiez and Michaud 1838; Vermeulen and Whitten 1998; Vermeulen and Liew 2022).

Notes: 

An introduced species. Widespread through­out Borneo. Only dry shells were found during the surveys. The representative is shown in Fig. 16. The identification of the species was based on the original description by Potiez and Michaud (1838) and species description by Marzuki et al. (2021). Type specimen, not seen.

Figure 16.  

Apertural, posterial, umbilical and apical views of Allopeas clavulinum (MZU.MOL.22.10). Scale = 5 mm.

Hemiplecta densa (H. Adams & Reeve, 1850)

Material   Download as CSV 
  1. family:
    Ariophantidae
    ; genus:
    Hemiplecta
    ; scientificNameAuthorship:
    (H. Adams & Reeve, 1850)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.18
    ; occurrenceID:
    E8D5B1BE-6672-5B4F-88B5-E844B6E70AD9
Distribution: 

Sarawak: Kuching, Serian and Samarahan Divisions (Marzuki et al. 2021). Sabah: West Coast, Kudat, Interior, Sandakan and Tawau Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: West and East Kalimantan Provinces, Java, Sumatra and the Philippines (Adams and Reeve 1850; Mousson 1857; Smith 1895).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 17. The identification of the species was based on the original description by Adams and Reeve (1850) and species description by Marzuki et al. (2021). Type specimen, not seen.

Figure 17.  

Apertural, posterial, umbilical and apical views of Hemiplecta densa (MZU.MOL.22.18). Scale = 10 mm.

Macrochlamys infans (Reeve, 1854)

Materials   Download as CSV 
  1. family:
    Ariophantidae
    ; genus:
    Macrochlamys
    ; scientificNameAuthorship:
    (Reeve, 1854)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.14
    ; occurrenceID:
    408EDBCE-1495-53F5-83B9-9571EC1C705F
  2. family:
    Ariophantidae
    ; genus:
    Macrochlamys
    ; scientificNameAuthorship:
    (Reeve, 1854)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    ME 13363
    ; occurrenceID:
    04B7E3D0-0014-5318-BB95-B82655CD9927
  3. family:
    Ariophantidae
    ; genus:
    Macrochlamys
    ; scientificNameAuthorship:
    (Reeve, 1854)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    ME 13898
    ; occurrenceID:
    B94B3B74-B564-541F-BB8A-E05761432E5B
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Reeve 1854; Marzuki et al. 2021). Sabah: Kudat, West Coast, Interior and Tawau Divisions (Vermeulen and Liew 2022). Endemic to Borneo.

Notes: 

Living snails were observed amongst the leaf-litter and plant debris at the base of the limestone hill cliff. The representative is shown in Fig. 18. The identification of the species was based on the original description by Reeve (1854) and species descriptions by Marzuki et al. (2021). Type specimen, not seen.

Figure 18.  

Apertural, posterial, umbilical and apical views of Macrochlamys infans (ME 13363). Scale = 5 mm.

Microcystina paripari Marzuki, Liew & Mohd-Azlan, 2021

Materials   Download as CSV 
  1. family:
    Ariophantidae
    ; genus:
    Microcystina
    ; scientificNameAuthorship:
    Marzuki, Liew & Mohd-Azlan, 2021
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.06
    ; occurrenceID:
    2347090F-E3CA-585B-A8BB-666A1981831B
  2. family:
    Ariophantidae
    ; genus:
    Microcystina
    ; scientificNameAuthorship:
    Marzuki, Liew & Mohd-Azlan, 2021
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    ME 13364
    ; occurrenceID:
    A277D6B6-649E-599F-BEAC-657B09E1E0A7
Distribution: 

Sarawak: Kuching and Samarahan Divisions (Marzuki et al. 2021). Endemic to western Sarawak.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 19. The identification of the species was based on the original description by Marzuki et al. (2021). Holotype, seen (MZU.MOL.20.12).

Figure 19.  

Apertural, posterial, umbilical and apical views of Microcystina paripari (ME 13364). Scale = 1 mm.

Helicarion dyakanum (Godwin-Austen, 1891)

Materials   Download as CSV 
  1. family:
    Helicarionidae
    ; genus:
    Helicarion
    ; scientificNameAuthorship:
    (Godwin-Austen, 1891)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    MZU.MOL.22.452
    ; occurrenceID:
    9501608E-3784-54A9-8992-A699C780D0B6
  2. family:
    Helicarionidae
    ; genus:
    Helicarion
    ; scientificNameAuthorship:
    (Godwin-Austen, 1891)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    ME 13367
    ; occurrenceID:
    FF103876-92B6-5BC6-B205-3DFBC37D5D70
  3. family:
    Helicarionidae
    ; genus:
    Helicarion
    ; scientificNameAuthorship:
    (Godwin-Austen, 1891)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    ME 13899
    ; occurrenceID:
    8E622615-3086-5C96-B118-8EC3F0636AD5
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Godwin-Austen 1891; Marzuki et al. 2021). Sabah: West Coast Division (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: Lombok (Smith 1899).

Notes: 

Living snails were observed within the arboreal area, on leaves of palms or trees at the base of the limestone cliff. The representative is shown in Fig. 20. The identification of the species was based on the original description by Godwin-Austen (1891) and species description by Marzuki et al. (2021). Holotype, not seen (NHMUK 91.3.9.4).

Figure 20.  

Apertural, posterial, umbilical and apical views of Helicarion dyakanum (ME 13367). Scale = 2.5 mm.

Landouria winteriana (Pfeiffer, 1842)

Materials   Download as CSV 
  1. family:
    Camaenidae
    ; genus:
    Landouria
    ; scientificNameAuthorship:
    (Pfeiffer, 1842)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    6
    ; catalogNumber:
    MZU.MOL.22.13
    ; occurrenceID:
    DD783247-DF63-5D9E-B49E-DFF82F571952
  2. family:
    Camaenidae
    ; genus:
    Landouria
    ; scientificNameAuthorship:
    (Pfeiffer, 1842)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    ME 13369
    ; occurrenceID:
    4C193EE9-FDD8-5575-91C0-373E4F5E14C9
  3. family:
    Camaenidae
    ; genus:
    Landouria
    ; scientificNameAuthorship:
    (Pfeiffer, 1842)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    6
    ; catalogNumber:
    ME 13903
    ; occurrenceID:
    A24031BC-9A09-5816-8C31-916CC6B9487C
Distribution: 

Sarawak: Kuching, Samarahan and Miri Divisions (Marzuki et al. 2021). Distribution elsewhere: Indo-Australian archipelago (Pfeiffer 1842; Vermeulen and Whitten 1998).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 21. The identification of the species was based on the original description by Pfeiffer (1842), species description by Marzuki et al. (2021). Neotype, not seen (ZMA 376193A).

Figure 21.  

Apertural, posterial, umbilical and apical views of Landouria winteriana (ME 13903). Scale = 5 mm.

Kaliella scandens (Cox, 1871)

Materials   Download as CSV 
  1. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Cox, 1871)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    MZU.MOL.22.453
    ; occurrenceID:
    01711D70-AFD0-5BCE-808B-3871A5491A04
  2. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Cox, 1871)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    7
    ; catalogNumber:
    ME 13371
    ; occurrenceID:
    6EF85010-4E63-5C49-AA76-E4A1DA725217
  3. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Cox, 1871)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    ME 13905
    ; occurrenceID:
    BEB223FF-BD1C-5BE7-939A-005BB243B239
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Sandakan, Kudat, Tawau and West Coast Divisions. Distribution elsewhere: Indonesia: Kalimantan, South-east Asia to Australia and the Pacific Islands (Cox 1871; Vermeulen et al. 2015; Vermeulen and Liew 2022).

Notes: 

Living snails were observed within the arboreal area, on leaves of palms or trees at the base of the limestone cliff. The representative is shown in Fig. 22. The identification of the species was based on the original description by Cox (1871) and species description by Marzuki et al. (2021). Syntype, not seen (NHMUK 1880.12.11.17).

Figure 22.  

Apertural, posterial, umbilical and apical views of Kaliella scandens (ME 13371). Scale = 1 mm.

Kaliella microconus (Mousson, 1865)

Materials   Download as CSV 
  1. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Mousson, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.454
    ; occurrenceID:
    530F5D89-E965-5072-91CC-AE4900E75034
  2. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Mousson, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    8
    ; catalogNumber:
    ME 13370
    ; occurrenceID:
    E4BC73B9-BBF9-5436-B98C-B9E3417A19DC
  3. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Mousson, 1865)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    5
    ; catalogNumber:
    ME 13904
    ; occurrenceID:
    B644A736-60E4-52A2-9701-3F4C77D03673
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Kudat, Sandakan, Tawau and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: South Kalimantan Provinces, South-east Asia to Australia and the Pacific Islands (Mousson 1865; Vermeulen and Whitten 1998).

Notes: 

Living snails were observed amongst the leaf litter and plant debris near the limestone cliff. The representative is shown in Fig. 23. The identification of the species was based on the original description by Mousson (1865) and species description by Marzuki et al. (2021). Neotype, not seen (MNHN-IM-2000-28605).

Figure 23.  

Apertural, posterial, umbilical and apical views of Kaliella microconus (ME 13370). Scale = 1 mm.

Kaliella calculosa (Gould, 1852)

Materials   Download as CSV 
  1. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Gould, 1852)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.455
    ; occurrenceID:
    0BD139EA-2937-504C-A3D7-0DF24A4643CA
  2. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    (Gould, 1852)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    ME 13906
    ; occurrenceID:
    388C3404-DCA5-5A0C-AB4B-3AB0EEB1E2E0
Distribution: 

Sarawak: Kuching, Serian, Samarahan and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Sandakan, Kudat, Tawau and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: South Asia mainland to Indo-Australian archipelago and the Pacific Islands (Gould 1852; Vermeulen et al. 2015).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 24. The identification of the species was based on the original description by Gould (1852) and species description by Marzuki et al. (2021). Syntype, not seen (USNM 5465).

Figure 24.  

Apertural, posterial, umbilical and apical views of Kaliella calculosa (ME 13906). Scale = 1 mm.

Kaliella punctata Vermeulen, Liew & Schilthuizen, 2015

Materials   Download as CSV 
  1. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    Vermeulen, Liew & Schilthuizen, 2015
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    MZU.MOL.22.456
    ; occurrenceID:
    61D9DE36-3B7E-5672-A0CC-5B7BCE4E4072
  2. family:
    Chronidae
    ; genus:
    Kaliella
    ; scientificNameAuthorship:
    Vermeulen, Liew & Schilthuizen, 2015
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    ME 13907
    ; occurrenceID:
    572C16E5-6115-5CFA-9442-ACD18F132DA5
Distribution: 

Sarawak: Samarahan Division (Marzuki et al. 2021). Sabah: West Coast, Interior, Sandakan and Tawau Provinces (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: Kalimantan (Vermeulen et al. 2015; Vermeulen and Liew 2022). Endemic to Borneo.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 25. The identification of the species was based on the original description by Vermeulen et al. (2015). Holotype, not seen (RMNH.5003925).

Figure 25.  

Apertural, posterial, umbilical and apical views of Kaliella punctata (ME 13907). Scale = 1 mm.

Everettia minuta Marzuki, Liew & Mohd-Azlan, 2021

Material   Download as CSV 
  1. family:
    Dyakiidae
    ; genus:
    Everettia
    ; scientificNameAuthorship:
    Marzuki, Liew & Mohd-Azlan, 2021
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    ME 13372
    ; occurrenceID:
    3002C6A6-E426-5DA2-9786-115B29F1E259
Distribution: 

Sarawak: Kuching, Serian and Samarahan Divisions (Marzuki et al. 2021). Endemic to western Sarawak.

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 26. The identification of the species was based on the original revision by Marzuki et al. (2021). Holotype, seen (MZU.MOL.20.23).

Figure 26.  

Apertural, posterial, umbilical and apical views of Everettia minuta (ME 13372). Scale = 10 mm.

Videna bicolor (von Martens, 1864)

Materials   Download as CSV 
  1. family:
    Trochomorphidae
    ; genus:
    Videna
    ; scientificNameAuthorship:
    (von Martens, 1864)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    ME 13368
    ; occurrenceID:
    5326F082-6FF2-5E94-9D62-CE2B7DD6C246
  2. family:
    Trochomorphidae
    ; genus:
    Videna
    ; scientificNameAuthorship:
    (von Martens, 1864)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    3
    ; catalogNumber:
    ME 13902
    ; occurrenceID:
    44E65735-68A5-5980-A3E7-457552A11050
Distribution: 

Sarawak: Kuching, Serian, Samarahan, Sibu, Mukah, Kapit and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Kudat, Sandakan, Tawau and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: West and South Kalimantan Provinces and Sumatra to Lesser Sunda (Martens 1864; Aldrich 1889; Martens and Thiele 1908; Vermeulen and Whitten 1998).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 27. The identification of the species was based on the original description by Martens (1864) and species description by Marzuki et al. (2021). Type specimen, not seen.

Figure 27.  

Apertural, posterial, umbilical and apical views of Videna bicolor (ME 13368). Scale = 5 mm.

Philalanka kusana (Aldrich, 1889)

Materials   Download as CSV 
  1. family:
    Charopidae
    ; genus:
    Philalanka
    ; scientificNameAuthorship:
    (Aldrich, 1889)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.457
    ; occurrenceID:
    B2E7F9CD-C11C-519A-88F7-C245F8676254
  2. family:
    Charopidae
    ; genus:
    Philalanka
    ; scientificNameAuthorship:
    (Aldrich, 1889)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    4
    ; catalogNumber:
    ME 13362
    ; occurrenceID:
    84946251-C838-532E-94C0-E80F65270C3B
Distribution: 

Sarawak: Kuching, Serian, Samarahan, Kapit and Miri Divisions (Marzuki et al. 2021). Sabah: Interior, Kudat, Sandakan, Tawau and West Coast Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Indonesia: South Kalimantan Provinces and West Malaysia to Papua (Aldrich 1889; Vermeulen et al. 2015).

Notes: 

Only dry shells were found during the surveys. The representative is shown in Fig. 28. The identification of the species was based on the original description by Aldrich (1889) and species description by Marzuki et al. (2021). Type specimen, not seen.

Figure 28.  

Apertural, posterial, umbilical and apical views of Philalanka kusana (ME 13362). Scale = 1 mm.

Pupisoma dioscoricola (C. B. Adams, 1845)

Materials   Download as CSV 
  1. family:
    Valloniidae
    ; genus:
    Pupisoma
    ; scientificNameAuthorship:
    (C. B. Adams, 1845)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    2
    ; catalogNumber:
    MZU.MOL.22.458
    ; occurrenceID:
    CB445AF8-F64D-5708-A26C-7F83917F9F4A
  2. family:
    Valloniidae
    ; genus:
    Pupisoma
    ; scientificNameAuthorship:
    (C. B. Adams, 1845)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    9
    ; catalogNumber:
    ME 13373
    ; occurrenceID:
    A538854D-6B46-5E28-AA76-8C9CEFBDD77F
  3. family:
    Valloniidae
    ; genus:
    Pupisoma
    ; scientificNameAuthorship:
    (C. B. Adams, 1845)
    ; locality:
    Batu Kudik, Simunjan, Sarawak
    ; individualCount:
    1
    ; catalogNumber:
    ME 13897
    ; occurrenceID:
    C2AEC3FE-0107-5EBA-97A5-960FC7397570
Distribution: 

Sarawak: Kuching, Samarahan, Bintulu, Miri and Limbang Divisions (Marzuki et al. 2021). Sabah: West Coast, Interior, Kudat, Tawau and Sandakan Divisions (Vermeulen and Liew 2022). Distribution elsewhere: Africa, Asia, Australia, Pacific Islands and America (Adams 1845; Pilsbry 1921; Hausdorf 2007; Vermeulen and Liew 2022).

Notes: 

Widely distributed. Only dry shells were found during the surveys. The representative is shown in Fig. 29. The identification of the species was based on the original description by Adams (1845). Syntype, not seen (NHMUK 1875.2.8.14).

Figure 29.  

Apertural, posterial, umbilical and apical views of Pupisoma dioscoricola (ME 13373). Scale = 1 mm.

Analysis

A total of 24 species of land snails, representing 18 genera and 14 families were recorded (see Table 1). The family Diplommatinidae (17%) and family Chronidae (17%) are the most species-rich family with four recorded species in each family, followed by Ariophantinidae (13%), family Achatinidae (8%) and family Hydrocenidae (8%) recorded in this limestone hill cluster. Diplommatina concinna, Diplommatina onyx and Plectostoma wallacei kudikense are new subspecies belonging to the Diplommatinidae family, whereas Kaliella scandens, Kaliella microconus, Kaliella calculosa and Kaliella punctata are classified under the family Chronidae. In terms of genera, the most diverse genus within the area was Kaliella with four species recorded. Additionally, Opisthostoma javanica, Georissa pyrrhoderma and Plectostoma wallacei kudikense are recorded as the most abundant species. Microsnails (size less than 5 mm) accounted for ca. 63% of the total number of species, while small to medium-sized snails (size between 5 to 20 mm) accounted for ca. 37% of the total species. Surprisingly, there are only two medium-sized snails (size more than 20 mm) encountered in this survey, namely, Everettia minuta and Hemiplecta densa.

Table 1.

The number of individuals and the relative abundance of land snails of Batu Kudik.

Family/ Genus Number of Individuals Relative Species Abundance (100%)
Achatinidae
Allopeas gracile 46 0.4887
Allopeas clavulinum 31 0.3293
Alycaeidae
Stomacosmethis jagori 186 1.9760
Assimineidae
Acmella cyrtoglyphe 3 0.0319
Ariophantidae
Hemiplecta densa 2 0.0212
Macrochlamys infans 8 0.0850
Microcystina paripari 7 0.0744
Camaenidae
Landouria winteriana 13 0.1381
Charopidae
Philalanka kusana 6 0.0637
Cyclophoridae
Japonia bellula 31 0.3293
Chronidae
Kaliella scandens 15 0.1594
Kaliella microconus 15 0.1594
Kaliella calculosa 5 0.0531
Kaliella punctata 3 0.0319
Diplommatinidae
Diplommatina concinna 552 5.8642
Diplommatina onyx 1 0.0106
Opisthostoma javanica 3522 37.4613
Plectostoma wallacei kudikense subsp. nov. 1828 19.4200
Dyakiidae
Everettia minuta 1 0.0106
Helicarionidae
Helicarion dyakanum 8 0.0850
Hydrocenidae
Georissa hungerfordi 44 0.0425
Georissa pyrrhoderma 3070 32.6145
Trochomorphidae
Videna bicolor 4 0.0425
Valloniidae
Pupisoma dioscoricola 12 0.1275

Discussion

During our fieldwork, it was observed that the majority of the inhabitants, including the land snails, were concentrated in the gaps between limestone boulders (Fig. 1c), rather than in the vicinity of the exposed outcrop (Fig. 1d). It is worth noting that the outcrop serves as the sole habitat for Plectostoma wallacei kudikense. Consequently, these findings have sparked renewed conservation efforts to prevent the endemic species from becoming extinct.

The land snail fauna in Batu Kudik exhibited a lower level of endemism, with only one endemic species (4%), in comparison to the slightly larger outcrops like Bukit Sarang and the larger karst cluster in the south, which have higher endemism levels of 31.3% and 38.5% for land snails, respectively. Previous studies by Roos et al. (2004) and Clement et al. (2008) have indicated that larger karst regions tend to support more endemic species due to their greater habitat diversity, which subsequently promotes higher rates of speciation (Losos and Schluter 2000; Clement et al. 2008). This trend is also observed in other groups of organisms, such as fishes and orchids, where a positive correlation exists between the size of the area and both species richness and endemism (Clement et al. 2006; Clement et al. 2008). Additionally, the presence of only two medium-sized snails at Batu Kudik can be attributed to the fact that larger snails require more resources, such as calcium carbonate, when compared to microsnails (Goodfriend 1986; Baur and Raboud 1988). It is highly probable that the current resources available at Batu Kudik are limited, which makes it challenging for the larger snails to thrive in this environment.

Moreover, a significant portion of the limestone hills in the south (Bau Region), falls within protected areas, indicating that many of the endemic species are safeguarded. However, Batu Kudik, situated between the south and areas with agricultural activities around the limestone karst, lack such protection. As a result, factors such as quarrying, deforestation and agricultural activities become crucial determinants that may affect level of endemism, including the land snails (Schilthuizen et al. 2005; Clement et al. 2008).

Acknowledgements

The authors would like to thank Sarawak Forestry Corporation for the permission to conduct research (Permit no.: SFC.810-4/6/1-119). The authors would like to thank the head of Semalatong Village for providing hospitality and allowing us to conduct fieldwork in the area. This research is supported by the Biodiversity Research Grant Scheme UNIMAS (UNI/I01/BRG/85910/2023). The authors extend their gratitude to the reviewers, Liew Thor-Seng, Barna Páll-Gergely and Ivailo Dedov, for their valuable and constructive comments and suggestions that significantly improved the manuscript.

Author contributions

Conceptualisation, M.Z.K., J.J.V., L.J.Y. and N.S.N.; Fieldwork, L.J.Y., N.S.N., M.E.M. and M.Z.K.; Laboratory work, L.J.Y., N.S.N., M.E.M. and M.Z.K.; Analysis, L.J.Y.; Data curation, L.J.Y.; Writing the manuscript L.J.Y., N.S.N., M.E.M., J.J.V. and M.Z.K; Supervision, M.Z.K.; Funding acquisition, M.Z.K.

References

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