Diplommatina rumbangensis, Nasir & Lee & Marzuki & Vermeulen & Mohd-Azlan & Khalik, 2024

Nasir, Nurul Syafiqah, Lee, Jie Ying, Marzuki, Mohammad Effendi, Vermeulen, Jaap J., Mohd-Azlan, Jayasilan & Khalik, Mohd Zacaery, 2024, Checklist of land snail species of Gua Rumbang, Sarawak, Malaysian Borneo (Mollusca, Gastropoda), with a description of a new species, Diplommatina rumbangensis sp. nov., ZooKeys 1198, pp. 295-340 : 295

publication ID

https://dx.doi.org/10.3897/zookeys.1198.116265

publication LSID

lsid:zoobank.org:pub:15665236-05DF-4C4F-A6E6-41A404EE6545

persistent identifier

https://treatment.plazi.org/id/C34336B3-6421-49FD-84AC-154E8A1C4691

taxon LSID

lsid:zoobank.org:act:C34336B3-6421-49FD-84AC-154E8A1C4691

treatment provided by

ZooKeys by Pensoft

scientific name

Diplommatina rumbangensis
status

sp. nov.

Diplommatina rumbangensis sp. nov.

Figs 2A-F View Figure 2 , 8E View Figure 8

Type material examined.

Holotype. Malaysia • (SH = 5.25 mm, SW = 2.52 mm); Sarawak, Gua Rumbang, near Kampung Semadang, along Sarawak Kanan River, ~ 11 miles Southwest Padawan, Kuching Division; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir and M. E. Marzuki leg.; MZU.MOL.22.132. Paratypes. Malaysia • 4 ex. (SH = 5.1 mm, SW = 2.7 mm; SH = 5.06 mm, SW = 2.5 mm; SH = 5.37 mm, SW = 2.58 mm; SH = 5.01 mm, SW = 2.65 mm); same data as holotype; MZU.MOL.22.491, ME 14983, ME 15021. Both holotype and paratypes were deposited in Zoological Museum UNIMAS (ZMU) and additional paratypes in the private collection of the third author.

Description.

Shell dextral, fusiform to moderately conical, reddish orange, shining and translucent, with the penultimate whorl widest, convex, well rounded. Suture impressed. Protoconch with 1½ whorls, punctate with small pits, without radial and spiral lines. Constriction nearly level with the edge between the parietal and columellar side of the peristome, with two parietales, two upper longitudinal palatales which are not covered by the peristome on the outer surface of the shell, one transversal palatalis and one columellaris. The columellaris positioned at the start of the constriction together with the longitudinal palatales. Tuba approximately ¾ whorl. Sculpture: Radial ribs on the top whorls only, widely spaced, inconspicuous, but halfway the whorl with an almost tubular projection, in adults sometimes abraded to a semi-circular scar. Spiral striation inconspicuous, on top whorls only. Aperture: Hardly tilted regarding the coiling axis; columellaris distinct, directed downwards. Peristome double, expanding; palatal side hardly sinuous, without edge; basal side with an edge; basal edge hardly sinuous, rounded; inner peristome somewhat expanding beyond the outer, with a palatal lip, free and erect on the columellar side, expanding on the parietal side. Umbilicus: Open, narrow. Dimensions: Height 5.01-5.37 mm; width 2.5-2.7 mm; number of whorls 6¾ -7; height and width aperture 1.91-2.05 mm; 2.05-2.09 mm.

Differential diagnosis.

Diplommatina rumbangensis sp. nov. has two distinct upper longitudinal palatales at the shell constriction that are not covered by the peristome on the outer surface of the shell (Fig. 3 View Figure 3 ). This differs from Diplommatina spinosa Godwin-Austen, 1889 which has one longitudinal palatalis only. Additionally, D. spinosa exhibits a tubular projection that extends to the penultimate whorl, whereas in D. rumbangensis sp. nov., this projection only reaches halfway through the ultimate whorl. Diplommatina spinosa is distributed in the Kuching and Serian divisions. It also differs from Diplommatina bicoronata bicoronata von Martens, 1884 which is endemic to Kalimantan, Indonesia by having two or three longitudinal palatales with two of them covered by the peristome. Diplommatina bicoronata bicoronata also has radial ribs near the suture of the whorls which is absent in D. rumbangensis sp. nov. This latter species can be distinguished from Diplommatina aurisdiaboli Vermeulen, 1993 by the absence of palatal lip expanding up the suture of the previous whorl.

Etymology.

The epithet rumbangensis refers to the type locality Gua Rumbang.

Geographic distribution and habitat.

Diplommatina rumbangensis sp. nov. is known from the type locality only. The living animals were not observed.

Remarks.

The spine or tubular projection of the shells of Diplommatina rumbangensis sp. nov. are mostly broken, leaving semi-circular scars.

Checklist

Class Gastropoda Cuvier, 1795,

Subclass Caenogastropoda Cox, 1960

Family Alycaeidae W. T. Blanford, 1864

Chamalycaeus specus (Godwin-Austen, 1889)

Fig. 4A View Figure 4

Type locality. "In limestone caves at Jambusan, Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14470, ME 14982, ME 15020, MZU.MOL.16.116.

Distribution. Widespread in Borneo. Endemic to Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Pincerna globosa (H. Adams, 1871)

Figs 4B View Figure 4 , 19A View Figure 19

Type locality. "Busan, near Sarawak, Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14468, ME 15018, MZU.MOL.16.109, MZU.MOL.22.135, MZU.MOL.23.139.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah, further to the north. Also found in Sabah and West Kalimantan. Endemic to Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Stomacosmethis hosei (Godwin-Austen, 1889)

Figs 4C View Figure 4 , 19B View Figure 19

Type locality. "Busan Hills, Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14469, ME 14981, ME 15019, MZU.MOL.16.108, MZU.MOL.22.136

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Living snails found on wet limestone surfaces covered with mosses. Empty shells were found among leaf litter at the base of limestone hills.

Family Assimineidae H. Adams & A. Adams, 1856

Solenomphala scalaris (Heude, 1882)

Fig. 4D View Figure 4

Type locality. "Ad parietes humidos in civitate Chang-hai sat copiosa" [= Shanghai, China].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14512.

Distribution. Widely distributed in Borneo. Also found in China and Peninsular Malaysia ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Only empty shells were found. An introduced species. Records show that it occurs in the damp areas around human settlements ( Chan 1997).

Family Cyclophoridae Gray, 1847

Craspedotropis borneensis (Godwin-Austen, 1889)

Figs 5A View Figure 5 , 19C View Figure 19

Type locality. "Busan Hills, Borneo" [= Jambusan Hills, Sarawak].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14980, ME 15016. MZU.MOL.22.137, MZU.MOL.23.141.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak.

Remarks. Living snails were found foraging on limestone surfaces and among leaf-litter and topsoil at the base of limestone cliffs. Living individuals of this species are always covered by dirt, which makes it difficult to be spotted.

Cyclophorus perdix borneensis (Metcalfe, 1852)

Fig. 5B View Figure 5

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14461, ME 15010, MZU.MOL.22.184.

Distribution. Widely distributed in Borneo and Sarawak but rare in Sabah ( Marzuki et al. 2021; Vermeulen and Liew 2022). Also found in West Malaysia ( Stoliczka 1872; Morgan 1885).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Ditropopsis everetti (E. A. Smith, 1895)

Fig. 5C View Figure 5

Type locality. "Rumbang, Sarawak" [= Rumbang Hills, Padawan, Sarawak].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14467, ME 15017.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Japonia barbata (L. Pfeiffer, 1855)

Fig. 6A View Figure 6

Type locality. "Borneo, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14464, ME 15012, MZU.MOL.22.149.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Mukah, also in central Sarawak. Endemic to Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Japonia bauensis Marzuki, Liew & Mohd-Azlan, 2021

Fig. 6B View Figure 6

Type locality. "Bau and Serian-Padawan limestone hill clusters."

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14465, ME 15013, MZU.MOL.22.156.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in Sarawak. Endemic to Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Japonia borneensis (E. A. Smith, 1893)

Figs 6C View Figure 6 , 19D View Figure 19

Type locality. "Westliches Borneo bei Bengkajang" [= Western Borneo near Bengkayang].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; MZU.MOL.23.138, MZU.MOL.22.155, MZU.MOL.16.110.

Distribution. Widely distributed in Borneo ( Vermeulen and Liew 2022).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Japonia mundyana (Godwin-Austen, 1889)

Fig. 6D View Figure 6

Type locality. "Busan Hills, Borneo" [= Jambusan Hills, Bau, Sarawak].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15014, MZU.MOL.22.133.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Living snail was observed foraging on leaf surface of plants at the base of limestone cliffs.

Leptopoma sericatum (L. Pfeiffer, 1851)

Fig. 7A View Figure 7

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15015, MZU.MOL.23.135.

Distribution. Widely distributed in Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Opisthoporus biciliatus (Mousson, 1849)

Figs 7B View Figure 7 , 20A View Figure 20

Type locality. “Java” [= Borneo ( Metcalfe 1852].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14463, ME 14979, ME 15011, MZU.MOL.22.152.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Mukah, also in central Sarawak. Endemic to Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Pterocyclos tenuilabiatus (Metcalfe, 1852)

Fig. 7C View Figure 7

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14462, ME 14978, MZU.MOL.22.129.

Distribution. Widely distributed in Borneo. Endemic to Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Diplommatinidae L. Pfeiffer, 1856

Diplommatina adversa (H. Adams & A. Adams, 1851)

Figs 8A View Figure 8 , 20B View Figure 20

Type locality. “Singapore”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14476, MZU.MOL.22.140, MZU.MOL.23.140.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. In Sabah found in Ulu Segama only ( Marzuki et al. 2021; Vermeulen and Liew 2022). Also found in West Malaysia and Singapore ( Laidlaw 1949).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Diplommatina baritensis E. A Smith, 1893

Figs 8B View Figure 8 , 20C View Figure 20

Type locality. "Barit Mountain, N.W. Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14472, ME 14984, ME 15022, MZU.MOL.22.169, MZU.MOL.23.137.

Distribution. Scattered localities between Padawan limestone hills at western Sarawak and Mulu limestone hills in northern Sarawak ( Smith 1895; Vermeulen 1993).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Diplommatina concinna H. Adams, 1872

Fig. 8C View Figure 8

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14473, MZU.MOL.22.83.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah, in northern Sarawak. Also found in Bunguran, Indonesia ( Marzuki et al. 2021) and Singapore ( Chan 2020).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Diplommatina maduana maduana Laidlaw, 1949

Fig. 8D View Figure 8

Type locality. "Gua Madu, Kelantan".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14474, ME 15023, MZU.MOL.22.190.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Mulu hills in northern Sarawak ( Marzuki et al. 2021). Also found in West Malaysia ( Laidlaw 1949).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Diplommatina subglaber subisensis (Vermeulen, 1993)

Fig. 8F View Figure 8

Type locality. "Sarawak 4th Div.: G. Subis (Batu Niah)".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14475.

Distribution. Scattered localities between Padawan limestone hills in western Sarawak and Niah limestone hills in northern Sarawak ( Vermeulen 1993, 1996).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Opisthostoma brachyacrum lambii (Vermeulen, 1991)

Fig. 9A View Figure 9

Type locality. "Sarawak 1st Div.: W of Kpg. Lobang Batu 12.5 km S of Tebakang".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14480, ME 15027, MZU.MOL.22.211.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Also found in Sabah. Endemic to Borneo ( Marzuki et al. 2021).

Remarks. Living snails were found foraging in leaf-litter and plant debris at the base of limestone cliffs.

Opisthostoma tridens Vermeulen, 1991

Fig. 9B View Figure 9

Type locality. "Sarawak 1st Div.: Kpg. Beratok along road Kuching-Serian".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14481, ME 15028, MZU.MOL.22.443.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak region ( Marzuki et al. 2021).

Remarks. Living snails found on wet vertical limestone surfaces covered with mosses.

Plectostoma anisopterum (Vermeulen, 1994)

Figs 9C View Figure 9 , 20D View Figure 20

Type locality. "G. Saak 1 mile W. of Begu, 24 miles S. of Kuching".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14479, ME 14987, ME 15026, MZU.MOL.16.112, MZU.MOL.22.134, MZU.MOL.23.142.

Distribution. Scattered localities in Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Vermeulen 1994).

Remarks. Living snails found on wet vertical limestone surfaces covered with mosses. It can also be found among boulders.

Plectostoma austeni (E. A. Smith, 1894a)

Figs 9D View Figure 9 , 21B View Figure 21

Type locality. "Rumbang, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14478, ME 14986, ME 15025, MZU.MOL.22.144, MZU.MOL.16.113.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak region ( Marzuki et al. 2021).

Remarks. Living snails found on wet vertical limestone surfaces and was observed foraging inside the rock crevices and cave walls, avoiding direct exposure to light.

Plectostoma pumilio (E. A Smith, 1894a)

Figs 9E View Figure 9 , 21A View Figure 21

Type locality. "Rumbang, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14477, ME 14985, ME 15024, MZU.MOL.16.114.

Distribution. Scattered localities in Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak region ( Vermeulen 1994).

Remarks. Living snails found on wet vertical limestone surfaces covered with mosses.

Subclass Heterobranchia Burmeister, 1837

Family Achatinidae Swainson, 1840

Allopeas clavulinum (Potiez & Michaud, 1838)

Fig. 10A View Figure 10

Type locality. “L’ile Bourbon" [= La Réunion].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14485, ME 14990, ME 15035, MZU.MOL.22.159.

Distribution. Widely distributed in Borneo. Circumtropical ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Allopeas gracile (T. Hutton, 1834)

Fig. 10B View Figure 10

Type locality. "Mirzapoor, India".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14486, ME 14991, ME 15036, MZU.MOL.22.161.

Distribution. Widely distributed in Borneo. Circumtropical ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Opeas hannense (Rang, 1831)

Fig. 10C View Figure 10

Type locality. "Village of Hann, Cap Vert peninsula, Dakar, Senegal".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14484, ME 14989, ME 15034, MZU.MOL.22.158.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Also found in Sabah. Distributed from Central America to Africa and Pacific ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Paropeas achatinaceum (L. Pfeiffer, 1846)

Fig. 10D View Figure 10

Type locality. “Java”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14487, ME 14992, ME 15037, MZU.MOL.16.147, MZU.MOL.22.160.

Distribution. Widely distributed in Borneo. Distributed from South to East Asia, South-east Asia, and Pacific Islands ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Achatinellidae Gulick, 1873

Elasmias sundanum ( Möllendorff, 1897)

Fig. 11A View Figure 11

Type locality. “Java”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14514, ME 15058, MZU.MOL.23.149.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah at further northern Sarawak ( Marzuki et al. 2021). Also found in Sumatra and Java ( van Benthem-Jutting 1952).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Ariophantidae Godwin-Austen, 1883

Rahula raricostulata (E. A. Smith, 1893)

Figs 11B View Figure 11 , 21C View Figure 21

Type locality. "Busau or Busan, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14495, ME 15043, MZU.MOL.22.139.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Macrochlamys sanctijohni (Godwin-Austen, 1891)

Fig. 11C View Figure 11

Type locality. "Busan Hills".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14500, ME 14998, ME 15048, MZU.MOL.22.451.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah in northern Sarawak ( Marzuki et al. 2021). Also found in Palawan, Philippines ( Smith 1895).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Macrochlamys infans (Reeve, 1854)

Figs 11D View Figure 11 , 21D View Figure 21

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14501, ME 15061, MZU.MOL.16.118, MZU.MOL.22.449, MZU.MOL.23.144.

Distribution. Widely distributed in Borneo. Distributed from Sumatra to Philippines ( Vermeulen and Liew 2022).

Remarks. Empty shells were found among leaf-litter and plant debris at the base of limestone cliffs while living snails were found foraging on leaf surfaces.

Vitrinula glutinosa (Metcalfe, 1852)

Figs 11E View Figure 11 , 22A View Figure 22

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14502, ME 15049, MZU.MOL.22.130, MZU.MOL.23.146.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Mulu at northern Sarawak. Endemic to Borneo ( Marzuki et al. 2021).

Remarks. Empty shells were found among leaf-litter and plant debris at the base of limestone cliffs while living snails were found foraging on leaf surfaces. Individuals of this species show variability in the height of the spire and in the colour (pale to dark brown) ( Marzuki et al. 2021).

Microcystina arabii Marzuki, Liew & Mohd-Azlan, 2021

Fig. 12A View Figure 12

Type locality. "Malaysia, Sarawak, Kuching, Division, Bukit Sokwang (Site 2), northern site of Gunung Doya, limestone hill along Skio road, 2.05 miles E Bau".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14505, MZU.MOL.23.152.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Microcystina kilat Marzuki, Liew & Mohd-Azlan, 2021

Fig. 12B View Figure 12

Type locality. "Malaysia, Sarawak, Kuching Division, Lobang Angin (Site 2), limestone outcrop near Sungai Sarawak Kanan, 1.75 miles W Bau".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15050, MZU.MOL.23.151.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Microcystina paripari Marzuki, Liew & Mohd-Azlan, 2021

Fig. 12C View Figure 12

Type locality. "Malaysia, Sarawak, Kuching Division, Fairy Cave (Site 2), south part of Gunung Kapor, 4 miles SW Bau".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14503, ME 15000, ME 15052, MZU.MOL.22.132.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Microcystina physotrochus Vermeulen, Liew & Schilthuizen, 2015

Fig. 12D View Figure 12

Type locality. "Malaysia, Sabah, Sandakan Province, Kinabatangan Valley, Batu Keruak 2, near Sukau".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15060.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah in northern Sarawak. Also found in Sabah. Endemic to Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Microcystina vitreiformis ( Möllendorff, 1897)

Fig. 12E View Figure 12

Type locality. “Java”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15051, MZU.MOL.16.117.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah in northern Sarawak. Also found in Java and its adjacent islands, Indonesia (Nurinsiyah, 2021).

Remarks. Only empty shells were found.

Family Camaenidae Pilsbry, 1895

Amphidromus angulatus Fulton, 1896

Fig. 13A View Figure 13

Type locality. “Sarawak”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; MZU.MOL.22.147.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak, to Niah, further northern Sarawak. Also found in West Kalimantan ( Marzuki et al. 2021).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Amphidromus epidemiae Wang, 2021

Fig. 13B View Figure 13

Type locality. "Sarawak, Kuching Division, Bau".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; ME 14507, ME 15004, ME 15054, MZU.MOL.22.183.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak.

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Ganesella acris (Benson, 1859)

Fig. 13C View Figure 13

Type locality. "Teria Ghát montium Khasiæ” [= Khasi Hills, Teria Ghat, India].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14508, MZU.MOL.22.150, MZU.MOL.16.146.

Distribution. Widely distributed with scattered localities in Borneo. Distributed from Sumatra to Java Indonesia, and South to Southeast Asian mainland ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Charopidae Hutton, 1884

Philalanka kusana (Aldrich, 1889)

Fig. 13D View Figure 13

Type locality. "Kusan and Penggiron districts in South-eastern Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14509, MZU.MOL.16.111.

Distribution. Widely distributed in Borneo. Distributed from West Malaysia to Papua ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Sundacharopa argos Vermeulen & Liew, 2022

Fig. 13E View Figure 13

Type locality. "Malaysia, Sabah, upper Padas River valley, Long Pa Sia".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14511.

Distribution. Widely distributed in Borneo. Endemic to Borneo ( Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Chronidae Thiele, 1931

Kaliella barrakporensis (Reeve, 1852)

Figs 14A View Figure 14 , 22B View Figure 22

Type locality. "Barrakpore Indiae (Bacon)" [= Barrackpore, West Bengal, India].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14489, ME 14994, ME 15039, MZU.MOL.22.148, MZU.MOL.23.143.

Distribution. Widely distributed in Borneo. Distributed from Africa and South Asia mainland to Indo-Australian archipelago and Europe ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Kaliella busauensis (E. A. Smith, 1895)

Figs 14B View Figure 14 , 22C View Figure 22

Type locality. "Busau, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Apr. 2016-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14488, ME 14993, ME 15038, MZU.MOL.16.115, MZU.MOL.22.144.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak.

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs. Vermeulen and Liew (2022) mentioned that this species is synonymous with K. barrakporensis . In contrast, Marzuki et al. (2021) listed it as separate species. Kaliella busauensis has a higher, dark brown shell with a cancellated shell surface caused by prominent spiral grooves and oblique radial riblets.

Kaliella calculosa (Gould, 1852)

Fig. 14C View Figure 14

Type locality. “Tahiti” [= Tahiti Island, French Polynesia].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14493, ME 14506, MZU.MOL.22.450.

Distribution. Widely distributed in Borneo. Distributed from India to Australia and Pacific ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Kaliella microconus (Mousson, 1865)

Fig. 14D View Figure 14

Type locality. "Lomma-Lomma (Viti)" [= Loma Loma, Fiji].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14490, ME 14995, ME 15040, MZU.MOL.22.168.

Distribution. Widely distributed in Borneo. Distributed from South-east Asia to Australia and the Pacific Islands ( Marzuki et al. 2021; Vermeulen and Whitten 1998).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Kaliella rumbangensis (E. A. Smith, 1895)

Figs 15A View Figure 15 , 22D View Figure 22

Type locality. "Rumbang, Sarawak and Mount Rabong".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14491, ME 14504, ME 14996, ME 15041, MZU.MOL.22.163, MZU.MOL.22.145.

Distribution. Padawan limestone hills in western Sarawak only. Endemic to western Sarawak (Smith, 1895).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs. Vermeulen and Liew (2022) listed this as synonymous with K. barrakporensis . Kaliella rumbangensis differs from K. barrakporensis by its smaller size and by the inconspicuous (or even absent) peripheral keel on the last whorl.

Kaliella scandens (Cox, 1872)

Fig. 15B View Figure 15

Type locality. "Port Macquarie, east coast of Australia".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14492, ME 14997, ME 15042, MZU.MOL.22.444.

Distribution. Widely distributed in Borneo. Distributed from South-east Asia to Australia and the Pacific Islands ( Marzuki et al. 2021; Vermeulen et al. 2015).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Exrhysota brookei (A. Adams & Reeve, 1850)

Figs 15C View Figure 15 , 23 View Figure 23

Type locality. "Mountains of Borneo".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; MZU.MOL.22.151.

Distribution. Widespread in Borneo. Endemic to Borneo ( Marzuki et al. 2021).

Remarks. Living snails were found foraging in limestone crevices and in leaf litter. This is the largest native land snail species in Borneo.

Family Diapheridae Panha & Naggs, 2010

Platycochlium sarawakense Laidlaw, 1950

Figs 16A View Figure 16 , 24A View Figure 24

Type locality. "Gunong Kapor, Bau District, Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14483, ME 14988, ME 15033, MZU.MOL.22.153.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Living snails found foraging among leaf-litter and plant debris at the base of limestone cliffs.

Family Dyakiidae Gude & B. B. Woodward, 1921

Dyakia subdebilis E. A. Smith, 1895

Figs 16B View Figure 16 , 24B View Figure 24

Type locality. “Sarawak”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14496, ME 15044, MZU.MOL.22.141, MZU.MOL.23.136.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Marzuki et al. 2021).

Remarks. Living snails were found foraging on leaf surface of trees at the base of limestone cliffs and on limestone surfaces covered with mosses and lichens.

Rhinocochlis nasuta (Metcalfe, 1852)

Fig. 16C View Figure 16

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14497, ME 15002, ME 15045, MZU.MOL.22.146.

Distribution. Widely distributed in Borneo. Endemic to Borneo ( Marzuki et al. 2021).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Family Geotrochidae Schileyko, 2002

Geotrochus conicoides (Metcalfe, 1852)

Fig. 16D View Figure 16

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15057, MZU.MOL.23.150

Distribution. Widely distributed in Borneo. Widespread. Also found in Sumatra, Indonesia and Palawan, Philippines ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Helicarionidae Bourguignat, 1877

Helicarion dyakanum (Godwin-Austen, 1891)

Figs 17A View Figure 17 , 24C View Figure 24

Type locality. "Busan Hills, Borneo" [= Jambusan Hills, Bau, Sarawak].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14499, ME 15001.

Distribution. Widely distributed in Sarawak. In Sabah on Mount Trusmadi only. Endemic to Borneo ( Marzuki et al. 2021; Vermeulen and Liew 2022).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Family Punctidae Morse, 1864

Paralaoma sarawakensis Marzuki, Liew & Mohd-Azlan, 2021

Figs 17B View Figure 17 , 24D View Figure 24

Type locality. "Limestone hill along Skio road, 2.05 miles E Bau, Northern site of Gua Doya, Bukit Sokwang (Site 3), Kuching Division, Sarawak, Malaysia".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14510, ME 15055, MZU.MOL.22.448.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Also found in Baram, in northern Sarawak. Endemic to Sarawak ( Marzuki et al. 2021).

Remarks. Living snails were found foraging among leaf-litter and plant debris at the base of limestone cliffs.

Family Pupinidae L. Pfeiffer, 1853

Pupina evansi Godwin-Austen, 1889

Fig. 17C View Figure 17

Type locality. "From deposit in Cave A, Borneo" [= Tupak Cave, Jambusan Hills, see Cranbrook 2013)].

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15029.

Distribution. Scattered localities in Serian-Padawan limestone hills in western Sarawak ( Marzuki et al. 2021). Also found in Sirhassen, Natuna Island ( Smith 1894b).

Remarks. Among leaf-litter and plant debris at the base of limestone cliffs. Only empty shells were found.

Family Trochomorphidae Möllendorff, 1890

Videna nepiadelphos Vermeulen & Liew, 2022

Fig. 17D View Figure 17

Type locality. "Danum valley Conservation Area, Tawau Prov., Sabah".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14513, ME 15056, MZU.MOL.22.447.

Distribution. Widely distributed in Borneo. Widespread. Also found in Panaitan island, Indonesia ( Vermeulen and Liew 2022)

Remarks. Only empty shells were found among leaf-litter and plant debris at the base of limestone cliffs.

Family Valloniidae Morse, 1864

Pupisoma dioscoricola (C. B. Adams, 1845)

Fig. 17E View Figure 17

Type locality. “Jamaica”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022-28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14498, ME 15003, ME 15046, MZU.MOL.22.445.

Distribution. Widely distributed in Borneo. Widespread. Distributed in Africa, Asia, Australia, and America ( Marzuki et al. 2021).

Remarks. Living snails were observed foraging on leaf surface of trees at the base of limestone cliffs.

Subclass Neritimorpha Golikov & Starobogatov, 1975

Family Hydrocenidae Troschel, 1857

Georissa everetti E. A. Smith, 1895

Fig. 18A View Figure 18

Type locality. "Rumbang, W. Sarawak".

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 2 Sep. 2022; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 14482, MZU.MOL.22.157.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak to Niah in northern Sarawak. Also found in Sabah, Sepulut valley. Widespread. Endemic to Borneo ( Khalik et al. 2019; Marzuki et al. 2021).

Remarks. Living snails were observed foraging on wet limestone wall surfaces covered with mosses.

Georissa hungerfordi Godwin-Austen, 1889

Fig. 18B View Figure 18

Type locality. “Borneo”.

Material examined. Malaysia • Sarawak, Padawan, Gua Rumbang; 1°16.77'N, 110°15.69'E; 28 Jun. 2023; N.S. Nasir, M.E Marzuki, J.Y. Lee, and M.Z Khalik leg.; ME 15032.

Distribution. Scattered localities between Bau and Serian-Padawan limestone hills in western Sarawak. Endemic to western Sarawak ( Khalik et al. 2019; Marzuki et al. 2021).

Remarks. Living snails were observed foraging on wet limestone wall surfaces covered with mosses.