Diplommatina tylocheilos Vermeulen, Liew & Schilthuizen

Vermeulen, Jaap J., Liew, Thor-Seng & Schilthuizen, Menno, 2015, Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species, ZooKeys 531, pp. 1-139: 21-22

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Diplommatina tylocheilos Vermeulen, Liew & Schilthuizen

sp. n.

Taxon classification Animalia Architaenioglossa Diplommatinidae

Diplommatina tylocheilos Vermeulen, Liew & Schilthuizen  sp. n. Figure 18

Holotype. Malaysia, Sabah, Interior Province , Gunung Trusmadi slopes , Gua Loloposon ( RMNH.5003953). View Materials 

Examined material from Sabah.

Interior Province. Gunung Trusmadi slopes, Gua Loloposon (leg. J.J. Vermeulen, V 13227).


Shell dextral, fusiform, with the penultimate whorl widest. Suture impressed. Constriction level with the angular edge of the peristome, or up to 1/8 whorl beyond this point, towards the apex, with 1 parietalis, 1 longitudinal palatalis, 1 transversal palatalis, 1 columellaris which continues as a lamella down to the aperture. Tuba 1-1 1/8 whorl. Sculpture. Radial ribs straight, distinct, rather low, narrow, rather densely placed (6-9 ribs/0.5 mm on the penultimate whorl). Spiral striation present, rather distinct, moderately spaced. Aperture hardly tilted with regard to the coiling axis; columellaris large, patent; a second conical, obtuse tooth present on the palatal side, just below the angular edge. Peristome double, expanding; palatal side sinuous, with or without a slight edge; basal side without edge; basal edge not sinuous; outer peristome somewhat expanding beyond the inner; inner peristome with a palatal lip, free and erect on the columellar side, somewhat expanding on the parietal side. Umbilicus closed. Dimensions. Height 1.75-2.05 mm; width 0.95-1.15 mm; number of whorls 6-6 1/4; height aperture 0.30-0.40 mm; width aperture 0.35-0.45 mm.

Habitat in Sabah and distribution.

Found in primary forest on limestone soil. Alt. 900-1000 m. Sabah: Gunung Trusmadi. Endemic to Sabah.

Cross diagnosis.

Uniquely identified among Sabah Diplommatina  species by the distinct, conical, obtuse tooth on the palatal peristome, close to the angular edge.

Diplommatina unicrenata  Godwin Austen, 1897 [1897-1914], from India, Naga Hills is the only known species with a similar structure on the palatal peristome; it differs in having two teeth with a distinct furrow in between.


The name refers to the diagnostic character [tulos (Gr.) = knob; cheilos (Gr.) = lip].