Diplommatina azlani, Marzuki, 2019

Marzuki, Mohammad Effendi bin, 2019, Diplommatina azlani, a new land snail species from Sarawak (Gastropoda: Cyclophoroidea: Diplommatinidae), Raffles Bulletin of Zoology 67, pp. 56-59 : 56-58

Diplommatina azlani , new species

( Fig. 1A–E )

Material examined. Holotype ( SH 3.38 mm, SW 1.50 mm) ( MZU.MOL.17.91), Malaysia, Sarawak, West side of Santubong National Park, approximately 20 kilometers north of Kuching , Kuching Division , 1°44′31.04″N, 110°19′32.20″E, coll. Mohammad Effendi bin Marzuki , 14 April 2017. Paratypes: 2 ex. ( MZU.MOL.17.92), 3 ex. ( ME0008720), same data as holotype; 2 ex. ( ZRC. MOL.13770), 4 ex. ( ME0009801), same locality as holotype, coll. Mohammad Effendi bin Marzuki, 25 February 2018.

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Description. Shell sinistral, fusiform to moderately conical, dark ruby red, moderately shiny and translucent (SH 3.23– 3.68 mm, SW 1.83–1.90 mm; AH 0.87 mm). Six whorls, last whorl widest, top whorls almost flat, others convex, well rounded. Suture impressed. Protoconch with 1½ whorls, punctate with small pits, without radial and spiral lines. Constriction level with angular edge of peristome, with one long transversal palatalis and one columellaris. Tuba approximately ¾ whorl. Radial ribs oblique, inconspicuous, not sinuous, and rather densely placed (6-8 ribs/0.5 mm on the penultimate whorl). Spiral striation present, inconspicuous (visible only under 40x magnification). Aperture tilted about 45° relative to the coiling axis. Columellaris distinct, slightly directed downwards. Peristome double, thickened, expanding; palatal side sinuous, without edge; basal side sinuous with sharp edge. Umbilicus closed. Living animal observed with creamy white head and a pair of black tentacles.

Cross diagnosis. The main shell characters differentiating Diplommatina azlani , new species, from other sinistral Bornean Diplommatina species are the lack of parietalis and longitudinal palatalis in the shell constriction, and its dark ruby red shell colour. In addition, this species differs from Diplommatina riedeli Maassen, 2007 , Diplommatina mongondowensis Maassen, 2007 , and Diplommatina soputensis Sarasin & Sarasin, 1899 , from Sulawesi, and Diplommatina kakenca Nurinsiyah & Hausdorf, 2017 , from Java by the lack of longitudinal palatalis in shell constriction and by the presence of inconspicuous radial ribs on the body whorl. This new species has more densely placed radial ribs compared to Diplommatina tardigrada Benthem-Jutting, 1959 , Diplommatina strophosa Benthem-Jutting, 1959 , and Diplommatina tweediei Laidlaw, 1949 , from Sumatra, Diplommatina laidlawi Sykes, 1903 from Peninsular Malaysia, and Diplommatina busanensis Godwin-Austen, 1889 from Sarawak.

Etymology. The specific epithet honours the zoologist Mohd. Azlan Jayasilan of Universiti Malaysia Sarawak (UNIMAS) for his contributions to Bornean wildlife conservation and his interest in ecological studies of the terrestrial snails of Sarawak.

Geographic distribution and habitat. Diplommatina azlani , new species, is thus far known only from the type locality ( Fig. 2 ). The animals were observed living among leaf litter and plant debris near a rocky stream in lowland mixed dipterocarp forest.

Figures

Fig. 1. Diplommatina azlani, new species. A–D, holotype (MZU.MOL.17.91) (Scale bar = 1 mm): A, left lateral view; B, ventral view; C, apical view; D, apertural view; E, live animal of paratype (MZU.MOL.17.92) in natural habitat.

Fig. 2. Type locality of Diplommatina azlani indicated by red dot, and its relative position in Borneo Island (Google Earth Pro, 2018).