Diplommatina laemsonensis Boonmachai & Nantarat, 2023

Boonmachai, Tuangthong, Bergey, Elizabeth A. & Nantarat, Nattawadee, 2023, First record and description of three new species in the land snail genus Diplommatina Benson, 1849 (Caenogastropoda, Diplommatinidae) from Satun Province, Thailand, Zoosystematics and Evolution 99 (1), pp. 195-207 : 195

publication ID	https://dx.doi.org/10.3897/zse.99.99030
publication LSID	lsid:zoobank.org:pub:E28DD35A-30EA-4C53-B5A6-F0A80CA0CFC0
persistent identifier	https://treatment.plazi.org/id/A1F06C5D-F1EC-41FC-8345-D9BA7693D8E2
taxon LSID	lsid:zoobank.org:act:A1F06C5D-F1EC-41FC-8345-D9BA7693D8E2
treatment provided by	Zoosystematics and Evolution by Pensoft
scientific name	Diplommatina laemsonensis Boonmachai & Nantarat
status	sp. nov.

Treatment

Diplommatina laemsonensis Boonmachai & Nantarat sp. nov.

Figs 2B View Figure 2 , 3D-F View Figure 3

Type material.

Holotype CMUZ 9050019 (Fig. 2B View Figure 2 ); Shell measurements: SH = 2.26 mm, SW = 1.17 mm, AH = 0.77 mm, AW = 0.83 mm, W = 7. Paratypes CMUZ 9050020-9050024 (5 shells); Shell measurements: SH = 2.14-2.49 mm, SW = 1.08-1.21 mm, AH = 0.76-0.91 mm, AW = 0.79-0.86 mm, W = 6 1/2-7.

Type locality.

Thailand, Satun Province, La-ngu District, Limestone Hill, 6°54'43.7"N, 99°41'59.0"E, 25 December 2020, coll. T. Booonmachai.

Other material examined.

Thailand, Satun Province; La-ngu District, Limestone Hill, 6°54'43.7"N, 99°41'59.0"E, 25 December 2020: CMUZ 9050025-9050047 (23 shells); La-ngu District , Khoa Yai Island , 6°83'08.6"N, 99°69'70.1"E, 21 December 2022: CMUZ 9050048-9050065 (18 shells) GoogleMaps .

Etymology.

The specific epithet laemsonensis is an adjective referring to the type locality (Laem Son subdistrict, Lan-gu district, Satun Province, Thailand).

Differential diagnosis.

Among the sinistral species of Diplommatina , Diplommatina laemsonensis sp. nov. is most similar to D. diminuta Möllendorff, 1891, D. sinistra Tomlin, 1938 and D. acme Laidlaw, 1949 (Table 1 View Table 1 ). All these species share a moderately slender fusiform shape, rounded periphery, shell height range and number of whorls (Table 1 View Table 1 ). However, Diplommatina laemsonensis differs from D. acme , D. diminuta and D. sinistra in the number of radial ribs in the penultimate whorl (Table 1 View Table 1 ). It differs from D. diminuta in shell width and the ratio of AH/AW (Table 1 View Table 1 ). Moreover, it differs from D. diminuta by the absence of teeth on the basal margin of the aperture and differs from D. sinistra in having a distinct columellar denticle in the aperture.

Description.

Shell sinistral, fusiform, convex and honey brown in color (Figs 2B View Figure 2 , 3D View Figure 3 ). The penultimate whorl widest. Spire conical with slightly convex sides. Suture impressed. Constriction level with the edge between the parietal and columellar side of the peristome, with three lamellae: one distinct parietalis which starts at the constriction, one transversal palatalis, one distinct columellaris which continues into the tuba and visible in the aperture (Fig. 4C, D View Figure 4 ). Protoconch sculpture smooth with fine pitting and about 1 whorl (Fig. 3E View Figure 3 ). Radial ribs straight, distinct, rather dense on top of the teleoconch, suddenly changing to a moderately spaced about 8-9 ribs/0.5 mm on the penultimate whorl (Table 1 View Table 1 ). The aperture tilted up to 30 °C in relation to the coiling axis, columellar denticle visible in the aperture, deflected downwards. Peristome double, expanding, palatal side rounded with slightly edge, basal side with edge slightly protruding. Outer peristome expands beyond the inner peristome with about four layers, inner peristome with distinct a palatal, basal and columellar lips. Umbilicus closed. Operculum multispiral, flat, corneous, transparent, slightly concave, outer surface smooth with small pits distributed over whole surface, inner surface smooth with raised peripheral circular margin (Fig. 3F View Figure 3 ). The radula of the taenioglossate type (Fig. 5A View Figure 5 ). Central tooth strong with a large central cusp, with 2 pairs of developed lateral cusps. Basal plate of central tooth prominent with 2 small cusps. The lateral teeth with six cusps, the third cusp longest. In the marginal teeth, the inner teeth larger than the outer, with six cusps, the third cusp longest. The outer tooth with four cusps (Fig. 5A View Figure 5 ).