Chamalycaeus erawan Páll-Gergely & Hunyadi, 2021

Páll-Gergely, Barna, Hunyadi, András, Grego, Jozef, Reischütz, Alexander & Auffenberg, Kurt, 2021, Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea), Zootaxa 4973 (1), pp. 1-61 : 8-9

Chamalycaeus erawan Páll-Gergely & Hunyadi n. sp.

Fig. 4

Material examined. Holotype: Thailand, Kanchanaburi Province, Erawan National Park, Erawan Falls Trail, 14°22.310’N, 99°8.699’E, 90 m a.s.l. (locality code: 2015/28), 17 Feb. 2015, A. Hunyadi leg., HNHM 104869 (D: 2.45 mm, H: 1.53 mm) . Paratypes: 4 shells, same data as for holotype, HA ; 1 shell, Thailand, Kanchanaburi Province, 4.3 km SW Kanchanaburi, Taoist Buddhist temple, 13°59’N, 99°31’E, 40 m a.s.l., 13 May 1988, K. Auffenberg leg., litter sample, UF 345935 .

Etymology. The specific epithet refers to the type locality (Erawan National Park).

Diagnosis. A small Chamalycaeus species with bluntly angled body whorl, short R2, rounded aperture, and strongly expanded outer peristome.

Description. Shell off-white to light grey, rather glossy, very slightly translucent; shell outline slightly oval in dorsal view; spire slightly elevated, conical-domed; body whorl rather bluntly angled, depressed inward basolaterally in apertural view; protoconch rather low, glossy, spiral striae lacking, 1.25–1.5 whorls; R1 of 1.5–1.75 whorls, with irregular, narrow, but rather low ribs and some weak spiral striation; boundary between R1 and R2 not distinct, but visible due to change in rib density; R2+R3 approximately a quarter whorl; R2 short, about one third of R3 length, only ca. 14–16 ribs; R2 ribs low, dorsally rounded; boundary between R2 and R3 distinct due to moderately deep constriction and almost smooth early R3; R3 with elongated, almost smooth (only a few low riblets/growth lines) central swelling; aperture oblique to shell axis, round; distance between inner and outer peristomes conspicuous, inner peristome protruding, thin, but robust, and slightly expanded; outer peristome strongly expanded, but not reflected, reduced in umbilical area; umbilicus narrow, less than one third shell width.

Measurements. D: 2.25–2.45 mm, H: 1.49–1.56 mm.

Operculum. Unknown.

Differential diagnosis. This new species differs from Chamalycaeus irmatallus n. sp. in the larger size, longer R3, and more expanded peristome.

Distribution. This species is known only from two nearby localities ( Fig. 5 ).

Figures

FIGURE 4. Chamalycaeus erawan Páll-Gergely & Hunyadi, n. sp., holotype (HNHM 104869).

FIGURE 5. Distribution of alycaeid species. Inverted empty triangle: Dicharax cyclostoma Páll-Gergely, n. sp., empty triangle: Chamalycaeus spiratus Páll-Gergely, n. sp., filled triangle: Metalycaeus bicarinatus Páll-Gergely & Hunyadi, n. sp., inverted filled triangles: Chamalycaeus erawan Páll-Gergely & Hunyadi n. sp., empty circles: Metalycaeus aries Páll-Gergely & Auffenberg, n. sp., filled circles: Metalycaeus heudei (Bavay & Dautzenberg, 1900) (the one in the north indicates the type locality of Alycaeus kengtungensis Godwin-Austen, 1914), square: Metalycaeus pygmachos Páll-Gergely & Hunyadi, n. sp.