Metalycaeus anas Páll-Gergely & A. Reischütz, 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 : 45-48

publication ID	https://doi.org/ 10.11646/zootaxa.4973.1.1
publication LSID	lsid:zoobank.org:pub:42EB4BF2-A571-4894-9EEF-783649A27E4F
DOI	https://doi.org/10.5281/zenodo.4771793
persistent identifier	https://treatment.plazi.org/id/038487E6-2F0C-2415-FF12-B0F7FBAEF87D
treatment provided by	Plazi
scientific name	Metalycaeus anas Páll-Gergely & A. Reischütz
status	sp. nov.

Treatment

Metalycaeus anas Páll-Gergely & A. Reischütz n. sp.

Figs 35–36 View FIGURE 35 View FIGURE 36

Material examined. Holotype: Thailand, Chiang Rai Province, Wat Phra That Tham Doi Khong Khao Meditation Centre, ca. 8 km W of Chiang Rai, cave clay at entrance of cave, 19°54.771’N, 99°46.607’E, ca. 420 m a.s.l. (locality code: Th6), Sep. 2007, A. Reischütz leg., NHMW 113489 View Materials (D: 3.3 mm, H: 2.05 mm) GoogleMaps . Paratypes: 1 shell (fig. 35B), same data as holotype, NHMW 113490 View Materials GoogleMaps ; 7 shells, same data as holotype, RE GoogleMaps ; 2 shells, same data as holotype, CUMZ 5270 View Materials GoogleMaps . Other Material: 4 broken shells, same data as holotype, RE GoogleMaps .

Etymology. The specific epithet (noun in apposition) derives from the shape of R3 that resembles a duck’s beak ( anas = duck in Latin).

Diagnosis. A medium-sized Metalycaeus species with a weakly sculptured R1 (fine growth lines and spiral striae), almost smooth R2, a R3 with convex, central swelling and a rounded aperture.

Description. Shell light grey, probably somewhat translucent when fresh; shell outline slightly oval in dorsal view, spire somewhat elevated, low conical; body whorl rounded (rather “parabolic”); protoconch conspicuously large to shell size, somewhat elevated, last whorl spirally striated, 1.5 whorls; R1 of 1.25 whorls, with very weak ribs (growth lines) occasionally moderately strong near suture, and fine spiral striations; boundary between R1 and R2 distinct due to R2 axial sculpture; R2 with narrow, somewhat elevated light-coloured stripes alternating with broader, darker stripes, ca. 24–32 R2 stripes present; R2+R3 approximately or slightly more than quarter whorl; R2 slightly shorter than R3; R3 practically smooth, bearing only low growth lines; boundary between R2 and R3 distinct due to lack of R3 light stripes (ribs) and rather deep constriction; R3 with elevated, convex central swelling with anterior slope steeper than posterior; aperture strongly oblique to shell axis; round; boundary between inner and outer peristomes distinct; inner peristome protruding, expanded, rather slim; outer peristome of comparable strength, expanded, and slightly reflected toward umbilicus; umbilicus relatively narrow, approximately one fourth the shell width.

A cross-sectional view of R2 of one specimen was examined ( Fig. 36E–G View FIGURE 36 ): anterior crust very slightly elevated, forming very low, blunt rib; anterior crust and the slightly weaker posterior crust adnate, forming slender microtunnel in cross-sectional view.

Measurements. D: 3.3–3.91 mm, H: 2.05–2.26 mm.

Operculum. unknown.

Differential diagnosis. Metalycaeus rubinus (Godwin-Austen, 1893) (examined material: Ruby Mines District, Up. Burma, leg. Doherty, NHMUK 1903.7.1.2685, 2 syntypes, Fig. 37 View FIGURE 37 ) is the only Metalycaeus species reported from Myanmar having atypical R2 ribbing. It is far larger and has an elevated spire.

Distribution. This new species is known only from the type locality ( Fig. 17 View FIGURE 17 ).