Chamalycaeus krabiensis Pall-Gergely & A. Reischutz 2021, n. sp.
Creators: name: Páll-Gergely, Barna
name: Hunyadi, András
name: Grego, Jozef
name: Reischütz, Alexander
name: Auffenberg, Kurt
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Architaenioglossa
Cyclophoridae
Chamalycaeus
Chamalycaeus krabiensis

description: Chamalycaeus krabiensis Páll-Gergely & A. Reischütz n. sp.
Fig. 11
Material examined. Holotype: Thailand, Krabi Province, Phi-Phi Islands, Phi Phi Don Island, climbing rock at W end of beach in Ton Sai Bay, 7°44.011’N, 98°45.936’E, ca. 70 m a.s.l. (locality code: Th22), Mar. 2010, A. Reischütz leg., at base of limestone rocks in the forest, NHMW 113487 (D: 3.61 mm, H: 2.62 mm). Paratypes: 1 shell, same data as holotype; 1 shell, Thailand, Krabi Province, Phi-Phi Islands, Phi Phi Don Island, ascent to climbing rock at W end of beach in Ton Sai Bay, 7°44.049’N, 98°45.966’E, ca. 20 m a.s.l. (locality code: Th 21), Mar. 2010, A. Reischütz leg., at base of limestone rocks in forest, NHMW 113488 (photographed paratype: Fig. 11B, D: 3.73 mm, H: 2.37 mm); 9 shells, same data as preceding, RE; 2 shells, same data as preceding, CUMZ 5269; 7 shells, Thailand, Krabi Province, Phi-Phi Islands, Phi Phi Don Island, limestone rocks at Monkey Beach, 7°43.386’N, 98°46.135’E, ca. 10 m a.s.l. (locality code: Th 23), Mar. 2010, A. Reischütz leg., RE. Other material: 4 juvenile / broken shells, Thailand, Krabi Province, Phi-Phi Islands, Phi Phi Don Island, ascent to climbing rock at W end of beach in Ton Sai Bay, 7°44.049’N, 98°45.966’E, ca. 20 m a.s.l. (locality code: Th 21), Mar. 2010, A. Reischütz leg., at base of limestone rocks in forest, RE; 5 juvenile /broken shells, Thailand, Krabi Province, Phi-Phi Islands, Phi Phi Don Island, limestone rocks at Monkey Beach, 7°43.386’N, 98°46.135’E, ca. 10 m a.s.l. (locality code: Th 23), Mar. 2010, A. Reischütz leg., RE; 7 shells, 1.5 km SE of Ao Luek Tai, 8°22.386’N, 98°44.130’E, 40–45 m a.s.l., 16–19 Mar. 2020, S. Aiken leg., SA; 4 shells (one photographed here: Fig. 11C), 1.7 km SE of Ao Luek Tai, 8°22.020’N, 98°44.004’E, 25 m a.s.l., 19 Mar. 2020, S. Aiken leg., in dry debris on rock, at base of limestone cliff, SA.
Etymology. This new species is named for the Thai province in which it occurs.
Diagnosis. A medium-sized Chamalycaeus species with R2 and R3 of almost a quarter whorl each, blunt, elongated swelling on R3, protruding inner peristome, and strongly expanded outer peristome.
Description. Shell off-white to light grey; shell outline slightly oval in dorsal view; spire elevated, conical; body whorl rounded or parabolic; protoconch somewhat elevated, finely granular, rather glossy, spiral striae lacking, 1.5 whorls; R1 of 1.75–2.5 whorls, with strong, narrow, elevated, regularly arranged ribs, spaces between ribs relatively wide, fine spiral striation between ribs; boundary between R1 and R2 distinct due to change in rib density; R2 ribs more elevated than those of R1, narrow, lamella-like; ca. 26–28 ribs present; R2 and R3 of comparable lengths, covering approximately a half whorl or slightly less; boundary between R2 and R3 distinct due to rather deep constriction and change in sculpture; R3 with elongated, convex, central swelling, posterior portion almost smooth, anterior bears ribs of similar density as on R1; aperture strongly oblique to shell axis, rounded, with a very small upper (parieto-palatal) incision; boundary between inner and outer peristomes conspicuous, inner peristome strongly protruding (extreme in some specimens) and slightly expanded; outer peristome slim, strongly expanded except in umbilical region; umbilicus narrow, ca. one fourth of shell width.
Measurements. D: 3.41–3.81 mm, H: 2.34–2.62 mm (type samples).
Operculum. Unknown.
Differential diagnosis. Chamalycaeus reinhardti (Mörch, 1872) (examined material: Great Nicobar, coll. Godwin-Austen, NHMUK 1903.7.1.2711, 1 shell) and Chamalycaeus reinhardti sabangensis (Rensch, 1933) (examined material: Sumatra: Wald b. Sabang, Pulu Weh., exp. Rensch, 1927, SMF 6241, 1 paratype) both have a narrower swelling on R3 and a more elevated spire.
Distribution. This species is known from the Phi-Phi Islands and the vicinity of Ao Luek Tai town, Krabi Province, Thailand (Fig. 3).
Remarks. The shells from the two sites near Ao Luek Tai are slightly smaller (D: 2.8–3.3 mm), more depressed and conical from above, have overall denser ribs, lower R3 swelling, and the outer peristome is expanded in a smaller portion of the lip. However, although these differences occur, we consider them conspecific with those from Phi-Phi Islands due to the overall similar sculpture and proportions of shell regions.
description: Published as part of Páll-Gergely, Barna, Hunyadi, András, Grego, Jozef, Reischütz, Alexander & Auffenberg, Kurt, 2021, Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea), pp. 1-61 in Zootaxa 4973 (1) on page 17, DOI: 10.11646/zootaxa.4973.1.1, http://zenodo.org/record/4771958