Angustopila psammion Pall-Gergely, Anker & Vermeulen 2022
- Dataset
- The world’s tiniest land snails from Laos and Vietnam (Gastropoda, Pulmonata, Hypselostomatidae)
- Rank
- SPECIES
- Published in
- Páll-Gergely, Barna, Jochum, Adrienne, J. Vermeulen, Jaap, Anker, Katja, Hunyadi, András, Örstan, Aydin, Szabó, Ábel, Dányi, László, Schilthuizen, Menno (2022): The world’s tiniest land snails from Laos and Vietnam (Gastropoda, Pulmonata, Hypselostomatidae). Contributions to Zoology 91: 62-78, DOI: 10.1163/18759866-BjA10025
Classification
- kingdom
- Animalia
- phylum
- Mollusca
- class
- Gastropoda
- order
- Stylommatophora
- family
- Gastrocoptidae
- genus
- Angustopila
- species
- Angustopila psammion
biology_ecology
Habitat: Angustopila psammion n. sp. was found in large numbers in small sediment deposits along the walls of a dry cave (Cap La Cave), in complete darkness. We assume that the sediment had fallen in through crevices in the rock, because it contains a species-rich assemblage of bleached, opaque shells of surface-dwelling terrestrial gastropods. Shells of Angustopila psammion n. sp., however, look fresh and are probably autochthonous.
description
Description: Shell tiny, off-white, depressed-globular form with domed spire; body whorl widest in standard apertural view; protoconch with 1.5 whorls and a minute and very uneven pattern of polygonal, rather sharp-crested ridges locally forming minute, conical peaks where ridges split (the structure also reminiscent of cross-sectional trabecular bone), no spiral striation discernible; teleoconch ornamented by some weak radial growth lines and much stronger, ropelike, equidistantly-arranged spiral striae (ca. 14 – 15 on body whorl from standard apertural view); the 3.25 – 3.5 whorls are separated by a deep suture; whorls slightly shouldered; aperture oblique to shell axis in lateral view; umbilicus relatively wide, less than one third of shell width; aperture kidney-shaped with strongly concave parietal side; sinulus wide, weakly separated due to weak parietal tooth; peristome expanded, not reflected; parietal callus strongly protruding, but in line with curvature of penultimate whorl and beyond aperture edge (profile) in lateral view (fig. 3 C), detached from penultimate whorl; parietal tooth weak, low, short, rounded, does not reach peristome. Soft anatomy unknown. Measurements (in mm): SW = 0.6 – 0.68, SH = 0.46 – 0.57 (n = 24).
diagnosis
Diagnosis: An Angustopila species with a depressed-globular shell with dome-shaped spire, thick spiral striae, kidney-shaped aperture with single parietal denticle not reaching parietal callus.
diagnosis
Differential diagnosis: Angustopila pallgergelyi Dumrongrojwattana, Chuenit & Wongkamhaeng, 2021 is similar in shell and aperture shape, but is larger, has a prominent palatal tooth (absent in Angustopila psammion n. sp.) and a stronger parietal tooth. Angustopila coprologos n. sp. is slightly larger, has a rough shell surface, and has an additional subcolumellar tooth and two palatal teeth.
distribution
Distribution: This new species is known only from the type locality, Cap La Cave, Ha Long Bay, Quang Ninh Province, Vietnam.
etymology
Etymology: The specific epithet (ΨαμμϯΟν) means a grain of sand in Greek and is used as a noun in apposition.
materials_examined
Type material: Vietnam, Quang Ninh Province, Ha Long Bay, Cap La Cave, 20 ° 51.793 ’ N, 107 ° 13.541 ’ E, soil deposit fallen through roof in pristine cave, vegetation outside cave tall and woody, leg. J. J. Vermeulen & K. Anker, 07 March 2018, holotype (HNHM 104886); CUMZ 7436 / 2 paratypes; SMF 365052 / 2 paratypes; VNMN / 2 paratypes; ZRC. MOL. 23218 / 2 paratypes, jjV 17633 / 409 paratypes.