Arinia (Notharinia) boucheti Páll-Gergely, 2018

Páll-Gergely, Barna & Hunyadi, András, 2018, Four new cyclophoroid species from Thailand and Laos (Gastropoda: Caenogastropoda: Alycaeidae, Diplommatinidae, Pupinidae), Zoosystema 40 (3), pp. 59-66 : 63-64

Arinia (Notharinia) boucheti Páll-Gergely , n. sp.

( Fig. 2 )

TYPE MATERIAL. — Northern Laos. Phuom Laong, coll. Saurin, MNHN-IM- 2014-6415 (holotype, H = 1.88 mm, D = 0.81 mm); same data, MNHN-IM- 2014-6416 (2 paratypes) .

ETYMOLOGY. — This species is dedicated to and named after Prof. Philippe Bouchet to acknowledge that he tracked Edmond Saurin’s (1904-1977) material in the late 1970’s, and made it available for study.

TYPE LOCALITY. — Northern Laos, Phuom Laong.

DIAGNOSIS. — A Notharinia species with strong, comparatively widely-spaced ribs, oblique aperture, and clearly separated inner and outer peristomes.

DIFFERENTIAL DIAGNOSIS. — The most similar species in terms of shell size, shape, and rib density is Arinia (Notharinia) crassilabris Vermeulen, Phung & Truong, 2007 . That species, however, differs from the new species in the following traits: aperture is less oblique to the shell axis; the boundary between the two peristomes is hardly visible; and the outer peristome is less reflected.

DISTRIBUTION. — This species is known from the type locality only.

DESCRIPTION

Shell whitish, semitransparent, cylindrical, typical to Notharinia ; constriction not observed; protoconch oblique, with 1-1.25 whorls, nearly smooth, extremely finely pitted; apex sunken; teleoconch rather regularly, strongly ribbed, rib density decreasing towards aperture; no spiral striation observed on entire shell; whorls 4.75-5.5; aperture rounded, strongly oblique to shell axis; peristome adnate to penultimate whorl; inner peristome protruding, outer peristome expanded but not reflected; boundary between two peristomes conspicuous; individual ribs elevated, slightly bent anteriorly; umbilicus closed. Operculum and soft anatomy unknown.

Measurements (in mm)

H = 1.57-1.88, D = 0.81 (n = 2).

REMARKS

Currently five species of the subgenus Notharinia are known: Arinia (Notharinia) attenuata ( Vermeulen, Phung & Truong, 2007) , A. (N.) brevior ( Vermeulen, Phung & Truong, 2007) , A. (N.) crassilabris , A. (N.) linnei ( Maassen, 2008) , and A. (N.) micro Marzuki & Foon, 2016 . The former three species were described from Southern Vietnam’s Kien Giang Province, whereas the latter two species are known from the Malay Peninsula. Two further undescribed species ( Notharinia sp. nov. ‘Khoe La’ and Notharinia sp. nov. ‘Khoe La & Ong’), also from Kien Giang Province, were assessed using to IUCN criteria ( Vermeulen & Anker 2016a, b). The type locality of Arinia (Notharinia) boucheti Páll-Gergely , n. sp. could not be located on the map, but it must be somewhere in Northern Laos. The occurrence of a Notharinia species in northern Laos considerably extends the distribution of the subgenus northwards.

There is an unusually large variation in terms of the number of whorls in Arinia (Notharinia) boucheti Páll-Gergely , n. sp. Similar observations were made by Marzuki & Foon (2016) in A. (N.) micro . We might assume that the high variability of whorl numbers is characteristic for this subgenus.

Figures

FIG. 2. — Arinia (Notharinia) boucheti Páll-Gergely, n. sp.: A, C, D, holotype; B, E, one of the paratypes. Photograph: Barna Páll-Gergely. Scale bars: A, B,