Sinoennea otostoma Páll-Gergely, A. Reischütz & Maassen, 2020

Páll-Gergely, Barna, Reischütz, Alexander, Maassen, Wim J. M., Grego, Jozef & Hunyadi, András, 2020, New taxa of Diapheridae Panha & Naggs in Sutcharit et al., 2010 from Laos and Thailand (Gastropoda: Eupulmonata: Stylommatophora), Raffles Bulletin of Zoology 68, pp. 1-13 : 7

Sinoennea otostoma Páll-Gergely, A. Reischütz & Maassen , new species

( Figs. 2A , 6K )

Type material. Holotype (1 shell, H: 3.15 mm, D: 1.78 mm; Fig. 2A ) ( NHMW 113109 ), Laos, Vientiane Province, cave Tham Pou Kham, west of Vang Vieng , 265 m a.s.l., 18°55.601′N, 102°23.711′E, at the base of limestone rocks near the cave entrance, coll. A. Reischütz, March 2010; 1 paratype (RE/1), same data as holotype.

Diagnosis. A medium-sized, glossy, ovoid species with ear-shaped (or bean-shaped) aperture.

Description. Shell translucent, glass-like, ovoid. Penultimate and last whorl are widest from standard apertural view. Entire shell with 5.25–5.75 whorls. Protoconch consisting of 1.75 whorls, glossy, very finely pitted, with traces of inconspicuous wrinkles near suture. Teleoconch glossy, with inconspicuous low ribs that are weakest on the cylindrical part (“body”) of the shell. The strongest ribs are behind the peristome, and some ribs are stronger on the body than others (these are probably indications of juvenile peristomes). Individual ribs look like wrinkles or waves created by pushing the shell surface in upper (towards protoconch) direction. Aperture bean-shaped, caused by the strong sinuous depression of the palatal wall. Parietal callus rounded, does not reach half of preceding whorl, relatively thick, and not “smeared” onto preceding whorl. Apertural dentition five-fold. Parietal lamella very strong, elevated, outer portion nearly straight, slightly oblique, bent in direction of columella. Inner part of parietal lamella lower, abruptly bent in the other direction. Sinulus relatively small, elongate, opens somewhat laterally. Outer thicker, larger palatal denticles and inner smaller, more pointed palatal denticles are situated on a ridge. Columellar tooth deeply situated, elongated, but relatively short and sharp. A blunt basal tooth is situated on the lip. Peristome thickened, expanded, and slightly reflected. Basal swelling situated some distance from peristome, relatively strong. Anterior to basal swelling with an elongate depression, which corresponds with the palatal ridge. Umbilicus narrowly open, rounded or teardrop-shaped due to the swollen inner part of the body whorl, whereby the swelling corresponds to deeply situated columellar tooth.

Measurements. H = 3.11–3.15 mm, D = 1.72–1.78 mm.

Differential diagnosis. In Laos, the most similar species is Sinoennea ljudmilena , new species. The glossy shell and the bean-shaped aperture makes its identification easy.

Etymology. The specific epithet is derived from the combination of the Greek words for ear and mouth, referring to the shape of the aperture.

Figures

Fig. 2. New Sinoennea Kobelt, 1904, species from Laos. A, Sinoennea otostoma Páll-Gergely, A. Reischütz & Maassen, new species (holotype); B, Sinoennea angustistoma Páll-Gergely, A. Reischütz & Maassen, new species (holotype). Scale bar represents 1 mm.

Fig. 6. Synoptic view of Sinoennea and Laoennea, new genus, species of Laos (all species shown) and northern Thailand. A, Laoennea carychioides Páll-Gergely, A. Reischütz & Maassen, new species; B, Sinoennea infantilis Páll-Gergely & Grego, new species; C–E, Sinoennea variabilis Páll-Gergely & Grego, new species; F, Sinoennea sutchariti Páll-Gergely & Hunyadi, new species; G, Sinoennea panhai Páll-Gergely & Hunyadi, new species; H, Sinoennea euryomphala Inkhavilay & Panha, 2016; I, Sinoennea ljudmilena Páll-Gergely, new species; J, Sinoennea lizae Maassen, 2008; K, Sinoennea otostoma Páll-Gergely, A. Reischütz & Maassen, new species; L, Sinoennea angustistoma Páll-Gergely, A. Reischütz & Maassen, new species. Scale bar represents 1 mm.