Sinoennea ljudmilena Páll-Gergely, 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 : 6-7

Sinoennea ljudmilena Páll-Gergely , new species

( Figs. 3 , 6I )

Type material. Holotype (1 shell, H: 4.47 mm, D: 2.56 mm; Fig. 3 ) (MNHN-IM-2012-27277), Laos, Pah Hia, Province du Tran Ninh, coll. Saurin; 19 paratypes ( MNHN- IM-2012-27278), same data as holotype.

Diagnosis. A large, glossy species with knots along the suture in the last three whorls, and an ovoid aperture with a very strong, curved parietal lamella.

Description. Shell yellowish, ovoid. Some specimens nearly cylindrical with domed upper side. Whorls of several specimens grow irregularly resulting in a roof tile-like structure ( Fig. 3C ). Penultimate or antepenultimate whorl is widest from standard apertural view. Entire shell consisting of 7–7.75 whorls. Protoconch consisting of 1.5–1.75 whorls, glossy, very finely pitted, sometimes with traces of inconspicuous radial wrinkles. Teleoconch with irregular sculpture. Initial whorls usually with full ribs extending from suture to suture, last ca. three whorls (cylindrical part of shell) glossy, with remains of ribs (knots) near upper suture, or very rarely with a few full ribs, which are probably indications of juvenile peristomes. Last half whorl again with full ribs. Individual ribs look like wrinkles or waves created by pushing the shell surface in upper (towards protoconch) direction. Aperture suboval to rectangular. Parietal callus rounded, reaches ca. half of preceding whorl, thin, “smeared” onto the preceding whorl. Apertural dentition five-fold, closes passage so effectively that it is hard to see inside aperture even by viewing obliquely. Parietal lamella very strong, elevated, outer portion strongly oblique, bent in direction of columella. Inner part of parietal lamella lower, abruptly bent in the other direction. Sinulus relatively small, strongly isolated (i.e., parietal lamella and upper palatal tooth nearly reaching each other), opens somewhat laterally. Three palatal denticles pointed, and of comparable size, situated along an oblique ridge. Outermost denticle sits on the edge of sinulus; columellar tooth deeply situated, elongated lamella-like, sharp. Peristome thickened, expanded, and slightly reflected. Basal swelling situated in some distance from peristome, very slight. Anterior to basal swelling with a point-like depression, which corresponds with the lower palatal denticle. Umbilicus narrow but open, teardrop-shaped due to the swollen inner part of the body whorl, whereby swelling corresponds with deeply situated columellar tooth.

Measurements. H = 4.37–5.31 mm, D = 2.39–2.78 mm (smallest and largest specimens measured).

Differential diagnosis. There are no similar species in Laos, Vietnam, or Thailand. The Chinese Sinoennea manyunensis B. Fan, M. Tian & Y.-X. Chen, 2014, is similar in its large size, oval shell, and aperture formation. However, it has ribs extending from suture to suture, and has a long palatal ridge running into the aperture from the peristome. Sinoennea otostoma , new species, has a similar aperture formation, and therefore, it is probably closely related. However, it is much smaller and glossier, and has a bean-shaped aperture.

Etymology. This species is named after its resemblance to the genus Ljudmilena Schileyko, 1984, of the Enidae B.B. Woodward, 1903 .

Remarks. The type locality (Pah Hia) could not be found on maps. In an earlier article, we speculated that its geographic position could be at 18°59′N, 103°16′E (see Páll-Gergely et al., 2016).

Figures

Fig. 3. A, Sinoennea ljudmilena Páll-Gergely, new species (holotype); B, C, paratypes. 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.