Sinoennea loeiensis Tanmuangpak & Dumrongrojwattana & Tumpeesuwan & Tumpeesuwan 2015, new species
Creators: name: Tanmuangpak, Kitti
name: Dumrongrojwattana, Pongrat
name: Tumpeesuwan, Chanidaporn
name: Tumpeesuwan, Sakboworn
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Streptaxidae
Sinoennea
Sinoennea loeiensis

description: Sinoennea loeiensis Tanmuangpak & S. Tumpeesuwan, new species
Figs. 2–5; Table 2
Type material. Holotype: NHMSU-0004 (Fig. 3). Measurements: shell height (SH) 4.10 mm, shell width (SW) 2.00 mm; type locality: Phu Pha Lom Limestone Hill in Mueang District, Loei Province, Northeastern Thailand, coll. K. Tanmuangpak, November 2012. Paratype: NHMSU-0005 (genital system and radula) (Figs. 4, 5); NHLRU-0002 (1 specimen in 70% alcohol and 1 shell); ZRCBUU 03396 (1 shell); ZRC.MOL.5794 (1 shell), coll. K. Tanmuangpak, November 2012 – May 2014.
Etymology. The specific epithet “ loeiensis ” refers to Loei Province, Northeastern Thailand, where this species was discovered.
Diagnosis. Shell surface rather smooth, regular vertical ribs retained in the deep suture. The parietal side of the peristome is attached to the umbilical keel. The umbilicus is very wide with many transverse ribs. In the aperture, one basal tooth is present. Two columellar teeth present near the peristome, of which a plate-like columellar tooth is deeper within the aperture (Fig. 3F).
Description. Shell: minute, dextral, ovoid-cylindrical, shell height 4.10–4.92 mm (holotype 4.10 mm), shell width 2.00– 2.27 mm (holotype 2.00 mm), aperture height 1.34–1.93 mm (holotype 1.34 mm), aperture width 0.86–1.12 mm (holotype 1.00 mm) (Table 2), glassy transparent and shiny (Figs. 2, 3A, B). Apex depressed and smooth (Fig. 3C). Middle part of each whorl convex and largely smooth, upper part of each whorl possesses regular vertical ribs (Fig. 3D), about 24–26 on the last whorl; suture deep. On the third to last whorl the ribs are rather distantly placed, the ribs bulge on the suture part and regularly attenuate towards the middle part of the each whorl. Umbilical ribs vertical, prominent, which continuously connect from the middle part of the last whorl. These ribs extend to the umbilicus (Fig. 3E). Whorls 6⅓, regularly increasing in size towards the last whorl of the shell. Last whorl is a little pinched around the rather wide umbilicus (Fig. 3E). Aperture almost vertical, irregularly quadrangular with rounded angles, peristome smooth, inner side of aperture possesses only small nodules (Fig. 3G). One large parietal tooth lies at the middle of parietal site, which its distal part points downward to the columellar tooth (C) direction (Fig. 3A, F). The palatal side comprises two unequal teeth (1 st PL and 2 nd PL), which lie deep inside the aperture (Fig. 3F). There is only one basal tooth (B) deep in aperture. On the columellar side there are two teeth, a low rounded knob (C) at the margin and a plate-like tooth (pC) that lies well inside aperture.
Body: Live specimens with a yellow foot and pale yellow tentacles (Fig. 2).
Genital system: Atrium (at) rather short. Penis (p) very long, central section cylindrical shape, distal section curved and bottom part narrow. Vas deferens (vd) very long and slender, entering penis subapically. Penial retractor muscle (pr) attached to flagellum apically.Vagina (v) short and rather stout. Free oviduct (fo) cylindrical shape and longer than vagina. Gametolytic sac (gs) with narrow, long stalk, reservoir ovate. Prostate gland (pro) long. Hermaphroditic duct (hd) loosely convoluted. Albumin gland (ag) yellowish and rather long (Fig. 4).
Radula: Radula teeth arranged in V-shape rows; 42 rows of teeth (n = 1), each row contains 19–21 teeth, for which the dentition formula is (9-10) + C + (9-10). Central tooth unicuspid, elongate mesocone narrowly pointed, ectocones absent. Latero-marginal teeth (LM) unicusid, gradual change from elongate and long narrow pointed mesocone to more elongate and slender mesocone (Fig. 5).
Remarks. Reproductive anatomy of S. loeiensis was compared with that of S. kanchingensis, which is presently the only congener with its reproductive anatomy studied and known (see Berry, 1963). The gametolytic sac is shorter than S. kanchingensis; vas deferens entering penis subapically. Vagina shorter than free oviduct. Uterus (u) of each of the two live collected specimens contained one large egg (eg) (Fig. 4).
description: Published as part of Tanmuangpak, Kitti, Dumrongrojwattana, Pongrat, Tumpeesuwan, Chanidaporn & Tumpeesuwan, Sakboworn, 2015, Sinoennea loeiensis, a new species of diapherid microsnail (Pulmonata: Streptaxoidea: Diapheridae) from Phu Pha Lom Limestone Hill, Loei Province, Northeastern Thailand, pp. 293-300 in Raffles Bulletin of Zoology 63 on pages 296-298, DOI: 10.5281/zenodo.4502341