Sinoennea loeiensis Tanmuangpak & S. Tumpeesuwan, 2015

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, Raffles Bulletin of Zoology 63, pp. 293-300 : 296-298

publication ID	https://doi.org/ 10.5281/zenodo.4502341
publication LSID	lsid:zoobank.org:pub:BE032FAC-72B0-4509-B05F-971789AD6F91
DOI	https://doi.org/10.5281/zenodo.4775982
persistent identifier	https://treatment.plazi.org/id/4924879C-FFA6-B65F-FFE6-140194E56C43
treatment provided by	Carolina
scientific name	Sinoennea loeiensis Tanmuangpak & S. Tumpeesuwan
status	sp. nov.

Treatment

Sinoennea loeiensis Tanmuangpak & S. Tumpeesuwan , new species

Figs. 2–5 View Fig View Fig View Fig View Fig ; Table 2 View Table 2

Type material. Holotype: NHMSU-0004 ( Fig. 3 View Fig ). 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 View Fig , 5 View Fig ); 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 View Fig ).

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 View Table 2 ), glassy transparent and shiny ( Figs. 2 View Fig , 3A, B View Fig ). Apex depressed and smooth ( Fig. 3C View Fig ). Middle part of each whorl convex and largely smooth, upper part of each whorl possesses regular vertical ribs ( Fig. 3D View Fig ), 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 View Fig ). 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 View Fig ). Aperture almost vertical, irregularly quadrangular with rounded angles, peristome smooth, inner side of aperture possesses only small nodules ( Fig. 3G View Fig ). 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 View Fig ). The palatal side comprises two unequal teeth (1 st PL and 2 nd PL), which lie deep inside the aperture ( Fig. 3F View Fig ). 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 View Fig ).

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 View Fig ).

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 View Fig ).

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 View Fig ).