Aulacospira nutadhirai, Dumrongrojwattana & Tanmuangpak, 2020

Dumrongrojwattana, Pongrat & Tanmuangpak, Kitti, 2020, The terrestrial microsnail genus Aulacospira Moellendorff, 1890 (Eupulmonata, Stylommatophora, Hypselostomatidae) in Thailand with key to Thai species, ZooKeys 980, pp. 23-42 : 23

Aulacospira nutadhirai sp. nov. Figure 4E-H

Types examined.

Holotype. ZRCBUU 0391; Thailand, Khao Thanan, an isolated limestone hill of Thung-wa District, Satun Province; 7°03'42.2"N, 99°41'32.9"E; 10.iv.2010; leg. Dumrongrojwattana, P. Paratypes. ZRCBUU 0392 (10 shells); 10.iv.2010; ZRCBUU 0420 (5 shells); THNHM-iv-18802 (2 shells); MNHN IM-2014-7121 (2 shells); NHLRU 0010 (2 shells); collected from location same as holotype, 27.iv.2015; leg. Dumrongrojwattana, P.

Measurments.

Holotype H = 1.54 mm, W = 2.89 mm. Paratypes H = 1.47-2.50 mm, W = 2.61-3.07 mm.

Diagnosis.

Shell minute, helicoid. Protoconch smooth; body whorl stout, with a short projecting downward tuba; peristome not expanded; aperture lacking teeth.

Aulacospira nutadhirai sp. nov. is very similar to the eastern Thai species, A. khaopratun , but differs in its lower spire and more greatly inflated last whorl. Compared to Philippines species, Aulacospira nutadhirai sp. nov. is similar to A. porrecta but differs in the shape of the shell and in having no keel on the body whorl.

Description.

Shell minute, helicoid, brownish, with 4- 4½ whorls. Body whorl stout. Last quarter of body whorl with a short tuba projecting downward. Protoconch, consisting of 1¼ whorls, with granulose wrinkles. Teleoconch smoothish, with uneven oblique growth striae. Suture deep. Shell narrowly umbilicate. Spire low; first two whorls rounded. Penultimate whorl and body whorl with two shallow spiral sulci that continuously to peristome. Peristome expanded; aperture round and lacking teeth (Fig. 4E ).

Radula.

As in A. depressa (Fig. 4F ).

Genital system.

Atrium shorter than vagina. Penis shorter than epiphallus, with anterior and central portion large, bulging and posterior portion curved. Epiphallus connected to distal end of penis. Epiphallus glossy white, longer than vas deferens, with anterior portion cylindrical, central and posterior portion cylindrical, and distal end curved. Epiphallic flagellum absent. Epiphallic retractor caecum rounded, connected to distal part of epiphallus. Vas deferens short, slender, entering epiphallus apically. Vagina and free oviduct cylindrical, with vagina large and shorter than free oviduct. Gametolytic sac long and cylindrical, with anterior portion connecting vagina and free oviduct, posterior portion swollen. Uterus long, large, with very thin prostate gland adhering to it. Hermaphroditic duct loosely convolute. Albumen gland large and yellowish. Dart apparatus absent (Fig. 4G, H ).

Type locality.

Thailand, Khao Thanan, an isolated limestone hill of Thungwa District, Satun Province; 7°03'42.2"N, 99°41'32.9"E.

Etymology.

We name this species in honor of Mr Thammarat Nutathira or Kru Nok, a former staff member of Kampang Wittaya School, Thailand, who contributed to the study of the biodiversity and paleontology of the limestone in Satun Province.

Distribution.

This species appears limited to the type locality (Fig. 1 ).

Figures

Figure 1. Distribution map of Aulacospira spp. in Thailand: 1 A. depressa 2 A. khaopratun 3 A. panhai 4 A. khaobote 5 A. lampangensis 6 A. smaesarnensis 7 A. pluangtong 8 Aulacospira tekavongae sp. nov. 9 Aulacospira nudtadhirai sp. nov. 10 Aulacospira vanwalleghemi sp. nov.

Figure 4. A-D Aulacospira pluangtong (ZRCBUU 357) A shell B radula C, D genital system E-H Aulacospira nutadhirai sp. nov. E holotype (ZRCBUU 0391) F radula G, H genital system.