Aulacospira vanwalleghemi, 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 vanwalleghemi sp. nov. Figure 5E-H

Types examined.

Holotype. ZRCBUU 0732; Thailand, Wat Khao Tam Ratt, an isolated limestone hill of Ta Takeab District, Chacheongsao Province; ca 35 m a.s.l.; 13°23'30.4"N, 101°44'39.1"E; 19.i.2020; leg. Dumrongrojwattana, P. Paratype. ZRCBUU 0733 (8 shells); as in holotype.

Measurments

(in mm). Holotype H = 3.17 mm, W = 3.28 mm. Paratypes H = 1.87-2.63 mm, W = 1.74-2.57 mm.

Diagnosis.

Shell minute, conical. Protoconch smooth; body whorl peripherally with a very with a very short projecting downward tuba; peristome expanded; aperture round and lacking teeth.

The shell shape and periphery of the last whorl of A. vanwalleghemi sp. nov. is similar to A. pluangtong , but apertural teeth are absent. Apertural teeth are present in A. pluangtong .

Description.

Shell minute, conical, brownish, with 4- 4½ whorls. Tuba very short, projecting downward. Protoconch consists of 1¼ whorls, granulosely wrinkled. Teleoconch smoothish, sculptured with uneven, oblique growth striae. Suture deep. Shell narrowly umbilicate. Spire high, with peripherally of most whorls rounded; penultimate and body whorls with strong keel at periphery continuously to peristome. Peristome expanded; aperture obliquely oval and lacking teeth (Fig. 5E ).

Radula.

As in A. depressa (Fig. 5F )

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 longer than vas deferens, with anterior portion with cylindrical, central and posterior portion cylindrical, distal end curved; white glossy. 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 a very long and slender, with anterior portion bulging, connects between vagina and free oviduct, posterior portion curved. Uterus long and large, with very thin prostate gland adhering to it. Hermaphroditic duct loosely convolute. Albumen gland large and yellowish. Dart apparatus absent (Fig. 5G, H ).

Type locality.

Thailand, Wat Khao Tam Ratt, an isolated limestone hill of Ta Takeab District, Chacheongsao Province; 13°23'30.4"N, 101°44'39.1"E; ca 35 m a.s.l.

Etymology.

We name this species in honor of Mr René Vanwalleghem, a Belgian conchologist who inspired the senior author to pursue mollusc research.

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 5. A-D Aulacospira tekavongae sp. nov. A holotype (ZRCBU 0610) B radula C, D genital system E-H Aulacospira vanwalleghemi sp. nov. E holotype (ZRCBUU 732) F radula G, H genital system.