Bakyietaia boettgeri (Möllendorff, 1890), Zhang & Yen & Chen & Du & Ng & Rintelen, 2025

Bakyietaia boettgeri (Möllendorff, 1890) gen. et comb. nov.

Figs 11–12 View Fig View Fig

Paludina boettgeri Möllendorff, 1890 in Heude 1882 –1890: 177, pl. 10 fig. 6 (“Hai-nan”, Hainan Province, China).

Viviparus ( Taia) boettgeri – Zilch 1938: 131.

Angulyagra boettgeri View in CoL – Yen 1939: 38, pl. 3 fig. 17. — Liu et al. 1995: 14.

Diagnosis

Adult shell medium to large (26.76 ± 6.67 mm), sturdy, conical, whorls not inflated, prominent keel above suture; columellar lip recurved, forming callus covering umbilicus completely; operculum with small nuclear region (around 1/5 of inner opercular region) with shiny grains or veins; outer marginal tooth of radula with 23 to 24 small sharp cusps.

Material examined

Paratypes

CHINA • 5 specs (preserved dry); Hainan Island; O. Böttger leg.; SMF.7651 • 2 specs (preserved dry); Hainan Island; O.v. Möllendorff leg.; SMF.7653 .

Other material

CHINA – Guangxi • 1 spec. (preserved in ethanol); Nanning City, Dawangtan Reservoir ; Aug. 2019; KIZ.240087 • 5 specs (preserved in ethanol); Baise City, Youjiang District, Wula Village , Sanglu , 0.5 m deep on rocks of creeks; 17 Oct. 2019; Jian-Zhuo Li leg.; ZMB.122687 • 3 specs (preserved dry); same data as for preceding; YHY-BAKBOE-SL-1 , YHY-BAKBOE-SL-2 , YHY-BAKBOE-SL-18 • 5 specs (preserved in ethanol); Guigang City, Gangnan District, Batang Village , a pond near Yapengling , 0.7 m deep on rocks; 31 Oct. 2020; Xia-Ming Li leg., ZMB.122759 • 1 spec. (preserved dry); same data as for preceding; YHY-BAKBOE-BT-1 • 1 spec. (preserved dry); Chongzuo City, Daxin County, Leiping Town , Heishui River , 1 m deep on rocks; 27 Mar. 2021; Yi-Wen Liang leg.; ZMB.122690 • 4 specs (preserved dry); same data as for preceding; YHY-BAKBOE-HSH-21 , YHY-BAKBOE-HSH-15 , YHY-BAKBOE-HSH-9 , YHY-BAKBOE-HSH- 3 • 4 specs (preserved in ethanol); Chongzuo City, Jiangzhou District, Tuozao Village , Zuo River , 0.5 to 1.5 m deep on rocks; 27 Mar. 2021; Yi-Wen Liang leg.; ZMB.122758 • 3 specs (preserved dry); same data as for preceding; YHY-BAKBOE-JZ-15 , YHY-BAKBOE-JZ-14 , YHY-BAKBOE-JZ-1 • 2 specs (preserved in ethanol); Nanning City, Mashan County, Shitang Village , 0.3 m deep on sand/mud substrate in the wetland; 19 Mar. 2022; Le-Jia Zhang leg.; ZMB.122734 • 3 specs (preserved in ethanol); Pingguo City, Yihao Village, Bujian River , 0.5 to 1 m deep on mud substrate; 19 Mar. 2022; Le-Jia Zhang leg.; ZMB.122720 . – Hainan Province • 2 specs (preserved dry); Hainan Island, Jetschin leg.; SMF.88400 • 5 specs (preserved in ethanol); Haikou, wetlands near Yangshan Reservoir ; 20 Oct. 2019; bought by Sheng-Zhuo Huang on local market; ZMB.122710 .

Description

Adult shell ( Fig. 11A–R View Fig ) medium to large (26.76 ± 6.67 mm), thin to thick, sturdy, conical, olive brown to dark brown, with five to six whorls, apex acute; teleoconch whorls not inflated, with three smooth primary keels, with one to two weaker smooth secondary keels located between suture and first keel, sometimes one additional weak keel located between first and second/second and third keels, base of shell with one to five weak keels, all keels usually darker than rest of shell surface, prominent keel above suture; aperture ovate, less than half of shell in height, inner shell surface bluish white, orange-red or dark purple, outer lip thin, always with an obvious angular periphery, columellar lip covered with thick inner shell layers, white or orange-red, adult columellar lip recurved, forming a relatively wide crescent-shaped callus, completely covering umbilicus.

Operculum ( Fig. 11S–T View Fig ) corneous, ovate, relatively thick, dark red; exterior surface smooth; interior surface with small nuclear region, around 1/5 of inner opercular region, with shiny grains or veins or smooth glossy surface.

Radular ( Fig. 12 View Fig ) (n = 3) central tooth with one broad central denticle and five to six small sharp cusps on either side; lateral tooth with one broad central denticle and four to five small sharp cusps on either side; inner marginal tooth narrow, about half of lateral tooth in width, with one broad central denticle and four small sharp cusps on either side; outer marginal tooth wide, almost same as lateral tooth in width, with 23 to 24 small sharp cusps.

Remarks

The newly collected specimens from Haikou City of Hainan have a shell that is very similar to that of the type specimens. Bakyietaia boettgeri can be distinguished from most congeners based on its medium-sized to large conical shell with non-inflated whorls, and strongly keeled suture. Some small individuals of this species may be confused with Bakyietaia jingweiae Yen, Zhang & von Rintelen gen. et sp. nov. based on shell morphology, but differ by possessing fewer cusps on the outer marginal tooth (23–24 vs 26–28). The COI tree supports B. boettgeri and B. jingweiae as distinct species, and the two species are allopatric ( Fig. 1 View Fig ). The recommended Chinese name is 伯氏ṉ田ª.

Habitat and distribution

Mud, sand and rock substrate in the shallow water of rivers, lakes and wetlands of northern Hainan and southern Guangxi, China.