Bakyietaia naiadica Zhang, Yen & von Rintelen, 2025

Bakyietaia naiadica Zhang, Yen & von Rintelen gen. et sp. nov.

urn:lsid:zoobank.org:act:

Figs 34–35 View Fig View Fig

Diagnosis

Shell medium in size (25.73 ± 0.62 mm), sturdy, cylindrical outline, with very weak primary keels, weak keel above suture, outer lip angular; 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 19–22 small sharp cusps.

Etymology

Named after Naiads, the nymphs of freshwater bodies such as springs in Greek mythology. The recommended Chinese name is żēṉ田ª.

Material examined

Holotype

CHINA • spec. preserved in ethanol; Hainan Province, Haikou City, spring near Longpo Temple , 0.1 m deep on rock; 5 Mar. 2022; Le-Jia Zhang leg.; KIZ.240044 .

Paratypes

CHINA • 1 spec. (preserved in ethanol); same data as for holotype; ZMB.122743 • 1 spec. (preserved in ethanol); Hainan Province, wetland in Xue Village , Haikou City, 0.1 m deep on rock substrate; 3 May 2022; Le-Jia Zhang leg.; KIZ.240045 .

Other material

CHINA • 1 spec. (preserved dry); Hainan Province, wetland in Xue Village , Haikou City, 0.1 m deep on rock substrate; 3 May 2022; Le-Jia Zhang leg.; YHY-BAKNAI-XC-1 .

Description

Adult shell ( Fig. 34A–G View Fig ) medium (25.73 ± 0.62 mm), thin but sturdy, conical, olive to dark olive brown, with five whorls; teleoconch whorls inflated, with shoulder, with three very weak smooth primary keels, with one to two even weaker smooth secondary keels located between suture and first keel, sometimes with one additional weak keel located between first and second/second and third keels, base of shell with two to four weak keels, all keels usually darker than rest of shell surface; aperture ovate, less than half of shell in height, inner shell surface bluish white, outer lip thin, always with an obvious angular periphery, columellar lip covered with thick inner shell layers, white or pale orange, adult columellar lip recurved, sometimes forming a crescent-shaped callus, this structure completely covering umbilicus.

Operculum ( Fig. 34H–I View Fig ) corneous, ovate, thin, 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. 35 View Fig ) (n = 1) central tooth with one broad central denticle and four to five 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 width of lateral tooth, with one broad central denticle and five to six small sharp cusps on either side; outer marginal tooth wide, almost same as lateral tooth in width, with 19 to 22 small sharp cusps.

Remarks

Bakyietaia naiadica gen. et sp. nov. can be easily distinguished from all congeners, especially the morphologically similar B. mutica , based on its more cylindrical shell with weaker primary keels and less prominent keel at suture.

Habitat and distribution

Rock substrate in the shallow water of springs and wetlands of northern Hainan Province, China.