Pseudostegodera qiului Chen, 2021

Chen, Zhe-Yu, Lyu, Zhi-Tong & Wu, Min, 2021, Systematic revision of Stegodera Martens, 1876 (Gastropoda, Stylommatophora, Camaenidae), with description of a new genus, ZooKeys 1059, pp. 1-21 : 1

Pseudostegodera qiului Chen sp. nov.

(Figs 1 , 2 , 3B-D , 4E-H , 7A-D , 9A-C)

Type material.

• Holotype, IZCAS TM206978, Zihuaping [紫花坪], core area of Shunhuang Mountain National Nature Reserve [舜皇山国家级自然保护区核心区], Huanglong Town [黄龙镇], Xinning County [新宁县], Shaoyang City [邵阳市], Hunan, China, 26°23'31"N, 110°0'25"E, 945 m a.s.l., 2020-VIII-23, leg. Lu Qiu. •Paratype, MYNU/1, same data as holotype.

Measurements.

SDmaj = 31.0 - 34.0 mm, SDmin = 25.0 - 26.4 mm, SH = 12.0 - 13.7 mm (n = 2).

Diagnosis.

Body whorl incompletely covering partial penultimate whorl. Dart sac apparatus absent. Flagellum present.

Description.

Shell (Fig. 3B-D ). Sinistral, large, depressed, thick and solid, dark reddish-brown. Shell with 51/2 convex whorls. Suture impressed. Protoconch 11/4-11/2 whorls, with regularly arranged fine axial striae that may be invisible by weathering or erosion. Growth lines clear, broken into microscopic tubercles of irregular shape. The last 1/8 to 1/4 body whorl compressed, partly covering penultimate whorl. At 1/4 whorl from the aperture, a spiral depression above periphery and a weak depression near umbilicus making a narrowing on body whorl. Whorl after the narrowing reverting to normal broadness. Aperture semilunar, slightly descending. Peristome white, strongly thickened, expanded, and slightly reflexed. Umbilicus broad, approximately 1/3 of shell major diameter. Protoconch visible through umbilicus.

General anatomy (Fig. 4E-H ). Eversible head wart absent. On internal body wall of head region between ommatophorous insertions with tiny pits rather than glands (Fig. 4F ). Each side of mantle edge with a leaf-shaped appendage (Fig. 4G, H ). Body reddish brown, central dorsa with light longitudinal stripes. Sole dirty white. Jaw arcuate, with ~ 14 more or less projecting ribs (Fig. 4E ).

Genitalia (Fig. 7A-D ). Penis sheath short but well developed. Penis somewhat swollen on proximal half, externally simple. In the middle of penis, internally with a single strong longitudinal pilaster almost as thick as epiphallus, ~ 2 mm long (Fig. 7D ). Epiphallic papilla absent (Fig. 7D ). Flagellum cylindrical, tapering. Vas deferens thin throughout, approximately as long as penis. Dart sac apparatus absent. Bursa copulatrix duct thickened basally. Bursa copulatrix duct longer than 50 mm. Bursa copulatrix rod-shaped.

Etymology.

This new species is named after Dr Lu Qiu [邱鹭], who provided the specimens and field data.

Ecology.

This species was found under rotten wood.

Distribution.

Only known from the type locality (Fig. 2 ).

Remarks.

See under the genus.

Figures

Figure 1. Bayesian Inferences of camaenids (representatives of genera in Table 1) based on partial mitochondrial 16 S and CO 1 sequences. Numbers near nodes indicate Bayesian posterior probabilities. The squares on the right of each taxon name indicate its character states. Abbreviations: PS: penial sheath; EpP: epiphallic papilla; PC: penial caecum; Fl: flagellum; DS: dart sac apparatus A phylogram without Australian camaenids B the results of ancestral states (tagged on branch in red, blue, or black) reconstruction mapping on the phylogram with some Australian camaenid genera added. Orange part: the topologies supported by the results respectively by using both Bayesian Inference and Maximum Likelihood methods. Character states are from Schileyko (2003) and Wu (2019). Scale bars for substitutions per site.

Figure 2. Distribution of Stegodera and Pseudostegodera qiului gen. et sp. nov. Triangle: new locality of Stegodera angusticollis (Martens, 1875); dashed range: area of Stegodera angusticollis; circle: type locality of Pseudostegodera qiului gen. et sp. nov.

Figure 3. Shells A Stegodera angusticollis Martens, 1876, HBUMM 08435 B-D Pseudostegodera qiului gen. et sp. nov., holotype IZCAS TM 206978 C p rotoconch, magnified D shell surface, magnified. Scale bar: 5 mm (A, B).

Figure 4. General anatomy A-D Stegodera angusticollis (Martens, 1875), HBUMM 08435 A lobe (arrowed) on the left side of mantle edge B lobe (arrowed) on the right side of mantle edge C internal surface of head region D jaw E-H Pseudostegodera qiului gen. et sp. nov., holotype IZCAS TM 206978 E jaw F internal surface of head region G lobe (arrowed) on the left side of mantle edge H lobe (arrowed) on the right side of mantle edge.

Figure 7. Genitalia of Pseudostegodera qiului gen. et sp. nov., holotype IZCAS TM 206978 A general view B, C male part, two sides D exposed penis.

Figure 9. Habitat and living specimens of Pseudostegodera qiului gen. et sp. nov. A habitat B, C a living specimen. Photographs Lu Qiu.