Zaitzevia pilosa, Bian & Jäch, 2025

Bian, Dong-Ju & Jäch, Manfred A., 2025, The species of the genus Zaitzevia Champion, 1923 (Coleoptera, Elmidae) from Shaanxi Province, China, ZooKeys 1264, pp. 129-157 : 129-157

Zaitzevia pilosa sp. nov.

Figs 2 A, B , 6 A – C , 11 A – C

Zaitzevia sp. : Jäch and Boukal 1995: figs 36, 37.

Material examined.

(237 exs) Holotype: China • ♂ ( IAECAS): “ China: Shaanxi \ Qinling, Ningshan County \ Ningdong Forest Agency | Dacigou , 2005. VI. 11 \ 1437 m, Leg. Wangm [ Wang Miao] ” . Paratypes: China, Shaanxi • 3 ♀♀ ( IAECAS), the same data as holotype • 1 ♀ ( IAECAS): “ China: Shaanxi \ Qinling, NingShan County, \ Ningdong Forest Agency | Dachigou \ 2005.5. 11 \ 1398 m \ Leg. Bian ” • 3 ♂♂, 1 ♀ ( IAECAS): “ China: Shaanxi, Ankang City, \ Ningshan County, Xunyang Dam | 33°33.473′N, 108°32.808′E, \ 1355 m, 2019.8. 20 \ Leg. Tong Y. F ” • 2 ♂♂, 3 ♀♀ ( NMW): “ China: Shaanxi, 5. 6. 1998 \ Ningshan Co., ca. 1900 m \ 5 km NW Huoditang \ leg. M. Wang ( CWBS 313 ) ” • 18 exs ( NMW): “ China: Shaanxi, 5. 6. 1998 \ Ningshan Co., ca. 1650 m \ 7 km NW Huoditang \ leg. M. Wang ( CWBS 314 ) ” • 27 exs ( NMW): “ China: Shaanxi, 6. 6. 1998 \ Ningshan Co., ca. 1 500 m \ 10 km NE Xunyangba \ leg. M. Wang ( CWBS 315 ) ” ; Hubei • 11 exs ( IAECAS): “ China: Hubei \ Shennongjia For. Dist. | 1600 m, 2004.10. 9 \ Leg. Wang ( CWBS 522 ) ” • 10 exs ( NMW): “ China: Hubei, 9. 10. 2004 \ Shennongjia Forest Distr. \ 10 km E Muyu, Chaiqi \ 1600 m, leg. Schönmann, \ & Wang ( CWBS 522 ) ” • 4 exs ( NMW): “ China: Hubei, 10. 10. 2004 \ Shennongjia Forest Distr. \ 3 km N Muyu, Duanjiang \ 1300 m, leg. Schönmann \ & Wang ( CWBS 523 ) ” • 3 exs ( NMW): “ China: Hubei, 10. 10. 2004 \ Shennongjia Forest Distr. \ 5 km SW Muyu \ 1350 m, leg. Schönmann \ & Wang ( CWBS 525 ) ” • 4 ♂♂, 4 ♀♀ ( IAECAS): “ China: Hubei \ Shennongjia Forest Dist. | 2004.10. 11 \ Leg. Wang ( CWBS 527 ) ” • 7 exs ( NMW): “ China, Hubei, 11. 10. 2004 \ Shennongjia Forest Distr. \ 4 km NW Muyu \ 1800 m, leg. Schönmann \ & Wang ( CWBS 527 ) ” • 5 exs ( NMW): “ China: Hubei, 11. 10. 2004 \ Shennongjia Forest Distr. \ 3 km N Muyu, Chaiqi env. \ 1 700 m, leg. Schönmann \ & Wang ( CWBS 528 ) ” • 2 exs ( NMW): “ China: Hubei, 12. 10. 2004 \ Shennongjia Forest Distr. \ 20 km E Muyu, 10 km E \ Chaiqi , 2150 m, leg. Wang \ & Schönmann ( CWBS 529 ) ” • 4 exs ( NMW): “ China: Hubei, 15. 10. 2004 \ Shennongjia Forest Distr. \ 25 km W pass Muyu - \ Shennongjia \ 1650 m, leg. Schönmann \ & Wang ( CWBS 536 ) ” • 2 exs ( NMW): “ China: Hubei, 17. X. 2004 \ Shennongjia Forest Distr. \ 35 km N Muyu \ 1600 m, leg. Schönmann \ & Wang ( CWBS 539 ) ” • 23 exs ( IAECAS): “ China: Hubei, Enshi \ 35 km N Muyu | 1600 m, 2004.10. 17 \ Leg. Wang ( CWBS 540 ) ” • 5 ♂♂, 48 exs ( IAECAS): “ China: Hubei, Enshi \ Lichuan | 1600 m, 2004.10. 23 \ Leg. Wang ( CWBS 549 ) ” • 33 exs ( NMW): “ China: Hubei, 23. 10. 2004 \ 50 km W Enshi \ 1 600 m, leg. Schönmann \ & Wang ( CWBS 549 ) ” ; Hunan • 10 exs ( NMW): “ China, NW-Hunan 1993 \ Wulingyuan, N Dayong \ Zangjiajie [ Zhangjiajie ], 29.10., 650 m \ leg. Schillhammer (1) [ CWBS 20 ] ” • 12 exs ( NMW): same locality data, but “ leg. Schönmann ” • 1 ♂, 1 ♀ ( IAECAS): “ China: Hunan, Zhangjiajie \ Suoxiyu Nat. Res. | 650 m, 1993.10. 29 \ Leg. L. Ji ( CWBS 21 ) ” • 1 ♂, 1 ♀ ( NMW): “ China, NW-Hunan 1993 \ Wulingyuan, N Dayong \ Zangjiajie [ Zhangjiajie ], 29.10., 650 m \ leg. L. Ji (2) [ CWBS 21 ] ” .

Differential diagnosis.

This species is well characterized by its size ( BL 2.4–2.9 mm) in combination with the conspicuous dorsal pilosity (if not rubbed off, as in many older specimens) and the granules on the elytral interval 5 more or less reaching the elytral base.

In habitus and body size the new species vaguely resembles Z. yingzuijieensis . It can be distinguished from the latter mainly by the conspicuous pubescence, the black dorsum (dark brown in Z. yingzuijieensis ), the narrow median pronotal sulcus extending from basal 0.2–0.6 (<0.33 length of pronotum in Z. yingzuijieensis ), the distinct sublateral pronotal carinae (faint in Z. yingzuijieensis ), the apex of the prosternal process being narrowly rounded (broadly rounded in Z. yingzuijieensis ), the symmetrical aedeagus (asymmetrical in Z. yingzuijieensis ), and several differences in the endophallus.

Description.

Male ( holotype). BL 2.5 mm, BW 1.1 mm. Body slender. Dorsal surface black, ventral surface dark brown to black. Legs dark brown to black but tarsi reddish brown. Antennae yellowish brown.

Labrum wider than long, microreticulate in basal 0.33 but smooth and shiny in distal 0.67; punctures and pubescence moderately dense. Anterior margin arched, not emarginate, densely pubescent laterally. Clypeus and frons densely pubescent and granulate. Clypeal suture shallowly impressed.

Pronotum ( PL 0.7 mm, PW 0.8 mm) subparallel in basal 0.4, distinctly attenuate anteriorly. Lateral margin narrowly rimmed, anterior 0.5 slightly serrate. Anterior corners acute, slightly produced; posterior corners almost right-angled. Disc smooth and shiny, densely punctate and covered by golden setae. Median sulcus extending from basal 0.2–0.6. Sublateral carinae present in basal 0.4. Areas near anterior and posterior corners densely and finely granulate.

Elytra ( EL 1.8 mm, EW 1.1 mm) broadest at anterior 0.67, slightly narrowed anteriorly and distinctly attenuate posteriorly, apices separately rounded. Strial punctures moderately large in basal 0.5, separated by 1–2 × their diameters, distinctly smaller and well separated in distal 0.5. Intervals flat, sparsely punctate, each with a row of moderately long setae. Carinae on intervals 5, 7 and 8 complete.

Prosternum laterally densely pubescent; prosternal process gradually narrowed from base to basal 0.8, distinctly narrowed in distal 0.2, apex narrowly rounded; lateral margin distinctly rimmed; disc rugose, sparsely punctate and pubescent. Metaventrite broadly and shallowly impressed, disc smooth and shiny, sparsely punctate, and pubescent, somewhat rugose in posterior 0.5; median sulcus broad in posterior 0.8, and narrowed in anterior 0.2; with a row of large punctures behind of mesocoxae and a shallow groove in front of metacoxae; base with a pair of large pits on each side of median sulcus.

Ventrite I with a pair of admedian carinae; disc distinctly impressed, microreticulate and sparsely punctate. Middle of ventrites II – IV and anterior 0.25 of ventrite V smooth and shiny, sparsely punctate and sparsely pubescent. Lateral areas of ventrites I – V densely pubescent. Distal 0.75 of ventrite V densely granulate and sparsely pubescent. Lateral margins of ventrite V fringed with short spines; apex of ventrite V widely and deeply emarginate medially; lateral corners forming long teeth.

Aedeagus. 1.1 mm long, elongate, cylindrical. Penis ~ 2.5 × as long as phallobase, subparallel in basal 0.7, distinctly narrowed in distal 0.3, apex acute. Sclerotizations of endophallus somewhat resembling a pair of overlapping banana leaves; apex of endophallus with a pair of large curved double-pointed teeth. Parameres very slim, reaching apical 0.3 of penis.

A specimen from Hunan ( CWBS 20 ) with everted endophallus has been illustrated by Jäch and Boukal (1995: figs 36, 37); unfortunately, this particular specimen could not be traced and is therefore not designated as paratype.

Females. Secondary sexual dimorphism rather poorly developed. Elytra apically often, but not always, more acuminate than in males. Metaventrite, including discrimen, a little less strongly or less comprehensively impressed. Disc of ventrite I less distinctly impressed. Ventrite V less widely and less deeply excised apically, lateral apical teeth distinctly shorter and smaller than in males; apical 0.33 of ventrite V less strongly granulate. Femora on average insignificantly slimmer than in males.

Measurements.

Males: BL 2.5–2.8 mm, BW 1.1–1.2 mm ( n = 10); females: BL 2.4–2.9 mm, BW 1.1–1.2 mm ( n = 12).

Variability.

Elytral apices of males usually conjointly rounded, but sometimes they are separately rounded or slightly excised. In some specimens from Hubei (e. g., CWBS 529 , 549), the elytral intervals are tendentially more convex, and specimens from Hunan ( CWBS 20 ) differ from the specimens from Shaanxi in the usually more glabrous surface, larger and deeper elytral punctures, and more convex elytral intervals, and the larger aedeagus (~ 1.30–1.36 mm long).

Distribution.

Hubei, Hunan, Shaanxi.

Habitat.

This species is normally found in cold mountains streams, but 23 specimens were surprisingly collected in a hydrothermal spring in Hubei ( CWBS 540 ).

Etymology.

The epithet is derived from the Latin adjective pilosus (hairy, pilose) and refers to the pronounced pilosity on the dorsal body surface often observed in fresh specimens.

Figures

Figure 2. Habitus. A, B. Zaitzevia pilosa sp. nov.; holotype, male; C, D. Z. coronifer sp. nov., holotype, male; A, C. Dorsal view; B, D. Ventral view.

Figure 6. Zaitzevia pilosa sp. nov., holotype, male; A. Pronotum; B. Prosternum; C. Metaventrite and abdominal ventrites.

Figure 11. Aedeagus. A – C. Zaitzevia pilosa sp. nov., holotype, male; D – F. Z. coronifer sp. nov., holotype, male; A, D. Ventral view; B, E. Dorsal view; C, F. Lateral view.