Zaitzevia robusta, 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 robusta sp. nov.

Figs 1 A – D , 5 A – C , 10 A – C

Material examined.

(41 exs) Holotype: China • ♂ ( IAECAS): “ China: Shaanxi, \ Foping County \ Gaozhuanggou | 33°34′18″N, 107°57′56″E \ 1035 m, 2019. VI. 21 \ Leg. Tong ” . Paratypes: China, Shaanxi • 1 ♂, 5 ♀♀ ( IAECAS): “ China: Shaanxi \ Qinling, NingShan County, \ Ningdong Forest Agency | Dacigou \ 2005.5. 11 \ 1398 m \ Leg. Wang ” • 5 ♀♀ ( IAECAS): “ China: Shaanxi \ Qinling, Ningshan County \ Ningdong Forest Agency | Dacigou , 2005. VI. 11 \ 1437 m, Leg. Wangm [ Wang Miao] ” • 2 ♂♂ ( IAECAS): “ China – Shaanxi \ Zhouzhi County l. w [leg. Wang] | Houzhenzi Ca 1200 m \ 2. VI 1998 ” [ CWBS 308 ] • 2 ♀♀ ( NMW): “ CHINA: Shaanxi, 2. 6. 1998 \ Zhouzhi County, ca. 1200 m \ 2 km W Houzhenzi Nat. Res. \ leg. M. Wang ( CWBS 308 ) ” • 1 ♀ ( NMW): “ China: Shaanxi, 3. 6. 1998 \ Houzhenzi County, ca. 1300 m \ 2 km E Houzhenzi Nat. Res. \ leg. M. Wang ( CWBS 309 ) ” • 1 ♂, 2 ♀♀ ( NMW): “ China: Shaanxi, 9. 6. 1998 \ Tiantai Shan Forest Park \ Feng Co., 7 km NE Qinling \ Train Station, ca. 2000 m \ leg. M. Wang ( CWBS 319 ) ” • 1 ♂ ( IAECAS): “ China – Shaanxi \ Feng County I. [leg.] W [ Wang] | Qinling Train Station \ ca. 1900 m; 9. VI. 1998 ” [ CWBS 320 ] • 1 ♂ ( NMW): “ China: Shaanxi, 10. 6. 1998 \ Tiantai Shan Forest Park \ Feng Co., 7 km NE Qinling \ Train Station, ca. 1850 m \ leg. M. Wang ( CWBS 321 ) ” • 2 ♂♂, 5 ♀♀ ( NMW), 1 ♂, 1 ♀ ( CPE): “ China: Shaanxi, Qin Ling Shan \ 110.06E, 34.27N \ Hua Shan Mt. N Valley , 1200–1400 m \ 180 km E Xian, sifted [crossed out with black pen] 18. / 20.08. 1995, leg. A. Pütz ” – type locality of Elmomorphus catenatus Selnekovič, Jäch & Kodada, 2024 ( Dryopidae ) ; Sichuan • 1 ♂ ( IAECAS): “ China: Sichuan \ Aba Pref., Mao County \ Daguan Town | Dadian Vill. 2012.04 [day not mentioned on label] \ 31°56'7.7"N, 103°40'18.8"E \ ca. 1830 m, leg. Wang & Guo ” • 1 ♂, 3 ♀♀ ( NMW): “ China: Sichuan, 29. 7. 1998 \ Mao Xian Co., Jiuding Shan \ 7 km NE Mao Xian, ca. 1850 m \ Schönmann, Ji, Wang ( CWBS 335 ) ” • 1 ♂ ( IAECAS): “ China-Sichuan \ Mao cty Jiudingshan | 1950 m leg Ji & W [ Wang] \ 7.29. 1998 ” [ CWBS 336 ] • 1 ♂, 1 ♀ ( NMW): “ China: Sichuan, 29. 7. 1998 \ Mao Xian Co., Jiuding Shan \ 10 km NE Mao Xian, ca. 1950 m \ Schönmann, Ji, Wang ( CWBS 336 ) ” • 1 ♂ ( NMW): “ China: Sichuan, 30. 7. 1998 \ Mao Xian Cty., Jiuding Shan \ 6 km NE Mao Xian, ca. 1750 m \ Schönmann, Ji, Wang ( CWBS 340 ) ” ; Hubei • 1 ♂ ( NMW): “ China: Hubei, 19. 10. 2004 \ Tienchanghuang Forest Park \ Enshi [Pref.], 60 km SSW Badong \ 1 600 m, leg. Schönmann \ & Wang ( CWBS 543 ) ” .

Differential diagnosis.

Zaitzevia robusta sp. nov. is the largest species ( BL 3.14–3.80 mm) of the genus described so far. The new species resembles Z. chenzhitengi , Z. fengtongzhaiensis , Z. muchenae , and Z. sichuanensis . Males can be distinguished from Z. chenzhitengi and Z. fengtongzhaiensis mainly by the longer aedeagus, which is distally not acuminate but apically rounded in ventral / dorsal views, and the elytral apices are more acuminate in Z. fengtongzhaiensis and the holotype of Z. chenzhitengi ; males are distinguished from Z. muchenae by the more robust body, the longer and broader pronotal median sulcus and by the distinctly longer and broadly rounded aedeagus; males differ from Z. sichuanensis in the larger and more robust body, and the straight and longer, apically broadly rounded aedeagus; from Z. triangularis ( BL: 2.9–3.2 mm) males differ in the slightly larger body size, the less acuminate elytral apices, and in the broadly rounded, not triangular aedeagal apex.

Description.

Male ( holotype). BL 3.6 mm, BW 1.5 mm. Body elongate obovate. Antennae yellowish brown, dorsum black, ventral surface reddish brown to dark brown, and legs reddish brown.

Labrum smooth and shiny, with only a few punctures and scarce pubescence, lateral margins densely covered with long setae; anterior margin broadly rounded, not emarginate. Clypeus and frons densely punctate and pubescent, sparsely granulate.

Pronotum ( PL 0.9 mm, PW 1.1 mm) broadest at basal 0.3, slightly narrowed posteriorly and distinctly attenuate anteriorly. Disc in basal 0.3 rugose, sparsely punctate and pubescent, in distal 0.7 smooth and shiny, densely punctate and sparsely pubescent. Lateral areas densely granulate and sparsely pubescent. Anterior corners acute, slightly produced, posterior corners almost right-angled. Lateral margin narrowly rimmed. Median sulcus extending from basal 0.2–0.8, broadest at basal 0.3, gradually narrowed anteriorly and posteriorly. Sublateral carinae present in basal 0.4 bending outwards at basal 0.3.

Elytra ( EL 2.7 mm, EW 1.5 mm) broadest at distal 0.33, slightly narrowed anteriorly and distinctly attenuate posteriorly. Lateral margin serrate. Strial punctures small in basal 0.5, separated by 0.5 their diameters, punctures in distal 0.5 smaller and well separated (1–3 × their diameters). Intervals rugose, sparsely punctate and pubescent. Intervals 2–4 slightly elevated in basal 0.2. Intervals 5, 7 and 8 carinate. Elytral apices separately rounded, densely granulate.

Prosternum with disc rugose, almost glabrous; lateral parts of prosternum granulate and pubescent. Prosternal process gradually narrowed from base to broadly rounded apex; disc glabrous, surface coarse, with a few small setae and scattered granules; lateral margins distinctly rimmed. Metaventrite broadly impressed medially, disc smooth and shiny, with some longitudinal rugosities; median sulcus broad in posterior 0.8 and narrow in anterior 0.2; lateral areas densely pubescent and sparsely granulate; with a row of large punctures behind of mesocoxa and another row of small punctures in front of metacoxa; base with a pair of pits on each side of median sulcus.

Ventrite I with a pair of admedian carinae; area between these carinae (disc) flat or slightly concave, anteriorly rugose, remaining parts with small punctures, interstices micropunctate. Lateral areas of ventrites I – V densely pubescent and sparsely granulate. Middle of ventrites II – IV and basal 0.5 of ventrite V glabrous and sparsely punctate. Distal 0.5 of ventrite V densely granulate; lateral margins sometimes fringed with very short, inconspicuous spines; apex deeply emarginate medially, lateral corners produced, tooth-like and slightly bent ventrad.

Mesal margin of mesotibia slightly expanded around middle.

Aedeagus. 1.9 mm long, elongate, penis ~ 2.2 × as long as phallobase. Lateral margins of penis in ventral / dorsal view more or less subparallel except for a very inconspicuous swelling and / or a very shallow emargination at apical 0.3; dorsal wide with a conspicuous gibbosity of variable size at apical 0.25 (best seen in lateral view); apex of penis broadly and evenly rounded in ventral / dorsal view, distinctly curved dorsad in lateral view. Endophallus in distal 0.33 with a pair of small curved teeth. Parameres short and inconspicuous, clinging to penis.

Females. Elytral apices not separately rounded but distinctly acuminate and produced to a remarkably variable extent; they vary from short to long and beak-like, and sometimes they are asymmetrically produced, being longer on one side than on the other. Metaventrite flat or slightly depressed, distinctly less strongly impressed than in males, smoother. Disc of ventrite I more or less convex. Ventrite V less widely and less deeply excised apically, lateral apical teeth shorter and smaller than in males; apical 0.33 of ventrite V less strongly granulate. The femora often appear to be more strongly-built in the males, but this depends largely on the body size (in larger specimens the femora are proportionately thicker).

Measurements.

Males: BL 3.50–3.80 mm ( n = 14), BW 1.40–1.55 mm ( n = 5); females: BL 3.14–3.78 mm ( n = 25), BW 1.40–1.60 mm ( n = 11).

Distribution.

Hubei, Shaanxi, Sichuan.

Etymology.

The name robustus, a Latin adjective, refers to the massive body.

Figures

Figure 1. Habitus. Zaitzevia robusta sp. nov. A, B. Holotype, male; C, D. Paratype, female. A, C. Dorsal view; B, D. Ventral view.

Figure 5. Zaitzevia robusta sp. nov., holotype, male; A. Pronotum; B. Prosternum; C. Metaventrite and abdominal ventrites.

Figure 10. Aedeagus. A – C. Zaitzevia robusta sp. nov., holotype, male; D – F. Z. cf. chenzhitengi, specimen from Shaanxi; A, D. Ventral view; B, E. Dorsal view; C, F. Lateral view.