Chimarrhometra yunnanensis, Ye, Zhen, Zhou, Yanyan & Bu, Wenjun, 2016

Ye, Zhen, Zhou, Yanyan & Bu, Wenjun, 2016, Description of a new species of Chimarrhometra Bianchi, 1896 (Hemiptera: Heteroptera: Gerridae) from China, Zootaxa 4175 (2), pp. 180-188 : 182-186

Chimarrhometra yunnanensis sp. n.

( Figs. 3, 4 , 7, 8 , 11, 12 , 16, 17, 18 , 21 , 22, 23 , 24 )

Material examined. Holotype: apterous male, China, Yunnan Prov., Yingjiang county, Tongbiguang village (24°35'N, 97°39'E), 1326 m, 13.VII.2016, coll. Zhen Ye ( NKUM) . Paratypes: 2 apterous males, 3 apterous females, same data as holotype ( NKUM) . 1 apterous male, 2 apterous females, Yingjiang county, Tongbiguang village, Dadieshui (24°36'N, 97°39'E), 20.V.2009, coll. Min Li ( NKUM) .

Diagnosis. The diagnostic features of C. yunnanensis sp. n. are the strongly incrassate male fore femur ( Fig. 3 ); abdominal segment VIII dorsally with a distinct depression in lateral view ( Fig. 8 ); the sub-ovate pygophore ( Figs. 11, 12 ); the antler-shaped processes on the caudal margin of the pygophore bear a narrower posterior lobe and a longer triangular anterior lobe ( Figs. 11, 12 ); the proctiger is slender and with dense hairs on the posterior margin ( Fig. 16 ); the parameres are falciform, with the medial part bending inwards and with apices crossing beneath the pygophore and gradually tapering ( Figs. 17, 18 ); the inner lobe of the first gonopophysis is relatively slender, less infuscated, and with several setae concentrated apically ( Fig. 21 ).

Description. Apterous male ( Fig. 3 ). Colour: ground colour yellowish brown; head dorsum yellowish brown with broad median blackish band, ventrally yellowish; antennal segments I–II brownish yellow, apex of segments darker, III–IV brownish; pronotum yellowish brown, with median and lateral narrow yellowish stripes; mesonotum yellowish brown, with pair of triangular dark, frosted spots; longitudinal bands on thoracic pleura and spots on acetabula blackish with prominent silvery pubescence; legs yellowish brown, with apices of femora, tibiae and tarsi weakly infuscated, fore femora and tibiae ventrally with rows of black spine-like hairs; abdominal dorsum brown, covered with minute golden hairs; ventrally, body including genital segments brownish yellow; abdominal segment VIII dorsally weakly infuscated; pygophore and paramere yellowish, strongly infuscated apically.

Structural characteristics: body length 7.60–7.80 (holotype: 7.75), body width (across acetabula) 2.68–2.72 (holotype: 2.70), body elongate and stout, bearing short, golden or silver, appressed pubescence; head directed forward, head length: 1.15–1.20, head width: 1.41–1.50, head width about 1.23 times length; eyes large, globose, with inner margin emarginated in posterior half; antennal segment I longest, without spine-like hairs, antenna about 0.80 times as long as body, lengths of antennal segments I–IV: 1.90, 1.47, 1.32, 1.38; pronotum width: 1.50–1.57, length: 1.06–1.10, about 1.55 times as wide as long; intersegmental suture between mesothorax and metathorax distinct laterally,; mesonotum about 3.6 times as long as metanotum; fore femur strongly incrassate ( Fig. 3 ); fore tibia slightly curved; middle tarsus about two fifths tibial length; hind femur shorter than middle femur; hind tibia shorter than hind femur; middle and hind tibiae and tarsi ventrally with rows of spine-like hairs; pretarsus inserted slightly before apex of last tarsal segment; lengths of leg segments (femur, tibia and tarsus): fore leg: 2.44, 2.30 and 0.59 (0.21+0.38), middle leg: 6.60, 4.61 and 1.97 (1.35+0.62), hind leg: 5.70, 3.41 and 1.50 (1.00+0.50); pregenital abdominal venter distinctly depressed posteriorly, connexiva slightly widened. Genital segments: abdominal segment VIII much shorter ventrally than dorsally, length: 1.30, width: 1.05, about 1.24 times as long as wide, posterior margin with short, erect, blackish hairs ( Figs. 7, 8 ); abdominal segment VIII dorsally with distinct depression in lateral view ( Fig. 8 ); pygophore sub-ovate ( Figs. 11, 12 ), forked into pair of prominent, vertically raised, antler-shaped processes ( Figs. 11, 12 ), lateral processes bear a narrower posterior lobe and a longer triangular anterior lobe ( Figs. 11, 12 ); proctiger slender, with dense hairs on posterior margin ( Fig. 16 ); paramere large, falciform, medial part bending inwards, with apices crossing beneath pygophore and gradually tapering ( Figs. 17, 18 ).

Apterous female ( Fig. 4 ). Body slightly longer and wider than male, other coloration and markings similar to that of male; body length 8.20–8.55, body width (across acetabula) 2.90–3.05; structure of head including antennae as in male, head length: 1.18–1.20; head width: 1.45–1.50; about 1.23 times as wide as long; antenna about 0.72 times as long as body; lengths of antennal segments I–IV: 1.88, 1.34, 1.30, 1.40; pronotum width: 1.50–1.62, length: 1.00–1.05, about 1.43 times as wide as long; legs similar to those of male except fore femur relatively slender ( Fig. 4 ); lengths of leg segments (femur, tibia and tarsus): fore leg: 2.61, 2.50 and 0.64 (0.23+0.41), middle leg: 6.80, 4.69 and 2.03 (1.38+0.65), hind leg: 5.90, 3.35 and 1.29 (0.78+0.51); genital segments protruding from abdominal apex, proctiger small and cone-shaped; inner lobe of first gonopophysis relatively slender, less infuscated, and with several setae concentrated apically ( Fig. 21 ).

Macropterous male and female: unknown.

Etymology. The specific name is derived from the type locality (Yunnan, China).

Distribution. China (Yunnan) ( Fig. 24 ).

Comparative notes: The general appearance of the new species, C. yunnanensis sp. n. is similar to C. orientalis . However, there are clear differences between the two species as follows. Abdominal segment VIII of C.

yunnanensis sp. n. has a distinct dorsal depression in lateral view ( Fig. 8 ), whereas that of C. orientalis has only a subtle depression ( Fig. 6 ). The antler-shaped processes on the caudal margin of the pygophore in C. yunnanensis sp. n. each bear a narrower posterior lobe and longer triangular anterior lobe ( Figs. 11, 12 ), but those of C. orientalis bear a broad posterior lobe and shorter triangular anterior lobe ( Figs. 9, 10 ). The apical half of the paramere in C. yunnanensis sp. n. is slightly longer than in C. orientalis ( Figs. 14, 15, 17, 18 ). In addition, the inner lobe of the first gonopophysis in C. yunnanensis sp. n. is relatively slender, less infuscated, and with several setae concentrated apically ( Fig. 21 ), whereas the inner lobe of first gonopophysis in C. orientalis is relatively stout, infuscated, and with several uniformly distributed setae ( Figs. 19, 20 ).

Figures

FIGURE 24. Geographical distribution of species of Chimarrhometra.

FIGURES 1 – 4. Habitus of Chimarrhometra spp. 1. C. orientalis (Distant, 1879), male; 2. C. orientalis (Distant, 1879), female; 3. C. yunnanensis sp. n., male (holotype); 4. C. yunnanensis sp. n., female (paratype); Scale = 4.0 mm.

FIGURES 5 – 8. Abdominal segment VIII of Chimarrhometra spp. (males). 5. C. orientalis (Distant, 1879), dorsal view; 6. C. orientalis (Distant, 1879), lateral view; 7. C. yunnanensis sp. n., dorsal view; 8. C. yunnanensis sp. n., lateral view; Scale = 0.2 mm.

FIGURES 9 – 12. Pygophore of Chimarrhometra spp. (males). 9. C. orientalis (Distant, 1879), ventral view; 10. C. orientalis (Distant, 1879), dorsal view; 11. C. yunnanensis sp. n., ventral view; 12. C. yunnanensis sp. n., dorsal view; Scale = 0.2 mm.

FIGURES 13 – 18. Proctiger and paramere of Chimarrhometra spp. (males). 13 – 15. C. orientalis (Distant, 1879), 13. proctiger in dorsal view; 14. paramere in ventral view; 15. paramere in dorsal view. 16 – 18. C. yunnanensis sp. n.: 16. proctiger in dorsal view; 17. paramere in ventral view; 18. paramere in dorsal view. Scale = 0.2 mm.

FIGURES 19 – 21. First gonocoxa (Gx 1) and first gonopophysis (Go 1) of Chimarrhometra spp. (females). 19. C. orientalis (Distant, 1879), Gx 1 + Go 1; 20. C. orientalis (Distant, 1879), inner lobe of Go 1; 21. C. yunnanensis sp. n., inner lobe of Go 1.

FIGURES 22 – 23. 22. Habitat of C. yunnanensis sp. n.; 23. adult C. yunnanensis sp. n. clinging to rock surface.