Metrocoris falciformis, Chen, Zhen Ye Ping-Ping & Bu, Wen-Jun, 2016

Chen, Zhen Ye Ping-Ping & Bu, Wen-Jun, 2016, Notes on the Metrocoris lituratus group (Heteroptera: Gerridae: Metrocoris) with descriptions of four new species in Sichuan Basin from China, Zootaxa 4117 (3), pp. 359-374 : 369-370

publication ID	https://doi.org/ 10.11646/zootaxa.4117.3.4
publication LSID	lsid:zoobank.org:pub:441C768B-FE38-47D6-819F-BE19CC167DB7
DOI	https://doi.org/10.5281/zenodo.6063138
persistent identifier	https://treatment.plazi.org/id/43435E3D-7210-E27E-FF40-4760FBB5FF0F
treatment provided by	Plazi
scientific name	Metrocoris falciformis
status	sp. nov.

Treatment

Metrocoris falciformis View in CoL sp. nov.

( Figs. 18 View FIGURES 13 – 20 , 26 View FIGURES 21 – 28 , 31 View FIGURES 29 – 33 , 36, 41, 46, 51, 56, 64, 69, 75–77, 84)

Material examined. Holotype: apterous male, CHINA, Sichuan Prov., Bazhong city, Pingchang county, Zhenlong mountain Forest Park (31°48'N, 107°31'E), 24 July 2015, 1120 m, leg. Zhen Ye ( NKUM). Paratypes: 1 apterous male and 1 apterous female ( NCTN), 2 apterous males and 2 apterous females ( NKUM), same data as holotype.

Diagnosis. The relatively large body size (male body length 6.81–6.88) ( Figs. 18 View FIGURES 13 – 20 , 26 View FIGURES 21 – 28 ); longitudinal dark stripe on the mesopleuron running at least 2/3 of its length, and very close to anterior margin; fore femora bearing only with a subapical indentation and a small single apical tooth ( Fig. 41 View FIGURES 39 – 43 ); the unmodified inner surface of the fore tibiae ( Fig. 41 View FIGURES 39 – 43 ); the male proctiger with a pair of blackish dots laterally ( Fig. 56 View FIGURES 44 – 58 ); the typically falciform shape of the paramere ( Figs. 64 View FIGURES 59 – 66 , 77 View FIGURES 72 – 83 ); the laterally constricted female abdominal sternite VII, with the apical half forming a halfround lobe, and the caudal margin without median notch (Fig. 36), are the diagnostic features of M. falciformis sp. nov..

Description. Apterous male ( Figs. 18 View FIGURES 13 – 20 , 26 View FIGURES 21 – 28 ). Body length 6.81–6.88, body width (across acetabula) 3.01–3.09. Colour: dorsum yellow with prominent black stripes; interocular dark mark usually arrowhead-shaped, bifid posteriorly, with narrow dark line along inner margin of eyes; first antennal segment yellowish brown, remaining segments usually blackish; rostrum yellowish with black apex; pronotum with T-shaped black stripe, lateral pronotal stripe very broad; mesonotum with slender longitudinal median stripe, sublateral stripes broader than lateral stripes, nearly equal in width to transverse bands; longitudinal dark stripe of mesopleuron slender, running at least 2/3 of its length, very close to anterior margin but far from short acetabular mark; anterior transverse stripe of metanotum laterally confluent with posterior stripe of metanotum; fore femora with apical dark ring and four longitudinal marks, ventral mark connected with ring, remaining marks not confluent, inner mark pale and bright, external mark broad and blackish brown; middle and hind femora yellowish, tibiae and tarsi black; abdomen mainly blackish dorsally, abdominal tergites II–V blackish, abdominal tergites VI–VII blackish anteriorly and yellowish posteriorly; abdominal segment VIII with a large sub-rectangular blackish mark in dorsal view. Genital segments yellowish. Structural characters: head length 0.68–0.71, head width 1.66–1.70, minimum interocular width 0.63–0.66; antenna about 0.83 times as long as body, lengths of antennal segments I–IV: 2.65, 1.31, 1.10, 0.62; pronotum slightly narrower than head, pronotum length 0.75–0.78, pronotum width 1.89–1.92; fore femora moderately incrassate ( Fig. 41 View FIGURES 39 – 43 ), ratio length/width 4.9, inner side not modified, with a subapical indentation, and a small single apical tooth ( Fig. 41 View FIGURES 39 – 43 ); inner surface of fore tibiae not modified ( Fig. 41 View FIGURES 39 – 43 ); lengths of leg segments (femur, tibia and tarsus): fore leg: 3.17, 2.70 and 1.09 (0.09+1.00), middle leg: 8.01, 6.08 and 2.79 (2.42+0.37), hind leg: 7.71, 5.36 and 0.80 (0.44+0.36); dorsum of abdomen clothed with short shiny golden hair, venter of abdomen densely clothed with pale yellow hairs. Male terminalia: abdominal segment VIII more or less rectangular, length 1.58, width 1.02, about 1.55 times as long as wide, posterior margin with dense brown erect hairs ( Fig. 46 View FIGURES 44 – 58 ); pygophore subovate ( Fig. 51 View FIGURES 44 – 58 ), proctiger laterally with a pair of blackish dots ( Fig. 56 View FIGURES 44 – 58 ); paramere relatively slender and falciformly curved upwards, extending beyond genital segments, lateral part with distinctly angular projection, apex narrowed and blunt ( Figs. 64 View FIGURES 59 – 66 , 77 View FIGURES 72 – 83 ). Endosoma ( Figs. 69 View FIGURES 67 – 71 , 75, 76 View FIGURES 72 – 83 ): dorsal sclerite long and recurved proximally, accessory lateral sclerites straight, ventral sclerites present and long.

Apterous female ( Fig. 31 View FIGURES 29 – 33 ). Body length 6.26–6.31, body width (across acetabula) 3.39–3.43. Colour similar to apterous male. Structural characters: head length 0.71–0.73, head width 1.60–1.63, minimum interocular width 0.59–0.63; antenna about 0.74 times as long as body, lengths of antennal segments I–IV: 2.12, 1.04, 1.15, 0.73; pronotum slightly narrower than head, pronotum length 0.49–0.51, pronotum width 1.80–1.83; fore femora slender without teeth, ratio length/width 5.2, inner surface of fore tibiae not modified; lengths of leg segments (femur, tibia and tarsus): fore leg: 2.60, 2.34 and 1.01 (0.10+0.91), middle leg: 7.02, 5.32 and 2.86 (2.48+0.38), hind leg: 6.86, 4.78 and 0.98 (0.51+0.47). Female terminalia: abdominal sternum VII large, about as long as length of preceding abdominal sterna together, laterally constricted, apical half forming a half-round lobe, caudal margin without median notch, not completely covering apex of abdomen in ventral view (Fig. 36).

Macropterous female and macropterous male. unknown.

Etymology. The specific epithet “ falciformis ” (from Latin, meaning acinaciform) refers to blade of paramere curved upwards and acinaciform-shaped.

Distribution. China (Sichuan) ( Fig. 84 View FIGURE 84 ).

Comparative notes: M. falciformis sp. nov. fits the diagnostic characters of the M. lituratus group as defined by Chen & Nieser (1993). The general appearance of this new species is similar to M. sichuanensis Chen & Nieser, 1993 . However, the paramere blade of M. falciformis sp. nov. is falciform-shaped, with the lateral part bearing a distinctly angular projection, and its blade apex narrowed ( Figs. 64 View FIGURES 59 – 66 , 77 View FIGURES 72 – 83 ), while in M. sichuanensis the paramere blade is relatively slender and straight, without an angular projection laterally, and the blade apex is slightly extended ( Figs. 5 View FIGURES 1 – 5 , 10 View FIGURES 6 – 12 , 59–62 View FIGURES 59 – 66 ). In addition, the larger male abdominal segment VIII ( Fig. 46 View FIGURES 44 – 58 ) and pygophore ( Fig. 51 View FIGURES 44 – 58 ) and the caudal margin of female abdominal sternum VII without median notch in M. falciformis sp. nov. (Fig. 36), represent further important differences between these two closely related species.