Metrocoris falciformis Chen & Bu, 2016, sp. nov.
Creators: name: Chen, Zhen Ye Ping-Ping
name: Bu, Wen-Jun
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Gerridae
Metrocoris
Metrocoris falciformis

description: Metrocoris falciformis sp. nov.
(Figs. 18, 26, 31, 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, 26); 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); the unmodified inner surface of the fore tibiae (Fig. 41); the male proctiger with a pair of blackish dots laterally (Fig. 56); the typically falciform shape of the paramere (Figs. 64, 77); 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, 26). 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), ratio length/width 4.9, inner side not modified, with a subapical indentation, and a small single apical tooth (Fig. 41); inner surface of fore tibiae not modified (Fig. 41); 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); pygophore subovate (Fig. 51), proctiger laterally with a pair of blackish dots (Fig. 56); paramere relatively slender and falciformly curved upwards, extending beyond genital segments, lateral part with distinctly angular projection, apex narrowed and blunt (Figs. 64, 77). Endosoma (Figs. 69, 75, 76): dorsal sclerite long and recurved proximally, accessory lateral sclerites straight, ventral sclerites present and long.
Apterous female (Fig. 31). 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).
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, 77), 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, 10, 59–62). In addition, the larger male abdominal segment VIII (Fig. 46) and pygophore (Fig. 51) 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.
description: Published as part of 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, pp. 359-374 in Zootaxa 4117 (3) on pages 369-370, DOI: 10.11646/zootaxa.4117.3.4, http://zenodo.org/record/269712