Two new and one little-known damsel bug of the subfamily Prostemmatinae Reuter (Hemiptera, Heteroptera, Nabidae) from China

Abstract Two damsel bugs belonging to two genera of the subfamily Prostemmatinae from China are reported as new to science: Alloeorhynchus (Alloeorhynchus) yunnanensissp. n. and Rhamphocorisguizhouensissp. n. The little-known species Alloeorhynchus (Alloeorhynchus) reinhardi Kerzhner & Günther, 1999 is redescribed. All species are illustrated in detail. Keys to the Chinese species of Rhamphocoris and Alloeorhynchus are provided aid in identification.


Introduction
Prostemmatinae is a small subfamily in the family Nabidae with five genera and approximately 150 species worldwide (Schuh and Štys 1991;Kerzhner and Konstantinov 2008;Cassis 2016;Brailovsky and Barrera 2017); four genera and 27 species are found in the Palaearctic Region (Kerzhner 1996). However, only 17 species and four genera of the subfamily were reported in China prior to this study, mainly from Yunnan Province and adjacent southern provinces (Hsiao and Ren 1981;Ren 1998;Li et al. 2012;Kerzhner and Günther 1999). During fieldwork to Guizhou and Yunnan provinces, we collected several rare specimens of Prostemmatinae. Herein two new species are described, illustrated, and keyed. Alloeorhynchus (Alloeorhynchus) reinhardi Kerzhner & Günther, 1999 was described based on two short-winged females from Sichuan Province of China. We found a third macropterous female from Guizhou Province of China, which is redecribed herein.
Species of Prostemmatinae are considered primarily ground-inhabiting predators (Kerzhner 1996;Kerzhner and Konstantinov 2008). However, we found several specimens of Rhamphocoris guizhouensis under the bark of dead broadleaved evergreen trees along with an unknown species of Aradidae (Figs 19,20), but nothing else is known about the biology of these three species.

Materials and methods
The material examined in this study is now deposited in Guangdong Institute of Applied Biological Resources, Guangzhou, China. The external structures were examined using a binocular dissecting microscope. Male genitalia were soaked in hot 90% lactic acid for approximately ten minutes to remove soft tissue, then in hot distilled water, and dissected under a microscope. The dissected parts of the genital structures were placed in a plastic microvial with lactic acid under the corresponding specimen. All drawings were traced with the aid of a camera lucida. Measurements were obtained using a calibrated micrometer. Body length was measured from the apex of head to the tip of the hemelytra in resting position. Maximum width of the pronotum was measured across humeral angles. All measurements are given in millimeters. Classification system and morphological terminology mainly follow those of Ren (1998) and Kerzhner (1992). The tribal, generic, and specific names in the text are arranged alphabetically.

Key to the Chinese Species of Rhamphocoris Kirkaldy
Description. Color. Body red, shiny. First antennal segment pale yellow, second antennal segments blackish brown, third to fourth antennal segments pale brown; vertex of head, dorsal surface of neck, anteocular area, eyes, anterior margin of collar of pronotum, propleural epimeron, pleuron and sternum of meso-and metathorax, fore wing (except strip or markings on basal part of membrane and basal part of clavus yellowish white) dark brown to blackish brown (Figs 1,19); posterior pronotal lobe (except basal part), anterior margin of each abdominal segment pale brown to brown; scutellum, small spines of underside of fore femur blackish brown to black; abdomen ventrally pale yellowish brown and laterally blackish brown; strip of basal part of membrane yellowish white (Figs 1, 19), basal part of clavus pale yellowish brown.
Structure. Body clothed with golden yellow setae. Body flattened dorsoventrally. Head with rounded processes ventrally (Fig. 2); pronotum distinctly transversely constricted between collar and anterior lobe and between anterior and posterior lobe; anterior pronotal lobe bulged, arcuately laterally shallowly sulcate, medially longitudinally sulcate; scutellum sub-basally concave and with two small rounded depressions, apical part produced; fore femur somewhat thickened, and beneath with acute angular process. Abdomen oblong, not covered completely by fore wing; posterior margin of abdomen in female straight; fore wing reaches to abdominal tip. Ostiolar peritreme of metathoracic scent gland shown in Fig. 4. Male. Unknown. Distribution. China (Guizhou). Etymology. The specific name is derived from the type locality of the species.
Remarks. The new species resemble to R. hasegawai in body shape and color, but in the latter the head and pronotum are totally black. The new species is similar to R. elegantulus but easily distinguished by the body color: the head (except the vertex) is black; the collar and most of the posterior lobe of pronotum black, the anterior lobe and basal part of posterior lobe red ( Fig. 19) (vs. the head and pronotum totally red in R. elegantulus) (Ren 1998). The five Chinese species in the genus Rhamphocoris, including the new one described herein, can be distinguished in the above key. The new species is flattened and the single specimen was collected together with the flat bug Aradus sp. (Aradidae) under the bark, and possibly feeds on flat bugs. The fifth-instar nymph is red except for the brown to yellow antennae and the blackish brown wing pads (Fig. 20).

Redescription. Color. Body blackish brown to black
Structure and vestiture. Macropterous. Body elongate oblong, posteriorly gradually widened (Fig. 5). Head, pronotum, ventral surface of abdomen, legs and antennae smooth and shiny (Fig. 21). Body sparsely clothed with white long setae; first antennal segment sparsely clothed with oblique setae, second to fourth segments densely clothed with oblique setae; tibiae and corium of fore wing clothed densely with setae (Fig. 5). Subapical part of first antennal segment curved outward. Anterior pronotal lobe somewhat bulged and twice as long as posterior pronotal lobe; scutellum sub-angular, apical part with small protuberance. Fore coxa strong, subequal to 2/5 of femur in length; fore and mid femora distinctly thickened, ventrally sub-basal 2/5 dilated in a protrusion, and apical half beneath with two lines of black dentate spines; fore tibia apically dilated with spongy fossula and underneath with two lines of black spines; mid tibia beneath with a line of distinct spines and a line of indistinct spines (Fig. 6). Abdomen in female widened posteriorly; fore wing extending to tip of abdomen (Figs 5, 7). Ostiolar peritreme of metathoracic scent gland shown in Fig. 9 Distribution. China (Guizhou, Sichuan). Remarks. Kerzhner and Günther (1999) described the species A. (A.) reinhardi in German based on two short-winged females collected from Sichuan Province in Southern China. We found a macropterous female in Guizhou Province, which is redescribed here in English to facilitate identification. We identified this species by comparing it with the description and the color illustration in the paper published by Kerzhner and Günther (1999) with the help of Dr Steffen Roth (University Museum of Bergen), but we were unable to examine the type specimens. Type material. Holotype, male, China, Yunnan, Xishuangbannan, Mengla, Mengman Town, Nanping Village, 23-IV-2013, 21°17'18.86"N, 101°17'48.86"E, Wan Renjing and Zhao Ping leg.
Diagnosis. Corium reddish brown, and its basal, middle and apical part with obscure yellow markings; fore femur beneath with four distinct tubercles; head greyish yellow, anterior pronotal lobe greyish brown with median longitudinal part yellow.
Structure and vestiture. Body elongate oblong (Fig. 10). Body clothed with yellowish to white setae; first antennal segment sparsely clothed with oblique setae, second to fourth segments densely clothed with oblique setae; scutellum and corium of fore wing clothed with blackish setae (Figs 10-12). Subapical part of first antennal segment somewhat curving outward. Pronotum smooth and shiny, anterior pronotal lobe somewhat bulged; scutellum sub-angular, apical part somewhat produced posteriorly. Fore coxa strong, subequal to 1/2 of femur in length; fore and mid femora thickened and ventrally sub-basal 2/5 dilated in a protrusion, and fore femur beneath inside with four small short spines and outside with numerous black denticles from the protrusion to apical part of femur; fore tibiae apically dilated with spongy fossula and beneath with two lines of black spines; mid tibiae beneath with a line of distinct spines and a line of indistinct spines (Figs 10, 11); fore wing extending beyond tip of abdomen. Pygophore round, median pygophore process broad and produced acutely laterally (Fig. 13) Female. Unknown.

Distribution. China (Yunnan).
Etymology. The specific name refers to the type locality of the new species. Remark. The general body shape and the structure of fore leg resemble those of Alloeorhynchus (Alloeorhynchus) maculosus Kerzhner, 1992 (India, Sumatra). In the new species the neck of the head is greyish, the anterior pronotal lobe is greyish brown with pale markings, the markings on the corium of fore wing is obscure, and the fourth to seventh connexival segments are yellow basally with brown markings (vs. the anterior pronotal lobe yellowish and its anterior margin darker, the head is yellow, the markings on the corium of fore wing are distinct, and the fourth to fifth connexival segments have brown markings in A. (A.) maculosus). The species is also similar to Alloeorhynchus (Alloeorhynchus) fuscescens Kerzhner, 1992 (Nepal, Vietnam) and Alloeorhynchus (Alloeorhynchus) himalayensis Kerzhner, 1992 (northern India) in the body coloration and the body size, but the paramere in the new species is triangular with an apical protuberance (Figs 15, 16)