Rihirbus kronganaensis Truong, Bui, Ha & Cai, 2020

Lam, Truong Xuan, Hoa, Bui Thi Quynh, Linh, Ha Ngoc & Cai, Wanzhi, 2020, A new species of the assassin bug genus Rihirbus (Hemiptera: Heteroptera Reduviidae) from Vietnam, Zootaxa 4780 (3), pp. 587-593 : 588-592

Rihirbus kronganaensis Truong, Bui, Ha & Cai , sp. nov.

( Figs 1–9 )

Diagnosis. This species can be easily distinguished from its two congeners by the body generally black except sixth and seventh abdominal segments and female genitalia dull yellow, the post-antennal protuberance being high and spine-shaped, the humeral angles of the pronotum beng more obtuse, and the tip of fore tibia produced into a sharp spine.

Description. Colour ( Figs 2–9 ). Body generally black, dorsal connexiva of fifth and sixth segments and female genitalia dull yellow. First antennal segment, head, rostrum, pronotum, scutellum, coxae, femora and tibiae, corium, dorsal connexiva of second to fifth segments, second to fourth abdominal segments and most of fifth abdominal segment (except small yellow portion) dark brown to black. Second and third antennal segments, apical part of third visible rostral segment, trochanters and tarsi, and a longitudinal area between Cu and PCu veins of hemelytra pale brown. The sixth and seventh abdominal segments (including connexiva) and the genital segments dull yellow. Small scattered hairy patches on corium white. Eyes grayish, ocellus whitish, spot between ocelli yellowish.

Structure. Head ( Figs 1–3 ) elongate elliptical, covered by somewhat oblique short setae, head subequal to pronotum in length, 4.2 times as long as width across eyes; anteocular portion 0.6 times as long as postocular portion, interocular furrow almost straight; with a pair of post-antennal protuberance long, spine-shaped, directed anterolaterad ( Figs 1–3 ); eyes ( Figs 2, 3 ) medium sized, not reaching level of ventral surface of head, approximately as wide as interocular space in dorsal view (0.9: 1), ocelli small and widely separated. Antennae ( Fig. 1 ) slender; segments I–III covered by somewhat short, curved, suberect setae, segment IV furnished with short, reclining setae; segment I longest, longer than head and pronotum together in length (1.2: 1); proportion of segments I to IV 2.1: 0.7: 1.5: 1; labium ( Fig. 3 ) covered by short suberect setae; first visible labial segment thickest, straight and longest, 1.8 time as long as length of second and distinctly extending beyond posterior margin of eyes; third labial segment shortest and reaching thorax; proportion of visible labial segments I to III 3.6: 1.8: 1.0.

Pronotum ( Figs 1–3 ) covered with short suberect setae; length subequal to width across humeri (0.9: 1); anterolateral angle short and conical; anterior lobe of pronotum approximately 0.6 times as long as its maximum width, with glabrous impression, anterior part with a shallow, middle part with a deep longitudinal sulcus, subbasal part with a pair of distinct protuberances; posterior lobe approximately 0.5 times as long as humeral width, 1.7 times as long as anterior lobe; posterior lobe of pronotum bulged, deeply rugose, discal part somewhat flat, humeral angles obtuse and slightly prominent; postolateral margin nearly straight and horizontal, posterior margin slightly convex. Scutellum approximately 0.56 times as long as maximum width of its exposed part, with a “V”-shaped carina, apical part rounded ( Figs 1 , 2 ).

Forelegs ( Figs 1 , 4 ) furnished with short, reclining or suberect setae, margin with short, dense setae; fore femur thickened, basal half distinctly incurved; femur 5.7 times as long as coxa, 8.3 times as long as trochanter, 6.0 times as long as its maximum width; fore tibiae 1.1 times as long as femur, strongly bent inward apically, and with a sharp spine on tip ( Fig. 4 ); tarsus two-segmented, 0.08 times as long as tibia. Maximum width of mid femur smaller than that of fore femur (0.4: 1); length of mid femur subequal to length of mid tibia (1: 1.1); maximum width of hind femur smaller than that of fore femur (0.3: 1), length of hind femur smaller than that of hind tibia (0.8: 1); femora and tibiae with short setae.

Abdomen ( Figs 1 , 6, 7 ) dilated, approximately twice as long as its maximum width, wider than maximum width of hemelytra in rest; abdominal segments III, IV, V and VI subequal in length (proportions from III to VI as 1.02: 1.08: 1.05: 1.00); dorsal connexivum moderately dilated, especially fourth to sixth segments. Hemelytra ( Figs 1 , 5 ) exceeding apex of abdomen. Female genitalia with gonapophyses VIII triangular, large and wide; gonocoxites VIII and IX wide; segments IX and X appear to be linked mesally and separated laterally, divided by a shallow line ( Figs 8, 9 ).

Measurements [♀ (n = 1), in mm]. Body length 21.63; maximum width (across abdomen) 6.01. Head length (including neck) 3.47; width across eyes 1.22; height of antenniferous tubercle 0.25; postocular part length 0.76; synthlipsis length 0.93; distant between 2 ocelli 0.51; ocellus diameter 0.18; eye maximum diameter 0.77; antennal segment length I–IV = 8.99: 2.80: 6.48: 4.22; lengths of visible rostral segments I–III = 2.15: 1.04: 0.59. Anterior pronotal lobe length 1.61; posterior pronotal lobe length 2.83; maximum thorax width 5.16; scutellum length 0.88; scutellum width 1.19; fore femur length 6.94; fore tibia length 8.26; mid femur length 6.09; mid tibia length 6.79; hind femur length 7.81; hind tibia length 9.45; hemelytron length 13.91; width across hemelytra 4.51.

Type material. Holotype: female, VIETNAM, Dac Lak Prov. , Krong Ana Distr., Dray Sap commune, 12º54’31.8”N 107º97’14.0”E, 25.vii.2019, ca. 540 m alt., leg. Bui Th ị Quynh Hoa.

Distribution. Central Vietnam (Dac Lak Province).

Etymology. The specific epithet refers to its locality, Krong Ana, Dac Lak Province, central Vietnam; an adjective.

DNA barcode. A partial sequence of the mitochondrial gene of cytochrome oxidase subunit I (COI) of the holotype was uploaded to GenBank with accession number MT 229686 .

Figures

FIGURE 1. Rihirbus kronganaensis sp. nov., female. Scale bar: 3 mm.

FIGURES 2–5. Rihirbus kronganaensis sp. nov., female. 2–3, head and pronotum; 4, foreleg; 5, left hemelytron; 2, 5, dorsal view; 3, 4, lateral view. Scale bars: 1 mm for Figs 2, 3, 5; 1.5 mm for Fig. 4.

FIGURES 6–9. Rihirbus kronganaensis sp. nov., female. 6–7, abdomen; 8–9, apical part of abdomen. 6, ventral view; 7, ventrolateral view; 8, lateral view; 9, posteroventral view. Scale bars: 1 mm for Figs 6, 7; 0.3 mm for Figs 8, 9.