Sycanus taynguyenensis Truong & Giang & Nguyen & Chau & Ha 2024, sp. nov.
Creators: name: Truong, Xuan Lam
name: Giang, Phan Thi
name: Nguyen, Dai Dac
name: Chau, Tran Pham Minh
name: Ha, Ngoc Linh
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Reduviidae
Sycanus
Sycanus taynguyenensis

description: Sycanus taynguyenensis Truong & Ha, sp. nov.
(Figs. 4B, 8, 9)
Type material. Holotype. ♂; NDD2019-285; Vietnam, Dak Lak Province, Ea So Natural Reserve; 19.ix.2019; DD Nguyen leg.; IEBR. Paratypes. 1♀; NDD2018-395; Vietnam, Gia Lai Province, Kon Chu Rang Natural Reserve; 26.ix.2018; DD Nguyen leg.; IEBR.
Non-type material. 1♂; Qhoa-M10-01; Vietnam, Dak Lak Province, Krong Ana, Dray Sap; 30.iii.2019; Nguyen Thi Quynh Hoa (Tay Nguyen University) leg.; IEBR. 1♂; TXL-M10-02; Vietnam, Dak Lak Province, Ea So Natural Reserve; 15.ix.2023; XL Truong leg.; IEBR.
Diagnosis. Body large-sized and pale orange brown; head long, almost black with a brownish yellow suffusion next to outer side of ocellus (Fig. 8D, E); base of scape blackish brown, scape interleaved brownish yellow and blackish brown, pedicel dark brown with a brown suffusion medially, first and second flagellomeres brown; anterior pronotal lobe orange brown, somewhat with irregular dark brown suffusion and posterior pronotal lobe rugulose, pale orange brown or reddish brown (Fig. 8F); scutellum black with orange brown centrally and scutellar spine sub-vertical, short, bifid at apex, and wholly orange brown or reddish brown (Fig 8B, F); basal 2/3 of coria and whole clavus black or dark brown; remaining of coria white or orange; clavus dark brown (Fig. 8G).
The general appearance and male genitalia of this species are highly similar to that of the Sycanus sichuanensis, However, this new species can be distinguished from the latter by the following features: pronotum with anterior pronotal lobe orange brown, somewhat with irregular dark brown suffusion and posterior pronotal lobe pale orange brown or reddish brown (Fig. 8F) (in S. sichuanensis pronotum wholly black); laterotergites much dilated, posto-lateral margin of each laterotegite elevated, slightly produced than antero-lateral margin of following laterotegite (Fig. 8A–C) (in S. sichuanensis laterotergites distinctly roundly laterally dilated, middle part of each laterotergite elevated); basal 2/3 of coria and whole clavus black or dark brown and remaining of coria white or orange (Fig. 8G) (in S. sichuanensis coria yellowish to milk-white with basal part and apical angle black); coxae orange brown or reddish brown (in S. sichuanensis coxae black).
Moreover, the new species and Sycanus minor have high similarity in general appearance, i.e., male genitalia structure and general body coloration, and a very close relationship in molecular phylogenetic analyses (minimum interspecific p-distance of 1.8 %). However, the new species is distinct from S. minor by the following features: pronotum with anterior pronotal lobe orange brown, somewhat with irregular dark brown suffusion and posterior pronotal lobe pale orange brown or reddish brown (Fig. 8F) (in S. minor pronotum black with lateral and posterior margins orange or anterior, lateral and posterior margins orange); abdominal sternites dark brown with discontinuous medial longitudinal black strip and small longitudinal black markings segmentally laterally (Fig. 8C) (in S. minor yellowish to red with median longitudinal stripe, segmental transversal stripe black); base of scape blackish brown, scape interleaved brownish yellow and blackish brown, pedicel dark brown with a brown suffusion medially, first and second flagellomeres brown (in S. minor black), distal dorsal lobe of endosoma (ddl) centrally covered longitudinally with tiny prickles, surrounded with four large and long horn-shaped prickles centrally, and a few smaller prickles (Fig. 9H–K) (in S. minor ddl with two feebly sclerotized stripe-shaped sclerites, apically with a feebly sclerotized horned process and laterally with five pairs of small spines).
Male description.
Colouration. Body pale orange brown. Head dorsum, neck, clypeus, antenniferous tubercles, labrum, and head venter black; maxillary plate, gena black or blackish brown; a brownish yellow suffusion next to outer side of ocellus; first visible labial segment blackish brown; base of second visible labial segment dark brown; remaining of labium brown, paler as pale brown toward tip (Fig. 8D, E). Base of scape blackish brown; scape alternating brownish yellow and blackish brown; pedicel dark brown with a brown suffusion medially; first and second flagellomeres brown. Collar pale orange brown or pale reddish brown (Fig. 8F); anterolateral angle, anterior pronotal lobe and prosternum orange brown, somewhat with irregular dark brown suffusion (Fig. 8F); anterior acetabulum orange brown; stridulatory sulcus luteous; posterior pronotal lobe pale orange brown or reddish brown (Fig. 8F); scutellum black with orange brown centrally (Fig. 8F); scutellar spine wholly orange brown or reddish brown (Fig. 8F); meso- and metapleura, meso- and metasterna, dark brown with irregular blackish brown sufusions; coxae orange brown or reddish brown; trochanters and basal half of femora dark brown; apical half of femora, tibiae, and tarsi blackish brown. Basal 2/3 of coria and whole clavus black or dark brown; remaining of coria white or orange; clavus dark brown; membrane pale bronzy brown, semi-hyaline (Fig. 8G). Hind wings faintly semi-hyaline. Abdominal mediotergites dark brown with irregular brown suffusions; laterotergites sanguineous or reddish orange (Fig. 8A, B); each laterotegites III–VII with large black markings in anterior and posterior margins ((Fig. 8B); abdominal sternites dark brown with discontinuous medial longitudinal black strip and small longitudinal black markings segmentally laterally (Fig. 8C). Pygophore orange or sanguineous (Fig. 8C).
Var. abdomen beneath black.
Structure. Body large-sized (15.50 mm), elongated and posteriorly widened. Head tubular, slender, elongated (Fig. 8D, E); head and neck together much longer than pronotum (Fig. 8A, B); anteocular area of head elongate-conical; anteclypeus cylindrical and prominent; postocular area of head weakly globose, distinctly wider than anteocular area, shorter than anteocular area, constricted behind compound eyes, with a wide and deep interocular sulcus; neck long (Fig. 8D, E). Compound eyes protruding laterally, nearly globose, oblique with respect to ventral margin of head; lateral ocelli produced, slightly elevated behind interocular sulcus, separated from each other; interspace between lateral ocelli wider than distance between compound eye and lateral ocellus (Fig. 8D, E). First visible labial segment slightly thicker and much shorter than second segment, longer than anteocular area of head, not extending beyond level of middle of compound eye when labium laid backward (Fig. 8D); proportional length of first to third visible labial segments 2.2:3.7:0.7. Scape about 1.7 times as long as head, about 2.4 times as long as pedicel, longer than second flagellomere; first flagellomere about half as long as pedicel and about 1/4 times as long as second flagellomere; proportional length of scape, pedicel, first and second flagellomeres 5.5:2.3:1.3:4.8. Collar thin, almost invisible in dorsal view, with anterolateral angle roundly produced anteriorly; anterior pronotal lobe small, hemisphered and bulged, smooth, deeply depressed at base; posterior pronotal lobe rugulose, shallowly depressed on disc, with slightly swollen anteromedial elevation (never sulcate or concave); humerus bluntly triangular, with round apex; posterior margin of pronotum substraight; posterior angles round, weakly exceeded to posterior margin of pronotum (Fig. 8F). Scutellum triangular, somewhat triangularly depressed basally, apically produced with a scutellar spine, and sloping downward, posterior apex round (Fig. 8F); scutellar spine sub-vertical, short (1.45 mm), bifid at apex (Fig. 8B, F). Femora elongated, slender but stout, moderate subnodulose apically; tibiae slender and elongated. Hemelytra surpassing beyond apex of abdomen when fully closed, 0.7 times as long as body length (Fig. 8A); discal cell nearly diamond-shaped, longer than width (Fig. 8G); Sc 0.7 times as long as hemelytron length, 1.4 times as long as R + M (Fig. 8G). Hind wing damaged. Laterotergites much dilated and ascending with segmental incisures, posto-lateral margin of each laterotegite slightly produced than antero-lateral margin of following laterotegite (Fig. 8B). Pygophore ovoid (Fig. 9B–D); median process of pygophore (mpp) posteriorly produced, 0.39 times as long as wide in dorsal view, with apical margin slightly convex, distinctly produced a round apex, apicolateral corner sub-round, distinctly produced posterolaterad (Fig. 9B–E); paramere long, slender, clavate, somewhat incurved and larger in apical part, with round apex (Fig. 9F–G). Aedeagus in dorsal view ovoid, dorsally sclerotized and in lateral view long and narrow (Figs. 9H, I); articulatory apparatus (aa) in ventral view with basal plate arms relatively slender and jointly forming a V-shape, and in lateral view arched strongly (Fig. 9H, I); dorsal phallothecal sclerite (dps) in lateral view with posteromedian weakly produced (Fig. 9I); spoon-like sclerites (sps) weakly anteriorly produced, hyaline and glabrous (Fig. 9H, I); membranous sac-like lobes almost disappeared (Fig. 9H); distal dorsal lobe of endosoma (ddl) round and weakly bulged, centrally covered longitudinally with tiny prickles, surrounded with four large and long horn-shaped prickles centrally, and a few smaller prickles (Fig. 9H–K).
Vestiture. Body clothed with yellow, shining, griseous setae interleaved with black setae. Head with moderately densely bent setae (Fig. 8D, E); first visible labial segment somewhat with a few bent setae; remaining labium without setae (Fig. 8D). Scape with some short, slender, oblique setae, denser apically; pedicel with short, oblique, setae, denser than first joint, and denser apically; first and second flagellomeres with abundantly short, slender, more oblique than second joint setae. Collar, anterolateral angles, posterior pronotal lobe, scutellum, pleuron, sternum, coxae, coria with dense of bent, yellowish griseous setae, interleaved with long, erect, vertical, black setae (Fig. 8H); abdomen beneath with straight, slender, oblique griseous setae; trochanter, femora, tibia with long, slender, erect, vertical, black setae; Male pygophore ventrally moderately densely with bent, slender, yellowish griseous setae, somewhat with black setae (Fig. 9B–E); paramere apically with some long, yellowish griseous setae (Fig. 9F, G).
Female description.
General external morphology similar to that of the male.
Coloration. Almost similar to male but differ in the following characters. Abdominal sternites wholly black; Gonocoxa VIII black with a reddish-brown spot near posterior apex; abdominal laterotergite VIII, abdominal tergite IX, and gonapophysis VIII black (Fig. 9A).
Structure. Almost the same as male but larger than male and differ in the following characters. Body large-sized (21.34 mm), elongated, and somewhat robust. Head together with neck shorter than or almost as long as pronotum. Proportional length of first to third visible labial segments 2.2:4.1:0.9. Scape about 1.8 times as long as head, about 2.5 times as long as pedicel, longer than second flagellomere; first flagellomere about half as long as pedicel and about 1/5 times as long as second flagellomere; proportional average length of scape, pedicel, first and second flagellomeres 6.4:2.5:1.3:5.9. Abdominal laterotergite VIII with thin posterior margin, not exceed the posterior margin of abdominal tergite IX; abdominal sternite VII forming a wide sub-pentagonal median concavity, with posteromedian margin gently U-shaped, with inner posterolateral margin slightly concave but weakly convex medially; gonocoxa VIII subtriangular, produced mesad and forming a pointed apex at apical inner corner, and with inner margin weakly incurved in posterior 3/4; gonapophysis VIII subtriangular, posteriorly produced; abdominal tergite IX small (Fig. 9A).
Vestiture. Almost the same as male except for the following characters. Anterior 1/3 of gonocoxa VIII almost no setae; posterior 2/3 of gonocoxa VIII covered with short and long slender black setae; posterior margin of gonapophysis VIII densely covered with long erect black setae; abdominal laterotergite VIII and abdominal tergite IX covered with short and long black setae (Fig. 9A).
Measurements. All dimensions are given in mm. Holotype (♂): BL 15.50; HL 3.29; AoL 1.47; AoW 0.77; PoL 1.02; PoW 1.08; NL 1.16; OE 1.42; IE 0.63; ED 0.89; OD 0.16; OCD 0.43; COD 0.17; R1L 2.22; R2L 3.68; R3L 0.71; A1L 5.47; A2L 2.25; A3L 1.33; A4L 4.80; PnL 2.82; PnW 3.36; APL 0.87; PPL 1.96; SPL 1.45; HeL 10.39; HeW 3.52; Sc 7.66; R+M 5.32; AFL 5.60; ATL 6.31; MFL 5.37; MTL 6.21; PFL 6.79; PTL 8.30. Paratype (♀): BL 21.34; HL 3.50; AoL 1.74; AoW 0.89; PoL 0.95; PoW 1.16; NL 1.37; OE 1.56; IE 0.70; ED 0.91; OD 0.15; OCD 0.42; COD 0.15; R1L 2.21; R2L 4.07; R3L 0.90; A1L 6.39; A2L 2.53; A3L 1.32; A4L 5.86; PnL 3.89; PnW 4.54; APL 1.17; PPL 2.72; SPL 2.31; HeL 12.24; HeW 4.58; Sc 9.43; R+M 6.53; AFL 6.20; ATL 7.24; MFL 5.63; MTL 6.87; PFL 7.36; PTL 9.67.
Distribution. Vietnam, Central Highlands (Dak Lak and Gia Lai Provinces).
Type locality. Vietnam, Central Highlands (Dak Lak and Gia Lai Provinces).
Etymology. This new species is named after the Tay Nguyen region, the local name of Central Highlands, Vietnam; an adjective.
description: Published as part of Truong, Xuan Lam, Giang, Phan Thi, Nguyen, Dai Dac, Chau, Tran Pham Minh & Ha, Ngoc Linh, 2024, Two new species of the genus Sycanus Amyot & Serville (Insecta: Hemiptera: Reduviidae: Harpactorinae) from Vietnam, pp. 301-325 in Zootaxa 5481 (3) on pages 318-322, DOI: 10.11646/zootaxa.5481.3.1, http://zenodo.org/record/12758808