Sisyrina vietnamica, Yang & Liu, 2021

Yang, Ying & Liu, Xingyue, 2021, New spongillaflies of the genus Sisyrina Banks, 1939 (Neuroptera: Sisyridae) from the Oriental faunal region, Zootaxa 5052 (4), pp. 552-566 : 558-559

Sisyrina vietnamica sp. nov.

( Fig. 5 )

Diagnosis. The new species is characterized by the antenna with scape and pedicel brown but with several basal flagellomeres pale yellow ( Fig. 5A–B ), the forewing with the distance between each crossvein of RP area and the forking point of each RP branch it connects slightly longer the length of corresponding marginal RP fork ( Fig. 5A ), the female tergum 9 with dorsal margin nearly twice as long as posterodorsal margin, and the female gonocoxite 9 nearly three times as long as wide ( Fig. 5D–E ).

Description. Female. Body length 2.4 mm; forewing length 2.8 mm and width 1.1 mm; hindwing length 2.5 mm and width 1.1 mm.

Body largely brown. Head ( Fig. 5A–B ) mostly brown, densely covered by long setae; vertex with anterior half, lateral and posterior margins paler; compound eyes prominent and black. Scape brown, densely covered by long setae, swollen medially, about twice as long as wide; pedicel brown, slightly longer than flagellomere; flagellum partially damaged, remaining basal three flagellomeres on left antenna and seven flagellomeres on right antenna pale yellow, each covered by many long setae. Maxillary and labial palpi brown; terminal segment of maxillary palpus triangular in lateral view, broadest at base, tapering distally.

Thorax brown, densely covered by long setae. Legs slender and pale, meso- and metatrochanter, meso- and metacoxae brown, densely covered by long setae; tarsomere 1 equal to combined length of tarsomeres 2-4; pretarsal claws simple; arolium present.

Forewing ( Fig. 5A ) oval, distally rounded; trichosors present along distal margin; distinct dark longitudinal stripes present among longitudinal veins; most crossveins with dark brown shadings except basal ones; most forked points of longitudinal veins with dark brown shadings; pterostigma indistinct, brownish, with indistinctive crossveins; costal area with eight crossveins proximad pterostigma; two scp-ra crossveins present basally and distally; ScP weakened distally, not running into RA; RP with three main branches; three ra-rp crossveins; MA dichotomously branched distally; two rp-ma crossveins present; MP branched into MP1 and MP2, both branches bifurcated or trifurcated; two ma-mp and one mp1-mp2 crossveins present; CuA with four pectinate and simple branches; three mp-cua crossveins; CuP and A1 single; one cua-cup crossvein; A2 distally bifurcated; seven subapical gradates with each interrupted centrally by a rounded hyaline spot except anterior-most one and posterior-most one; distance between each crossvein of RP area and forking point of each RP branch it connects to slightly longer corresponding marginal RP fork; 2rp-ma, 2ma-mp and mp1-mp2 crossveins respectively connecting stem of MA, MP1 and MP2.

Hindwing ( Fig. 5A ) oval, distally rounded; trichosors present along distal margin; most cossveins with brown shadings except basal ones; pterostigma indistinct, brownish, with indistinctive crossveins; costal area with six crossveins proximad pterostigma; one scp-ra crossvein present distally; ScP weaken distally, not running into RA; RP with three main branches; two ra-rp crossveins present; MA dichotomously branched distally; one rp-ma crossvein present; MP branched into MP1 and MP2, both dichotomously forked; two ma-mp and one mp1-mp2 crossveins present; CuA with four pectinate and simple branches; CuP bifurcated, A1 and A2 simple; one a1-a2 crossvein; seven subapical gradates with each interrupted centrally by a rounded hyaline spot except anterior-most one and posterior-most one, basal ma-mp crossvein similarly interrupted.

Abdomen ( Fig. 5C–E ) pale brown; pregenital segment with small tergum and larger sternum, covered by many long setae. Tergum 8 covered by many short setae; dorsally separated, dorsolaterally broadened, surrounding spiracle; ventrolaterally narrowed and extending ventrad. Gonocoxites 8 fused into a small sclerite that is concaved posteriorly. Tergum 9 densely covered by short setae, nearly pentagonal, slightly longer than wide, dorsal margin nearly twice as long as posterodorsal margin; anterodorsal corner weakly sclerotized. Gonocoxite 9 densely covered by long setae, abruptly curved downward distally, nearly three times as long as wide. Ectoprocts densely covered by long setae, posteroventrally tapering and posteromedially concaved nearly to its half-length; callus cerci with four trichobothria.

Male. Unknown.

Type material. Holotype ♀, Vietnam: Dak Lak, Yok Don National Park [12°87′N, 107°80′E], 200 m, 7.Ⅴ.2012, Xingyue Liu ( CAU).

Etymology. The specific epithet “ vietnamica ” refers to the distribution of the new species only known from Vietnam.

Distribution. Vietnam (Dak Lak).

Remarks. This species appears to be closely related to S. fashengi sp. nov. in having similar antennal coloration (scape and pedicel brown, but flagellum pale yellow), but S. fashengi sp. nov. can be distinguished from S. vietnamica sp. nov. by the female tergum 9 in which the dorsal margin is nearly as long as posterodorsal margin, and the female gonocoxite 9 nearly four times as long as wide, with feebly curved apex. In S. vietnamica sp. nov. the dorsal margin of female tergum 9 is nearly twice as long as posterodorsal margin, and the female gonocoxite 9 is three times as long as wide, with hook-like apex. Considering the consistent characteristics within S. fashengi sp. nov., especially the female genitalia that has no intraspecific variation, this new species albeit being described based on a single female should be justified. Moreover, the occurrence of this new species from southern Vietnam, which is distinctly far from the distribution of S. fashengi sp. nov., may also suggest a distinct species status of this new species.

Similar to S. fashengi sp. nov., S. vietnamica sp. nov. can be distinguished from S. nirvana , S. tropica and S. qiong by the color of antenna and the female tergum 9. In S. vietnamica sp. nov., the antenna has only the basal two segments darker than remaining part, and the female tergum 9 is slightly longer than wide. However, in the latter three species, the antenna has the basal seven to eight segments darker than remaining part, and the female tergum 9 is much longer than wide (the female of S. qiong is unknown).

Figures

FIGURE 5. Sisyrina vietnamica sp. nov., holotype, female.A. Habitus photograph, lateral view; B. Photograph of head, dorsal view; C. Photograph of genitalia, dorsal view; D. Photograph of genitalia, lateral view; E. Drawing of genitalia, lateral view. S: sternum; T: tergum; cc: callus cerci; ect: ectoprocts; gst: gonostylus; gx: gonocoxite. Scale bar = 1.0 mm (A), 0.5 mm (B), 0.1 mm (C–E)