Stenopsyche formosan

Nozaki, Takao, Saito, Rie, Nishimura, Noboru & Tojo, Koji, 2016, Larvae and females of two Stenopsyche species in Taiwan with redescription of the male of S. formosana (Insecta: Trichoptera), Zootaxa 4121 (4), pp. 485-494 : 487-490

Stenopsyche formosan a Kobayashi 1987

( Figs. 2 , 3 )

Stenopsyche formosana Kobayashi 1987 , 37–38, 43, male, Taiwan; Malicky 2014, 1624, Taiwan. Stenopsyche banksi: Mosely 1942 (in part), 359, Taiwan; Nishimura et al. 2015, 78, Taiwan.

Adult. Forewings of male each 21–22 mm long (n=2) and of female 19–23 (n=3), brown with many pale spots, irregularly reticulated; hind wings white or slightly pale brown, subhyaline. Antennae more than 1.5 times as long as forewings in male, slightly longer than forewings in female. Legs yellowish brown, with dark markings on fore- and middle tibiae and on 1st to 2nd (often 3rd) segments of middle tarsi. Tibial spurs 3, 4, 4.

Male genitalia. Segment IX (IX) short dorsally, long ventrally, anteroventral margins round in lateral aspect, posterolateral margins each with long triangular projection in middle. Segment X (X) forming isosceles trapezoid in dorsal aspect, semimembranous in apical half; apex slightly concave, with pair of stout lateral lobes. Pair of intermediate appendages (int) dorsolaterally near base, each with apex round, directed posterad. Preanal appendages (pr) long, more than 3 times as long as segment X. Inferior appendages (inf) long triangular in ventral aspect, each with round apex; superior arms (sup) about half as long as preanal appendages, evenly curved outward, apically semicircular in dorsal aspect. Phallus long, endotheca with numerous stout spines along its entire length.

Female genitalia. Segment IX (IX) rectangular in lateral aspect, mostly sclerotized but membranous posterodorsally and bearing 1 to 3 setae on each anterodorsal side, with long apodemal extension on each anteroventral corner. Segment X (X) (segment XI of Schmid 1969) membranous dorsally, with pair of setose longitudinal sclerites dorsolaterally; ventral setose area weakly sclerotized, but membranous apicomesally; with pair of setose distal lobes, each bearing cercus. Vulvar scale (vs) large, each side sclerotized, thumb-like in lateral aspect, with long stout setae apicolaterally; posterolateral margins round in ventral aspect, semimembranous mesally, projecting slightly beyond lateral corners. Vaginal chamber (vc) sclerotized, expanded anterad and dorsad in lateral aspect; ventral part wide, vase-shaped in ventral view.

Final instar larva. General appearance as in genus. Length up to 35 mm. Head 4.4–5.0 mm long (n=5); anterior part about 1.6 mm wide (eye level), posterior widest part about 1.8 mm; ground color yellowish to reddish brown, with many small dark spots; frontoclypeus with dark brown longitudinal band on mid-line, crossing three black transverse stripes; primary setae 1, 4, 10, 11, 13 not dark pigmented; setae 8, 15, 18 located ventrally; each seta 18 (18) bifurcated, about 0.2 mm long, located near postoccipital ridge, each surrounded by rugged semicircular area. Pronotum 2.3–2.5 mm long, about 2.3 mm wide; ground color yellowish brown, with many dark spots except for anterodorsal area, posterior margin black. Forecoxae pentagonal in mesal view; each apicodorsal process (ap) finger-like, straight, directed anterad, with short semitransparent spine-like seta apically; each basodorsal process (bp) elongate triangular, slightly longer than apicodorsal process, with long mesal seta in middle; each central process (cp) on mesal face small, with short stout seta apicodorsally.

Specimens examined. Holotype male (with handwritten label “7143 ♂”), [ TAIWAN] Nangzunkei, wulia, 16.iv.1982, S. Uchida (CBM). [ TAIWAN] Beigang River, Huisun Forest Area, Ren’ai Xiang, Nantou, 24°4.992’N, 121°0.651’E, alt. 490 m, 3.iii.2015, N. Nishimura, 1 male (SU); same locality, 3.iii.2015, L.P. Hsu, 1 male (TN); Huisun Forest Area, Ren'ai Xiang, Nantou, 24°5.628’N, 121°1.843’E, alt. 910 m, 30.iv.2010, K. Tojo, 2 larvae (SU); Meiyuan River, Ren'ai Xiang, Nantou, 24°5.09’N, 120°57.22’E, alt. 504 m, 3.iii.2015, N. Nishimura, 2 larvae (SU); same locality, 4.iii.2015, N. Nishimura, 3 females (1 female: SU, 2 females: TN); Sankeng Ecology Park, Dahan River, Longtan Xiang, Taoyuan, 24°50.169’N, 121°15.329’E, alt. 127 m, 26.xi.2010, K. Tojo, 1 larva (SU).

Remarks. We examined the holotype of S. formosana deposited in the CBM, and confirmed it to be identical with males used in this study. The type locality of this species was recorded as “Nangzunkei, wulia” by Kobayashi (1987). Although we could not understand the meaning of “wulia” but “Nangzunkei” must be a Japanese reading of a Chinese locality name “Nanshan stream.” The collector of this specimen visited this stream in Ren'ai Xiang, Nantou County on 16 April 1982 (Uchida personal communication).

On the other hand, Mosely (1942) described S. banksi , a species similar to S. formosana , from Foochow (Fuzhou, P.R. China: the holotype) in China, and also recorded it from Taiwan based on a male specimen designated as a paratype. Stenopsyche banksi has been recorded from north to central Taiwan (Biodiversity Research Center, Academia Sinica 2015). For confirming the taxonomic status of S. formosana , we compared males of S. formosana with photographs of the holotype and paratype males of S. banksi kindly provided by Dr. B. Price, The Natural History Museum, London. The paratype male of S. banksi from Taiwan is identical to our males of S. formosana . However the S. banksi holotype from continental China is slightly different from the paratype. Segment IX in lateral aspect is longer in S. formosana than that in the holotype of S. banksi ( Figs. 2 A, 4B); a pair of intermediate appendages is directed posterad in S. formosana ( Fig. 2 A) but they are large and strongly curved ventrad in the holotype of S. banksi ( Fig. 4 B; Mosely 1942, fig. 51); spines arising from the base of the endotheca are short in S. formosana ( Figs. 2 B, 2D), but very long in the S. banksi holotype ( Fig. 4 B; Mosely 1942, figs. 51, 53). Furthermore, in S. formosana a pair of intermediate appendages of the segment X arise from the dorsolateral sides of segment X ( Fig. 2 C), but they arise dorsally and close to each other in the S. banksi holotype ( Mosely 1942, 358, fig. 52). Although S. formosana may be a subspecies level taxon of S. banksi , we treat them as distinct species. Further study with molecular data is needed to confirm the taxonomic status of this/these species.

The larva of this species is very similar to those of S. angustata Martynov 1930 ( Hoang & Bae 2007, Xu et al. 2015) and S. schmidi Weaver 1987 ( Tanida 2003, Nozaki & Shimura 2015), but is distinguishable from them by the shape or length of the apicodorsal processes of the forecoxae. In this species, the apicodorsal process of each forecoxa is straight and slightly shorter than the basodorsal process, but it is curved ventrad in S. angustata and less than half as long as the dorsal process in S. schmidi .

Figures

FIGURE 2. Male genitalia of Stenopsyche formosana. A, left, lateral; B, phallus, left lateral; C, dorsal; D, ventral. Abbreviations: IX = segment IX, X = segment X, inf = inferior appendage, int = intermediate appendage, pr = preanal appendage, sup = superior arm of an inferior appendage.

FIGURE 3. Female and larva of Stenopsyche formosana. A – C, female genitalia: A, left lateral; B, ventral; C, dorsal. D – G, larva: D, head, dorsal; E, head, ventral; F, prothorax, dorsal; G, mesal surface of right forecoxa, left lateral. Abbrebiations: 18 = primary seta no. 18 of larval head, VIIIs = sternum VIII, VIIIt = tergum VIII, IX = segment IX, X = segment X, ap = apicodorsal process of a forecoxa, bp = basodorsal process of a forecoxa, cp = central process of mesal face of a forecoxa, vs = vulvar scale; vc = vaginal chamber.

FIGURE 4. Holotype male of Stenopsyche banksi (Photos B. Price). A, body and genitalia (mounted), B, genitalia, left lateral. Abbreviations: IX = segment IX, int = intermediate appendage. Arrows indicate long spines arising on basal part of endotheca.