Psilotreta bitubercula, Kawase, 2022

Kawase, Naoki, 2022, The genus Psilotreta Banks (Trichoptera, Odontoceridae) in Japan, Zootaxa 5195 (6), pp. 501-521 : 513-515

Psilotreta bitubercula sp. nov.

( Figs 7A–7G , 11E )

Diagnosis. The male of this species is very similar to that of P. flavida , but is easily distinguishable from the latter by the shape of the median dorsal process of tergum X. A pair of small tubercules are present apicoventrally in this species ( Figs 7A, 7B ), but are lacking in P. flavida . The female of this species is also very similar to that of P. flavida but can be distinguished from the latter by having a pair of dark bands on sternum IX in ventral view ( Fig. 7G ).

Adult. General coloration pale brown in body, antennae and wings (in alcohol). Length of each forewing: male 6.0– 6.2 mm (mean = 6.1, n = 2), female 6.1–6.5 mm (mean = 6.26, n = 5). In head, thoracic nota, and venation, general morphology most similar to P. flavida ( Figs 8A–8C ), but in each female forewing, M3+4 and Cu1a connected by short crossvein m-cu in P. bitubercula sp. nov., same as P. atrocaudata sp. nov. ( Fig. 5A ) (those veins directly connected with each other without crossvein m-cu in P. flavida as in Fig. 8C )).

Male genitalia ( Figs 7A–7E ). Tergum IX subtriangular in dorsal view, with steep sides above rounded basal setal warts ( Figs 7A, 7C ). Basal segment of each inferior appendage long, extending beyond posterior of lateral processes of tergum X, cylindrical and covered with setae, tapered ( Fig. 7C ); apical segment about 1/3 length of basal segment, cylindrical, with many brown teeth on apical half. Preanal appendages oval and tapered apically in lateral view ( Fig. 7C ), extending to posterior margin of median dorsal process of tergum X in dorsal view ( Fig. 7A ). Tergum X bears median dorsal process heavily sclerotized dorsally and laterally, thick, turtle-head shaped in dorsal view ( Fig. 7A ), sparsely setose apically, with pair of small setose tubercules apicoventrally (marked with arrow in Fig. 7B ); lateral processes each with long, acute ventral projection angled posterad ( Fig. 7C ); pair of intermediate appendages heavily sclerotized, sharply curved posteroventrad, forming C-shaped in lateral view, positioned on lower 2/3 of each lateral process ( Fig. 7C ).

Phallus with phallotheca short, cylindrical; endotheca with pair of short and thick parameres located lateroventrally, each about 3 times as long as its basal width; aedeagus membranous with ventral plate weakly sclerotized, phallotremal sclerite distinct V-shaped in ventral view, strongly C-shaped in lateral view ( Figs 7D, 7E ).

Female genitalia ( Figs 7F–7G ). Sternum IX semicircular with pair of dark bands in ventral view ( Fig. 7G ). Segment X bilobed in dorsal view, each round lobe setose ( Fig.7F ). Vaginal apparatus almost 2 times as long as sternum IX in ventral view ( Fig. 7G ).

Larva. Unknown.

Holotype. Male (in alcohol), Amami Island, Yakugachi-gawa , Sumiyo-cho , Amami-shi , Kagoshima Pref., Japan , 33°45'N, 133°11'E, 23.vi.2007, M. Takai. ( LBM1410012577 ).

Paratypes. Amami Island , 2 females, same locality as holotype, 23.vi.2007, M. Takai ( LBM1410012578 – LBM1410012579 ) ; 1 male, 1 female, same locality, 24.vi.2007, M. Takai ( LBM1410012580 – LBM1410012581 ) ; 1 female, same locality, 24.vi.2007, M. Takai. ( LBM1410012583 ) .

Etymology. The species name “ bitubercula ” refers to two tubercules on the apical part of the median dorsal process of segment X in the male genitalia.

Distribution and habitat. Psilotreta bitubercula sp. nov. is an Oriental species distributed on Amami Island in the Ryukyu Archipelago, southwestern Japan ( Fig. 11E ). All specimens used in this study were collected streamside by light traps.

Japanese name. Futakobu-kiso-tobikera

Figures

FIGURE 5 Psilotreta atrocaudata sp. nov. 5A, female right wings, dorsal; 5B–5G, male genitalia: 5B, dorsal; 5C, ventral; 5D, left lateral; 5E, lateral process of tergum X and intermediate appendage, left lateral; 5F, phallus, left lateral; 5G, same, ventral. 5H, female genitalia, ventral. Abbreviations: I, II, III, V = apical forks I, II, III, V; Cu1, Cu1a, Cu1b = cubital veins 1, 1a, 1b; int.app. = intermediate appendage (paired); lat.pr. = lateral process of tergum X (paired); M1, M2, M3, M4 = median veins 1–4; m-cu = crossvein between median and cubital veins; par. = paramere (paired); sIX = sternum IX; tIX = tergum IX; va. = vaginal apparatus; v.pr. = ventral projection (paired); X = segment X. Arrows see text.

FIGURE 7. Psilotreta bitubercula sp. nov. 7A–7E, male genitalia: 7A, dorsal; 7B, ventral; 7C, left lateral; 7D, phallus, left lateral; 7E, same, ventral. 7F–7G, female genitalia: 7F, dorsal; 7G, ventral. Abbreviations: int.app. = intermediate appendage (paired); lat.pr. = lateral process of tergum X (paired); mdp.tX = median dorsal process of tergum X; par. = paramere (paired); sIX = sternum IX; va. = vaginal apparatus; v.pr. = ventral projection (paired). Arrow see text.

FIGURE 8. Psilotreta flavida Kawase 2021. 8A, head, dorsal; 8B, male right wings, dorsal; 8C, female right wings, dorsal. 8D–8G, male genitalia: 8D, dorsal; 8E, left lateral; 8F, phallus, left lateral; 8G, same, ventral. 8H, female genitalia, ventral. Abbreviations: I, II, III, V = apical forks I, II, III, V; Cu1, Cu1a, Cu1b = cubital veins 1, 1a, 1b; int.app. = intermediate appendage (paired); lat.pr. = lateral process of tergum X (paired); M1, M2, M3, M4 = median veins 1–4; m-cu = crossvein between median and cubital veins; par. = paramere (paired); sIX = sternum IX; tIX = tergum IX; va. = vaginal apparatus; v.pr. = ventral projection (paired). 8A–8B, 8D–8H.

FIGURE 11. Distributions of Japanese Psilotreta species.