Rhyacophila clemens, Tsuda, 1940

Kawase, Naoki, 2024, Redescription of Rhyacophila clemens Tsuda 1940 (Trichoptera, Rhyacophilidae), with descriptions of five new, allied species from Japan, Zootaxa 5447 (1), pp. 55-76 : 73

Rhyacophila clemens Species Group Ross 1956

In this study, I have recognized six Japanese species and one Korean species belonging to the R. clemens Species Group. As mentioned above in the introduction, the males of this species group are similar to those of the R. viquaea Species Group in having two pairs of anal sclerites, but the males of the seven species of the R. clemens Species Group in this study were distinguishable from those of the R. viquaea Species Group by the shape of the apical band: The apical band is large and oval in lateral view and independent of the root of the anal sclerites in the R. clemens Species Group ( Figs 1H , 3B , 4D , 5B , 6B , 7B ), but the ends of the apical band are joined with the root of the ventral pair of the anal sclerites in the R. viquaea Species Group ( Ross 1956). Schmid (1970) treated the ventral pair of the anal sclerites in the R. viquaea Species Group as the apical band of the tergal strap, whereas Lee & Ruiter (2011) agreed with Ross’s interpretation. Furthermore, the male of each species in the R. clemens Species Group bears the apical hinged process on segment X posteroventrally and the ventral plate of the aedeagus, but those of the R. viquaea Species Group lack such a process and plate ( Ross 1956, Schmid 1970, Lee & Ruiter 2011). Consequently, the male diagnostic characters for the R. clemens Species Group are as follows: Segment IX is long dorsally; the preanal appendages are absent; segment X bears an apical hinged process posteroventrally; two pairs of anal sclerites have a common internal root; a pair of large apical bands surrounds the anus and the root of the anal sclerites; the aedeagus bears a large sclerotized ventral plate; and parameres are absent.

Figures

FIGURE 1. Rhyacophila clemens Tsuda 1940. 1A–1J: 1A, male habitus, left dorsolateral (photographed by K. Inazu); 1B, male head and pro-, meso- and metanota, dorsal; 1C, male head, left lateral; 1D, male right wings, dorsal; 1E, lectotype (in glass tube) and labels preserved in INHS; 1F, male right wings, paralectotype (balsam mounted slide) preserved in OMNH; 1G–1J, male genitalia: 1G, left lateral; 1H, segment X and phallic apparatus, left lateral; 1I, same, posterodorsal; 1J, phallic apparatus, left dorsolateral. Abbreviations: I, II, III, IV, V = apical forks I, II, III, IV, V; IX, X = abdominal segments IX, X; A1, A2, A3 = anal veins 1–3; ab = apical band; aed = aedeagus; adl = apicodorsal lobe of segment IX; ahp = apical hinged process of segment X; as = anal sclerite; asia = apical segment of inferior appendage (paired); bsia = basal segment of inferior appendage (paired); C = costa; Cu1, Cu1a, Cu1b = cubital veins 1, 1a, 1b; hp = horizontal part of segment X; M1, M2, M3, M4 = median veins 1–4; m-cu = crossvein between median and cubital veins; phb = phallobase; R1, R2, R3, R4, R5 = radial veins 1–5; r-m = crossvein between radial and median veins; Sc = subcosta; tb = tergal band; TC = thyridial cell; vp = vertical part of segment X; vpl = ventral plate of aedeagus.

FIGURE 3. Rhyacophila vesperalis sp. nov. 3A–3E, male genitalia: 3A, left lateral; 3B, segment X and phallic apparatus, left lateral; 3C, dorsal (left inferior appendage omitted); 3D, ventral (left inferior appendage and apical segment of right inferior appendage omitted); 3E1, apical hinged process of segment X, enlarged, ventral; 3E2, ventral plate of aedeagus, enlarged, ventral. 3F–3K, female genitalia: 3F, left lateral; 3G, segment VIII, left lateral; 3H, same dorsal; 3I, same ventral; 3J, vaginal apparatus, left lateral; 3K, same, ventral. Arrows see text.

FIGURE 4. Rhyacophila inazui sp. nov. 4A, male habitus, left dorsolateral (photographed by K. Inazu); 4B, female right forewing (in alcohol), dorsal; 4C–4H, male genitalia: 4C, left lateral; 4D, segment X and phallic apparatus, left lateral; 4E, dorsal (left inferior appendage omitted); 4F, ventral (left inferior appendage and apical segment of right inferior appendage omitted); 4G1, apical hinged process of segment X, enlarged, ventral; 4G2, ventral plate of aedeagus, enlarged, ventral; 4H, posterodorsal. 4I–4N, female genitalia: 4I, left lateral; 4J, ventral; 4K, segment VIII, left lateral; 4L, same, ventral; 4M, vaginal apparatus, left lateral; 4N, same, ventral. Abbreviation: vr = ventral ridge. Arrows see text.

FIGURE 5. Rhyacophila angulicauda sp. nov. 5A–5D, male genitalia: 5A, left lateral; 5B, segment X and phallic apparatus, left lateral; 5C, dorsal (left inferior appendage omitted); 5D, ventral (left inferior appendage and apex of apical segment of right inferior appendage omitted). 5E–5I, female genitalia: 5E, left lateral; 5F, segment VIII, left lateral; 5G, same, ventral; 5H, vaginal apparatus, left lateral; 5I, same, ventral. Arrows see text.

FIGURE 6. Rhyacophila parvicauda sp. nov. 6A–6D, male genitalia: 6A, left lateral; 6B, segment X and phallic apparatus, left lateral; 6C, dorsal (left inferior appendage omitted); 6D, ventral (left inferior appendage omitted). 6E–6H, female genitalia: 6E, segment VIII, left lateral; 6F, same, ventral; 6G, vaginal apparatus, left lateral; 6H, same, ventral. Abbreviation: vr = ventral ridge.Arrows see text.

FIGURE 7. Rhyacophila furcicauda sp. nov. 7A–7F, male genitalia: 7A, left lateral; 7B, segment X and phallic apparatus, left lateral; 7C, same, posterodorsal; 7D, dorsal (left inferior appendage omitted); 7E, apical segment of right inferior appendage, mesal; 7F, segment X and phallic apparatus, ventral. 7G–7J, female genitalia: 7G, segment VIII, left lateral; 7H, same, ventral; 7I, vaginal apparatus, left lateral; 7J, same, ventral. Abbreviation: vr = ventral ridge. Arrows see text.