Rhyacophila longicaudata, Suwannarat & Malicky & Morse & Laudee, 2019

Suwannarat, Nannaphat, Malicky, Hans, Morse, John C. & Laudee, Pongsak, 2019, Four new species of Rhyacophila Pictet 1834 (Trichoptera: Rhyacophilidae) from Southeast Asia, Zootaxa 4657 (2), pp. 369-376 : 370-375

Rhyacophilidae

Rhyacophila longicaudata n. sp. Suwannarat & Malicky

Figs. 1 A–1E

Type material. Holotype male ( PSUNHM). THAILAND: Surat Thani Province, Tai Rom Yen National Park, Pha San Yen stream, 8°42′43″N, 99°30′36″E, ca. 1100 m a.s.l., 12 February 2017, leg. Pongsak Laudee.

Paratypes: Same data as holotype, 1 male ( PSUNHM) .

Etymology. The species epithet comes from Latin adjectives longus, -a, -um and caudatus, -a, -um, meaning “long tailed,” in reference to the long inferior appendages.

Description. Length of each male forewing 7.0 mm (n = 2); specimens in alcohol with head, thorax, and forewings dark brown.

Male genitalia ( Figures 1 A–1E5). In lateral view ( Fig. 1A ), segment IX subrectangular with broad posterolateral excision below midline, its apicodorsal lobe very long, lancet-like with short setae subapicodorsally, acute apically; in dorsal view ( Fig. 1B ), annular portion of segment IX transversely straight anteriorly, appearing separated by concave suture from its apicodorsal lobe ( Schmid 1970), apicodorsal lobe of segment IX very long, hourglass-like with very deep incision in apical 3/4 of posterior margin, apices acute. Preanal appendages located at posterodorsal margin of annular portion of segment IX, very short, black, wart-like. Segment X reduced, obscure, except anal sclerites, the latter oval in lateral view, rounded posteriorly, positioned underneath anterior portion of apicodorsal lobe of segment IX. Inferior appendages very long, more than twice as long as apicodorsal lobe of segment IX, cylindrical; each with basal segment about six times as long as apical segment, dorsal and ventral margins parallel in lateral view ( Fig. 1A ), broader basally in ventral view ( Fig. 1C ), with longitudinal ridge dorsomesally; apical segment short and ovoid in lateral and ventral views, with numerous stout subapicomesal setae. Tergal band from dorsal base of phallotheca terminating in sagittal appendage articulating with apical band connected with root of anal sclerite. In dorsal and ventral views ( Figs. 1A, 1D ), retracted phallus clavate, with phallotheca rectangular, endotheca thicker and oval with numerous spines, and aedeagus long and spoon-like with two long internal spines and five curved hooks apically (only four visible ventrally); in lateral view ( Fig. 1E ) protracted phallus long, phallotheca cylindrical, endotheca with numerous spines basally and membranous apically; aedeagus slender and cylindrical with two long internal spines of which dorsal spine about twice as long as ventral spine and with five long hooks apically.

Diagnosis. Rhyacophila longicaudata n. sp. is a member of R. nigrocephala Group ( Schmid 1970) in which there is a long apicodorsal lobe of segment IX extending caudad from the annular portion of that segment, the fused anal sclerites are reduced, apical and tergal bands are present and sclerotized, and in most species (including this new species) the phallic parameres are absent and the basal segments of the inferior appendages are fused with each other at their extreme bases. This species is similar to R. drosampa Schmid 1970, R. laocai Armitage & Arefina 2003, R. lhabu Schmid 1970 , R. paratecta Mey 1996 , and R. mayestril Malicky 1991 . However, R. longicaudata n. sp. differs from those by the unusually long inferior appendages and by the presence of long hooks at the apex of the aedeagus.

Rhyacophila aksornkoaei sp. n. Laudee & Malicky

Figs. 2 A–2C

Type material. Holotype male ( PSUNHM). THAILAND: Surat Thani Province, Khao Luang National Park, Tha Di stream, 8°28′46″N, 99°45′07″E, ca. 802 m a.s.l., 31 March 2018, leg. Nannaphat Suwannarat.

Paratypes: Same data as holotype, 5 male ( PSUNHM) .

Etymology. The species is dedicated to Prof. Dr. Sanit Aksornkoae, who is a prominent Thai ecologist.

Description. Length of each male forewing 11.0 mm (n = 2); specimens in alcohol with head, thorax, and forewings dark brown.

Male genitalia ( Figures 2 A–2C). Segment IX anterior margins convex dorsally and concave ventrally, posterior margins convex below its apicodorsal lobe, longitudinally longest at 2/3 height, anterodorsal margin concave except for small triangular mesal projection, its apicodorsal lobe about as long as annular portion of segment, divided by deep V-shaped apical incision nearly half its length mesally, slightly concave laterally, dark brown apically and subapically. Preanal appendages drop-like, shorter than apicodorsal lobe of segment IX. Segment X trapezoid, hidden below apicodorsal lobe of segment IX and between preanal appendages. Anal sclerite flat oval, oblique in lateral view. Inferior appendages each with basal segment shaped as pararellogram in lateral view, in ventral view slender in middle; apical segment mitten-shaped in mesal and ventral views, with short triangular “thumb” and with stout marginal and submarginal setae along subapicomesal and apicomesal margins. Phallus complex; phallobase short, tubular, its dorsal process somewhat triangular, convex dorsally, acute apically; ventral process tubular with expanded base and blunt apex; parameres long, tubular, expanded and bent slightly upward, each with tuft of bristles subapicomesally and apically, slightly expanded and truncate in lateral view and slightly convergent and blunt in ventral view; aedeagus as long as parameres, needle-like, expanded basally and upturned apically in lateral view ( Fig. 2A ), uniformly slender and straight in ventral view ( Fig. 2C ).

Diagnosis. This new species is a member of Rhyacophila anatina Group ( Schmid 1970) and is similar to other species of this Group found in Asia. According to Sun (2016), the males of this Group can be diagnosed as follows: “segment IX is short ventrally; the apicodorsal lobe of segment IX is strong and bilobed; the preanal appendages are large and closely joined to the apicodorsal lobe, segment X is vertical; the anal sclerites are usually paired, without roots; the apical band is strongly sclerotized and with its two lateral arms not joined to each other at the base; the tergal band is short and membranous; the basal segment of the inferior appendages are usually long, and the apical segments are short, the phallotheca is cylindrical and the endotheca well developed; the aedeagus is slender, tubular; parameres are slender, with the distal ends heavily bristled.” Rhyacophila aksornkoaei sp. n. is very similar to R. suratthaniensis Laudee & Malicky 2014 and R. petersorum Schmid & Denning 1971 (in Denning & Schmid 1971), but can be distinguished in that (1) the phallus of the new species is armed with a ventral plate that is absent in R. suratthaniensis Laudee & Malicky 2014 and R. petersorum Schmid & Denning 1971 (in Denning & Schmid 1971), (2) the distal ends of the parameres of Rhyacophila aksornkoaei sp. n. are bent upward and bristled apically, but bristles are arranged like a toothbrush in R. suratthaniensis and the paramere apices bear several thin and long spines directed distad in R. petersorum .

Rhyacophila limsakuli sp. n. Laudee & Malicky

Figs. 3 A–3D

Type material. Holotype male ( PSUNHM). THAILAND: Phetchaburi Province, Kaeng Krachan National Park, Ban Klang stream, 12°47′54″N, 99°27′09″E, ca. 352 m a.s.l., 1 June 2017, leg. Pongsak Laudee.

Paratypes: Same data as holotype, 1 male ( PSUNHM) .

Etymology. The species is dedicated to Assoc. Prof. Dr. Chusak Limsakul, who was the President of Prince of Songkla University during 2013–2018.

Description. Length of each male forewing 7.0 mm (n = 2); specimens in alcohol with head, thorax, and forewings dark brown.

Male genitalia ( Figures 3 A–3D). Anterolateral margins of segment IX convex subdorsally and concave subventrally, posterolateral margins convex; apicodorsal lobe of segment IX about as long as preanal appendages, convex dorsally and apically blunt in lateral view; in dorsal view slightly concave laterally and with V-shaped incision in apicomesal 1/3. Preanal appendages as long as apicodorsal lobe of segment IX, oval in lateral view, blunt in dorsal view. Anal sclerite flat, oval in lateral view, oriented obliquely dorsad from root. Basal segment of each inferior appendage tubular, tapered anteriorly, rounded posteriorly, and with longitudinal ridge subdorsally in apical half, apical segment nearly rectangular with broad and shallow invagination apically; in ventral view basal segment of each inferior appendage cylindrical and apical segment peanut-like with subapicomesal setae. Phallus complex; phallotheca tubular with lateral tenons; in lateral view dorsal process somewhat bird-head-like with round “crown” dorsally and long “beak” apically; aedeagus as long as parameres, needle-like; parameres fused basally, thick especially basally, their apices horizontally flattened and hooked ventromesad and caudad.

Diagnosis. This new species is a member of R. anatina Group ( Schmid 1970). It is similar to other species from Asia and can be diagnosed by the characters mentioned by Sun (2016). Rhyacophila limsakuli sp. n. closely resembles R. noeibia Malicky & Chantaramongkol 1993 , but the two species can be distinguished in that (1) the basal segment of each inferior appendage of R. limsakuli sp. n. is 4.5 times as long as the apical segment, but only 2.5 times as long in R. noeibia , (2) the apical segment of each inferior appendage of R. noeibia is boot-shaped and projected dorsad, but that of R. limsakuli sp. n. is rectangular and lacks a dorsal projection, and (3) the apices of the parameres of R. noeibia are bent upward, but in R. limsakuli sp. n. they are bent downward.

Rhyacophila kengtungensis sp. n. Morse & Malicky

Figs. 4 A–4C

Type material. Holotype male ( PSUNHM). MYANMAR: Shan State, Keng Tung Province, Pin Tao Waterfall , 21°26′37″N, 99°34′42″E, ca. 977 m a.s.l., 13 January 2015, leg. Pongsak Laudee.

Paratypes: Same data as holotype, 1 male ( CUAC) .

Etymology. The species epithet refers to the province where the new species was found.

Description. Length of each male forewing 5.0 mm (n = 2); specimens in alcohol with head, thorax, and forewings light yellow.

Male genitalia ( Figures 4 A–4C). Segment IX anterolateral margins nearly straight, posterolateral margins sinuous below apicodorsal lobe, apicodorsal lobe short, half as long as inferior appendages, and nearly as wide as annular portion of segment, tubular. Preanal appendages strongly sclerotized, extending beyond apicodorsal lobe of segment IX, their mesal surfaces covered with short dark brown setae, oval in lateral view, subtriangular in dorsal view. Anal sclerites small, beneath preanal appendages. Inferior appendages long, cylindrical, each with basal seg- ment twice as long as apical segment; apical segment subtriangular, its dorsal margin forming 50° angle with dorsal margin of basal segment, blunt apically, mesal surface covered with numerous setae. Phallus ( Fig. 4C ) small, dorsal appendage of phallic apparatus cylindrical, aedeagus short, apically acute; pair of ventral appendages of phallic apparatus very large, curved upward, covered with strong setae.

Diagnosis. Rhyacophila kengtungensis sp. n. is a member of the R. yishepa Group, in which males each have a short and broad apicodorsal lobe of segment IX, a reduced anal sclerite, and no parameres ( Schmid 1970). This species is close to R. ligulata Malicky & Sun 2002 and R. suah Malicky & Chantaramongkol 2009 (in Malicky 2009). However, R. kengtungensis sp. n. differs from those species by (1) the subtriangular shape of the preanal appendages in dorsal view in R. kengtungensis sp. n., but hooked in R. ligulata and bilobed in R. suah ; (2) the right-angled triangular shape of the apical segment of each inferior appendage in R. kengtungensis sp. n., contrasting with the oval apical segment of each inferior appendage in R. ligulata and R. suah ; and (3) the ventral plate of the aedeagus of R. kentungensis is obscured by the setose dorsal appendages of the phallic apparatus, but is conspicuous, slender, tubular, and acute in R. ligulata and R. suah ..

Figures

FIGURES 1A–1E. Male genitalia of Rhyacophila longicaudata n. sp. 1A, left lateral, with left inferior appendage omitted. 1B, dorsal. 1C, ventral. 1D, phallus, ventral. 1E, phallus, left lateral. IX = segment IX, Pre = preanal appendages, Api IX = apicodorsal lobe of segment IX, Ana = anal sclerites, Api B = apical band, Sag = sagittal appendage, Ter = tergal band, Pha = phallus, Bas Seg = basal segment of an inferior appendage (paired), Api Seg = apical segment of an inferior appendage (paired), Aed = aedeagus, Phal= phallotheca, End = endotheca.

FIGURES 2A–2C. Male genitalia of Rhyacophila aksornkoaei n. sp. 2A, left lateral, with left inferior appendage omitted. 2B, dorsal. 2C, ventral. Par = parameres, Dor = dorsal process of the phallic apparatus, Ven = ventral plate of the aedeagus.

FIGURES 3A–3D. Male genitalia of Rhyacophila limsakuli n. sp. 3A, left lateral, with left inferior appendage and phallus omitted. 3B, dorsal. 3C, ventral. 3D, phallus, left lateral. Ana = anal sclerites.

FIGURES 4A–4C. Male genitalia of Rhyacophila kengtungensis n. sp. 4A, left lateral, with left inferior appendage and phallus omitted. 4B, dorsal. 4C, phallus, left lateral. Pre = preanal appendages, Api IX = apicodorsal lobe of segment IX, Ana = anal sclerites.