Oriental Hydrocyphon (Coleoptera: Scirtidae: Scirtinae): Seven New Species from Indonesia, Thailand, Malaysia, and India

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Introduction
The genus Hydrocyphon Redtenbacher is represented by 100 species divided into 13 species groups from the Palaearctic and the Oriental Regions (see, e.g., [1,2] and Tables 1 and 2). The larvae of this genus inhabit running water, for example, small rivers and streams, and the adults are frequently collected by sweeping around the larval habitat. The genus is well defined by certain characteristics (e.g., small body, deeply notched anterior margin of the mesosternum, well-developed parameres and parameroids), and has been comparatively well studied taxonomically [1,2]. In the present paper, I describe seven new species from Indonesia, Thailand, Malaysia, and India. In addition, new combination and additional specimens examined are presented. This is the twelfth part of my comprehensive study of "Scirtidae of the Oriental Region" [2][3][4][5][6][7][8][9][10][11][12].

Materials and Mandhods
Psyche Table 1: The list of the species, distribution, ZooBank LSID, and species group of the genus Hydrocyphon. An Excel file version is also available at the following URL: https:// sites.google.com/site/waterbeandlesofjapan/home/support-files-on-articles/Appendix 1.xls.
No.    No.    Caudal margin of sternite VII gently arcuate. Tergites VIII-IX moderately sclerotized, trapezoidal. Tegmen short, well sclerotized; proximal part short, fan-shaped, arcuate in basal margin; parameres stout, gently expanded laterally in basal parts, arrow-like shape in apical parts. Penis long, well sclerotized, asymmetrical, about 1.7 times as long as tegmen; pala subtrapezoidal, widest at base; parameroids long and slender, slightly asymmetrical, gently widened and punctuate in apical parts, obtuse at apices; trigonium with one long and slender projection, a little shorter than parameroids, obtuse at apex; median plate indistinct.

Species
Female. Similar to male; pronotum yellow (probably teneral specimen); antennae relatively stout; PW/PL 2.55; EL/EW  the penis, but differs from them by the apices of the parameres which have an arrow-like shape.
Biological Notes. The type locality was a small river situated halfway up Mount Merapi (Figure 11(a)). The river was somewhat polluted by waste water flowing from cichlid fish farms.
Etymology. The species is named after the type locality. Figures 1(c), 1(d) Male Description. Body oval, well convex dorsally, shiny, closely covered with yellowish white short setae. Coloration of head, mouth parts, antennal segments I-IV, prothorax and legs yellowish-brown, but posterior part of head and tarsi infuscate; antennal segments V-XI, scutellum, elytra, mesoand metaventries, and abdominal segments brown.

Hydrocyphon takizawai sp.n. (See
Head moderate in size, slightly convex dorsally, finely punctuate; clypeus rather long, straight in front margin; the distance between eyes about 1.7 times as long as the maximum diameter of an eye. Eyes moderate in size, prominent. Antennae short, reaching about proximal 1/6 of elytra. Pronotum punctuate as in head, slightly convex dorsally, depressed ventrally in lateral parts; front margin straight; anteroand posterolateral corners obtuse; lateral and posterior margins gently arcuate; PW/PL 2.51. Scutellum small, equilateral-triangular. Elytra oval, convex dorsally, broadest at the middle; humeral parts gently projecting dorsally; EL/EW 1.41; EL/PL 4.83; EW/PW 1.36; TL/EW 1.70.
Caudal margin of sternite VII arcuate. Tergite VIII moderately sclerotized, transversal trapezoidal, bearing short spines in caudal part, with a pair of short apodemes. Sternite IX well sclerotized, consisting of a pair of hemisternites, with pointed at apices. Tegmen large, well sclerotized; proximal part short, subparallel-sided; parameres long, minutely serrate in apical 1/3 of inner parts, distinctly protruding  postero-interiorly in postero-lateral corners, projecting anteriorly in anterolateral corners. Penis asymmetrical, short, well sclerotized, about 0.8 times as long as tegmen; pala oblong, widest near base, tapered in proximal 2/3; parameroids short and almost straight, obtuse at apices, finely punctuate, left one long and slender, right one short and stout; trigonium consisting of a small lobe. Larvae. Body about 4.0 mm length in fully expanded specimens, subparallel-sided in thorax and abdomen which bearing short and long setae on lateral and posterior margins. Coloration of body right brown.
Head slightly protruding laterally, with three pairs of nonmelanized stemmata situated near anterolateral corners. Antennae relatively long, reaching at abdominal segment I; scape slightly curved posteriorly; flagellum 51-73 (64) segmented (n = 4). Labrum transverse, covered with long setae on dorsal surface; ventral lobes projecting anteriorly, with 12 pairs of stout and short setae on inner margins. Maxillary palpi long and slender; 1st segment covered sparsely with short and long setae on dorsal surface; 3rd rounded at apex, with widely apical sensory area; relative length of each segment (n = 1) as 1.0 : 1.0 : 1.3. Mandibles and hypopharynx typical for the genus. Thorax widest at posterior margin of mesothorax. Abdomen subparallel-sided, widest at segment V, then gently tapering posteriorly, bearing two (II-V) or one (VI-VII) pairs of short setae on lateral part. Tergite VIII trapezoidal, shallowly concave in posterior margin, with a pair of very long setae protruding from posterolateral corners. Sternite VIII semicircular, bearing long setae on lateral and posterior margins, two of those very long. Tergite IX semicircular, convex at apex, with a pair of long setae at apex, bearing pectinate short setae on lateral margin. Sternite IX transversal semicircular, with pectinate setae on posterior margin.   The larva of this species is distinguished from the three previously known species of the larvae in the genus (H. deflexicollis [13], H. satoi [14], H. sp. [4]) by the following characteristics: (1) segment III of maxillary palpi somewhat short (about 1.5 times as long as segment I in H. deflexicollis and H. satoi); (2) the short setae on the lateral and posterior margins of tergite IX and sternite IX pectinate (simple setae in H. satoi and H. sp.).
Biological Notes. The type locality was a small stream in the Kinabalu National Park (Figure 11(b)). The stream was clear, and many aquatic insects were collected with this species.
Etymology. The species is named after Dr. H. Takizawa. Figures 1(e)   Head moderate in size, flat in dorsally, finely punctuate; clypeus short, straight in front margin; the distance between eyes about 2.1 times as long as the maximum diameter of an eye. Eyes moderate in size, prominent. Antennae short, reaching about proximal 1/8 of elytra. Pronotum punctuate as in head, slightly convex dorsally, depressed ventrally in lateral parts; front margin straight; antero-and posterolateral corners obtuse; lateral and posterior margins gently arcuate; PW/PL 2.57. Scutellum small, equilateral-triangular. Elytra oval, strongly convex dorsally, broadest at the middle; humeral parts gently projecting dorsally; EL/EW 1.26; EL/PL 4.65; EW/PW 1.43; TL/EW 1.54.

Hydrocyphon sagittiger sp.n. (See
Tegmen large, well sclerotized; proximal part long, peglike; parameres wide, distinctly projecting anteriorly in antero-lateral corners, projecting subtriangularly in inner and outer corners of apices. Penis long, slightly asymmetrical, well sclerotized, about 1.5 times as long as tegmen; pala short, oblong, widest at proximal 1/3 of pala; parameroids very long, asymmetrical, almost straight, left one slightly longer than right one, excised at inner margin of left apex; trigonium consisting of a long lobe, straight, shorter than parameroids, obtuse at apex; median plate indistinct.
Remarks. The species belongs to the pallidicollis species group, and is related to H. jogjaensis sp.n., H. trilobus Yoshitomi and M. Satô, 2005, and H. subtrilobus Yoshitomi and M. Satô, 2005. It differs from them by the following characteristics: inner corner of parameres projecting interiorly; left parameroid excised at apex; pala oblong.
Etemology. The species name refers to the shape of the apices of the tegmen. Figures 1(f)  Male Description. Body oval, well convex dorsally, shiny, closely covered with yellowish-white setae. Coloration of head, scutellum, elytra, and ventral surface of thorax and abdomen blackish-brown; pronotum, legs, and antennae yellowish-brown.

Hydrocyphon serratibasialis sp.n. (See
Head moderate in size, slightly convex dorsally, finely punctuate; clypeus short, straight in front margin; the distance between eyes about 2.2 times as long as the maximum diameter of an eye. Eyes moderate in size, prominent. Antennae rather stout. Pronotum punctuate as in head, lightly depressed ventrally in lateral parts; front and lateral margins straight; antero-lateral corners about 120 • ; postero-lateral corners right-angle; posterior margin gently arcuate; PW/PL  Caudal margin of sternite VII gently arcuate. Tergite VIII moderately sclerotized, trapezoidal, bearing short spines along caudal margin, sparsely covered with short setae in caudal part, with a pair of slender apodemes, Sternites IX slightly sclerotized, upturned in postero-lateral parts, with a pair of long apodemes. Tegmen long, well sclerotized; proximal part short, expanded antero-laterally; parameres long, minutely serrate in mesal part of inner margin, distinctly protruding postero-laterally in apical parts, projecting anteriorly in antero-lateral corners. Penis asymmetrical, long, well sclerotized, about 0.9 times as long as tegmen; pala oblong, widest at basal 1/6; parameroids longer than trigonium, finely punctuate; trigonium consisting of two lobes, longer one forked, shorter one slender; median plate indistinct.
Remarks. The species belongs to the deflexicollis species group, but is a distinct species having a characterized tegmen.
Etymology. The species name refers to the shape of the tegmen: "serrati−" = serrate + "basialis" = basal. Figures 1(g)  Remarks. The species belongs to the deflexicollis species group. This species is distinguished from the previously known species by the concave posterior margin of the sternite and tergite IX and the shape of the parameres of the tegmen.

Hydrocyphon doiinthanonensis sp.n. (See
Etymology. The species is named after the type locality. Figures 1(h)  Male Description. Body oval, convex dorsally, shiny, closely covered with yellowish-white setae. Coloration of body blackish-brown, but lateral parts of pronotum and legs paler.

Hydrocyphon klapperichi sp.n. (See
Head moderate in size, flat in dorsal surface, finely punctuate; clypeus short, straight in front margin; the distance between eyes about 2.2 times as long as the maximum diameter of an eye. Eyes relatively large, prominent. Pronotum punctuate as in head, slightly depressed ventrally in lateral parts; front and lateral margins straight; anterolateral corners 120 • ; postero-lateral corners right-angle;  Tergite IX slightly sclerotized, bearing short setae in apical part, with a pair of long apodemes. Tegmen relatively large, moderately sclerotized; proximal part peg-like, short; parameres obscure, serrate at lateral margins, projecting and bifid in antero-lateral corners, punctuate; lateral projections very long, as long as parameres. Penis asymmetrical, long, well sclerotized, about 2.1 times as long as tegmen; pala oblong, gently tapered anteriorly; parameroids distinctly asymmetrical, closely punctuate, almost straight, left one wider and longer than right one; trigonium consisting of a long lobe, shorter than parameroids, obtuse at apex; median plate indistinct. Remarks. The shape of the tegmen of this species is similar to that of the mirabilis, the tamilensis, the kinabalensis, and the renati species groups, but this species is easily distinguished from the latter by the serrate parameres and the shape of the penis. Judging from the shape of the penis (e.g., asymmetrical parameroids and single projection of trigonium), this species probably belongs to the pallidicollis species group.
Etymology. The species is named after Dr. J. Klapperich, who was the collector of the holotype. Male Description. Body oval, well convex dorsally, strongly shiny, closely covered with yellowish-white setae. Coloration blackish-brown, but lateral parts of pronotum, mouth parts, antennae, and legs paler.
Head moderate in size, flat in dorsal surface, finely punctuate; clypeus relatively long, straight in front margin; the distance between eyes about 2.5 times as long as the maximum diameter of an eye. Eyes moderate in size, prominent. Antennae short and stout, reaching about proximal 1/3 of elytra. Pronotum strongly transverse, punctuate as in head, depressed ventrally in lateral parts; front and lateral margins straight; antero-lateral corners obtuse, postero-lateral corners almost right-angle; posterior margin arcuate; PW/PL 2.80. Scutellum relatively large, equilateral triangular. Elytra semicircular, well convex dorsally, broadest at basal 1/3; humeral parts slightly projecting dorsally; EL/EW 1.14; EL/ PL 4.57; EW/PW 1.43; TL/EW 1.39. Legs relatively long.
Caudal margin of sternite VII gently arcuate. Tergite VIII moderately sclerotized, trapezoidal, bearing short setae and spines along caudal margin, with a pair of short apodemes. Tergite IX membranous, with a pair of long and slender apodemes. Sternite IX slightly sclerotized, oblong, bearing short setae in postero-lateral parts. Tegmen moderately sclerotized; proximal part peg-like, short; parameres short, obtuse at