Nanocladius (Plecopteracoluthus) shigaensis, Inoue, Yasue, Komori, Chiharu, Kobayashi, Tadashi, Kondo, Natsuko, Ueno, Ryuhei & Takamura, Kenzi, 2015

Inoue, Yasue, Komori, Chiharu, Kobayashi, Tadashi, Kondo, Natsuko, Ueno, Ryuhei & Takamura, Kenzi, 2015, Nanocladius (Plecopteracoluthus) shigaensis sp. nov. (Chironomidae: Orthocladiinae) whose larvae are phoretic on nymphs of stoneflies (Plecoptera) from Japan, Zootaxa 3931 (4), pp. 551-567 : 554-559

Nanocladius (Plecopteracoluthus) shigaensis sp. nov.

Type material. Holotype: Adult male, JAPAN: Aso River, Kutsuki-Aso, Takashima City, Shiga Prefecture (35°37'15"N, 135°89'37"E), collected on 01.XI.2012, emerged on 10.XII.2012, host Oyamia lugubris, Y. Inoue leg. (NSMT-I-Dip 7002). Paratypes: Adult male, sampling site, host, and collector as for the holotype, collected on 01.XI.2012, emerged on 07.XII.2012 (NSMT-I-Dip 7003); Adult male with PEX (pupal exuviae), Mugi River, Sembiki Bridge, Gifu Prefecture (35°29'27"N, 136°50'36"E), collected on 29.I.2013, emerged on 10.IV.2013, host Oyamia seminigra, Y. Inoue leg. (NSMT-I-Dip 7004); Adult male, Mugi River, Taniguchi-Waterfront Park, Mugigawa Town, Gifu Prefecture (35°32'31"N, 136°49'26"E), collected on 25.I.2013, emerged on 20.III.2013, host Oyamia cryptomeria, Y. Inoue leg. (NSMT-I-Dip 7005); Adult female, locality, host, and collector as for the holotype, collected on 01.XI.2012 and emerged on 06.II.2013 (NSMT-I-Dip 7006). Additional specimens from Aso River and Mugi River. Nanocladius (P.) shigaensis : Adult males 16, females 4, PEX 21, larvae 28; N. (P.) asiaticus : Adult males 8, females 9, PEX 8, larvae 31. All types including other specimens are deposited at the National Museum of Nature and Science, Tsukuba, Japan.

Etymology. From the prefectural name (Shiga) of the type locality of the holotype.

Adult male. Total length 2.1–3.4, 2.6 mm (16); wing length 1480–1900, 1706 Μm (13). Head brown, eyes darker, antennae and palpi light brown, thorax uniformly brown, vittae unclear, abdomen uniformly light brown; all fe (femora) brown, all ti (tibiae) with paler ring on apical half; fore ta (tarsi) light brown, mid and hind ta pale brown. Wing without pigmentation. Head ( Fig. 1 A): Eye pear-shaped, without dorsomedial extension, densely hairy; ocelli lacking, genae not excavated; temporals generally reduced, IV (inner verticals), OV (outer verticals) 3–4, 3.6 (17). Coronal triangle filaments (called “setae” by Hayashi 1998) present ( Fig. 1 B), apart from coronal triangle setae, as 2 pairs of long hyaline filaments branched at apical part, situated in and out of coronal triangle, inner filaments longer than outer: inner 60‒80, 70 Μm (15), outer 50‒70, 59 Μm (9). Tentorium 130–160, 146 Μm long (15), 17–30, 21 Μm wide (15). Clypeals 7–19, 11 (17). Antennal lengths 827–1030, 924 Μm (17), with 13 flagellomeres, AR 1.33–1.63, 1.40 (17), apical part slightly swollen, groove begins at 4th flagellomere. Pm (palpomeres) without SCh (sensilla chaetica), lengths of each Pm, I 20–70, 37 Μm (14); II 60 –90, 76 Μm (16); III 140–175, 151 Μm (16); IV 140–170, 153 Μm (16); V 220–300, 261 Μm (16). Thorax: Ap (antepronotal lobes) slightly gaping dorsomedially, with 1–7, 4.7 (13) lateroventral Aps (antepronotals); midscutum with longitudinal pale line area, but without Ac (acrostichals); numbers of Dc (dorsocentrals) 9–14, 11.3 (18) uniserial; Pa (prealars) 3–6, 4.7 (15); Scts (scutellars) 3–8, 5.6 (17). Wing ( Fig. 1 C): Membrane bare, anal lobe developed, costa extended shortly, ending slightly beyond tip of M3+4, VR (venarum ratio) 1.10–1.25, 1.16 (11), R2+3 running near R4+5 ending close to end of R4+5, basal part of R with 0–2, 1.1 (8) setae, other veins without setae. Squamals 11–17, 13.5 (13). Legs: Ps (pseudospurs) absent, but spiniform setae present on tarsi of mid and hind legs; SCh absent; pulvilli well developed. Spur of fore tibia 43–60, 51.3 Μm (16); outer spur of middle tibia 14–20, 17.2 Μm (14), inner spur 20–27, 22.3 Μm (14); outer spur of hind tibia 15–23, 19.5 Μm (16), inner spur 42–60, 48.9 Μm (17), comb spines 14–17, 16.0 (15). Lengths and proportions of legs as in Table 2. Abdomen ( Fig. 1 D): Tergal setae irregularly scattered, each seta arising from pale spot, number of setae on tergite I 34, II 55, III 53, IV 53, V 46, VI 35, VII 25, and VIII 22 (n =1). Hypopygium ( Fig. 1 E): Anal point completely absent, apical margin broad and rounded bearing several short setae; Sa (sternapodeme) concave, oral projection weakly developed, Vi (virga) absent; SVo (superior volsella) bare, broadly rounded; IVo (inferior volsella) well developed, triangular, setose caudally; Gs (gonostylus) parallel-sided, without distinct CD (crista dorsalis).

fe ti ta1 ta 2 ta3 ta4

N. (P.) PI 570‒710, 656, 655‒800, 755, 470‒580, 525, 395‒480, 438, 260‒330, 290, 160‒220, 196, shigaensis 41, n=14 43, n=16 28, n=16 27, n=15 17, n=15 14, n= 15 N. (P.) 590‒630, 610, 560‒730, 683, 390‒530, 479, 310‒430, 392, 210‒295, 259, 140‒200, 182, asiaticus 16, n=4 53, n=7 44, n=7 40, n=7 40, n=7 20, n=7

PII 450‒650, 586, 520‒660, 594, 280‒360, 315, 150‒200, 183, 100‒125, 116, 50‒60, 57, 5,

59, n=12 35, n=13 22, n=13 16, n=13 10, n=13 n=13

420‒570, 526, 440‒580, 539, 220‒300, 283, 120‒185, 165, 90‒120, 106, 9, 40‒60, 51, 7,

50, n=7 44, n=8 27, n=8 22, n=8 n=8 n=8

PIII 550‒720, 628, 680‒890, 798, 370‒490, 426, 230‒310, 274, 165‒200, 191, 100‒125, 109,

43, n=15 51, n=16 30, n=16 23, n=16 11, n=16 9, n=16

460‒640, 580, 530‒750, 701, 300‒410, 382, 200‒280, 250, 130‒190, 176, 80‒105, 99, 8,

60, n=7 72, n=8 36, n=8 23, n=8 20, n=8 n=8

continued.

ta5 LR ti spur (PI), outer ti inner spur Number of ti spur (PII, III) comb spines

N. (P.) PI 70‒100, 94, 8, n=15 0.67‒0.73, 0.70, 43‒60, 51, 4,

shigaensis 0.02, n=15 n=16

N. (P.) 70‒95, 90, 9, n=7 0.68‒0.73, 0.70, 35‒65, 49, 8, n=8

asiaticus 0.02, n=6

PII 45‒60, 55, 5, n=13 0.51‒0.55, 0.53, 14‒20, 17, 2, 20‒27, 22, 2, 0.01, n=13 n=14 n=14

40‒60, 49, 6, n=8 0.50‒0.54, 0.52, 15‒20, 19, 2, n= 8 18‒25, 22, 3, n=8 0.01, n=8

PIII 60‒95, 80, 9, n=16 0.50‒0.56, 0.53, 15‒23, 20, 2, 42‒60, 49, 4, 14‒17, 16, 1, 0.02, n=16 n=16 n=17 n=15 50‒80, 70, 10, n=8 0.53‒0.57, 0.55, 19‒20, 20, 0.4, 35‒50, 43, 5, n= 8 14‒17, 16, 1, n=5 0.01, n=8 n=8

Adult female. Total length 2.0–3.2, 2.6 mm (6), Coloration: Head, antennae pale brown, eyes dark; thorax brown, vittae darker; wing bare, no markings; basal half and apical parts of all fe darker; all ta pale; abdomen brown. Head ( Fig. 2 A): Genae not excavated. Labella about 2 times larger than those of the male. Eyes as in the male. In female adult coronal triangle absent, but 2 pairs of coronal triangle filaments present at frontal area ( Fig. 2 B), inner filament 70 Μm long (1), outer filament 40 Μm long (1); IV absent, OV 2–4, 3.2 (6); tentorium 140–150, 145 Μm long (3), 10–15, 12 Μm wide (3); clypeals 11–18, 13.5 (4); antenna with 5 flagellomeres, lengths of fl-I 60–70, 64.6 Μm (5), fl-II 45–52, 49.2 Μm (5), fl-III 60–70, 65.4 Μm (5), fl-IV 60–80, 69.0 Μm (5), fl-V 102–120, 113 Μm (5); AR (5th/1st–4th) 0.44–0.48, 0.46 (5). Thorax: Ac completely absent, Dc 13–20, 15.8 (5), uniserial; lateroventral Aps 6–8, 6.8 (4); Scts 8–11, 9.0 (5); Pa 5–7, 6.0 (4). Wing ( Fig. 2 C): Length 1580–1760, 1685 Μm (5), VR 1.08–1.14, 1.11 (3), squamals 8–15, 12.3 (6). Abdomen: Tergal setae irregularly scattered. Legs: Lengths and proportions as in Table 3; pulvilli well developed. Genitalia ( Fig. 2 D): SCa (seminal capsule) oblong, without microtrichia on surface, 90–100, 96.7 Μm long (3), 60–70, 63.3 Μm wide (3), with SDu (spermathecal duct) placed on mesal long side of SCa, with weak bend, without loop; No (notum) 170–180, 175 Μm long (2); Gc IX (gonocoxite IX) 14–22, 17.6 (5) setae, without caudomesal pointed projection (cf. Saether 1977b: 89 couplet 26), Gp VIII (gonapophysis VIII) divided into three parts: VlL (ventrolateral lobe) rounded and setose, ApL (apodeme lobe) nearly straight, narrow, and bare, and DmL (dorsomesal lobe) surrounding vagina, setose; post-genital plate developed.

fe ti ta1 ta 2 ta3 ta4

N. (P.) PI 550‒650, 612, 690‒795, 731, 460‒510, 495, 350‒410, 387, 240‒290, 262 100‒195, 159,

shigaensis 40, n=5 39, n=5 20, n=5 23, n=5 19, n=5 36, n=5

PII 530‒595, 575, 550‒600, 584, 280‒300, 295, 150‒170, 158, 95‒105, 100, 4, 40‒55, 49, 6, 31, n=4 23, n=4 10, n=4 10, n=4 n=4 n=4

PIII 540‒630, 590, 690‒800, 745, 370‒400, 390, 210‒240, 226, 160‒180, 169, 95‒100, 99, 3, 46, n=3 47, n=4 14, n=4 14, n=4 10, n=4 n=4

continued.

ta5 LR ti spur (PI), outer ti inner spur Number of ti

spur (PII, III) comb spines

N. (P.) PI 80‒95, 91, 7, n=5 0.63‒0.71, 0.68, 30‒32, 32, 0.9,

shigaensis 0.03, n=5 n=5

PII 50‒60, 54, 5, n=4 0.50‒0.51, 0.51, 15‒18, 16, 1.5, 20‒21, 21, 0.5,

0.004, n=4 n=4 n=4

PIII 70‒80, 75, 6, n=4 0.50‒0.55, 0.52, 15‒18, 17, 2, n=3 45‒55, 51, 5, n= 4 15‒18, 17, 2, n=3

0.02, n=4

Pupa (pupal exuviae). Total lengths 3.044–3.830, 3.476 mm (20). FA (frontal apotome) (Fig. 3A) without additional warts, nearly smooth; FS (frontal setae) 22–77, 56.6 Μm (9); 2 medial and 1 lateral Aps present. TH (thoracic horn) (Fig. 3B) 150–250, 198 Μm long (20), elongate, tapering toward apex covered with scale-like spinules in distal half; Pc2 (Precorneals) much longer and stronger than 3rd (Fig. 3B); 4 Dc present, 2nd and 3rd closer to each other than to 1st and 4th, respectively; Pa absent. Abdominal tergites: PSA (pedes spurii A) and PSB (pedes spurii B) absent; T-II with row of posterior hooklets not on protuberance; T-IV–VI with median patch of spines, patch on VII vestigial (Figs 3C, D). Posterior margins of T-II–VII with hooklets. Tergite setation: T-I with D (dorsal seta) 4 and L (lateral seta) 1; T-II D4, L2; T-III D4, L2; T-IV D5, L3; T-V D5, L3; T-VI D5, L3; T-VII D4, L2; T-VIII D2, L3 (n =1), L2 on T-VIII long; AL (anal lobe) with 38–40 taeniae in number and 3 pairs of macrosetae.

Larva. Total length 3.0–6.0, 5.0 mm (27). Coloration of 4th instar: Head capsule yellowish brown, eye spot in pale circle ( Fig. 4 B), segments I–III (thorax) covered in large irregular dark markings, oral part of segment I changes to yellow before pupation, other segments pale yellow. Head capsule: lengths 380–510, 414 Μm (20); widths 290–400, 327 Μm (20); IC 0.73–0.89, 0.79 (20). Head capsule setation ( Fig. 5 , bottom): S5 and S8 very close compared with those of N. (P.) asiaticus ( Fig. 5 , top). Antenna (Fig. 6A): with 5 consecutively smaller segments; AR 1.40–1.97, 1.61 (22); RO in basal 1/6 of segment I, occasionally antennal hair at base (1/22) [in N. (P.) asiaticu s more often (4/27)]. Bl (blade) shorter than segment II, LO (Lauterborn organ) distinct, as long as 3rd segment. Labrum: SI spoon-shaped, apical margin finely serrate (Fig. 6B); SII and SIII simple, ChL (chaetulae laterals) consist of 2–4 pairs of fish-shaped lamellae (Fig. 6B). Mentum (Fig. 6B): median tooth broad, with median shallow notch, 4 pairs of lateral teeth, VmP (ventromental plate) not elongate, beard absent, straight at caudal apex. SSm (seta submenti) 40 Μm long. MP (maxillary palp) (Fig. 6C) consists of 2 parts: MP in narrow sense and lower bisensillum, each with some sensory organs. Pm (premandible) (Fig. 6D): with faintly divided apical tooth, without brush. Mandible (Fig. 6E): apical tooth longer than combined width of 3 inner teeth; SSd (seta subdentalis) long; Si (seta interna) with 7–8 branches, Parapods well developed, anterior parapod claws thin and long, serrated apical half, basal part of parapod covered with numerous short claws strongly serrated; claws of posterior parapod all simple.

FIGURE 3. Pupa (PEX): A. Frontal apotome (scale bar 100 Μm); host Oyamia lugubris (Plecoptera) . B. Thoracic horn, ring organ, and precorneals (Pc1–Pc3) (200 Μm); host O. lugubris . C. Pupal abdominal tergite III–VI (1000 Μm); host O. lugubris . D. Pupal abdominal tergite VI ‒ anal lobe (400 Μm); host O. lugubris .

Each body segment with short (c. 20 Μm long) setae, I and II 8, III 6, IV 4, V 6, VI–IX 8, X and XI 6; XII 0 or 2 in number. Procercus with 1 short (12–15 Μm) seta. Anal setae 4–6. Basoventral part of posterior parapod with 1 or 2 rather long (40 Μm) setae.

Figures

FIGURE 1. Male: A. Head (scale bar 500 Μm); host Oyamia lugubris (Plecoptera). B. Coronal triangle hyaline filaments (100 Μm); host Oyamia lugubris. C. Wing (1000 Μm). D. Abdomen (1000 Μm); host O. lugubris. E. Hypopygium (100 Μm); host O. lugubris.

FIGURE 2. Female: A. Head (scale bar 500 Μm); host Oyamia lugubris (Plecoptera). B. Coronal hyaline filaments (50 Μm); O. lugubris. C. Wing (1000 Μm). D. Genitalia (200 Μm). R: dorsal view, L: ventral view; host O. lugubris. Abbreviations. AL: aedeagal lobe, DmL: dorsomesal lobe, VIL: ventrolateral lobe, Gc IX: gonocoxite IX, Gca: gonocoxapodeme, Csa: coxosternapodeme, Gp VIII: gonapophyses VIII, Gp IX: gonapophysis IX, S VII: sternite VII, S VIII: sternite VIII, T VII: tergite VII, T VIII: tergite VIII.

FIGURE 4. Larval head capsules (somewhat faded by 10 % KOH treatment), showing differences of colors and shapes. A. Nanocladius (Plecopteracoluthus) asiaticus (host Protohermes grandis [Megaloptera]). B. Nanocladius (Plecopteracoluthus) shigaensis sp. nov. (host Oyamia cryptomeria [Plecoptera]).

FIGURE 5. Setation of larval head capsules, top: Nanocladius (Plecopteracoluthus) asiaticus (host Protohermes grandis [Megaloptera]); bottom: Nanocladius (Plecopteracoluthus) shigaensis (host Oyamia cryptomeria [Plecoptera]). FA, frontal apotome; Po, postoccipital margin; Te, tentorium; MSu, median suture.