Paramerina yunouresia (Sasa)

Niitsuma, Hiromi, Suzuki, Risa & Kato, Hideaki, 2011, Review of the Japanese species of Paramerina (Diptera: Chironomidae: Tanypodinae), with a key to the known males, Zootaxa 2821, pp. 1-18 : 2-7

Paramerina yunouresia (Sasa)

( Figures 1 –14)

Krenopelopia yunouresia Sasa, 1989: 152 .

Krenopelopia amaminova Sasa, 1990: 138 (male holotype; paratype series mixed). Syn. n. Paramerina tokararesea Sasa et Suzuki, 1995: 285 . Syn. n.

Paramerina divisa [nec Walker, 1856]: Kobayashi & Endo 2008: 52 .

Material examined. Holotype of Krenopelopia yunouresia : male ( NSMT), labeled, “No. 52: 23b”, JAPAN: Tochigi, Nikko, Lake Yunoko, 31.vii.1976. Paratype of Krenopelopia yunouresia : 1 male ( NSMT), mounted on same glass slide with holotype, and labeled, “No. 52: 23a”, same data as holotype. Holotype of Krenopelopia amaminova : male ( NSMT), labeled, “No. 179: 61”, JAPAN: Kagoshima, Amami Island, Yakkachi River, 18.v.1989.

Paratypes of Krenopelopia amaminova : 15 males ( NSMT), labeled respectively, “No. 179: 62, 63, 65, 67–78”, same data as holotype. Holotype of Paramerina tokararesea : male ( NSMT), labeled, “No. 290: 75”, JAPAN: Kagoshima, Tokara Islands, Nakanoshima, 20.v.1994. Non-types. JAPAN: Fukushima, Hirono, Asami River, 9 males with 9 pupal and 3 larval exuviae (SUM-IC-T0374–0382), 3 females with 3 pupal and 2 larval exuviae (SUM-IC-T0383–0385), and 1 larva (SUM-IC-T0386), 2.i.2001 (adults emerged 15–31.i.2001); 1 female with pupal exuviae (SUM-IC-T0387), as previous except 30.iii.2002 (adult emerged 27.iv.2002); 1 male with pupal exuviae (SUM-IC-T0388), as previous except 5.v.2002 (adult emerged 25.v.2002).

Description. Male (n = 29). Body length 2.7–3.0 (2.8, n = 10) mm.

Coloration. Thorax yellow with dark 4 scutal vittae, anepisternum II and postnotum ( Fig. 1 ). Abdomen yellow with anterior dark bands on tergites II–VIII; widths of these bands varied among individuals, usually more or less broad on tergites II–IV, VI and VIII, and narrow on tergites V and VII. Wing without pattern. Foreleg brown, except pale basal half of femur; mid- and hind legs generally pale brown.

Head. Temporals 10–15 in number, uniserial. AR 1.2–1.5. Clypeus rounded with 15–20 setae. Lengths of palpomeres 1–5 (in μm) 25–40 (33, n = 9), 45–60 (56, n = 9), 100–130 (114, n = 9), 100–125 (114, n = 9), 200–245 (225, n = 9); Pm4 1.0–1.1 times as long as Pm3; Pm5 1.9–2.1 times as long as Pm4.

Thorax. Aps 0–2 in number, located laterally. Ac 25–36, biserial, evenly diverging posteriorly; Dc 18–27 including 1–2 Prs, bi- to multiserial on each side; H 5–11; Pa 9–14, multiserial; Su 1. Scutellum with group of 6–11 short anterior setae and transverse row of 7–11 long posterior setae.

Wing ( Fig. 2 ). Length 1.8–2.2 (2.0, n = 10) mm. Squama with 18–27 setae; VR 0.84–0.90.

Legs. Spur of foretibia 43–53 (48, n = 10) μm long with 2–4 lateral teeth; spurs of midtibia 60–73 (64, n = 10) and 25–35 (32, n = 10) μm long, each with 2 or 3 lateral teeth; spurs of hind tibia 65–78 (71, n = 10) and 25–35 (30, n = 10) μm long, each with 2 or 3 lateral teeth; hind tibial comb consisting of 5–8 spines. Pseudospurs present on ta1–3 or ta1–4 of all legs; claw with 1 long basoventral spine. Lengths and proportions of leg segments as in Table 1.

TABLE 1. Lengths (in μm) and proportions of legs of Paramerina yunouresia (Sasa) , male (n = 9) and female (n = 4). fe ti ta1 ta2 ta3 ta4 ta5 LR BR

Male

p1 677–798 768–919 646–788 414–505 313–384 202–242 91–111 0.79–0.86 5.5–6.5

(726) (848) (711) (459) (349) (231) (107)

p2 798–929 727–869 697–869 394–465 253–303 162–192 91–101 0.93–1.00 5.7–6.9

(866) (799) (781) (440) (282) (183) (99)

p3 677–788 909–1071 737–889 414–475 303–354 202–242 91–111 0.76–0.83 6.4–7.5

(735) (997) (808) (452) (329) (221) (104)

Female

p1 626–697 737–848 667–758 414–465 293–343 202–222 91–101 0.88–0.92 (662) (778) (697) (432) (311) (207) (97)

p2 788–909 768–859 727–848 394–475 242–283 162–172 91 0.95–1.00 (841) (798) (780) (422) (255) (164) (91)

p3 697–788 929–1061 758–899 414–485 293–333 202–222 91–101 0.82–0.86 (732) (970) (813) (434) (308) (207) (96)

Hypopygium ( Fig. 3 ). Tergite IX without setae. Gonocoxite 150–185 (173, n = 10) μm long, 2.8–3.1 times as long as broad at middle, with pubescent field basally. Gonostylus 103–123 (111, n = 10) μm long; HR 1.4–1.7. Posterior tip of phallapodeme reaching 0.40–0.45 from base of gonocoxite.

Female (n = 4). Body length 1.9–2.0 (2.0, n = 3) mm.

Coloration. Similar to male.

Head. Temporals 9–13 in number. Antenna with terminal flagellomere as long as or slightly longer than preceding 2 flagellomeres together; AR 0.22–0.27. Clypeus with 19–25 setae. Lengths of palpomeres 1–5 (in μm) 25– 33 (29), 50–60 (54), 100–118 (106), 108–130 (122), 208–230 (223); Pm4 1.1–1.3 times as long as Pm3; Pm5 1.8–1.9 times as long as Pm4.

Thorax. Aps 1–2 in number, Ac 31–34, Dc 23–36 including 1–2 Prs, H 13–18, Pa 10–16, Su 1. Scts composed of 15–18 short anterior and 9–14 long posterior setae.

Wing. Length 1.8–2.0 (1.9) mm. Squama with 17–26 setae; VR 0.81–0.87.

Legs. Spur of foretibia 43–53 (47) μm long with 3 or 4 lateral teeth; spurs of midtibia 60–65 (61) and 28–40 (31) μm long, each with 3 lateral teeth; spurs of hind tibia 63–75 (69) and 25–33 (28) μm long, with 3–4 and 2–3 lateral teeth, respectively; hind tibial comb consisting of 5–6 spines. Lengths and proportions of leg segments as in Table 1.

Genitalia ( Fig. 4 ). Labium with fine setae. Notum 95–115 (108) μm long. Seminal capsule oval, 60–80 (69, n = 3) μm long and 55–73 (63, n = 3) μm wide. Segment X with 10–14 short setae on each side.

Pupa (n = 14). Body length 3.0–3.6 (3.3) mm.

Coloration. Exuviae generally light brown. Abdomen light brown with dark scar and apophyses; posterolateral parts of tergite III–VI extensively pale.

Cephalothorax. Thoracic horn (Fig. 5a, b) 203–235 (218) μm long, and 4.2–5.0 times as long as broad; corona 80–95 (86) μm long, oval, occupying apical 0.36–0.44 of horn. Plastron plate 33–40 (35) μm long, 0.36–0.50 times as long as corona, and 3.3–5.3 times as long as width of its neck. Respiratory atrium irregularly alveolar, more or less rugged on surface, with distinct apical diverticulum. Thoracic comb composed of 6–8 apically rounded tubercles.

FIGURES 5–14. Paramerina yunouresia (Sasa) , pupa (5–8) and larva (9–14). 5a, b, Thoracic horn, showing variation; 6, abdominal segments VII–IX, dorsal view, left lateral setae omitted; 7, shagreen on posteromedial part of abdominal tergite IV; 8, shagreen on posteromedial part of abdominal sternite II; 9, arrangement of ventral cephalic setae and sensory pore; 10, antenna; 11, mandible, seta subdentalis and ventrolateral setae omitted; 12, maxillary palp with apical stylets; 13, ligula and paraligula; 14, medium- and small-sized claws of posterior parapod. Abbreviations: S9, 10, cephalic setae 9, 10; SSm, seta submenti; VP, ventral sensory pore.

Abdomen (Fig. 6). Shagreen consisting of weak and sparse spinules on tergites and sternites (Fig. 7), except sternite II with somewhat strong shagreen (Fig. 8). Segment VII with 4 LS-setae and 1 L-seta on each side; LS1- seta positioned 0.38–0.43 from anterior margin of segment. Segment VIII with 5 LS-setae on each side; LS1-seta positioned 0.24–0.30 from anterior margin of segment. Anal lobe 310–365 (339) μm long, 3.0–3.6 times as long as wide, with 13–23 infuscated spines along outer boarder; anterior and posterior anal macrosetae located respectively 0.40–0.45 and 0.55–0.60 from anterior margin of anal lobe. Male genital sac 1.1–1.2 times as long as anal lobe.

Fourth instar larva (n = 6). Body length about 5 (n = 1) mm.

Coloration. Head somewhat infuscate along brown postoccipital margin, and body reddish when alive.

Head. Length 535–606 (566, n = 4) μm; cephalic index 0.53–0.56. All cephalic setae thin and weak, these structures unknown. Dorsal cephalic seta S8 posteromedial to S7, and anterolateral to S5; dorsal sensory pore absent. Ventral sensory pore directly posterior to S9, posterolateral to S10, and these setae and sensory pore all anterolateral to SSm; S9, S10 and SSm located almost in line (Fig. 9). Antenna (Fig. 10) 0.49–0.53 times as long as head capsule; lengths of first to fourth segments (in μm) 200–205 (203, n = 3), 65–68 (67, n = 3), 5 (5, n = 3) and 4–5 (4, n = 3); AR 2.6–2.8. First segment 10.0–10.8 times as long as its basal width, with ring organ positioned 0.58–0.60 from base; blade 73–80 (76, n = 3) μm long, reaching middle of segment 4; accessory blade almost as long as blade. Second segment 9.6–10.8 times as long as its basal width; style 8 (n = 1) μm long, reaching middle of segment 4; peg sensillum 4 (n = 2) μm long. Mandible (Fig. 11) 83–88 (84, n = 3) μm long, 0.29–0.31 times as long as antenna, with apical tooth 2.5–2.7 times as long as basal width. Basal segment of maxillary palp (Fig. 12) subdivided into 2 parts, 38–40 (39, n = 4) μm in total length, and 3.9–4.2 times as long as its basal width; apical part 2.8–3.3 times as long as basal part. Ligula (Fig. 13) 73–78 (75, n = 3) μm long, 1.9–2.1 times as long as its toothed width, with granulose area occupying basal 0.19–0.24; median tooth 1.7–1.8 times as long as wide. Paraligula 33–35 (33, n = 3) μm long with fork positioned 0.49–0.61 from base; outer spine 3.3–3.7 times as long as inner spine. Pecten hypopharyngis with row of 11–16 teeth.

Body. Procercus 3.7 times as long as wide, with 7 anal setae. Posterior parapod with 16 pale brown claws; one medium-sized claw somewhat darker than others; small claws simple, and larger claws serrated along inner and/or outer margin (Fig. 14).

Remarks. Sasa (1989) described Krenopelopia yunouresia on the basis of many male and female adults, and noted (p. 153), “Phallapodemes relatively long and apically hooked. Gonocoxite roughly egg-shaped, with a setigerous pad at the base.” These features, however, do not fit those of Krenopelopia , of which hypopygium has neither distinct phallapodeme nor setigerous pad, according to Murray & Fittkau (1989). Re-examinations of the holotype and paratype males have shown that he had mistaken the basal field of short setae on the gonocoxite for a setigerous pad, and that the species has a conspicuously elongated main tooth in the inner midtibial spur, and abdominal tergite IX without setae. The species belongs to Paramerina , as pointed out by Kobayashi & Endo (2008).

Krenopelopia amaminova was described on the basis of many male and female adults. The author ( Sasa 1990: 139) wrote concerning the wing vein C, “It ends distinctly proximal to tip of M in the present species.” He illustrated the male hypopygium with distinct phallapodemes and bare abdominal tergite IX in the original description (see his fig. 26 j). Also the species belongs to Paramerina because of these features and the inner midtibial spur with a very long main tooth (see his fig. 26f). Further, he (p. 139) wrote regarding his K. amaminova that the abdominal tergite II has a transverse brownish yellow band, and the tergite V is pale, and that the antennal ratio varies from 1.09 to 1.32. A re-examination of the holotype has shown that the male has somewhat great value (1.3) of antennal ratio, four brown vittae on the scutum, and anterior dark bands on the abdominal tergites II–VIII. The species is conspecific with P. yunouresia . On the other hand, re-examinations of seventeen paratype males revealed that the paratype series contains at least two specimens (No. 179: 64 and 66) of P. okigenga , of which abdominal tergites II and V are pale, and values of antennal ratio are relatively low, almost 1.0.

Paramerina tokararesea was described by Sasa & Suzuki (1995) on the basis of the holotype male. The male is characterized by the abdominal tergites II–VIII each with a broad brown band. A re-examination of the holotype has shown that the male has four brown vittae on the scutum, and the value of antennal ratio is 1.23, somewhat greater than that (1.12) in the original description. Also the species is a junior synonym of P. yunouresia .

Kobayashi & Endo treated P. yunouresia as a junior synonym of the European species P. d i v i s a (Walker). However, the species is distinct from P. d i v i s a in the male abdominal tergites II and V each with an anterior dark band; the pupal thoracic horn with a relatively large plastron plate and an alveolar-type respiratory atrium, the pupal abdominal segment VII with four pairs of LS-setae; and the uni-colored larval head capsule. While P. d i v i s a is characterized by the entirely pale male abdominal tergites II and V ( Goetghebuer 1936, Fittkau 1962, Pinder 1978); the pupal thoracic horn with a small plastron plate and a respiratory atrium smoothed on surface, the pupal abdominal segment with three pairs of LS-setae ( Zavȓel & Thienemann 1921, Fittkau 1962, Langton 1984); and the bicolored larval head capsule ( Rieradevall & Brooks 2001).

The male of P. yunouresia most resembles that of the North African species P. vaillanti Fittkau in the yellow abdominal tergites II–VIII each with an anterior dark band, the wing without any marking, the great value of the middle leg ratio (more than 0.9) and the abdominal tergite IX without setae, but differs from it in the abdominal tergite IX distinctly sticking out of the tergite VIII. In P. vaillanti , the abdominal tergite IX is widely covered by the tergite VIII, according to Fittkau (1962).

Also the male of the North American species P. s m i th ae (Sublette) is similar to that of P. yunouresia in the body size (about 2 mm in the wing length) and the abdominal color pattern, but separable from it by the foretibial spur with a relatively short main tooth ( Roback 1971). Differences between both the species are more distinct in the larval and pupal stages. According to Roback (1972), P. s m i t h a e has one pectinate and two bifid claws on the larval posterior parapod, and a relatively smooth respiratory atrium surface in the pupal thoracic horn. In contrast, the larval posterior parapod of P. yunouresia possesses neither pectinate nor bifid claw, and the pupal thoracic horn has an irregular alveolar-type respiratory atrium surface, which is somewhat similar in appearance to one found in Larsia atrocincta (Goetghebuer) (see Fittkau 1962, fig. 291).

Figures

FIGURES 1 – 4. Paramerina yunouresia (Sasa), male (1 – 3) and female (4). 1, Thorax, showing marking pattern, dorsal view; 2, wing; 3, hypopygium, dorsal view; 4, genitalia, ventral view.