Polypedilum panacu, Mendes, Humberto F., Andersen, Trond & Jocqué, Merlijn, 2011

Mendes, Humberto F., Andersen, Trond & Jocqué, Merlijn, 2011, A new species of Polypedilum Kieffer from bromeliads in Parque Nacional Cusuco, Honduras (Chironomidae: Chironominae), Zootaxa 3062, pp. 46-54 : 47-54

Polypedilum panacu sp. n.

( Figs 1–22 )

Type material. Holotype male with larval and pupal exuviae. HONDURAS: San Pedro Sula, Parque Nacional Cusuco ( PANACU ), close to Operation Wallacea's base camp, 15°32'N 88°15'W, vii.2008, in Tillandsia guatemalensis, H.F. Mendes & M. Jocqué ( ZMBN Type No. 447 (PAN 01)). Allotype female with pupal exuviae: as holotype except (TG-4). Paratypes: 1 male with pupal exuviae, as holotype except (TG-2); 1 female with pupal exuviae, as holotype except (TG-8).

Diagnostic characters. The spotted wings combined with the shape of the superior volsella and the number of setae on tergite IX will separate the male from all other Neotropical Polypedilum s. str. species. The female can also be recognized on the two dark spots on the anal part of the wings. The pupae can be readily separated from other described Neotropical species on the presence of spinules on conjunctives III–IV, IV–V and V–VI; the larva on the shape of mentum and pecten epipharyngis.

Etymology. From " PANACU ", the abbreviation for Parque Nacional Cusuco, San Pedro Sula, Honduras, the type locality of the species. The name is to be treated as a noun in apposition.

Male (n = 1–2). Total length not measurable. Wing length 2.06–2.22 mm. Wing length / length of profemur 1.98–2.14.

Coloration. Body, head and antennae dark brown; legs light brown with darker rings subapicaly on all femora; wing with dark spots.

Head. AR 1.09. Ultimate flagellomere 534 µm long. Temporal setae 12–13 composed of 5 inner verticals, 3 outer verticals, and 4–5 postorbitals. Clypeus with 27–41 setae. Tentorium 141–143 µm long, 23–24 µm wide; stipes 134–136 µm long, 43–45 µm wide. Palp segment lengths (in µm): 45–58, 41–47, 129–138, 145–150, 177– 225. Apex of third palpomere with 3–4 sensilla, longest 27–29 µm long.

Thorax. Acrostichals 13–19, biserial; dorsocentrals 15–16; prealars 6–11, uniserial to biserial; humerals 2–3. Scutellum with 10–12 setae, irregularly biserial.

Wing ( Fig. 1 ). VR 1.13–1.22. R2+3 ends close to where R1 meets Sc, R4+5 ending at apex of wing. Brachiolum with 1–2 setae, R with 26–31, R1 with 13–17, R4+5 with 23–27 setae. Squama with 8–9 setae.

Legs. Scale of fore tibia 48–52 µm long, including 7–9 µm long spur ( Fig. 2 ); spur of mid tibia 57–61 µm long; spur of hind tibia 73–75 µm long. Unspurred comb of mid tibia 25–27 µm long, of hind tibia 26–29 µm long. Apex of fore tibia 63–68 µm wide, of mid tibia 54–66 µm wide, of hind tibia 73–75 µm wide. Length and proportions of legs as in Table 1.

Hypopygium ( Figs 3–5 ). Anal point 93–98 µm long, 20–23 µm wide at base, 3–4 µm wide at apex. Tergite IX with 15–16 setae medially and 16–19 setae at base of anal point of which 10–11 strong dorsally, remaining weaker ventrally. Phallapodeme 113–123 µm long; transverse sternapodeme 73–75 µm long. Gonocoxite 185–186 µm long. Superior volsella curved, lacking strong lateral seta, 102–11 µm long, 28–36 µm wide at base, 4–5 µm wide at apex, with 3 strong setae on base. Inferior volsella digitiform 138–143 µm long, 25–27 µm wide at base, 13–16 µm wide at apex, with 8–12 split setae subapically and one stout seta at apex. Gonostylus 198–236 µm long. HR 0.79–0.93.

Female (n = 1–2). Total length not measurable. Wing length 2.04–2.38 mm. Wing length / length of profemur 1.68–1.79.

Coloration. As in male.

Head. AR 0.38. Flagellomere length / width (in µm): 188–197 / 41–43, 118–129 / 36–39, 127 / 34, 75 / 29, 195 / 25. Temporal setae 15–19 composed of 8–9 inner verticals, 3–5 outer verticals, and 4–5 postorbitals. Clypeus with 38–43 setae. Tentorium 136–174 µm long, 24–25 µm wide; stipes 149–150 µm long, 50 µm wide. Palp segment lengths (in µm): 41–52, 43–57, 102, 147, 168. Apex of third palpomere with 9 sensilla, longest about 20 µm long.

Thorax. Acrostichals 20–23, biserial; dorsocentrals 21–38, irregularly triserial; prealars 13–17, triserial; humerals 4–6. Scutellum with 15–17 setae, irregularly biserial.

Wing ( Fig. 6 ). VR 1.13–1.28. R2+3 ends close to where R1 meets Sc, R4+5 ending at apex of wing. Brachiolum with 1–2 setae, R with 33–37, R1 with 25–28, R4+5 with 58–62 setae. Squama with 8–11 setae.

Legs. Scale of fore tibia 52–55 µm long, including 11–14 µm long spur; spur of mid tibia 54–59 µm long; spur of hind tibia 68–77 µm long. Unspurred comb of mid tibia 25–27 µm long, of hind tibia 24–27 µm long. Apex of fore tibia 73–75 µm wide, of mid tibia 73–75 µm wide, of hind tibia 77–82 µm wide. Length and proportions of legs as in Table 2.

G enitalia ( Figs 7–11 ). Gonocoxapodeme with main branch on dorsomesal lobe, with distinct connection anterior of vagina. Gonocoxite IX with 3–6 strong setae, 57 μm long. Tergite IX with 46–62 setae. Segment X with 12– 18 setae to each side. Cercus 111–116 μm long, 141 μm wide. Seminal capsule ovoid, 95 μm long, including 11–14 μm long neck, 4–6 μm wide at the apex. Notum 168–195 μm long. Dorsomesal lobe 104–107 μm long from base of vagina to apex, 54 μm wide at its widest point. Ventrolateral lobe tapering, 30 μm long, 16 μm wide at base, without microtrichia.

Pupal exuviae (n = 1–2). Total length 5.31–6.02 mm.

Coloration. Exuviae translucent; antennal sheaths, oral parts of thorax, wing, and leg sheaths as well as pleurae on abdomen light brown; posterior part of thorax with darker brown patches.

Cephalothorax ( Fig. 12 ). Frontal apotome smooth, frontal setae 41–48 µm long ( Fig. 13 ). Antennal sheaths smooth. Thoracic horn with 8 filaments; basal ring oval, 47–58 µm long, 29–32 µm wide. Scutum with field of few weak tubercles. Antepronotals 3, median 95 µm long, lateral 40–44 µm long. Precorneals 2, 90–97 and 43–47 µm long. Dorsocentrals 4, Dc1 42–46 µm long, Dc2 50–61 µm long, Dc3 40–41 µm long, and Dc4 58–65 µm long; Dc1 and Dc2, and Dc3 and Dc4 grouped, Dc 1 9–23 µm in front of Dc2, Dc2 212–239 µm in front of Dc3, Dc 3 9–11 µm in front of Dc4. Prealar absent.

Abdomen ( Figs 14–16 ). Tergite I bare; tergites II–VIII with transverse anterior band of somewhat stronger spinules; tergites III–VII with posterior patches or band of fine to somewhat stronger spinules; tergites III–VII with caudal field of fine shagreen; on tergites IV–V and VII the anterior and posterior shagreen fields appears connected by very fine shagreen, tergites III and VI with separated anterior and posterior shagreen fields; tergite IX bare. Tergite II with 50–52 hooks occupying about one third of the segment width, longest hook 10–11 µm long, shortest 3–6 µm long. Conjunctives III/IV, IV/V and V/VI with 6–8 irregular rows of spinules. Pedes spurii A well developed on segment IV, composed of 59–63 µm wide, 73–82 µm long area with 6–7 µm long spinules. Pedes spurii B weakly developed on segment II, 54 µm long, 57–64 µm wide. Anal comb with 5–6 spurs, longest 14–18 µm long, shortest 3–5 µm long.

Abdominal setation. Lateral setae on segments I–VIII as: 0, 3, 3, 3, 3, 3, 4, 5; setae on segments I–IV hair-like, on segments V–VIII taeniate; setae on segement II 83, 122 and 92 µm long; on segment III 101, 115 and 97 µm long; on segment IV 100, 119 and 94 µm long; on segment V 475, 551 and 684 µm long; on segment VI 680, 662 and 670 µm long; on segment VII 558, 709, 655 and 612 µm long; on segment VIII 651, 565, 656, 490 and 673 µm long. All tergites with 1 pair of O setae.

Anal lobe. With complete fringe of 58–62 taeniae on each side, longest about 650 µm long, shortest about 240 µm long. Male genital sac overreaches anal lobe by 356 µm.

Larval exuviae (n = 1). Total length not measurable. Frontoclypeus 162 μm long ( Fig. 17 ). Postmentum 227 μm long.

Coloration. Mentum and mandible brown; postoccipital margin black.

Head. AR 1.21. Antenna as in Figure 18 ; antennal segment lengths (in μm): 59, 19, 10, 12, 7. Basal antennal segment 18 μm wide, ring organ about 14 μm from base, blade 52 μm long. Pecten epipharyngis composed of three scales, each with 6–7 teeth ( Fig. 19 ). Premandible 73 μm long, with well developed brush ( Fig. 20 ). Mandible 150 μm long, seta subdentalis 18 μm long, pecten mandibularis as in Figure 21 . Mentum ( Fig. 22 ) 109 μm wide, 70 μm long; median teeth 10 μm wide, 9 μm long; first lateral teeth 7 μm wide, 7 μm long; second lateral teeth 10 μm wide, 11 μm long; ventromental plate 150 μm wide, 43 μm long, with 40 striae; distance between plates 36 μm.

Setae submenti situated below inner posterior corner of ventromental plates, between 4th and 5th lateral teeth. Anterior parapod with 11 simple claws, shortest 16 μm long, longest 27 μm long.

Abdomen. Procercus well developed, with 8 anal setae, longest 443 μm long. Supraanal setae not observed. Posterior parapods and anal tubules not measurable.

Remarks. Saether et al. (2010) states that the few female imagines of Polypedilum subgenus Polypedilum sufficiently described have nearly straight spermathecal ducts. In Polypedilum (P.) panacu sp. n., however, the spermathecal duct is strongly bent.

Distribution and biology. Polypedilum panacu n. sp. is known only from the type locality in Parque Nacional Cusuco, Honduras, where the larvae were collected in the leaf axils of the bromeliad Tillandsia guatemalensis . This bromeliad species is living epiphytic on various trees ( Fig. 23 ) and is distributed from Mexico south to Panama ( Morales & Alfaro 2003).

Other chironomid larvae belonging to the orthoclad genera Limnophyes Eaton, 1875 , Metriocnemus van der Wulp, 1874 and to the subfamily Tanypodinae were collected together with the larva of the new species.

Figures

FIGURE 23. The bromeliad Tillandsia guatemalensis L. B. Smith is an epiphyte in the cloud forest in Parque Nacional Cusuco, Honduras (photo Merlijn Jocqué).

FIGURES 1 – 5. Polypedilum panacu sp. n., male. 1 — wing; 2 — scale and spur of fore leg; 3 — hypopygium, dorsal view; 4 — hypopygium with anal point and tergite IX removed, dorsal aspect to the left and ventral aspect to the right; 5 — superior volsella, dorsal view.

FIGURES 6 – 11. Polypedilum panacu sp. n., female. 6 — wing; 7 — genitalia, ventral view; 8 — genitalia, dorsal view; 9 — ventrolateral lobe; 10 — dorsomesal lobe; 11 — apodeme lobe.

FIGURES 12 – 16. Polypedilum panacu sp. n., pupa. 12 — thorax and wing sheath; 13 — frontal apotome; 14 — tergites I – VII, 15 — tergite VIII and anal lobe; 16 — anal comb.

FIGURES 17 – 22. Polypedilum panacu sp. n., larva. 17 — dorsal sclerites of head; 18 — antenna; 19 — labro-epipharyngeal region; 20 — premandible; 21 — mandible; 22 — mentum and ventromental plates.