Clinotanypus gymnos, Oliveira & Silva & Trivinho-Strixino, 2013

Oliveira, Caroline Silva Neubern de, Silva, Fabio Laurindo da & Trivinho-Strixino, Susana, 2013, Four new species of Clinotanypus Kieffer, 1913 (Diptera: Chironomidae: Tanypodinae) from Neotropical region, Journal of Natural History (J. Nat. Hist.) 48 (5 - 6), pp. 317-343 : 325-330

Clinotanypus gymnos sp. nov.

( Figures 4–6 )

Type material

Holotype male with pupal and larval exuviae, BRAZIL, SP, Pirassununga , Aquaculture Research and Training Center – CEPTA / IBAMA, New Reservoir, 21 ◦ 55 ′ 44 ′′ S, 47 ◦ 22 ′ 23 ′′ W, 627 m a.s.l., 19 March 2002, L. C. Correia . Paratype 1 larva, same data as holotype .

Etymology

From Greek, gymnós , meaning bare, referring to larval mandible without outer lateral row of setae.

Diagnostic characters

Clinotanypus gymnos sp. nov. differs from other Clinotanypus species by the combination of the following characters. Male: wing length 1.78 mm, fore femur with apical portion brown and tibia completely brown, mid and hind femurs yellow and tibiae with basal and apical portion brown, TIX with 14 setae, anal point bilobed, gonostylus with 5 setae. Pupa: base of scar without shagreenation, segment VII with 6 taeniae and anal lobe 688 µm long. Larva: mandible without row of setae at the lateral outer margin and M appendage with lateral teeth.

Descriptions

Adult male (n = 1)

Dimensions. Total length 3.96 mm. Wing length 1.78 mm. Total length / wing length 2.22. Wing length / length of profemur 1.87.

Coloration. Head, pedicel, antenna and maxillary palp brown. Thorax with microtrichia, yellow; antepronotum with two brown verticals spots; scutellum, postnotum, anepisternum and preepisternum brown. Wing membrane transparent without spots, veins brown and macrotrichia on C and R 1 veins. Legs pale brown with dark brown bands as in Figure 4C–E . Abdomen brown and hypopygium yellow.

Head ( Figure 4A ). Antenna with 14 flagellomeres, AR 1.91, flagellum 1275 µm long. Temporal setae 17, multiserial ( Figure 4A ). Eyes bare, with dorsomedian extension containing 4 terminal facets. Tentorium 166 µm long, stipes not measurable. Clypeus 102 µm long, 103 µm wide at largest part, bearing 21 setae. Cibarial pump with anterior margin concave, 266 µm long. Palpomere lengths 1–5 (in µm): 69; 92; 135, 215; 246.

Thorax. Acrostichals biserial; dorsocentrals 44, merging with the acrostichals posteriorly; prealars 35; supraalars 1; scutellars 14; postnotals 22; posterior anepisternals II, epimerals and preepisternals inconspicuous.

Wing ( Figure 4B ). Width 0.55 mm long. Costa 1.73 mm long, produced beyond R 4+5. R 1 with 26 setae. VR 0.88. WW 0.31. Brachiolum with 1 seta. Squama with 29 setae.

Legs ( Figure 4C–H ). Fore leg: tibia one apical spur 55 µm long (Figure F). Mid leg: tibia with two apical spurs 54; 48 µm long ( Figure 4G ); tarsomeres 1–3 with two pseudospurs 37–40, 35–40, 39 and 30–32 µm respectively. Hind leg: tibia with two apical spur 92; 54 µm long ( Figure 4H ); tarsomeres 1–3 each with one pseudospur 40, 34 and 25 µm long, respectively; double comb present. All legs with claws pointed. Pulvilli absent. Lengths and proportion of leg segments as in Table 2.

Hypopygium ( Figure 4I ). Tergite IX with irregular row of 14 dorsal setae. Anal point small and simple. Phallapodeme long and wide, 92 µm long. Sternapodeme curved anteriorly, 135 µm long. Gonocoxite conical, 219 µm long, with slightly concave inner margin. Gonostylus simple, 112 µm long; megaseta 19 µm long. HR 1.95. HV 3.54.

Pupa (n = 1)

Coloration. Exuviae pale brown with brown spots. Thoracic horn mostly brown.

Cephalothorax ( Figure 5A ). Wing sheath smooth 1.34 mm long and 0.46 mm wide. Frontal apotome 273 µm wide. Thoracic horn 439 µm long and 145 µm wide, with few spinules on the surface; plastron plate large, 201 µm long ( Figure 5A ); aeropyle tube 235 µm long. Respiratory atrium tubular. Basal lobe present.

Abdomen ( Figure 5B, C ) 3.80 mm long. Tergites I–VII with shagreen consisting of sparse and solitary spinules ( Figure 5C ). T I with pigmented scar, 138 µm long, without shagreenation at the base. Dorsal chaetotaxy as in Figure 5B. T VII with 6 taeniae. T VIII with 5 taeniae. Anal lobe as in Figure 5C , 688 µm long and 638 µm wide, with two anal macrosetae. Genital sac smaller than anal lobe, 313 µm long. GS / AL 0.45.

Fourth instar larva (n = 2)

Coloration. Head pale yellow, postoccipital margin brown; antenna pale yellow; apical tooth of mandible brown; ligula pale yellow. Abdomen pale yellow, procercus, anal setae and posterior parapod claws pale yellow.

Head ( Figure 6A ). Length 663–800 µm, 525–670 µm wide; cephalic index 0.79–0.83. Chaetotaxy as in Figure 6A .

Antenna. Length 662–741 µm long, A 1 609–681 µm long, with ring organ placed 517–600 µm from base, A 2 37–45 µm long. AR 11–12.

Maxilla ( Figure 6B ). Palp segment 118–127 µm long and 14–15 µm wide, with ring organ 59–69 µm from base, A 1 / P 1 5.16–5.36, A 2 / P 1 0.31–0.35.

Mandible ( Figure 6C ). Length 100–112, with 3 lateral setae. A 1 / MD 6.08–6.09. Row of setae at the lateral outer margin absent.

Mentum and M appendage ( Figure 6D ). Dorsomentum with 4–5 pairs of lateral teeth; pseudoradula uniformly granulate; M appendage with lateral teeth.

Hypopharyngeal complex ( Figure 6E ). Ligula 87–103 µm long, maximum width 39–46 µm, with 6–7 accessory teeth, anterior toothed margin slightly concave. Paraligula pectinate, 56–60 µm long. Pecten hypopharyngis with 22 teeth equal in size.

Body. With lateral fringe. Anterior parapods with simple claws. Procercus 197–206 µm long, 55–70 µm wide, with 14 anal setae 710–739 µm long. L / W 2.94–3.58. Supraanal seta 500–636 µm long. Anal tubules not measurable. Posterior parapod apex with 10 simple and 5 hook-shape claws.

Ecology

The larva of Clinotanypus gymnos was collected from sandy sediments in a reservoir at the Aquaculture Research and Training Center, in Pirassununga, São Paulo.

Figures

Figure 4. Clinotanypus gymnos sp. nov.: adult. (A) Head, frontal view. (B) Wing. (C–E) Legs, P1 (C), P2 (D) and P3 (E). (F–H) Tibial spurs of P1 (F), P2 (G), and P3 (H). (I) Hypopygium with tergite IX, left: ventral aspect, right: dorsal aspect.

Figure 5. Clinotanypus gymnos sp. nov.: pupa. (A) Thoracic horn. (B) Tergites chaetotaxy, anal lobe and male genital sac. (C) Shagreen pattern on abdominal segments I–VII.

Figure 6. Clinotanypus gymnos sp. nov.: larva. (A) Head with chaetotaxy, left: dorsal aspect, right: ventral aspect. (B) Maxillary palp detail. (C) Mandible. (D) Mentum and M appendage. (E). Ligula and paraligula.