Coelotanypus delpontei ( Edwards, 1931 )

Paggi, Analía C. & Zilli, Florencia, 2018, Redescription of two species of Coelotanypus (Kieffer) 1913 (Diptera: Chironomidae) in rivers of the Parano-Platense basin (Argentina, South America), Zootaxa 4486 (1), pp. 67-75 : 68-70

Coelotanypus delpontei ( Edwards, 1931)

Coelotanypus delpontei Roback 1965: 30 .

Diagnostic characters. Males of C. delpontei can be distinguished from other Coelotanypus species by having thorax almost uniformly brown reddish, abdomen pale yellowish with two dark bands; all legs with femur, tibia and tarsi 1 yellowish with distal part brownish, ta2 of PI, ta2,3 of PII and PIII distal part brownish, rest of all tarsi brownish. Wings with two dark bands and slight cubital fork. Total length 6.98. AR 0.27–0.28. VR 0.95. LR (PI) 0.74, (PII) 0.67, (PIII) 0.63. Thorax with about 55 dorsocentrals in three rows. HR 1.88. HV 3.75.

The pupa is brown yellowish, 5.81 long. Thoracic horn 621 long. Scar of TI 290 long; TVII with 6–7 L taeniate setae; TVIII with 5 L taeniate setae; anal lobe with 2 macrosetae.

The larva is 9.84 long. Ligula slightly arcuate with 7 teeth. AR 6.81, basal antennal segment 325 long. Parapods with about 15 claws.

Material examined. Paratypes. ARGENTINA, Santo Tomé, Santa Fe (31°39'56.99"S and 60°45'21.08"W), two males, light trap, 8.x.2008, Zilli col. ( MLP); floodplain lake located at the Paraná River, Santa Fe, (31°40'20.50"S and 60°34'20.60"W), one reared female, one larval exuvia, one pupal exuvia, 22.ix.2007, bottom sediment samples collected with grabs, Zilli col., one pupal exuvia same place, 21.iii.2010, Montalto col. ( ILPLA).

Redescription ( Figs 1–13 ).

Male (n =2 except when otherwise stated). Total length 6.74–7.22; wing length 2.97–3.94; total length / wing length 2.23–2.27; wing length/ length of profemur 2.20.

Coloration: General coloration uniformly brown yellowish. Wing hyaline with yellow veins and two dark bands ( Fig.1 ). All legs with femur and tibia yellow, distal part brownish, fore leg with distal part of ta 1, 2 brownish and ta 3-5 all brown, mid and hind legs with distal part of ta 1-3 brownish and ta 4,5 all brown, ( Fig. 2 ).

Head. ( Fig. 3 ) ER= 0,96–1,20. AR = 3,52–3,68; last flagellomere length 70–74, temporal setae 30–33. Clypeus with 20–28 setae. Tentorium not mensurable in the specimens. Palpomere lengths (µm) 7–8; 5–6; 18–21; 22–25; 33–35.

Thorax. Antepronotals 14; 21–27 setae joined over mesonotal tubercle ( Fig.4 ); dorsocentrals 54–56 in three rows; prealars 11–13; scutellum with 60–80 setae irregularly distributed.

Wing ( Fig. 1 ). VR = 0.94–0.96, R with 13–17 setae, C/WL 0.96–0.97, Cu/WL 0.41–0.42; cubital fork 42 long. Squama with 40–65 setae.

Legs. ( Fig. 2 ). Spur of foretibia 104–166 long; spurs of midtibia 99 and 116 µm long; spurs of hind tibia 75–83 and 124–141 long, comb in two rows 11–14 and 7–11 teeth respectively, tarsal spurs PII: ta1 both 57 long, ta2 both 49 long, ta3 47 and 53 long; tarsal spurs PIII: ta1 57–61 long, ta2 47–57 and 51–59 long, ta3 47–49 long. Sensilla chaetica 6–7 on ta1 of PIII. Length (in µm) and proportions of legs as in Table 1.

Abdomen. ( Fig. 5 ). Pale yellow with tergite IV and VII dark brownish. Abundant irregularly distributed setae.

Hypopygium ( Fig. 6 ). Posterior margin of tergite IX slightly protrude difficult to observe in slides. Laterosternite IX with 9 setae. Phalapodeme 124–141 long. Transverse sternapodeme 190–248, 211 (3) long. Gonocoxite 331–348, 342 (3) µm long. Gonostylus 17 4––190, 182 (3) long ( Fig. 7 ). HR = 1,83–1,91,1,88 (3); HV = 3,70–3,79. Megaseta 20–24 long.

Female (n =1). Total length 6,43; wing length 2,91; total length / wing length 2,21; wing length/ length of profemur 2,69.

Coloration: the specimen reared presented a slight color pigmentation.

Head. Eye Ratio (ER) 1, 75. AR = (antenae lost); temporal setae 45. Clypeus with 50 setae. Tentorium 290 long. Palpomere lengths (µm) 41; 50; 157; 190; 248.

Thorax. Antepronotals 15–16; 11–12 setae joined over mesonotal tubercle; dorsocentrals 85–90 in three rows; prealars 8; scutellum with 86 setae irregularly distributed.

Wing. VR = 1, R with 20 setae, R4+5 3 at tip, C/WL 0.94, Cu/WL 0,39; cu fork 83 long. Squama with 52 setae.

Legs. Spur of foretibia 83 long; spurs of midtibia 66 and 91 µm long; spurs of hind tibia 66 and 108 long, comb in two rows each with 18 teeth respectively, tarsal spurs PI: ta 1–2 41 long; PII: ta1 47 long, ta2 both 39 long, ta3 both 37 long; PIII: ta1 45–49 long, ta2 both 41 long, ta3 37 long. Sensilla chaetica 12 on ta1 of PIII. Length (in µm) and proportions of legs as in Table 2.

Abdomen. Abundant irregularly distributed setae as in male.

Genitalia. Cerci 116 long, seminal capsule 75 long 50 wide; noto not mensurable in this specimen.

Pupa (n = 2 except when otherwise stated). Total length 6,66–7,88 mm. Exuvium brown yellowish.

Cephalotorax. Thoracic horn ( Fig. 8 ), 505–613 long, 58–83 wide, plastron plate L/W 0,67–0,70.

Abdomen. TI: Scar 215–273 long. D2 and L2 ± 6–8 multibranched setae, L1 simple; TII: L2 multibranched, L1 simple, D2 multibranched, D4 simple setae; T III–VI: L1 simple, L2 multibranched, D2,3,5 multibranched, D4 simple ( Fig. 9 ); TVII: D2,3,5 multibranched, one L2 multibranched seven L1 setae; TVIII: five L1 setae. Anal lobe 61–47 long, 25–33 wide, L/W 1,85–1,88; Ratio length anal lobe/ gen. sac 3,81–3,92; two macrosetae; number of hairs of anal lobe ± 170 ( Fig. 10 ).

Larval exuviae (n = 1 reared larvae). Total length 9,84 mm.

Coloration. Head brown yellowish; mandibular teeth dark brown.

Head. Head 828 long 745 wide, head length/ antennal length (HL/antL) 2. Antenna: AR = 6,81; basal antennal 325 length, antennal flagellum 49 long; distance from base to ring organ 41 long; antennal blade 41 long. Mandible ( Fig.11 ) 162 long. Basal segment of maxillary palp 83 long. Number of dorsomental teeth 7 ( Fig.12 ); ligula 122 long, paraligula 65 long ( Fig.13 ).

Abdomen. Procercus 207 long, 99 wide, ratio L/W: 2, number of setae 23, basal setae 704 long. Posterior parapods 787 long, 290 wide, two basal setae 331 and 414 long, number of claws 15.

Figures

FIGURES 1–7. Coelotanypus delpontei Edwards, male. 1, wing (scale= 500 µm); 2, color pattern of legs, a,anterior; b, mid; c, hind; 3, head (scale= 500 µm); 4, detail of mesonotal tubercle; 5,color pattern of abdominal tergites; 6, hypopygium, dorsal view, half right tergite IX removed; 7, gonostylus. Scales= 100 µm.

FIGURES 8–13. Coelotanypus delpontei Edwards, pupa: 8, thoracic horn; 9, tergite IV dorsal (D) and ventral (V) setae distribution (scale= 500 µm); 10, anal lobes; larva: 11, mandible, 12, dorsomental teeth; 13, ligula, paraligula and hipofaringeal teeth. Scales = 100 µm.