Pseudochironomus viridis ( Kieffer, 1925 )

Paggi, Analía C. & Rodriguez Garay, Gretel N., 2015, The presence of species of Pseudochironomus Malloch 1915 (Diptera: Chironomidae) in watercourses of Chaco Serrano Ecoregion (Argentina, South America), Zootaxa 3957 (3), pp. 334-341 : 335-339

Pseudochironomus viridis ( Kieffer, 1925)

Pseudochironomus viridis (=Proriethia viridis ) Kieffer 1925: 79 –81. Pseudochironomus viridis Roback 1960: 98 .

Diagnostic characters. Males of P. v i r i d i s can be distinguished from other Pseudochironomus species by having thorax and abdomen almost uniformly brownish with pale areas at setae bases; all legs with pale femur, tibia of PI entirely brown, tibia of PII and PIII and basal 2/ 3 of ta1 of PIII pale, rest of all tarsi brownish. Third palpomere with a slight fingerlike process. Total length 5.23–5.96. AR 1.41–1.63. VR 1.12–1.14. LR (PI) 0.96–1.00, (PII) 0.50–0.57, (PIII) 0.58–0.62. Thorax with about 15 dorsocentrals in one row. Gonostylus smaller than gonocoxite, HR 1.44–1.53. HV 3.93–4.24. Pars ventralis divided only join at base. Superior volsella curved toward each other, apically concave ending as two points, completely naked.

The pupa is brown yellowish, 5.33–6.93 long, thoracic horn 414–580 long, smooth, shorter branch not discernible, probably not present. Abdomen with TI with two patches of shagreen well defined or slightly produced; TII with 84–124 posterior hooklets; SI with one pair of tubercles fully covered with spines and the other granulose or with few and very small spines; segments V–VIII with 3, 4, 4, 5 L taeniate setae; anal lobe with 257– 356 in a double fringe of taeniate setae and a pair of dorsal setae, SVIII with 3–8 comb-like caudo lateral spines.

The larva has a slightly arcuate mentum with 13 teeth, second lateral tooth small, fifth very wide tooth and sixth normal laterally displaced. AR 1.7–2.5, basal antennal segment 73–89 long, third antennal segment 0.6 times as long as second, antennal blade equal or slightly longer than segments 2–5. Parapods with about 15 claws.

Material examined. ARGENTINA, Catamarca Province, El Simbolar stream (28° 39'02, 21' S and 66 ° 03'11.69' W) located at 980 m a s l; one male and pupal exuviae associated, 13.vii.12, drift net ( MLP); one male, 26.v.12, light trap; two pupal exuviae, 13.vii.12, (El Simbolar pools) hand net; two associated larval and pupal exuviae, 11.viii.06, drift net, Rodriguez Garay col., ( ILPLA); San Luis Province, Rio Grande river (32º50'S and 66º05'O) located at 1600 m a s l one male and pupal exuvia, two larval exuviae, one pupal exuvia, 11.v.06; one male, 17.xi.06; one pupal exuvia, 27.ii.08; two pupal exuvia, 16.xi.08, Paggi & Medina col. ( ILPLA).

Description ( Figs 1–17 ).

Male (n =4 except when otherwise stated)

Total length 5.23–5.96, 5.49; wing length 2.59–2.86, 2.75 (3); total length / wing length 1.97–2.16, 2.09 (3); wing length/ length of profemur 2.38–3.01, 2.76 (3).

Coloration: General coloration uniformly brown. Wing hyaline with yellow veins. Fore leg with femur yellow, tibia and tarsi all brown; mid leg with femur yellow, tibia light brown and tarsi all brown; hind leg with femur yellow, tibia and proximal 2/3 of ta 1 yellow to light brown, distal part of ta 1 and ta 2–5 brown ( Fig. 1 ).

Head. AR = 1.41–1.63, 1.53 (3); last flagellomere length 654–696, 679 (3); temporal setae 25–33, 30. Clypeus with 10–17, 14 setae. Tentorium 182–199, 190 (3) long. Palpomere -lengths (µm) 58–75, 66; 58–75, 67; 116–166, 137; 124–215, 174; 182–273, 242. Third palpomere with a slight fingerlike process.

Thorax. Antepronotals 6–8, 7, small; dorsocentrals 14–16, 15 in a single row, arising from pale areas; prealars 3–5, 5; scutellum with 19–24, 22 setae irregularly distributed ( Fig.2 ).

Wing ( Fig. 3 ). VR = 1.12–1.14 (3); brachiolum with 2 setae, R with 13–17 setae, R1 with 1 sensitive organ, R4+ 5 10–11 apical setae. Squama with 16–18, 17 (3) setae.

Legs. Spur of foretibia 57–61, 58 (3) long; spurs of midtibia 55–65, 58 (3) and 49–61 µm long; spurs of hind tibia 57–91, 73 and 63–65 long. Sensilla chaetica 7–8 on ta1 of each PII and PIII. Length (in µm) and proportions of legs as in Table 1 .

Abdomen. Dark brown colored with pale areas in the base of setae wich are homogeneously distributed in all the segments. Hypopygium ( Fig. 4 ). Posterior margin of tergite IX with median notch ( Fig. 5 ) with 32 setae. Laterosternite IX with 9 setae. Phallapodeme 83–91, 85 long. Transverse sternapodeme 83–157, 126 long. Superior volsella 81–101, 87 long curved toward each other, apically concave ending as two points, totally naked; inferior volsella foot shaped, 75–83, 79 long, with microtrichia and long setae, longest apical setae 51 long, median volsella (2a) 8 µm long bears 1 apical setae and 1 subapical setae 30 µm long. Gonocoxite 199–215, 207 µm long. Gonostylus 133–149, 139 long. HR = 1.44–1.53, 1.49; HV = 3.93–4.24, 4.04. Pars ventralis divided into two 49– 61, 56 long and 14–18, 16 wide lobes, join at base ( Fig. 6 ).

continued.

Female only pharate not well discernible.

Pupa (n = 8 except when otherwise stated)

Total length 5.33–6.93, 6.41 mm. Exuviae brownish yellow.

Cephalotorax. Frontal apotome as in figure 7, frontal setae absent. Thoracic horn ( Fig. 8 ), 414–580, 511 (3) long, smooth, shorter branch not discernible. Three precorneals, anterior 53–108, 73 (5), median 122–172, 154 (5), posterior 41–81, 66 (5) long; 2 median antepronotals 99–157, 127 (5(not drawn), dorsocentrals, 1st 33–83, 52 (3), 2nd 37–50, 43 (3), 3th 31–50, 41 (3), 4th 31–41, 38 (3), 1st–2nd separated from 3th–4th by 373 long.

Abdomen. ( Fig. 9 ). TI with 2 patches of shagreen, patches weakly visible in the specimens from San Luis; TII with 84–124, 109 posterior hooklets; TII–TVI covered with shagreen except postero lateral margins, oral shagreen stronger; T III-VII with antero median patch of spinules over a light pigmentation background; TVI with posterior band of strong spinules; TVIII with antero median and lateral shagreen. Paratergites V–VII with anterior field of fine shagreen. Conjunctives III/IV to IV/V with 3–5 rows of sclerotized spinules with light base. SI with one pair of tubercles fully covered with spines, the other granulose (San Luis specimens) or with few and very small spines (Catamarca specimens) ( Fig. 10 ); SII, III with anterior transverse band of spinules; V–VIII with anterolateral patch of spinules. Pedes spurii A on SIV-VII. Segment VIII with 3–8, 5 comb-like caudolateral spines 8–30 µm long ( Fig. 11 ). Segment II–IV with 2 small L setae and a 3rd. dorsolateral, segment V–VIII with 3, 4, 4, 5 L taeniate setae. Anal lobe 257–356, 315 µm long, with 25–54, 35 double fringe of taeniate setae and a pair of dorsal setae ( Fig. 12 ).

Larval exuviae (n = 4 except when otherwise stated)

Coloration. Head brown; mentum, mandibular teeth except apical tooth and occipital margin dark brown.

Head. Antenna ( Fig.13 ), with 5 segments, length of antennal segments 73–89, 78; 16–20, 18; 10–14, 11; 8–6, 7; 4, AR = 1.7–2.5, 1.8; second antennal segment 1.4–1.6 times as long as third; blade equal or slightly longer than segments 2–5, 41–45, 43 long; basal antennal segment 20–22, 21 wide, distance from base to ring organ 12–14, 13, to basal mark of setae 18–22 to distal mark 57–61. Premandible 106–108 long as in Fig. 14 . Pecten epipharyngis as in figure 15. Mentum ( Fig. 16 ), with median tooth and 6 lateral teeth, second lateral tooth small, fifth very wide that makes sixth appeared like separated, ventromental plates narrow. Mandible ( Fig. 17 ), 173–203, 192 long.

Abdomen. Not measurable in the exuviae.

Figures

FIGURES 1 – 6. Pseudochironomus viridis (Kieffer), male: 1, color pattern of legs, anterior to posterior from right to left (scale = 500 µm); 2, thorax (scale = 100 µm); 3, wing (scale = 500 µm); 4, hypopygium, dorsal view, half right tergite IX removed (scale = 100 µm); 5, detail of posterior margin of tergite IX (scale = 100 µm); 6, pars ventralis (scale = 100 µm).

FIGURES 7 – 12. Pseudochironomus viridis (Kieffer), pupa: 7, frontal apotome; 8, thorax frontal part with thoracic horn; 9, tergites I – VII shagreen; 10, detail of tubercles of SI; 11, caudolateral spines of sternite VIII; 12, tergite VIII and anal lobus (scales = 100 µm).

FIGURES 13 – 17. Pseudochironomus viridis (Kieffer), larva: 13, antenna; 14, premandible; 15, pecten epipharyngis; 16, mentum; 17, mandible (scales = 100 µm).

Tables

TABLE 1. Lengths (in Μm) and proportions of legs of Pseudochironomus viridis (Kieffer) (male, n = 3).

	Fe	Ti	Ta1	Ta2	Ta3
P1	934–1100, 1010	1141–1370, 1259	1100–1328, 1231	498–540, 519	394–436, 415
P2	1058–1245, 1162	1079–1204, 1155	540–685, 629	291–311	228–249
P3	1100–1307, 1176	1141–1411, 1266	664–872, 754	311–457, 401	228–353, 304