Limnophyes guarani, Pinho, Luiz Carlos & Andersen, Trond, 2015

Pinho, Luiz Carlos & Andersen, Trond, 2015, Limnophyes guarani sp. n., a new hygropetric Orthocladiinae from southern Brazil (Diptera: Chironomidae), Zootaxa 3948 (1), pp. 137-144 : 138-143

Limnophyes guarani sp. n.

( Figures 1–18 )

Type material. Holotype: male adult with pupal exuviae: Brazil, Santa Catarina State, Grão-Pará, Serra do Corvo Branco, 28°03’21” S 49°22’00” W, 1241m a.s.l., 07.x.2014, seepage, LC Pinho & A Pitaluga leg. ( MZUSP). Paratypes: 1 female adult with larval and pupal exuvia, as holotype ( MZUSP).

Etymology. The specific epithet refers to the Guarani Aquifer, that seeps at the road cut where the larvae were collected.

Diagnostic characters. The adults group with L. griseata ( Edwards, 1931) and L. bidumus Saether, 1990 in having a pronounced humeral pit with lanceolate setae and an additional group of lanceolate setae just posterior to antepronotum. They are, however, smaller with a wing length of 0.97 mm in the male and 0.85 mm in the female, compared to 1.54 mm in male L. griseata , on average 1.61 mm in male L. bidumus and 1.25 mm in female L. bidumus ; the female of L. griseata is not known. The new species also has a lower AR, 0.24 in the male and 0.36 in the female, compared to 0.41 in male L. griseata , on average 0.60 in male L. bidumus and 0.45 in female L. bidumus . Further, the new species has a distinctly higher number of lanceolate setae in the group directly behind antepronotum, 17 in the male and 15 in the female, compared to 6 in male L. griseata , 2–6 in male L. bidumus and 3 in female L. bidumus . Further, L. griseata and L. bidumus have at most two short, dorsal antepronotals, while there are 7 and 10 comparatively long, dorsal setae in male and female L. guarani sp.n., respectively. It shares a dorsal projection of the antepronotal lobe with long, numerous dorsal setae with L. gercinoi , but this projection is much more pronounced in L. gercinoi .

The pupa of the new species can easily be separated from the pupa of L. bidumus as the anal macroseta is longer than the anal lobe, while in L. bidumus these setae are only about 0.6 times as long as the anal lobe. Further, L1–L5 on segment VIII increase in size for L. guarani sp. n., while in L. bidumus they are alternate in size; the pupa of L. griseata is not known. The only pupae with anal macrosetae longer than anal lobe, like L. guarani , are L. asquamatus Andersen, 1937 , L. spinigus Saether, 1990 and maybe L. gurgicola (Edwards, 1929) .

The larvae of neither L. griseata nor L. bidumus are known. The larva of L. guarani sp. n. can be distinguished from other described Limnophyes larvae by its smaller size, with a head capsule length of 0.22 mm, while the lengths in the remaining described species range between 0.24 and 0.33 mm. Well developed supraanal macrosetae 235 µm long, procercus 25 µm high, AR 2.00, and antennal blade distinctly longer than flagellum will also help to characterize the larva of L. guarani sp. n.

Description. Male (n = 1). Total length 2.00 mm. Wing length 0.97 mm. Total length/wing length 2.06. Wing length/length of profemur 2.46.

Colouration: Blackish brown; wings light brown; legs uniformly dark brown except for trocanther and the very base of femora pale.

Head. Antenna with 12 flagellomeres, AR 0.24. Ultimate flagellomere 93 µm long. Temporal setae 4, including 1 inner vertical, 1 outer vertical and 2 postorbitals. Clypeus with 13 setae. Tentorium 100 µm long, 17 µm wide. Stipes 87 µm long, 32 µm wide. Palp segment lengths (in µm): 22, 25, 57, 65, 105. Third palpomere with 1 sensillum clavatum in apical third; 10 µm long.

Thorax ( Figure 1 ). Antepronotal lobes slightly projected dorsally. Antepronotals consisting of 3 lateral and 7 dorsal setae. Acrostichals very small and difficult to observe, apparently 4 in mid scutum. Dorsocentrals consisting of 17 lanceolate close to antepronotum, 15 lanceolate in dorsal humeral pit, 18 lanceolate prescutellar setae and 13 simple setae; prealars 7, extending anteriorly; supraalar absent; preepisternum with 4 setae; posterior anepisternum II with 2 setae; epimeron II with 6 setae. Scutellum with 7 setae.

Wing ( Figure 2 ). VR 1.42. Costal extension 47 µm long. R with 4 setae, brachiolum with 1 seta, other veins bare. Squama with 2 setae.

Legs. Spur of fore tibia 37 µm long, spurs of mid tibia 17 µm and 20 µm long, spurs of hind tibia 40 µm and 17 µm long. Width at apex of fore tibia 27 µm, of mid tibia 27 µm, of hind tibia 35 µm. Comb with 13 setae, longest 37 µm, shortest 15 µm. Tarsomere 4 shorter than 5. Lengths and proportions of legs as in Table 1 .

Hypopygium ( Figures 3 and 4 ). Anal point low, broad based, bluntly triangular, covered with microtrichia and with about 12 marginal setae; laterosternite IX with 2 setae. Phallapodeme 67 µm long; transverse sternapodeme 62 µm long. Virga consisting of two spines, 27 µm long. Gonocoxite 110 µm long; inferior volsella of minimus -group type. Gonostylus 72 µm long; crista dorsalis absent; megaseta 15 µm long. HR 1.53; HV 1.81.

Female (n = 1). Total length 1.74 mm. Wing length 0.85 mm. Total length/wing length 2.05. Wing length/ length of profemur 2.47.

Colouration: As in male.

Head. AR 0.36. Flagellomere length/width (in µm): 37/22, 37/22, 42/20, 42/20, 57/25. Temporal setae 4, including 1 inner vertical, 1 outer vertical, and 2 postorbitals. Clypeus with 14 setae. Tentorium 75 µm long, 10 µm wide. Stipes 75 µm long, 30 µm wide. Palp segment lengths (in µm): 20, 22, 60, 62, 62. Third palpal segment with 1 sensillum clavatum in apical third, 12 µm long.

Thorax ( Figure 5 ). Antepronotal lobes slightly projected dorsally. Antepronotals consisting of 4 lateral, 3 median, and 10 dorsal setae. Acrostichals 5 in mid scutum. Dorsocentrals consisting of 15 lanceolate close to antepronotum, 14 lanceolate in dorsal humeral pit, 12 lanceolate prescutellar setae and 19 simple setae; prealars 6, extended anteriorly; supraalar 1; preepisternum with 4 setae; posterior anepisternum II with 2 setae; epimeron II with 5 setae. Scutellum with 6 setae.

Wing ( Figure 6 ). VR 1.36. Costal extension 80 µm long, with 2 non marginal setae. R with 7 setae, R1 with 3 setae, R4+5 with 12 setae, brachiolum with 1 seta, remaining veins bare. Squama bare.

Legs. Spur of fore tibia 25 µm long, spurs of mid tibia 17 µm and 15 µm long, spurs of hind tibia 27 µm and 15 µm long. Width at apex of fore tibia 27 µm, of mid tibia 30 µm, of hind tibia 35 µm. Comb with 11 setae, longest 30 µm, shortest 22 µm. Tarsomere 4 shorter than 5. Lengths and proportions of legs as in Table 2 .

Genitalia ( Figures 7–10 ). Gonocoxite IX 60 µm long, with 3 strong and 2 weak setae. Tergite IX undivided, with 20 setae. Cercus 55 µm long. Seminal capsules 50 µm long, neck not observed. Notum 72 µm long.

Pupa (n = 1–2). Total length 2.07–2.22 mm. Exuviae transparent.

Cephalothorax. Frontal setae ( Fig. 15 ) 67–70 Μm long. Longest median antepronotal 68–92 Μm long. Distance between Dc1 and Dc2 7–8 Μm ( Fig. 16 ), between Dc2 and Dc3 7–8 Μm, between Dc3 and Dc4 55–60 Μm.

Abdomen ( Figures 17–18 ). Tergite I bare, T II–VIII with coarse and extensive shagreen, T IX with relative coarse anterior shagreen. Sternite I bare; S II–VIII with fine, sparse median spinules; S IX bare. Number of caudal spines on T II–VIII as: 88–120, 99–103, 109–112, 91–103, 68–86, 61–72, 52–54. Maximum length of caudal spines 47–60 Μm long, slightly shorter on T II–III. Conjunctives II/III–VI/VII with 4–6 rows of spinules. Lengths (in Μm) of L1 to L5 on segment VIII as: 95–105, 100–112, 110–120, 125 (1), 132–149, increasing in size. L4 absent in female. Anal lobe 132–154 Μm long; anal macrosetae 187–207 Μm long. Genital sac of male reaching apex of anal lobe; 40 Μm short of apex of lobe in female.

Larva (n = 1). Total length 2.05 mm. Head capsule 0.22 mm long.

Head. Antenna as in Figure 11 . Length of antennal segments (in Μm): 40, 10, 2, 6, 2. AR = 2.00. Basal antennal segment 13 Μm wide; distance from base to ring organ 15 Μm, to basal mark of seta 17 Μm, to distal mark 20 Μm. Blade 27 Μm long; accessory blade and apical style of second segment not distinguishable; Lauterborn organ 6 Μm long. S1 with branches reduced; median chaetulae laterales apparently smooth. Premandible ( Fig. 12 ) 48 Μm long, with 2 teeth; premandibular brush present. Mandible ( Fig. 13 ) blackish in apical half, 62 Μm long, with four inner teeth; seta subdentalis indistinguishable. Seta interna 6 Μm long. Mentum ( Fig. 14 ) apparently with 12 teeth. Postmentum 132 Μm long.

Abdomen. Procercus 25 Μm high, 20 Μm wide, with 6 anal setae, 270 Μm long. Supraanal seta 235 Μm long. Longest body seta 55 Μm long.

Distribution and bionomics. The larvae were collected in the Corvo Branco Mountains in southern Brazil, where they were found in the thin water film running down the vertical rock surface in a road cut. Larvae of Podonomus sp. and an undescribed species of Thaumaleidae were also found at the same site.

Figures

FIGURES 1 – 4. Limnophyes guarani sp. n., male adult. 1, Thorax. 2, Wing. 3, Hypopygium, dorsal view. 4, Hypopygium with anal point and tergite IX removed, dorsal aspect to the left and ventral aspect to the right.

FIGURES 5 – 10. Limnophyes guarani sp. n., female adult. 5, Thorax. 6, Wing. 7, Genitalia, dorsal aspect. 8, Genitalia, ventral aspect. 9, Apodeme lobe. 10, Dorsomesal lobe.

FIGURES 11 – 18. Limnophyes guarani sp. n., larva (11 – 14) and pupa (15 – 18). 11, Antenna. 12, Premandible. 13, Mandible. 14, Mentum. 15, Frontal apotome. 16, Dorsocentrals. 17, Abdomen, dorsal view. 18, Abdomen, ventral view.

Tables

TABLE 1. Lengths (in µm) and proportions of legs of Limnophyes guarani sp. n., male (n = 1).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BV	SV	BR
p1	394	463	246	148	108	59	64	0.53	2.91	3.48	2.1
p2	414	424	187	99	69	39	49	0.44	3.47	4.48	2.5
p3	414	463	266	128	118	49	59	0.57	3.29	3.30	2.1

TABLE 2. Lengths (in µm) and proportions of legs of Limnophyes guarani sp. n., female (n = 1).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BV	SV	BR
p1	343	392	201	123	83	44	54	0.51	3.08	3.66	1.2
p2	353	358	162	74	54	34	49	0.45	4.14	4.39	1.6
p3	387	407	221	98	103	39	49	0.54	3.51	3.59	2.5