Tanytarsus kaxinawa, Dantas & Hamada & Giłka, 2023

Dantas, Galileu P. S., Hamada, Neusa & Giłka, Wojciech, 2023, Tanytarsus van der Wulp (Chironomidae, Diptera): new species from the western Amazon region in Peru and Brazil, new records from the Neotropics, and remarks on the taxonomy of the genus, Zootaxa 5271 (1), pp. 115-139 : 122-123

Tanytarsus kaxinawa sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:86ACEDC7-AC6C-4E35-A911-4D1C228D7282

( Fig. 4A–G )

Type material. Holotype ♁, BRAZIL, Acre, Mâncio Lima, PARNA Serra do Divisor, Morro da Poranga stream, 7°25′47″S, 73°39′43″W, 260 m a.s.l., 19–27.vii.2022, Malaise trap, G. R . Desidério, A.M.O. Pes, J.O. Silva, R . B. Pinedo , H.L.M.S. Ferreira ( INPA) . Paratypes: 3 ♁♁, PERU, Cusco, Quincemil, Araza river tributary, 13º20′10′′S, 70º50′57′′W, 874 m a.s.l., 23–31.viii.2012, Malaise trap, J.A. Rafael, R . R . Cavichioli, D.M. Takiya ( MUSM) .

Derivatio nominis. The specific epithet is a tribute to the Kaxinawá indigenous people (also known as Huni Kuin), who live in the western Amazon (in Brazil and Peru), which is exactly the known distribution of the new species. Noun in apposition.

Diagnosis. Tergite IX covered with microtrichia on entire surface, median setae and lateral teeth absent, tergite bands short, broadly separated. Anal point slender, tapering to narrowly rounded apex, without crests, bars or spinulae. Superior volsella rhombus-shaped, posteriomedian part slightly projected, with small ventral lip; digitus well-developed, pointed, reaching or extending slightly beyond posteromedian margin of superior volsella. Median volsella with setiform and foliate lamellae.

Description. Adult male (n = 4)

Body size and proportions. Total length 1.81–2.24 mm. Wing length 1.02–1.22 mm. Total length/wing length 1.77–1.90. Wing length/length of profemur 1.86–2.03.

Colouration. Head capsule and palps yellow to faint brown, eyes black, antenna brown. Scutal vittae and postnotum brown, median anepisternum II (MA II) and ventral portion of preepisternum light brown, ground colour of thorax, scutellum, and haltere yellow to faint brown. Foreleg: femur and tibia brown, tarsus yellowish. Mid and hind legs: yellowish to light brown. Wing veins yellowish to light brown, membrane with faint brownish undertone. Abdomen yellow to light brown.

Head. Eyes bare, with well-developed dorsomedian extensions. Antenna with 13 flagellomeres; ultimate flagellomere 160–194 μm long; AR 0.36–0.42. Frontal tubercles in shape of minute swellings (~2 μm). Tentorium 80–105 μm long. Temporal setae 7–10 on each side. Clypeus with 12–14 setae. Lengths of palpomeres 1–5 (in μm): 18–30, 20–31, 96–105, 95–106, 177; third palpomere with 2 sensilla clavata subapically, 12 μm long.

Thorax. Ac 20–24, restricted to anterior region of scutum; Dc 6–8 on each side, uniserial; Pa 1 on each side; Scts 3–4. Scutum projected and rounded anteriorly, overreaching antepronotum.

Wing. Typical of the genus. Almost all veins (except subcosta) and entire membrane posterior to radial veins area (except 1/5 basal of m and 2/3 of cu cell) covered with macrotrichia. Brachiolum with 2 setae. VRCu 1.31–1.32.

Legs. Foreleg tibia with short lanceolate spur 18–23 μm long. Tibial combs of mid and hind legs separated; spurs of mid leg unequal: one apically curved, 20–22 μm long, second straight, 10–12 μm long; spurs of hind leg unequal: one apically curved, 24–27 μm long, second straight, 15–18 μm long. Basitarsus of mid leg without sensilla chaetica. Lengths and proportions of legs as in Table 3.

Hypopygium. Tergite IX covered with dense short microtrichia on entire surface, median setae absent, 4–6 setae on each side of anal point (2–3 laterodorsal, 2–3 ventral); lateral teeth absent; tergite bands short, broadly separated ( Fig. 4A ). Anal point hyaline, slender, tapering toward narrowly rounded apex, without crests, bars or spinulae ( Fig. 4A, C, D ). Superior volsella 28–33 μm long, somewhat rhombus-shaped, posteriomedian part slightly projected, with small ventral lip; 3–5 setae dorsally 2 setae on median margin and 1 seta on anteroventral tubercle, microtrichia on dorsal surface absent; digitus well-developed, pointed, 16–20 μm long, reaching or extending slightly beyond posteromedian margin of superior volsella ( Fig. 4A, B, C, E ). Stem of median volsella simple, 15–18 μm long, with setiform and foliate lamellae ( Fig. 4B, F, G ). Inferior volsella 50–60 μm long, with slightly swollen and posteromedially directed distal part ( Fig. 4A, B ). Phallapodeme sinuous, 70–74 μm long; transverse sternapodeme 45–55 μm long, with well-developed oral projections. Gonocoxite 63–72 μm long. Gonostylus 52–60 μm long, slightly swollen at mid length, tapering to slender tip. HR 1.14–1.20, HV 3.20–3.70.

Female and immature stages. Unknown.

Taxonomy. The combination of characters given in the diagnosis of Tanytarsus kaxinawa is unknown among Tanytarsus males. Noteworthy is the structure of the anal point, slender, lacking spinulae or crests (the structures known from the majority of Tanytarsus ), as well as the shape of the superior volsella, more or less rhomboid, and the well-developed digitus ( Fig. 4 ). For comparison of Neotropical Tanytarsus with the slender and bare anal points see also T. pinedoi described below.

Geographical distribution and bionomics. Tanytarsus kaxinawa is known from the western Amazon in Brazil and Peru ( Fig. 1 ). The adult male specimens examined were obtained along with those of other five species described in the present paper. For further information on the ecology and bionomics refer to the notes on T. aries and T. chicomendesi (above).

Figures

FIGURE 1. Sites of sampling the type material in Peru (A, B) and Brazil (C, D).

FIGURE 4. Tanytarsus kaxinawa sp. nov., male. A, B: hypopygium in dorsal (A) and ventral aspect (B); C: anal point and superior volsellae in dorsal aspect; D: anal point in lateral aspect; E: superior volsella and digitus; F, G: median volsellae photographed (F) and drawn (G); C–G magnified × 1.5–3 relative to A and B; superior volsella in the drawings (red) with anteroventral tubercle (yellow), and digitus (green).