Nilotanypus yanomami, Shimabukuro & Dantas & Lamas, 2021

Shimabukuro, Erika Mayumi, Dantas, Galileu P. S. & Lamas, Carlos José Einicker, 2021, A new madicolous species of Nilotanypus Kieffer (Diptera: Chironomidae) from Amazon region, northwestern Brazil, Zootaxa 4948 (3), pp. 431-438: 432-436

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Nilotanypus yanomami

sp. n.

Nilotanypus yanomami   sp. n.

Type material. Holotype male, BRAZIL, Amazonas State , PARNA Pico da Neblina, Bebedouro Velho, slide #95_ E400, 00°41’55”N, 65°55’42”W, 412 m a.s.l., 19.vii.2019, emergence trap, EM Shimabukuro ( MZUSP) GoogleMaps   . Paratypes: pupa with pharate male, same as holotype, except for slide VAR400, D-net (250 µm-mesh) GoogleMaps   ; larva, same as holotype, except for slide #212_E400, D-net (250 µm-mesh) GoogleMaps   .

Etymology. The specific epithet honors the Yanomami people, who lives at this Amazon territory and have been constantly struggling to protect the forest. The name should be treated as a noun in apposition.

Diagnosis. The male of Nilotanypus yanomami   sp. n. can be easily segregated from his congeners by the low AR (0.34), the absence of pseudospurs on fore and mid tarsi, the abdomen uniformly pale and the presence of only two setae in tergite IX. The pupa of the new species is completely pale and present an elongate thoracic horn with a large corona, extending for about ¾ of the thoracic horn length. The larva present one pectinate claw with 11 equal-sized spines, the apical tooth of mandibula is long and slender, the abdomen is pale with brown spots, and the cephalic index is about 0.6.

Description. Male (n=1). Total length 1.55 mm. Wing length 0.77 mm. Total length/wing length 2.02. Wing length/length of profemur 2.86.

Coloration. Head including antenna brown, last flagellomere darker than others. Thorax brown, scutum darker. Abdomen uniformly pale. Legs pale brown. Wing without marks.

Head. AR 0.34, ultimate flagellomere 40 μm long ( Fig. 1B View FIGURE 1 ), apical seta 68 μm long. Temporal setae 15. Clypeus with 14 setae. Tentorium 74 μm long, 12 μm wide. Palpomeres 1–4 lengths (in μm): 20; 23; 42; 80, last palpomere not measurable.

Wing ( Fig. 1A View FIGURE 1 ). VR 0.81. WW 0.36. Maximum wing width 0.28 μm. Wing membrane covered with setae. All veins densely covered with setae, R with 27; R 1 with 30; R 4+5 with 36; M with 2; M 1+2 with more than 70 setae; Cu with 8; M 3+4 with more than 40 setae; Cu 1 with 38 setae. Brachiolum with 2 setae. Squama with 12 setae.

Thorax. Antepronotal 1, lateral; dorsocentrals 17, starting close to antepronotum; acrostichals 19, irregularly biserial, starting close to antepronotum; prealars 8, anterior group with 3 setae and posterior group with 5 setae; supraalar 1. Scutellum with 5 setae.

Legs. Apex of fore tibia 20 μm wide, apex of mid tibia 15 μm wide, apex of hind tibia 23 μm wide. Spur on fore tibia 32 μm long ( Fig. 1C View FIGURE 1 ); fore tarsi lost in the holotype but visible in the pharate male, without pseudospurs. Spur on mid tibia 52 μm long ( Fig. 1D View FIGURE 1 ), spur on hind tibia 55 μm long ( Fig. 1E View FIGURE 1 ); comb on hind tibia with 6 setae ( Fig. 1E View FIGURE 1 ), longest seta 32 μm long, shortest seta 23 μm long. Mid tarsi without pseudospurs. Lengths (in μm) and proportions of legs as in Table 1 View TABLE 1 .

Hypopygium ( Fig. 1F–G View FIGURE 1 ). Posterior margin of tergite IX concave, with one seta on each side ( Fig. 1F View FIGURE 1 ). Anal point conical. Phallapodeme 35 μm long ( Fig. 1G View FIGURE 1 ). Transverse sternapodeme 72 ( Fig. 1G View FIGURE 1 ). Gonocoxite 57 μm long, internal margin dorsally concave. Gonostylus 42 μm long, curved, simple and slender; megaseta 8 μm long ( Fig. 1F View FIGURE 1 ). HR 1.37. HV 3.73.

Female. Unknown.

Pupa (n=1). Total length 1.68 mm (abdomen and thorax of male).

Coloration. Cephalothorax and wing sheath pale; abdomen pale.

Cephalothorax. Frontal apotome subtriangular, apically pointed ( Fig. 2B View FIGURE 2 ), 94 μm wide at base. Wing sheath smooth, 488 μm long, 206 μm maximum width. Thoracic horn elongated, rounded at apex, external membrane covered with scattered spines ( Fig. 2C View FIGURE 2 ), 128 μm long, 34 μm maximum width. Corona well developed, 94 μm long, 26 μm maximum width. Respiratory atrium occupying most of the thoracic horn volume. Basal lobe 9 μm long; thoracic comb composed by 19 tubercles.

Abdomen. First abdominal segment 89 μm long partially damaged, only some small lateral spines visible. Sternite II with a posterior row of small spines; SIII–VIII with a posterior row of triangular spines, which are larger and tapered in SVIII; shagreen apparently absent in SI–SVIII. Tergites II–VII anteriorly with small, scattered spines; posteriorly the small spines are arranged in 3 to 4 rows and followed by a caudal row of triangular strong spines. Tergite VII with 1 LS setae on each side of the segment situated in the posterior half ( Fig. 2A View FIGURE 2 ). Tergite VIII with 5 lateral filaments, distal margin straight ( Fig. 2A View FIGURE 2 ). All segments with small scattered lateral spines. Anal lobe as in Figure 2A View FIGURE 2 , 140 μm long, 117 μm wide at base, with 2 lateral macrosetae; Genital sac well developed, 234 μm long, 85 μm wide at base ( Fig. 2A View FIGURE 2 ), surpassing the apex of anal lobe in 94 μm. GS/AL 1.67.

Larva (n=1). Coloration. Head pale yellow; antenna, maxillary palps and mandible yellow, apical teeth of mandibula gradually darkened towards the apex; ligula brown. Abdomen pale with brown spots; procercus pale; anal, sub-basal and supra-anal setae all yellow; claws of posterior parapods yellow.

Head ( Fig. 2D View FIGURE 2 ). Head capsule narrow with smooth surface, 328 μm long; cephalic index 0.6. Ventral chaetotaxy as in Figure 2D View FIGURE 2 . Ventrally, SSm located far posterior to S9 and S10; VP large and oval-shaped, posterior to S10, which in turn is posteromedial to S9. S9 simple, S5, S7, S8, S10 and SSm missing. Dorsal chaetotaxy distorted.

Antenna. A 1 126 μm long, 9 μm maximum width, ring organ placed 89 μm from base. Remaining segments missing.

Maxilla. Basal palpomere 8 μm long and 5 μm wide, ring organ not observed. A 1 / P 1 16.4.

Mandible ( Fig. 2E View FIGURE 2 ). Strongly curved apically, gradually narrowed towards apex, 35 μm long. Apical tooth slender, 11 μm long; inner tooth small and conical; seta subdentalis 3 μm long. A 1 /MD 3.57.

Mentum and M appendage   . Dorsomental teeth absent. M appendage   rounded apically.

Hypopharyngeal complex ( Fig. 2F View FIGURE 2 ). Ligula 29 μm long, 15, 9 and 15 μm wide at apex, middle and base respectively, with 5 teeth; muscle attachment 11 μm long. Paraligula bifid, 11 μm long.

Body. Posterior parapods with a single pectinate claw 34 μm long, with 11 inner equal-sized spines, 4 μm long ( Fig. 2H View FIGURE 2 ). Posterior parapods with a simple strong sub-basal seta 69 μm long, distally broken ( Fig. 2G View FIGURE 2 ). Procercus 35 μm long ( Fig. 2G View FIGURE 2 ), 9 μm wide at base, with 7 anal setae, all broken; L/ W 3.83. Supraanal seta 138 μm long, distally broken ( Fig. 2G View FIGURE 2 ). Anal tubules markedly elongate and thin, 300 μm long ( Fig. 2G View FIGURE 2 ).

Distribution and ecological notes. Nilotanypus yanomami   sp. n. is known only from the type-locality at Pico da Neblina (Neblina Peak), Northern Amazonia, and along with N. pusillus Andersen & Pinho   and N. urubici Andersen & Pinho   encompasses the Neotropical species of the genus ( Fig. 3 View FIGURE 3 ). Despite the intensive field work and sampling effort—using light, Malaise and emergence traps from base, at 100 m a.s.l., to summit, at 2900 m a.s.l., of Neblina Peak— Nilotanypus yanomami   sp. n. was only found at a single small stream at 400 m a.s.l. Neblina Peak is the highest mountain of Brazil, and belongs to one of the oldest geological formations in the world, the Guiana Shield ( Hammond 2005). However, due to extreme spatial isolation, few researches on biodiversity have already been developed at the region.

The male was collected with an emergence trap developed for madicolous habitat ( Shimabukuro et al. 2015). At the same locality, the larva was removed from the rocky substrate using a D-net. The immature stages of Nilotanypus   are known to occur in small streams with cold water and good water quality, frequently associated to sand substrate ( Roback 1986). Although immatures can be occasionally found in rock substrates, this is the first time that a species is evidenced in madicolous biotope. The madicolous habitat where the specimens were found was characterized by exposed wet rocks emerging from the stream bed. The stream was shallow, with low water flow and sand deposits. The water temperature was about 22 ºC, dissolved oxygen 8 mg.L- 1, conductivity 23 µS. cm-1 and pH 6.5.

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

  Fe Ti ta1 ta2 ta3 ta4 ta5 LR BV SV
P1 269 228
P2 344 219 344 100 81 53 50 1.57 3.19 1.64
P3 344 300 294 131 106 72 53 0.98 2.59 2.19