Tanytarsus alaidae, Trivinho-Strixino, Susana & Shimabukuro, Erika Mayumi, 2017

Trivinho-Strixino, Susana & Shimabukuro, Erika Mayumi, 2017, Tanytarsini (Diptera: Chironomidae) from madicolous habitat in Southeast Brazil: new species and new records, Zootaxa 4269 (3), pp. 427-437 : 429-433

Tanytarsus alaidae sp. n.

Type material. Holotype male, Brazil, Minas Gerais State, Passa-Quatro, Pedra da Mina Mountain , 22˚25'410''S/ 44˚50'380''W 2575 m a.s.l., madicolous habitat, on rocks at the banks of a stream, leg E.M. Shimabukuro, G. Perbiche-Neves, V. Saito. 14.x.2014 (A3-40, LEIA-UFSCar).

Etymology. Named in honour of Dr. Alaide Fonseca Gessner, a friend and great researcher of Brazilian aquatic insects.

Diagnostic characters. Tanytarsus alaidae sp. n. can be distinguished from other Tanytarsus species by the combination of the following characters: abdominal tergite without setae; anal point large, without crests but with setae on median part. Superior volsella semi oval with short projection on distal posterior margin; digitus very long, finger-like, extending beyond posterior margin of superior volsella.

Description. Adult male (n = 1). Small, total length 2.51 mm. Wing length 1.69 mm.

Coloration: Head, flagellum and maxillary palp yellowish. Thorax, abdomen and legs yellow.

Head: AR 0.30. Total length of antenna 744 µm. Eyes without dorsomedian extension; temporals 7; clypeus with 10 setae. Palpomeres deformed and not measured.

Thorax: Length 0.77 mm. Scutal tubercle absent; acrostichals 7, biserial, beginning near antepronotum; dorsocentrals 6; prealar 1; scutellars 4.

Wing: 0.42 mm wide, VR= 1.25. Wing membrane with few setae on distal portion. All wing veins setose.

Legs: Fore leg tibia bearing single spur, 28 µm long. Mid leg tibia bearing two pectinate spurs, 18; 26 µm long and two separated combs. Hind leg tibia bearing two pectinate spurs, 26; 32 µm long and two separated combs. Lengths and proportions of the legs as in Table 2.

Hypopygium ( Fig. 2 a): Tergite IX without apical and median setae. Orolateral spine of laterosternite IX absent. Anal tergal bands V-type. Anal point 80 µm long, rounded at tip and with 6 spines in anteromedian part; anal crests absent. Superior volsella 89 µm long and 46 µm wide ( Fig. 2 b). Digitus elongate 94 µm long, extending beyond posterior margin of superior volsella ( Fig. 2 b). Median volsella as in Figure 2 c. Gonocoxite length 77 µm long; gonostylus 103 µm long, somewhat elongate and slender; hypopygium ratio (HR) 0.74.

Remarks. T. alaidae sp. n. also shares the absence of anal crest and V-type anal bands with other Neotropical species reviewed by Sanseverino op.cit. The main differential characteristic is the setae in the middle of the anal point, the shape of digitus which extends below the lower margin of superior volsella and the shape of median volsella.

The type material was collected with emergence traps at the edges of a first order stream at approximately 2,500 m a.s.l.

Tanytarsus alienus sp. n.

Type material. Holotype male, Brazil, Minas Gerais State, Passa-Quatro, Pedra da Mina Mountain , 22˚25'410''S/ 44˚50'380''W 2575 m a.s.l., madicolous habitat, rock marginal to a stream, leg E.M. Shimabukuro, G. Perbiche- Neves, V. Saito. 14.x.2014 (A3-37, LEIA-UFSCar). 1 Paratype female, same data as holotype (A3-38, LEIA- UFSCar).

Etymology. From Latin “ alienus ” (different) in reference to unusual characteristics on the male and female head.

Diagnostic characters. The male of Tanytarsus alienus sp. n. can be distinguished from other Tanytarsus species by the combination of the following characters: hairy eyes; strong sclerotized process in the head, which differs from current known frontal tubercles. Anal tergite bands separate; anal point with crests. Hypopygium with wide and robust gonocoxite and gonostylus.

Description. Adult male (n = 1) Small, total length 2.72 mm. Wing length 1.66 mm.

Coloration: Head and thorax brown, flagellum and maxillary palp, abdomen and legs yellowish in slide preparation.

Head: Antenna 681 µm long, with 12 flagellomere. AR 0.35. Eyes with large dorsomedian extension and hairy ( Figs 3 a, b); temporal 6; clypeus with 10 setae. Prominent cephalic process 48 µm long and 35 µm large ( Fig.3 a). Palpomeres 2–4 with 28, 109, 63 µm.

Thorax: Length 0.72 mm. Scutal tubercle absent; acrostichals 6, biserial, dorsocentrals 6, prealar 1, scutellars 4.

Wing: 0.42 mm width, VR= 1.48. Wing membrane with setae on distal portion. All wing veins setose. Legs: Fore leg bearing single tibial spur, 28 µm long. Mid leg tibia bearing two pectinate spurs, 15; 34 µm long and two separated combs. Hind leg tibia bearing two tibial pectinate spurs, 15; 36 µm long and two separated combs. Lengths and proportions as in Table 3.

Hypopygium ( Fig. 4 a): Tergite IX without apical and median setae. Orolateral spine of laterosternite IX absent. Anal tergal bands V-type. Anal point 51µm long, large and rounded at tip; anal crests present. Superior volsella near 50 µm long and 40 µm wide. Digitus short, extending weakly beyond the inner of margin of superior volsella. Median volsella as Figure 4 . Gonocoxite length 62 µm long; gonostylus 100 µm long, somewhat elongate and slender; hypopygium ratio (HR) 0.62.

Adult female (n=1). Small. Wing length 1.60 mm.

Coloration: Head and thorax brown; abdomen and legs yellowish in slide preparation.

Head: Antenna lost. Eyes hairy with short dorsomedian extension; temporal 6; clypeus with 13 setae Palpomeres 2–5 with 15, 81, 81, 125 µm.

Thorax: Length 1.92 mm. Scutal tubercle absent; acrostichals 4, dorsocentrals 9, prealar 1, scutellars 3.

Wing: 0.47 mm width, VR= 1.61. Wing membrane with setae on distal portion. All wing veins setose.

Legs: Fore leg bearing single tibial spur, 26 µm long. Mid leg tibia bearing two tibial pectinate spurs, 21; 31 µm long and two separated combs. Hind leg tibia bearing two pectinate spurs, 28; 34 µm long and two separated combs. Lengths segments distorted and not measured.

Genitalia ( Fig.4 b). Sternite VIII bearing 12 setae distributed regularly, on each side. GcaVIII curved, running diagonally to posterior corner of SVIII. SVIII form a short floor under anterior part of vagina; posteromedian contour of SVIII rounded. GpVIII long, and covered with caudolateral microtrichia. Notum long, 143 µm, 5 times longer than free rami. Seminal vesicles ovoid, near 65 µm long, without neck. Spermathecal duct not discernible in slide preparation. GcIX without setae. Postgenital plate short, triangular, slightly larger than long. Cerci near 54 µm long.

Remarks. The main characteristics that differentiate T. alienus sp. n. are the hairy eyes present in both male and female head (uncommon among Tanytarsini tribe and not yet registered in Tanytarsus ) and the large sclerotic process in male’s head that does not appear to be the frontal tubercle. In addition, the presence of the robust hypopygium with strong gonocoxite and gonostylus seems also unusual. The presence of anal tergal bands V-type and anal crest with only 1 spine present in T. alienus is also observed in T. monospinosus Ekrem & Reiss 1999 and T. jacaretingensis Sanseverino 2006 but the hairy eyes in T. alienus is sufficient to differentiate from these species.

Figures

FIGURE 2. Tanytarsus alaidae sp. n. a. Hypopygium, left dorsal view, right dorsal view, tergite IX removed. b. Median volsella. c. Superior volsella.

FIGURE 3. Tanytarsus alienus sp. n. a. Head, with indication of dorsal process. b. Detail of the eyes view with indication of the hairs.

FIGURE 4. Tanytarsus alienus sp. n. a. Male hypopygium, left dorsal view, right dorsal view, tergite IX removed. b. Female genitalia, ventral view