Thienemanniella biobio, Wiedenbrug, Sofia, Lamas, Carlos E. & Trivinho-Strixino, Susana, 2013

Wiedenbrug, Sofia, Lamas, Carlos E. & Trivinho-Strixino, Susana, 2013, A review of Neotropical species in Thienemanniella Kieffer (Diptera, Chironomidae), Zootaxa 3670 (2), pp. 215-237 : 216-220

Thienemanniella biobio sp. n.

( Fig. 1 )

Type material. Holotype pharate male with pupal exuviae; CHILE, Concepción, nr. mouth of Rio Bio Bio, 2003, R. Barahona, P. Camus.

Diagnostic characters. The male of Thienemanniella biobio sp. n. can be differentiated from other species by having the antenna with 12 flagellomeres, AR=0.55; transverse sternapodeme narrow, without oral projections; inferior volsella low, rectangular, placed basally on gonocoxite, with straight posterior margin. The pupa differs from other neotropical species by the homogeneous tergite shagreen, with posterior spinules as large as median spinules, shagreen spinules longer on posterior tergites; tergal conjunctive VII/VIII with few small spinules, segments III–VIII with 4 taeniate lateral setae each; anal lobe rounded, with complete fringe.

Etymology. Named after the Bio Bio river, where the specimen was collected. The specific epithet is treated as a noun in apposition.

Description. Pharate male (n = 1)

Thorax length 0.60 mm.

Head. AR = 0.55. Antenna with 12 flagellomeres, apical flagellomere 152 µm long. Eyes hairy.

Thorax. Antepronotal lobes dorsally tapering.

Legs. Fore and hind trochanter with dorsal keel. Hind tibial scale 7 µm long, with a short spur and seta ( Fig. 1 A).

Tergites. TI and TVIII with 2 setae, TII and TIV with 4, TIII with 5, TV–VII with 3 setae.

Hypopygium ( Fig. 1 B–C). Tergite IX with 6 small setae. Laterosternite IX with one seta. Superior volsella small and triangular. Inferior volsella rectangular, ending at approximately 2/3 of the gonocoxite length. Transverse sternapodeme narrow, 17 µm long. Gonostylus long, without crista dorsalis.

For measurements, see Table 1 .

Pupa (n = 1). Total length 1.52 mm.

Cephalothorax. Frontal apotome slightly rugose. Thorax suture with very fine rugosity, with a smooth hump in the region corresponding to adult scutellum. Dc-setae in two pairs. Wing sheaths without pearl rows.

Abdomen. Tergite I and sternites impossible to observe in detail; sternite II without long spinules. Tergite II with few short shagreen points; tergites III–IV with homogeneous shagreen of short points; tergites V–IX with homogeneous shagreen of longer spinules ( Fig. 1 D–F). Conjunctives between tergites III/IV–VI/VII and between sternites IV/V–VII/VIII with small spinules. Segment II with 3 lateral setae, L2 slightly taeniate. Segments III–VIII with 4 lateral taeniate setae each. Anal lobe rounded, with almost complete fringe, 3 macrosetae and 1 medial seta, all taeniate.

For measurements, see Table 3 .

Remarks. The pharate male was collected near the mouth of the Bio Bio river, where salinity was approximately 3‰.

In the key for the Nearctic region ( Hestenes & Saether 2000) the male and the pupa of T. biobio sp. n. run to T. xena (Roback) . However, the narrow sternapodeme without oral projections and the inferior volsella with straight posterior margin distinguish T. biobio from T. xena . The diagnostic characters given separate this species from all other known species ( Makarchenko 2006; Fu et al. 2010a, 2010b; Fu & Saether 2012).

Species T. biobio T. manihuales T. medialis T. sancticaroli T. ubatuba sp. n. sp. n. Sublette & Sasa sp. n. sp. n.

Type material. Holotype pharate male with pupal exuviae; CHILE, Region XI, Carretera austral, Rio Manihuales , La balse, 45°13.210´S, 72°12.775´W, 158 m a.s.l., 21.III.1999, T. Andersen, ZMBN No. chi 4451.

Diagnostic characters. The male of T. manihuales is characterized by the antenna with 12 flagellomeres, AR 0.50; laterosternite IX with 7 setae; the shape and relatively proximal position of the inferior volsella; and the wide sternapodeme with oral projections. The pupa has wing sheath apex with pearl rows; tergites II–VIII with fine shagreen and posterior row of strong and wide spines; anal lobe with almost complete fringe, with about 60 setae.

Etymology. Named after the Manihuales river, where the specimens were collected. The specific epithet is treated as a noun in apposition.

Description. Male (n = 1)

Head. AR = 0.50. Antenna with 12 flagellomeres, apical flagellomere 177 µm long. Eyes hairy.

Thorax. Antepronotal lobes dorsally tapering.

Legs. Fore and hind trochanter with dorsal keel. Hind tibiae without scale, with a short spur and a seta ( Fig. 2 A).

Tergites. TII with 6 setae, TIII–VIII with 4 setae. Sternites III–VIII with one seta.

Hypopygium ( Fig. 2 B–C). Tergite IX with 17 setae. Laterosternite IX with 7 setae. Anterior margin of gonocoxite, with short setae on a low and rounded lobe; inferior volsella positioned basally on gonocoxite, strong, triangular with rounded apex. Transverse sternapodeme wide with oral projections; phallapodeme strongly curved to posterior.

For measurements, see Table 1 .

Pupa (n = 1). Cephalothorax. Thorax slightly rugose. All Dc-setae non-taeniate, grouped in two pairs; Dc1 and Dc4 stronger. Wing sheath apex with pearl rows ( Fig. 2 D).

Abdomen ( Fig. 2 E–G). Tergites II–VIII with fine shagreen and a posterior row of strong spinules with wide bases. Sternites II–VIII with shagreen slightly increasing in size posteriorly. Conjunctives between tergites III/IV– VI/VII and between sternites IV/V–VII/VIII with small spinules. Segment II with 4 L-setae, III-VIII with 4 long, taeniate L-setae. Anal lobe slightly triangular, with complete fringe, 3 taeniate macrosetae and 1 taeniate medial seta.

For measurements, see Table 3 .

Remarks. The shape and position of the inferior volsella in T. manihuales sp. n. resembles the condition commonly found in the genus Onconeura . The rugosity on the pupal wing sheath apex is similar to pearl rows as found in Corynoneura . However, the combination of hairy eyes, fore trochanter keel without dorso-posterior step (see discussion section), apex of hind tibia without scale, and pupa with rounded anal lobe with three macrosetae is characteristic for Thienemanniella .

Material from Chile, Region XI, Puerto Aisen, (one pharate male and several pupal exuviae) deposited in ZMBN was also examined. The pharate male hypopygium is similar to that in T. manihuales sp. n., but the inferior volsella is smaller. The pupa has the spines in the posterior row on the tergites narrower than in T. manihuales sp. n. Unfortunately, this pharate male is not in sufficient condition to be described.

Figures

FIGURE 1. Thienemanniella biobio sp. n. A – C. Adult male. D – F. Pupa. A. Apex of hind tibia. B. Hypopygium, general view. C. Hypopygium with tergite IX removed, internal sclerites hatched; left: dorsal view, right: ventral view. D. Tergites II – III. E. Tergite IV. F. Tergites VII – IX and anal lobes in ventral (left) and dorsal view (right).

FIGURE 2. Thienemanniella manihuales sp. n. A – C. Adult male. D – G. Pupa. A. Apex of hind tibia. B. Hypopygium, general view. C. Hypopygium with tergite IX removed, internal sclerites hatched; left: ventral view, right: dorsal view. D. Wing sheath apex. E. Abdominal segment II; left: sternite, right: tergite. F. Tergite IV. G. Tergites VII – IX, anal lobes in ventral (left) and dorsal view (right).

Tables

TABLE 1. Mensural characters of adult males of neotropical Thienemanniella species; measurements in µm.

Character Thorax length	(n = 1) 600	(n = 1) –	(n = 1) –	(n = 1) –	(n = 3) 510–530
Abdomen length		–	–	–	670–1075
AR	0.55	0.50	0.35	0.45	0.33–0.38