Heleniella helvetica J. Moubayed-Breil &amp; B. Lods-Crozet 2016, sp. n.
Creators: name: J. Moubayed-Breil
name: B. Lods-Crozet
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Heleniella
Heleniella helvetica

description: Heleniella helvetica sp. n. <b>Material examined: Holotype. Switzerland. Upper catchment of the Rhône River, springfed stream (tributary of the Mutt stream), crenal, altitude 2600 m, 1 male adult, leg. B. Lods-Crozet, 17.09.1997.</b> <b>Paratypes (all leg. B. L-C). Switzerland. Same locality as holotype and Mutt stream, 6 male adults, leg. B. Lods-Crozet, 19.09.1997.</b> <b>Holotype (on 1 slide) (GBIFCH 00190363) and 2 male paratypes (mounted on 2 slides)) (GBIFCH 0 0 190364 + GBIFCH00190365) are deposited in the collections of the ‘Musée cantonal de Zoologie, Palais de Rumine, 6 place de la Riponne, CH-1014 Lausanne, Switzerland. Remaining paratypes are deposited in the collection of the senior author’s. Type material was preserved in 75% alcohol, and later mount- ed in polyvinyl lactophenol. For each adult, the head, thorax and abdomen were cleared in 90% lactic acid before mounting on slides.</b> <b>Etymology: the new species is named <i>heloetica</i> after the name of ‘Swiss confederation’ given in Italian of the country of Switzerland, where the type material was collected.</b> Diagnostic characters <b>Adult male: Small sized species with a brownish general colouration. <i>H. heloetica</i> sp. n. closely resembles <i>H. extrema.</i> They are considered as sister species, which can be easily distinguished from all other members of the <i>Heleniella</i> genus in having an unusual twisted gonostylus, which is bearing a median prominence where is inserted the megaseta. However, the new species is separated from <i>H. extrema</i> and from the remaining <i>Heleniella</i> species by the following characters found in the male adult: - AR 0.50-0.51; thorax with 33-35 antepronotals, 40-45 dorsocentrals, 24-26 prealars, 16-17 episternals, 45-50 preepisternals and 42-44 scutellars; wing length 1.65-1.85; low value of the BR (PI, 1.83; PII, 1.50; PIII, 1.60); - virga very long (145-150 µm long), consisting of 2 long filaments; - tergite IX with semicircular margin, which is bearing 10-12 setae (5-6 on each side of the anal point); anal point conical, broad at base and paralle-sided medially; - inferior volsella long nose-like, projecting and bent downwards; - gonostylus unusually twisted and contorted, truncate proximally, broader and sub-rectangular distally with a truncate apex, magaseta placed medially on a cylindrical to cup-like projecting prominence, crista dorsalis absent.</b> Male imago (n = 5; Figures 1-3, 5-8, 11-15) <b>Small sized species. Total length 2.10-2.20 mm. Wing length 1.65- 1.85 mm. General colouration brown to dark brown with blackish head; antenna brown to dark brown; thorax brown to dark brown; mesonotal stripes distinct; legs light brown to brown, tarsomere of PI, PII and PIII darker than remaining tarsomeres; abdomen brown to dark brown, anal segment dark brown.</b> <b>Head (Figure 1). Eyes pubescent, inner eye margin bare; proximal part of eye enlarged, distal part narrowed downwards. Temporals consist of about 33-35 setae including 21-22 inner verticals and 10-11postorbitals; distal area of the eye bare. Palp 5-segmented; first palpomere weakly developed; length (µm) of palpomeres 20, 50, 75, 85, 115; sensilla clavata present on distal part of third segment. Antenna 13-segmented, 750-760 µm long; sensilla chaetica present on segments 2-3 and 13; antennal groove indistinct, beginning on segments 4-5 and reaching ultimate flagellomere; last flagellomere nearly clubbed apically, 250-260 µm long, remaining segments 500-510 µm long; AR 0.50-0.51. Thorax (Figures 2-3). All thoracic setae are decumbent except for the dorcentrals, which are arising from distinct pale spots. Acrostichals absent. Humeral pit as in Figure 2. Antepronotum densely covered with setae (33-35), antepronotal lobes in close contact; dorsocentral area densely covered with setae (about 55 setae in 1-3 rows), prealars 24-27 in 2-3 rows, episternals about 45-50, preepisternals about 40-45. Scutellum with 44 setae placed in 3-4 rows rows. Wing. Brachiolum with 2 setae. Distribution of setae on veins: R, 13-14; R</b> <b>1</b> <b>, 6-7; remaining veins bare. Squama bare. Legs. The low value of the BR ratio (1.50-1.83) apparently represents a consistent distinguishing character (PI, 1.83; PII, 1.50; PIII, 1.6). Tarsomere 5 of PI weakly shorter than tarsomere 4. Pulvilli apparently absent. Average length (µm) and proportions of legs:</b> <b>Abdomen. Hypopygium in dorsal, ventral and lateral view (Figures 5-8). Tergite IX broad and circular, anteromedian area bare, posterior area with 8-10 setae (4-5 placed on each side of the base of the anal point), posterior margin broadly expanded and bearing 10-12 setae (5- 6 on each side of the anal point). Anal point (Figures 5, 7, 8, 11) 23-25 µm long, maximum width 20-21 µm at base, minimum width 9-11 µm at apex, broad at base and narrowed distally, apex rounded in both dorsal (Figures 5, 11) and lateral view (Figures 7-8); presence of 3 setae on dorsal side and 6 on lateral side (3 on each side). Phallapodeme and sternapodeme as in Figure 6. Sternapodeme arc-like orally produced, lateral sternapodeme nearly vertical; phallapodeme 90-95 µm long, broadly linear basally and medially, hammer-like at base. Virga (Figures 5, 12) 145-150 µm long, consists of 2 fused long filaments elongated vertically. Gonocoxite 180-185 µm long, 45-50 µm wide, apex rounded to nearly truncate; basal margin sinuous, inferior volsella 7 5-80 µm long, maximum width 75 µm, minimum width 9 µm; long nose-like lobe shaped, rounded apically, bearing 5-7 setae dorsally and ventrally on distal part. Gonostylus (Figures 5, 8, 13-15) 75 µm long, maximum width 30 µm, unusually shaped, twisted and contorted; crista dorsalis absent. Megaseta 18 µm long, inserted medially on a cylindrical to cuplike prominence projecting on the anteromedian part of the gonostylus; the prominence is about 23 µm high and probably retractable.</b> <b>Larva: known but not described.</b> Taxonomic remarks <b>Male imaginal characters of <i>H. heloetica</i> sp. n. are nearly similar to those of <i>H. extrema</i>. These two species can be considered as sister species based on the following common characters: - both species are bearing an unusual gonostylus, which is twisted and characterized by the placement of the megaseta on its median part (Figures 5, 8 13-15 for <i>H. heloetica</i> sp.n.; Figures 10, 22 for <i>H. extrema</i>); - both species are confined to cold stenothermic high mountain streams (crystalline water for <i>H. heloetica</i> sp. n.; karstic water for <i>H. extrema</i>).</b> <b>The <i>extrema</i> -group is emended here as well as in Moubayed-Breil (unpublished data, 2016) according to the unusual shape of the gonostylus, which is contorted and bearing the megaseta medially. This group currently includes <i>H. extrema</i>, <i>H. heloetica</i> sp. n. and two additional new undescribed species known from glaciers located in C- Switzerland (<i>H.</i> sp. 1) and the Eastern Pyrenees, France (<i>H.</i> sp. A). However, <i>H. heloetica</i> sp. n. is easily distinguished from other members of the <i>Heleniella</i> genus and in particular from <i>H. extrema</i> by a combination of differentiating characters including: - AR 0.50-0.51; wing length 1.65-1.85; - distribution pattern of setae on tergite IX and anal point (Figures 5, 11), otherwise figured in <i>H. extrema</i> (Figure 9; Albu 1972, Figure 2); - anal point broadly rectangular at base and parallelsided medially (Figures 5, 11), while it is triangular and narrowed in <i>H. extrema</i> (Figure 9) and absent in <i>H.</i> sp. 1 (Figure 16); - phallapodeme broadly linear proximally and medially (Figure 16), thicker in <i>H. extrema</i> (Figure 10, 21) and sickle-like in <i>H.</i> sp. 1 (Figure 19); - virga composed of 2 fused long filaments (Figures 5, 12), differently shaped in <i>H.</i> sp. 1 (Figures 17-18); - inferior volsella long nose-like shaped and projecting downwards (Figures 5, 8, 15), broader and sub-rectangular in <i>H. extrema</i> (Figure 9); - gonostylus distinctly twisted (Figures 5, 8, 13-15) and bearing a cylindrical median prominence, differently figured in <i>H. extrema</i> (Figures 10, 22) and <i>H</i>. sp. 1 (Figure 20).</b>
description: Published as part of <i>J. Moubayed-Breil &amp; B. Lods-Crozet, 2016, Heleniella helvetica sp. n., a cold stenothermic species inhabiting the upper Rhône catchment in central Switzerland [Diptera, Chironomidae, Orthocladiinae], pp. 339-344 in Journal of Entomological and Acarological Research 48 (6026)</i> on pages 340-341, DOI: 10.4081/jear.2016.6026, http://zenodo.org/record/886181
description: {"references": ["ALBU P., 1972 - Doua specii de Chironomidae noi Pentru Stinta in Massivul Retezat. - Stud. Cercet. Biol. Ser. Biol. Anim. 24: 15 - 20."]}