Cladotanytarsus (Lenziella) bicornutus ( Kieffer, 1922 )

Giłka, Wojciech & Spies, Martin, 2012, Neotype designation for Cladotanytarsus (Lenziella) bicornutus (Kieffer), and first description of the distinctive female (Diptera: Chironomidae: Tanytarsini), Zootaxa 3545, pp. 83-88 : 84-87

Cladotanytarsus (Lenziella) bicornutus ( Kieffer, 1922)

Lenziella bicornuta Kieffer, 1922: 361 .

Cladotanytarsus wexionensis Brundin, 1947: 81 ; Thienemann (1951: 642).

Cladotanytarsus (Lenziella) bicornutus ( Kieffer, 1922) : Giłka (2011: 4) .

Material examined. Neotype, designated below; slide-mounted ( Fig. 1), deposited at ZSM: adult male; GERMANY, Mecklenburg-Vorpommern, lower Peene river between Anklam and Peenemünde, 1941 or 1942 (see Thienemann 1951: 633), leg. F.W.C. Krüger.

Additional material (same data as neotype, except as follows): 2 adult males (deposited at DIZP) , 1 pharate male ( ZSM), 4 adult females (3 DIZP, 1 ZSM), 1 pharate female ( ZSM) , 5 pupal exuviae (2 DIZP, 3 ZSM).

Designation of neotype. A neotype fixation for Lenziella bicornuta Kieffer, 1922 is necessary to define objectively not only this species name but also the genus-group name Lenziella Kieffer, 1922 , for which the former serves as the type species. Therefore a neotype is designated here, with the following particulars (as required in ICZN 1999: Article 75.3).

(1) The neotype is designated to permanently clarify the taxonomic status of the nominal taxon Cladotanytarsus bicornutus (Kieffer) .

(2) Character-state combinations differentiating the known life stages of C. bicornutus from those of other taxa are given in Giłka (2011) and below.

(3) The specimen designated is identified above (see "Material examined").

(4) The original type material of Lenziella bicornuta Kieffer consisted of a single male caught (not reared) by A. Thienemann in Germany, Schleswig-Holstein, at Passader See [a lake east of Kiel] on 12 May 1921. These data are documented beyond doubt by entries of Kieffer's and Thienemann's on the original letter sheet exchanged along with the material (preserved at ZSM under letter code T 24/7), and by entry of Thienemann's on the species-specific sheet in his personal taxon register ( ZSM register code 1992). The (absence of) evidence in the literature strongly suggests that no one other than Kieffer ever studied that holotype, and there has been no trace of it in the collections known to contain what little has been preserved of Kieffer's specimens of Chironomidae (e.g. ZSM; Institut royal des Sciences naturelles de Belgique, Brussels; Museum national d'Histoire naturelle, Paris; Senckenberg Deutsches Entomologisches Institut, Müncheberg). Therefore, the holotype must be considered as lost.

(5) The neotype and the current species concept it represents are consistent in morphology with what is known of the holotype from the original description; see also Giłka (2011).

(6) Krüger's study area on the lower Peene river lies a little under 300 km east of Passader See, and in similar proximity to the German coastline along the Baltic Sea. No source of extant specimens of C. bicornutus is known that would be closer to the original type locality.

(7) The neotype is the property of ZSM, a recognized scientific institution that houses and permanently preserves numerous name-bearing types and other zoological voucher specimens.

Description of adult female. General dimensions. Total length 2.50–2.95 mm; abdomen stout, elongate ( Fig. 2A). Wing length 0.86–0.95 mm. Total length / wing length ratio c. 2.7–3.4 (emerged specimens).

Colouration (in alcohol). Similar to that of relatively light-coloured males; see Giłka (2011). Antennal pedicel, tentorium, scutal stripes, postnotum and sternum light brown. Eyes reddish brown. Other parts of body yellowish green to pale brownish. Wing transparent, with membrane slightly darker at apex ( Fig. 3A).

Head ( Fig. 2B–D). Eyes small, oval, broadly separated, with short pubescence at ventromedial margins. Frontal lobes wide, bearing 5– 12 µm long tubercles. Antennal flagellum composed of 4 or 5 segments, with proximal flagellomeres fused in part or separated ( Fig. 2C); AR 0.49–0.60. Palp short, variable ( Fig. 2B, D); lengths of palpomeres 2–5 (µm): 20–24, 34–48, 36–48, 79–95. Clypeus elliptic or lens-shaped, with 15–23 strong setae.

Thorax chaetotaxy. Setae and their sockets weak, poorly observable. Ac 5–12; Dc 7–8(?), only posterior setae and/or tubercles well developed; Pa 1–2; Scts 4 in single row, outermost pair minute.

Wing ( Fig. 3A). Somewhat cuneiform, bevelled or slightly concave at apex, broadest at 2/3 length. Veins bare except C, R, R 1 and distal half of R 4+5; membrane completely bare.

Legs. Short but stout, as in male. Tibial spurs absent; single combs observed only on hind legs, vestigial, composed of 3–4 short teeth. Tibial apices of middle and hind leg as in male (see Giłka 2011: fig. 2C, D, variations drawn in full), enlarged, covered with relatively short setae on mid leg, and with tuft of long and finely bent setae on hind leg. Fourth tarsomere shorter than fifth (p 2, p 3), third tarsomere longer than second (p 3). For lengths of leg segments and leg ratios, see Table.

Genitalia ( Fig. 3B). Gonocoxite with 1–3 setae. Tergite IX broadly subtriangular to semicircular, with 12–30 setae; lateral teeth bifid. Sternite VIII with 24–44 stout setae in extensive central field, and 6–8 weaker setae in a pair of rows close to margins of vaginal floor. Gonapophysis VIII single-lobed, extensive, its caudomedial margins broadly rounded, converging to moderately wide floor covering about one-fourth of anterior part of vagina, with dense and numerous microtrichia directed posteromedially. Rami robust, tapering to 91–99 µm long notum. Labia wide, with parallel posteromedial margins, broadly rounded caudally, reaching posterior margin of SVIII. Gonocoxapodeme almost straight or slightly curved. Coxosternapodeme angular, with well developed medial lobes connected by sinuous transverse bridge. Seminal capsules ovoid, the larger one 60–79 µm long and 52–64 µm wide, the smaller one 56–67 µm long and 48–60 µm wide, with necks in posterolateral positions; spermathecal ducts strongly curved, 205–255 µm long. Postgenital plate triangular. Cercus 70–75 µm long, roundish, with dorsomedial lobe extending slightly beyond ventromedial margin.