Orthocladius (Euorthocladius) annellae, Saether, Ole A., 2005

Saether, Ole A., 2005, A new subgenus and new species of Orthocladius van der Wulp, with a phylogenetic evaluation of the validity of the subgenera of the genus (Diptera: Chironomidae), Zootaxa 974, pp. 1-56 : 42-48

publication ID	https://doi.org/ 10.5281/zenodo.171314
DOI	https://doi.org/10.5281/zenodo.6266208
persistent identifier	https://treatment.plazi.org/id/03BF87F4-FF9C-257B-FE9E-FAB1065CFC96
treatment provided by	Plazi
scientific name	Orthocladius (Euorthocladius) annellae
status	sp. nov.

Treatment

Orthocladius (Euorthocladius) annellae View in CoL sp. n.

(Figs. 47–55, 66, 67)

Orthocladius (Euorthocladius) rivicola Soponis, 1990: 26 View in CoL , pro parte not Kieffer, 1911.

Type material

Holotype mature ɗ pupa, CANADA: Northwest Territories, FWI Pipeline Project,?Oscar Creek, 25 v 1972, det. A. Soponis as O. rivicola ( ZMBN Type No. 408). Paratypes: 5 ɗ, 1 Ψ, 1 ɗ reared from pupa, 2 mature ɗ pupae, 15 pupal exuviae; as holotype ( ZMBN)

Etymology

Named in honour of Annelle R. Soponis who has revised both the subgenus Euorthocladius , and the nominal subgenus, and has additional publications on this important genus.

Diagnostic characters

The male imago is separable from those of the other species of the subgenus Euorthocladius , except O. (E.) rivicola , by having uniserial scutellar setae , robust crista dorsalis, sensilla chaetica on ta1 of p2, low antennal ratio (1.0–1.2), virga present, and inferior volsella with ventral part extended relatively prominently below dorsal part (see Remarks). The female imago differs from those of O. (E.) rivicola and O. (E.) ashei by having smaller seminal capsules and completely straight spermathecal ducts. The pupa differs from those of other members of the subgenus by lacking posterior spines or hooklets on tergites II and III, no pedes spurii A on sternite VI, precorneals and dorsocentrals not spinelike and less than 30 spines on tergite VI. The larva is unknown.

Male imago (n = 9 except when otherwise stated)

Total length 2.66–3.13, 2.95 mm (7). Wing length 1.75–2.24, 1.95 mm (5). Total length/wing length 1.39–1.69, 1.53 (5). Wing length/length of profemur 3.02–3.08, 3.05 (5). Coloration light brown with vittae, lower part of preepisternum and postnotum blackish brown.

Head (Fig. 47). AR 1.02–1.23, 1.09. Ultimate flagellomere 394–529, 442 µm long. Temporal setae 13–18, 15; including 3–8, 6 inner verticals; 3–9, 6 outer verticals; and 1–6, 3 postorbitals. Clypeus with 7–12, 10 setae . Tentorium 131–173, 167 µm (6) long; 38–41, 39 µm (6) wide. Stipes 105–169, 131 µm (6) long; 23–49, 36 µm (6) wide. Palpomere lengths (in µm, n = 5–6): 36–41, 39; 53–71, 61; 86–128, 101; 71–98, 87; 120–150, 135.

Thorax (Fig. 48). Antepronotum with 3–5, 3 (7) setae . Dorsocentrals 7–14,10; acrostichals 0–5, 2; prealars 4–6, 5. Scutellum with 10–13, 12 setae , uniserial.

Wing (Fig. 49). Anal lobe moderately produced. VR 1.03–1.12 (2). Costa not extended. Brachiolum with 1 seta; R with 4–8, 5 setae ; other veins bare. Squama with 12– 21, 16 setae .

Legs (n = 5–6). Spur of front tibia 45–64, 55 µm long; spurs of middle tibia 23–34, 29 and 23–30, 27 µm long; of hind tibia 49–71, 66 and 23–26, 25 µm long. Width at apex of front and middle tibia each 36–43, 39 µm: of hind tibia 41–49, 46 µm. Pseudospurs present on ta1 and ta2 of mid and hind leg, 26–38 µm long. Sensilla chaetica 5–10, 7 at 0.06–0.11, 0.08 to 0.19–0.26, 0.23 of ta1 of mid leg; absent on of hind leg. Lengths (in µm) and proportions of legs:

Hypopygium (Fig. 50). Anal point including triangular base 41–54, 49 µm long; robust, tapering with rounded apex; with 10–17,12 setae including on base, some directed lateral and even anterior; laterosternite IX with 4–7, 6 setae . Phallapodeme 64–79, 68 µm long; transverse sternapodeme 83–105, 87 µm long, oral projections well developed. Gonocoxite 195–244, 205 µm long; superior volsella collarlike to rounded; inferior volsella with ventral part prominently extended beyond dorsal part. Gonostylus 94–109, 101 µm long; crista dorsalis apical, rounded; megaseta 8–11, 9 µm long. Virga 23–43, 32 µm long; consisting of cluster of about 5 spines. HR 1.93–2.24, 2.03; HV 2.63–3.15, 2.91 (7).

Female imago (n = 1)

Total length 4.10 mm. Wing length 2.08 mm. Total length/wing length 1.51. Wing length/length of profemur 3.33. Coloration not as dark as in male.

Head. AR 0.65. Flagellomere lengths (in µm): 79, 41, 38, 39, 128. Coronal suture 68 µm long. Temporal setae about 10, consisting of 5 inner and 5 outer verticals, postorbitals not observed. Clypeus with 8 setae . Tentorium 135 µm long, 24 µm wide. Stipes 139 µm long, 19 µm wide. Palpomere lengths (in µm): 38, 49, 90, 86, 135.

Thorax. Dorsocentrals 10, acrostichals 6, prealars 4, no supraalar. Scutellum with 12 setae .

Wing. Brachiolum with 1 seta; R with more than 8 setae , R1 with more than 2 and R4+5 with more than 3 setae . Squama with 14 setae . Other details not measurable.

Legs. Spur of front tibia 38 µm long, spurs of middle tibia 26 and 21 µm long, of hind tibia 53 and 19 µm long. Width at apex of front and middle tibia each 38 µm, of hind tibia 45 µm. Pseudospurs present on ta1 of mid leg and hind leg and ta2 of mid hind leg, 26–34 µm long. Sensilla chaetica 14 at 0.06–0.23 on ta1 of mid leg, 7 at 0.13–0.16 on ta1 of hind leg. Lengths (in µm) and proportions of legs:

Abdomen. Number of setae on tergites I–VIII as: 55, 36, 26, 26, 26, 22, 19, 17; on sternites I–VIII: 0, 2, 8, 10, 18, 17, 22, 15.

Genitalia ( Figs. 51–55 View FIGURES 51 – 65 ). Tergite IX strongly divided with margins clearly delimited, with 24 setae . Gonocoxite with 24 setae of which 12 are shorter. Cercus 143 µm long. Seminal capsule ovoid with 15 µm long sclerotised neck, 56 µm long, anterior 38 µm darker sclerotised, 28 µm wide. Spermathecal ducts completely straight with separate openings. Notum 124 µm long.

Pupa (n = 13–15 except when otherwise stated)

Total length 2.28–3.31, 2.94 mm. Exuviae pale greyish brown with area of tergite points blackish brown.

Cephalothorax. Frontal setae absent. Thoracic horn ( Fig. 67 View FIGURES 66 – 69 ) ellipsoid, clear, stalked, 34–60, 49 µm long; 19–26, 23 µm wide; 1.80–2.60, 2.04 times as long as wide; 1.00–1.62, 1.22 times as long as anal macrosetae. Precorneal setae respectively 68–94, 82 µm; 30–60, 39 µm; and 38–64, 52 µm long. Anterior dorsocentral (Dc1) 56–86, 68 µm (12) long; Dc2, 60–86, 71 µm; and Dc3 56–86, 67 µm long. Distances (in µm): Dc1–Dc 2 30–68, 42; Dc2– Dc 3 21–64, 41.

Abdomen ( Fig. 66 View FIGURES 66 – 69 ). Tergite I bare, tergite II with 2 weak anterior patches of spinules, tergites III–IX with stronger anterior patches. Sternites bare. Pedes spurii A and B absent. Caudal hooklets on tergite II absent. Posterior points on tergites IV–VIII in 2–3 rows.

Number of points on tergites IV–VIII in male as (n = 7–8): 9–29, 15; 14–34, 22; 11–22, 18; 10–18, 12; 8–14, 12. Number of points in female as (n = 7–8): 16–30, 23; 24–35, 31; 20– 27, 23; 17–21, 29; 19–21, 16. Segments II–VII each with 3 L setae , VIII with 2 L setae . L1 and L2 setae on segment VIII less than 25 µm long. No O setae .

Anal lobe 150–191, 160 µm long. Two strongly reduced anal macrosetae in distal half, 30–60, 38 µm long. Male genital sac overreaching anal lobe by 45–135, 101 µm (7); female genital sac overreaching anal lobe by 15 µm to ending 30 µm short of apex of anal lobe, mean 7 µm short.

Remarks

The description by Soponis (1990: 26) of O. (E.) rivicola includes O. (E.) annellae . At least some and probably all the specimens from the Northwest Territories and probably the specimens from Yukon and Alaska belong to the new species. The two species may perhaps be separated by O. (E) annellae having the ventral part of the inferior volsella more prominently extended below the dorsal part, as illustrated in Fig. 50 and Soponis (1990 Fig. 33 View FIGURES 28 – 34 c). However, several of the specimens of O. (E.) rivicola from Norway appear to have a nearly equally extended ventral part.