Olecryptotendipes secundus ( Zorina, 2003 )

Orel, Oksana V., 2022, Additional data on Olecryptotendipes secundus (Zorina, 2003) from Russian Far East, with a description of preimaginal stages (Diptera: Chironomidae), Zootaxa 5205 (1), pp. 87-96 : 88-95

Olecryptotendipes secundus ( Zorina, 2003)

Figs. 1–29 .

Cryptotendipes secundus Zorina, 2003: 221 , Figs. 1–2

Olecryptotendipes secundus ( Zorina, 2003) , Zorina, 2007: 350, Figs. 1–17

Material examined. Male, Russia, SAKHALIN ISLAND, Rybnoe Lake near Nogliki Village , 27.vii.2002 (E. Makarchenko) (Holotype) ; males, KHABAROVSK TERRITORY, Sunny region, Amur River basin, spring, near the city of Amursk , 12.vi.2010 (leg. I. Tiunov); pupa with larval exuviae, same data, Amur River near the village of Nizhneleninskoye , 01.vi.2018 (leg. S. Kulbachny); pupa, N 48⁰44.827 ’ E 135⁰26.607 ’, same data, the Amur River below the city of Khabarovsk and above the Noevskaya channel, 05.vi.2018 (leg. O. Kudrevsky); 2 pupae, N 48⁰44.894 ’ E 135⁰26.669 ’, same data, the Amur River below the city of Khabarovsk, 06.vi.2019 (leg. S. Kulbachny); larva, AMUR REGION, mouth of the Selemdzha River , 19.ix.2008 (leg. T. Tiunova) .

Description

Male imago (n = 3).

General colour yellowish. Total length 3.5–4.7 mm; total length/wing length 1.89–3.26.

Head ( Fig. 1 ). Frontal tubercles absent. Temporal setae 11–16. Clypeus with 6–10 setae. Maxillary palp brown, lengths of last 4 palpal segments (µm): 33–55, 81–121, 90–132, 132–165. Palp length/head width 0.78. Scapus yellowish brown, flagellomeres (1–11) dark-brown, 880–1210 µm long. AR 1.75–1.89. Antenna length/palp length 2.49–2.62.

Thorax. Ground colour of scutum pale yellow, mesonotal strips yellow. Aps 0–1, Ac 0, Dc 5–7, Pa 2–4, Su 1–2. Scutellum pale yellow, with 6–8 setae. Postnotum in distal 2/3 dark brown.

Wings. Wing length 1.44–1.85 mm. Squama with 1–5 setae. R, R 1 without setae, R 4+5 with 2 apical setae. VR 1.11. Haltere pale yellow.

Legs ( Table 1 ). Legs pale yellow, with exception of distal end of Fe 1, proximal 1/3 and distal end of Ti 1 (sometimes all Ti), distal 1/3 or 2/3 of Ta 1, Ta 2–5 brown. Р 2 and Р 3 yellowish, with exception of brown Ta 5. Terminal combs of Ti 2 and Ti 3 with 15–18 µm long spurs. BR 1 2.5–3.2, BR 2 3.3–4.3, BR 3 3.0–3.6.

Abdomen. Pale yellow.

Hypopygium ( Figs. 2–6 ). Anal tergite bands Y-type. Anal point 54–63 µm long, wide at about apical 1/3 (9–12 µm), apically rounded. Anterior margin of tergite IX with caudolateral shoulders bearing 4–5 setae. Gonocoxite 90– 105 µm long. Inner margin of gonocoxite with 5–6 setae. Width of transverse sternapodeme 45 μm. Phallapodeme 60 μm long. Superior volsella 51–60 µm long, without microtrichia, bearing usually apical dorsal seta (length 21–24 µm) and ventral seta (length 24–30 µm) on preapical lobe ( Fig. 2 ). Gonostylus 120–135 µm long, curved medially, with 4–5 setae in apical part and 1 short apical seta. HR 0.75–0.78.

Female. Unknown.

Pupa (n = 4)

Cephalothorax. Length of thorax 0.90– 0.90 mm. Frontal tubercles 30–36 µm high, 81–90 µm wide, with short, 9–15 µm long, rod-shaped, apically serrated outgrowths ( Figs 7 , 13 ). Thorax granulose along median suture ( Fig. 8 ). Thoracic horn plumose; basal ring oval, 30 µm long, 24 µm wide. Antepronotal 1 (median, 90–105 µm long). Precorneals 2–3 (length 60, 45, 75 µm). DC 1 strong, sometimes split, 30–45 µm long, DC 2 hairy, 45–90 µm long, DC 3 hairy, 45–60 µm long, DC 4 strong, 30–45 µm long. Distance between DC 1 and DC 2 54–90 µm, DC 3 and DC 4 6–15 µm, DC 2 and DC 3 63–96 µm. Wing sheath 900 µm long, 220 µm wide. Prealar tubercle present.

Abdomen ( Figs 9–12 , 14–16 ) 2.4– 2.8 mm long. Hook rows divided into two parts, each part with 12–17 hooks, 64–80 µm wide, distance between hook rows 40 µm. Tergites I–III with mesh structure. Tergites I–VI with a median longitudinal band of spines. Tergite I: length of stripe 64 µm, with ~15 spines; tergite II: length of stripe 96–144 µm, with 30–45 spines; tergite III: length of stripe 136–240 µm, with 42–65 spines; tergite IV: length of stripe 224–264 µm, with 82–100 spines; tergite V: length of stripe 240–256 µm, with 80–85 spines; tergite VI: length of stripe 240–264 µm, with 65–105 spines. Tergites VII–VIII with two lateral bands of spines. Pedes spurii B present on segment I and absent on segment II; pedes spurii A well-developed on sternite IV. Sternites I–IV with shagreen. Laterosternites IV–VII with spines posterolaterally. Segment VIII without posterolateral comb or spur. Segment I with 1 L seta, II–IV with 3 L setae, V–VIII with 4 LS setae.Anal lobe well-developed with complete fringe of 44–53 taeniae in a single row, with 1–2 dorsal setae. Anal segment 224–256 µm long and 176–224 µm wide.

Fourth instar larva (n = 3)

Coloration white (in alcohol), with yellowish head capsule. Head capsule 1.41 mm long, 1.10 mm wide, cephalic index (W/L) 0.78.

Head ( Figs 17–22 , 25–29 ). Posterior part of head capsule dorsally convex with several rounded small pits. Setae on dorsal surface: S 7 plumose, S 9 two-branched.

Antenna ( Figs 21 , 26 ). Six segmented, total length 81–101 µm, length of each segment (in µm): 30–36; 18–24; 21–27; 3; 4.5–9; 6. AR 0.56–0.59. Basal segment with ring organ at 12–15 µm from base. Blade 36 µm long, situated medially on second segment, extending to apex of fourth segment. Lauterborn organ 6 µm long, at apex of third segment, reaching apex of fifth segment.

Labrum ( Figs 19 , 25 ). S I 21–27 µm long, blade-like; S II 18 µm, slender and simple; S III 12–15 µm, short, and simple; S IV 56–71 µm long, 3-segmented (length of each segment (in µm): 15–23, 24–30, 14–18). Pecten epipharyngis consists of 3 scales, median one slightly longer than lateral ones. Premandible 45–54 µm long, with 2 large apical and 2 small basal teeth; brush absent.

Mandible ( Figs 20 , 27 ) 60–75 µm long, 18–24 µm wide, with an apical (15–18 µm long) and two inner teeth and a blade-like dorsal tooth (21 µm long). Seta subdentalis 18 µm long. Pecten mandibularis with 6 branches. Seta interna absent.

Maxillary palp ( Figs 22 , 28 ). Basal segment 21–24 µm long, ring organ located near base, with two 2-segmented (24 and 9–12 µm long, respectively) and one simple (21 µm long) sensillae.

Mentum ( Figs 22 , 29 ) 33–45 µm wide; 2 median teeth and 5 pairs lateral teeth. Ventromental plate 27–30 µm wide, 24–30 µm long.

Abdomen. Anterior parapods large, with large claws ( Fig. 23 ). Posterior parapods 328–344 µm long, with 10 simple hooks ( Fig. 24 ). Procercus 30 µm high, 21 µm wide. Anal tubules 104 µm long.

Remarks. The male of O. secundus (Zorina) can be distinguished from all known species of the genus by having a superior volsella without microtrichia and bearing apical and ventral setae, and by the absence of acrostichals and setae on both R and R 1.

The pupa is well distinguished by the presence of rod-shaped outgrowths on the frontal tubercles and longitudinally located shagreen in the form of stripes on the tergites I–VI.

Collected pupae are similar to Chironomini gen.? sp.? Pe 5 Langton & Visser (2003, Fig. 149b) with respect to location of shagreen on tergites II–IV, medially interrupted band of hook-shaped spines, number of setae on segments V–VIII and absence of caudolateral spur, but differ from the latter in the above features.

The larva of O. secundus (Zorina) is similar to the larvae of O. lenzi (Zorina) and Harnischia complex genus C sp. Epler, but differs from the latter in the following features: AR 0.56–0.59, S IV 3-segmented (2nd and 3rd segments about the same length), premandible with 2 large apical and 2 small basal teeth. Mandible with 2 inner teeth, seta interna absent. Maxillary palp with two 2-segmented and one simple sensillae apically. Mentum with 12 pale teeth, 2 median teeth and 5 pairs lateral teeth.

The larvae of O. secundus (Zorina) , which we found in the Amur River basin, are very similar in structure of the body and head capsule to Cryptochironomus macropodus Lyakhov , that was described from the Volga River basin. Despite the rather detailed description and figure of the larva C. macropodus given by Pankratova (1983), we cannot reliably say that this is one and the same species. At present, it is not possible to carry out a comparative morphometric analysis of the larvae found by us with the type specimens of C. macropodus .

Distribution. The species is known from Amur River basin and Sakhalin Island, Russian Far East. The larvae live on sandy-pebbly soils of large rivers.

Figures

FIGURES 1–6. Details of the structure of the adult male of Olecryptotendipes secundus (Zorina). 1—head; 2—variations in the structure of the superior volsella; 3, 4—hypopygium, dorsal view; 5, 6—hypopygium, ventral view. Scale bar 20 µm.

FIGURES 7–12. Details of the structure of the pupa of Olecryptotendipes secundus (Zorina). 7—frontal tubercles; 8—thorax, lateral view; 9—tergites II–III; 10—tergites IV–V; 11—tergites VI–VII; 12—tergites VIII–IX. Scale bar 20 µm.

FIGURES 13–16. Pupa of Olecryptotendipes secundus (Zorina). 13—frontal tubercle; 14—tergites I–II; 15—tergites III–V; 16—tergites VI–VIII. Scale bar 50 µm.

FIGURES 17–24. Details of the structure of the larva of Olecryptotendipes secundus (Zorina). 17—head capsule, dorsal view; 18—head capsule, ventral view; 19—labrum; 120—mandible; 21—antenna; 22—mentum, ventromental plates and maxillary palp; 23—anterior parapods; 24—posterior parapods. Scale bar 20 µm.

FIGURES 25–29. Larva of Olecryptotendipes secundus (Zorina). 25—labrum; 26—antenna; 27—mandible; 28—maxillary palp; 29—mentum and ventromental plates. Scale bar 50 µm.