Cyphomella cana ( Strobl, 1910 )

Orel, Oksana V., 2025, Redescription of Cyphomella cana (Strobl, 1910) (Diptera, Chironomidae) from the Russian Far East, Zootaxa 5661 (1), pp. 142-150 : 143-150

Cyphomella cana ( Strobl, 1910)

Figs 1–28 .

Chironomus canus Strobl, 1910: 266

Cyphomella cana ( Strobl, 1910) , Vallenduuk 2019: 167, Fig. 136

Cyphomella cornea Saether, 1977: 105 , Fig. 37 E–F; Langton & Visser 2003; Zorina 2006: 386; Moller Pillot 2009: 95 Material examined. 2 males, RUSSIA, SAKHALIN ISLAND, Poronaisky District, Leonidovka River 8 km below the village, 9–10.vii. 2001 (Makarchenko E.A.); 1 male, same data, Nogliki district, Rybnoe Lake , 27.vii.2002 (Makarchenko E.A.); 1 male, same data, Tym River 2 km from the automobile bridge over the Parkata River , 02.viii.2003 (Makarchenko E.A.); 6 males, same data, Dolinsky district, “Sokol” biological station, Belaya River , 19–20.viii.2003 (Makarchenko E.A.); 1 male, AMUR REGION, Selemdzha river basin, Aldikon River near the of Norsk Town , 16.vi.2004 (Tiunova T.M.); 1 mature pupa with larval exuviae, Zeya river basin, Bolshaya Pera River , 14.ix.2021 (Yavorskaya N.M.); 2 male, JEWISH AUTONOMOUS REGION, Amur River, Petrovskaya channel, 123rd km, 01.vii.2006 (Yavorskaya N.M.); 1 male, KHABAROVCK TERRITORY, Verkhnebureinsky district, Bureya river basin, Urgal River 4 km from the mouth, 21.ix.2006 (Tiunova T.M.); 1 mature pupa, Amur River , lower course, 05.vi.2018 (Yavorskaya N.M.); 1 immature pupa, Amur River basin, Tunguska River , 05.vi.2018 (Yavorskaya N.M.); 5 males, Anyuisky National Park, Amur River basin, Troitskoye village , unnamed stream near the ANP office, 26.v.2019 (Yavorskaya N.M.); 1 male Komsomolsky Nature Reserve, Beach-Khauni Lake , 21.v.2020 (Yavorskaya N.M.).

Diagnosis. Male: dark brown coloured species, with wing 1.91–2.40 mm long and AR 1.63–1.94; LRPI 1.40–1.51; anal point narrow, apically widened and rounded; superior volsella with 4–7 setae and microtrichia on ventromedian margin; membranous apical part of the superior volsella may be curved dorsally; inferior volsella without setae. Pupa: total body length 3.0– 4.4 mm; cephalic tubercles 75–84 μm long; Pedes spurii B on segment II present, hook rows with 59–71 hooks, sometimes narrowly interrupted medially and with a group of hooks medially. Larva: AR 1.36; antenna blade length 42 µm; mandible with light apical and three inner teeth; the first lateral teeth of the mentum are light.

Description. Adult male (n = 6)

Body size and proportions. Total length 3.2–3.8 mm. Wing length 2.12–2.40 mm. Total length/wing length ratio 1.45–1.58.

Colouration. Antenna and palps brown. Scutal vittae, scutellum and postnotum brown, ground colour of thorax and haltere yellow brown, legs and abdomen brown.

Head. Antenna 1020–1060 μm long; ultimate flagellomere 660–700 μm long; AR 1.65–1.94. Frontal tubercles subcylindrical/conical with round apex, 15–21 μm long, 9–15 μm wide ( Fig. 1 ). Temporal setae 12–16 on each side. Clypeus with 8–14 setae. Lengths of 2–4 palpomeres (in μm): 48–54, 144–152, 136–160, 200–240.

Thorax. Aps 5–9, Ac absent, Dc 5–9 on each side, uniserial; Pa 2–4 on each side; Scts 8–12.

Wing 0.58–0.68 μm wide. R with 6–10 setae, R 4+5 with 2–7 setae (of which 2 are apical). Brachiolum with 2 setae; squama with 6–11 setae. VR 1.0–1.2.

Legs. Tibial combs of mid and hind legs fused, with straight spur: 18–24 (mid leg) and 24–30 μm long (hind leg). Basitarsus of mid leg with 2–6 sensillum chaeticum (n=6).

Lengths and proportions of legs as in Table 1 .

Hypopygium ( Figs 2–8 ). Tergite IX reticulated; with 8–12 setae on each side of anal point (2–4 setae may be located at the base of the anal point), tergite bands weakly expressed; laterosternites with 2–5 setae on each side. Anal point narrow, apically widened and rounded (69–81 μm long, 15 μm wide apically). Gonocoxite 105–135 μm long, with 3–4 setae along the inner margin. Phallapodeme 84–114 μm long; transverse sternapodeme 60–81 μm long. Superior volsella 42–60 μm long, with 4–7 setae and microtrichia on ventromedian margin; membranous apical part of the superior volsella may be curved dorsally. Inferior volsella without setae. Gonostylus 141–165 μm long, widened in the proximal part and gradually narrows apically. HR 0.7–0.9.

Pupa (n = 3) 3.0– 3.3 mm long.

Cephalothorax. Frontal tubercles well-developed, conical, 75–84 μm long, 36–45 μm wide at base ( Fig. 9 ). Frontal setae short (18–24 μm long) located subapically. Thorax granulose along median suture ( Fig. 10 ). Antepronotals 2 (median (105 μm long and lateral (120 μm long), taeniate). Precorneals 2 (60–75 μm long, taeniate). Dc 1–4 simple, 30–45 μm long. Distance between Dc 1 and Dc 2 27–30 μm, Dc 3 and Dc 4 12–24 μm, Dc 2 and Dc 3 141–144 μm. Wing sheath 1000–1100 μm long. Prealar tubercle well-developed.

Abdomen ( Figs 11–16 ) 2.7 mm long. Hook rows with 59–68 hooks, 336 μm wide, narrowly interrupted medially and with group of hooks medially. Tergite I bare; II–VI with median shagreen: weak anteromedian spines grading over into stronger posterior spines; VII in proximal part with transverse stripe of shagreen; VIII with anterolateral patches of shagreen. Sternite II–III with a medial longitudinal strip of shagreen; IV with a medial triangular strip of shagreen; V without of shagreen; VI–VIII with anterolateral patches of shagreen. Segment VIII with 5–12 strong dark spurs (6–30 μm long) ( Figs 15–16 ). Segment II–IV with 3 L setae, V with 3 LS setae, VI–VII with 4 LS setae, and VIII with 4 (rarely 5) LS setae. Anal lobe well developed with two patches of shagreen and complete fringe of 38–50 taeniate setae. Anal segment 168–210 μm long and 195–270 μm wide, with shagreen.

Fourth instar larva (n = 1)

Colouration white (in alcohol), with yellowish head capsule.

Head. Head capsule 0.28 mm long, 0.24 mm wide. Dorsal surface smooth; sclerite 1 21 μm long and 12 μm wide; clypeus 21 μm long and 9 μm wide; S 3 39 –45 μm long, apically divided into 2–3 branches ( Fig. 24 ). Antenna 5- segmented (but only 4 segments are clearly visible) total length 168 μm, length of each segment (in μm): 45; 25.5; 4,5; 3. AR 1.36. Ring organ located at base of basal segment; wide of basal segment 1.5 μm. Blade 42 μm long, situated apically on basal segment, extending to apex of segment 4 ( Figs 19 , 25 ). Labrum ( Figs 18 , 23 ). S I 24 μm long, blade-like; S II 45 μm long, blade-like; S III 15 μm, simple; S IV 3-segmeted, 24 μm long. Premandible 66 μm long, with 2 large apical and 2 shorter basal teeth; brush present. Mandible ( Figs 20 , 26 ) 90 μm long, 36 μm wide, with light apical and three inner teeth. Seta subdentalis 18 μm long, extending to apex the 2nd inner tooth. Seta interna consisting of 4 branches, 30–36 μm long. Ventral seta 30 μm long. Maxillary palp ( Fig. 27 ) 1-segmented, 45 μm long, apically with 2–3 2-segmented setae, the rest setae simple. Mentum ( Figs 21 , 28 ) 103 μm wide, with pale a broad median tooth (27 μm) having a weak medial notch and with a pair of pale lateral teeth, and with 6 pairs brown lateral teeth. Ventromental plate 29 μm wide, 84 μm high, with about 40 striae; distance between ventromental plates 66 μm.

Body. Posterior parapods with 16 simple hooks ( Fig. 22 ). Procercus 24 μm long and 39 μm wide. Anal setae nearly 400 μm long.

Remarks. The genus Kuzinia was described by Shilova in 2001 from the Eastern Pamirs (Ashil-Kul Lake) based on the morphology of the male imago, and included only one species— Kuzinia ariadnae Shilova, 2001 . Later this genus was given a new name Pamirocesa Kocak & Kemal, 2008 . According to Shilova’s article, the genus Kuzinia has the following diagnostic characteristics: Ac absent, Aps present, frontal tubercles are well developed, superior volsellae are club-shaped, apically expanded, with setae, gonostylus with a short “spiny” seta. The above morphometric features fully correspond to the diagnostic characteristics of the genus Cyphomella . Therefore, I believe that Kuzinia / Pamirocesa is a junior synonym of the genus Cyphomella .

The males of Cyphomella cana ( Strobl, 1910) from Russian Far East practically do not differ from American and Western European males’ specimens in morphometric parameters and structure of the hypopygium (See Table 2 ). The male of C. cana is most similar to C. ariadnae (Shilova) , but differs in the smaller body size, the presence of a dorsal tubercle on the scutum, as well as the structure of the hypopygium: the anal point is expanded near the apex, setae on the superior volsella are located ventromedially, the gonostylus is slightly expanded in the proximal part (See Table 2 ). In cointrast male of C. ariadnae (Shilova) are larger, the dorsal tubercle on the scutum is absent, the anal point is expanded in the apical third, the setae on the superior volsella are located apicomedially, and the gonostylus is strongly expanded in the proximal third ( Shilova, 2001: 1278, Fig. 2 ).

Far Eastern pupae of C. cana (Strobl) have slight morphometric differences from pupae described from Germany by Langton and Visser (2003), which are listed in Table 3 . The pupa of C. cana (Strobl) is most similar to Cyphomella sp. (Saether 1977: 107, Fig. 38), but differs from the latter by the following features: total body length 3.0– 4.4 mm, cephalic tubercles 75–84 μm long, Pedes spurii B on segment II present, hook rows with 59–71 hooks. In contrast, the pupa of Cyphomella sp. has a total body length of 2.72 mm, cephalic tubercles 53 μm long, Pedes spurii B on segment II absent, and hook rows with 38 hooks.

The larva of C. cana (Strobl) is most similar to Cyphomella sp. , but is distinguished by the pale teeth of the mandible and the first lateral teeth of the mentum, and an AR of 1.36 (See Table 4 ). Cyphomella sp. has dark teeth of the mandible and first lateral teeth of the mentum, and AR 1.78 (Saether 1977: 107, Fig. 38).

Distribution. Holarctic species. Widespread in the Russian Far East.

Figures

FIGURES 1–8. Details of the structure of the male imago Cyphomella cana (Strobl, 1910). 1—frontal tubercles; 2–3, 5— hypopygium, dorsal view; 3, 6–8—superior volsella. Scale bar 50 μm.

FIGURES 9–16. Details of the structure of the pupa Cyphomella cana (Strobl, 1910). 9—frontal tubercles; 10—thorax, lateral view; 11—tergite II; 12—tergites III; 13—tergite V; 14—tergites VIII–IX; 15–16—anal comb. Scale bar 20 μm (10–14) and 50 μm (9, 15–16).

FIGURES 17–22. Details of the structure of the larva Cyphomella cana (Strobl, 1910). 17—setae S 3; 18—labrum; 19— antenna; 20—mandible; 21—mentum and ventromental plates; 22—posterior parapods and procerci; Scale bar 20 μm (22) and 50 μm (17–21).

FIGURES 23–28. Details of the structure of the larva Cyphomella cana (Strobl, 1910). 23—labrum; 24—sclerite 1, clypeus and frontal apotome; 25—antenna; 26—mandible; 27—maxillary palp; 28—mentum and ventromental plates. Scale bar 50 μm.

Tables

TABLE 1. Lengths (in μm) and proportions of leg segments of Cyphomella cana (Strobl, 1910) adult male .

P	f t	Ta 1 Ta 2	Ta 3	Ta 4	Ta 5
P 1	760–880 560–700	840–1000 420–500	340–400	240–300 130–160
P 2	700–820 680–800	340–400 220–260	160–200	100–130	80–100
P 3	840–940 840–960	520–600 320–380	260–300	160–180	100–120
P	LR	SV	BV		BR
P1	1.42–1.50	1.56–1.60	1.71–1.98		2.5
P2	0.49–0.56	3.63–4.17	2.97–3.21	3.4–5.0
P3	0.62–0.67	3.00–3.23	2.55–2.80	4.5–5.9