Chironomids are commensals of the larvae and pupae of Blephariceridae and Simuliidae from the North Caucasus (Diptera: Chironomidae: Orthocladiinae) Author Makarchenko, Eugenyi A. Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far East Branch of the Russian Academy of Sciences, 100 let Vladivostoku 159, 690022 Vladivostok, Russia Author Semenchenko, Alexander A. 0000-0001-7207-9529 Laboratory of Ecology and Evolutionary Biology of Aquatic Organisms, Far Eastern Federal University, Suhanova St. 8, 690950 Vladivostok, Russia. semenchenko _ alexander @ mail. ru; https: // orcid. org / 0000 - 0001 - 7207 - 9529 semenchenko_alexander@mail.ru Author Palatov, Dmitry M. 0000-0002-8826-9316 A. N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Leninskij prosp. 33, 119071 Moscow, Russia triops @ yandex. ru; https: // orcid. org / 0000 - 0002 - 8826 - 9316 triops@yandex.ru text Zootaxa 2022 2022-05-27 5141 4 373 384 journal article 61371 10.11646/zootaxa.5141.4.5 7f551f08-1613-40f4-bcf6-8e028bd08c2c 1175-5326 6592978 91F6C839-70DC-44DF-B3BC-1CED8953B560 Cardiocladius sp. 1 ( Figs. 7–17 ) Material examined. 4 larvae of IV instar removed from larval Blephariceridae , RUSSIA : Republic of Dagestan , Tlyaratinsky District , Greater Caucasus , Avar Koysu River basin, the left tributary of the Dzhurmut River opposite of Choroda Village , altitude 1696 m above sea level , 41º58.654’N , 46º29.865’E , 08. V .2021 ; 3 larvae of III instar and 1 larva of IV instar removed from larval Blephariceridae , the same locality, except stream on the slope of the Dzhurmut River valley near of the Salda Village , altitude 1763 m above sea level , 41º58.046’N , 46º31.029’E , 09. V .2021 . 3 larvae of IV instar removed from larval Blephariceridae , RUSSIA : Republic of North Ossetia – Alania , Alagirsky District , Greater Caucasus , Tseyskoye Gorge , Terek River basin, waterfall on the Shalatsikomdon River , altitude 1755 m above sea level , 42.79266 N , 43.920051 E , 29.VII.2021 ; 2 larvae of II instar removed from larval Blephariceridae , the same locality, except Skazdon River near the Tsey (Tseyskoe gorge) ski resort, altitude 2025 m above sea level , 42.781545 N , 43.901025 E , 29.VII.2021 . Larva of III–IV instar (n= 9). Total length 2.6–3.2 mm . Head dark brown to black, thoracic segments greenish, abdominal segments bluish-violet. Head. Length 295–3328 μm, width 197–213 µm. Labral setae S I– S 2 simple ( Fig. 7 ). Premandible distally with 1 wide apical tooth ( Fig. 7 ). Antenna with 5 segments; length 1–5 segments (in µm) (n=5): 39–44: 11–15: 8–9: 7: 5; AR 1.22–1.39; apex of segment 2 with large Lauterborn organs ending at base of 4 th segment; antennal blade 31 µm long, its apex reaches the base of the 5 th segment, its internal branch reaches the middle of the 3 rd segment; one large ring organs in proximal 1/3 of basal segment and one small in distal 1/3 ( Fig. 12 ). Mandible with apical tooth and 3 inner teeth ( Fig. 14 ); seta interna with long basal part (18–20 µm) and distal with 5 branches ( Fig. 15 ); seta subdentalis leaf-shaped, with pointed apex; inner margin of mandible with 2 long serrations. Mentum with 5 pairs of lateral teeth; median tooth single, truncated or trapezoidal, in 3.3–4 times wider than 2 nd lateral tooth; 1 st lateral tooth reduced and appressed to median tooth; ventromental plates large, pointed basally ( Figs. 8–10 ). Maxilla without pecten galearis. Abdomen. Anal tubules subequal, 120–124 µm long. Posterior parapods long, 400–408 µm long ( Fig. 16 ), length/width ratio 3.5–5,7; posterior parapods length/anal tubules length 3.2–3.3. Procerci greatly reduced, hardly protruding, in the form of tubercles or incompletely sclerotized ring (as in some Diamesa ), each bearing 4 anal setae, 3 of which are 96–124 µm long and 1 is 60–84 µm long; lateral seta 20–32 µm long sits directly on body ( Fig. 17 ). Larva of II instar (n=2). Total length 1.6–2.0 mm. Head dark brown to black, thoracic segments greenish, abdominal segments bluish-violet. FIGURES 7–17. Larva of Cardiocladius sp. 1 . 7, labrum with S-setae; 8–11, mentum; 12–13, antenna; 14, mandible; 15, inner setae of mandible; 16, anal segment with procercus, posterior parapods and anal tubules; 17, procercus with anal setae. Head. Premandible distally with 1 wide apical tooth. Antenna with 5 segments; length 1–5 segments (in µm): 15–23: 9–10: 4–7: 3–4: 2–4; AR 0.83–0.92; apex of segment 2 with large Lauterborn organs ending at base of 4 th segment; apex of antennal blade reaches middle of 4 th segment, its internal branch reaches 2/3 of the 3 rd segment; one large ring organs in proximal 1/3 of basal segment ( Fig. 13 ). Mentum with 5 pairs of lateral teeth; median tooth single, truncated or trapezoidal, in 4.2–4.3 times wider than 2 nd lateral tooth; 1 st lateral tooth reduced and appressed to median tooth ( Fig. 11 ). Abdomen. Anal tubules subequal, 56–84 µm long. Posterior parapods long, 200–280 µm long; posterior parapods length/anal tubules length 2.9–3.3. Procerci greatly reduced, hardly protruding, in the form of tubercles or incompletely sclerotized ring, each bearing 4 anal setae, 2 of which are 56–68 µm long and 2 are 28–32 µm long; lateral seta 12–14 µm long sits directly on body. Remarks. The larvae of Cardiocladius sp. 1 , which found on blepharicerids, according to the identification key of Cranston (1982) and Schmid (1993) are closely related to C. capucinus (Zetterstedt) but without a pupa and an adult male we cannot confirm it. Also, this is not supported by the results of DNA barcoding ( Fig. 34 ). In the process of identifying the larvae of Cardiocladius sp. 1 we also used the work of Bode (1983) , according to which our species could be attributed to the Eukiefferiella cyanea group. In our opinion, this group of species should be transferred from the genus Eukiefferiella to Cardiocladius . Ecology. Chironomid larvae on blepharicerids were collected on large stones and rocks of mountain rivers and in a waterfall at a current speed of 0.6–1 m /s, at an altitude of 1696 m a.s.l. in Dagestan and 2025 m a.s.l. in North Ossetia ( Figs. 30–32 ).