Chaetocladius egorych Makarchenko et Makarchenko

Makarchenko, Eugenyi A., Makarchenko, Marina A. & Semenchenko, Alexander A., 2017, New or little-known species of Chaetocladius s. str. Kieffer, 1911 (Diptera: Chironomidae: Orthocladiinae) from the Amur River basin (Russian Far East), Zootaxa 4247 (3), pp. 313-330 : 315-318

Chaetocladius egorych Makarchenko et Makarchenko , sp. nov.

( Figs. 1–13 , 34–38 )

Chaetocladius sp.2 Makarchenko et al. 2014: 425.

Material. Holotype: adult male, Russian Far East, Jewish Autonomous Region, Obluchie District, Lopatinskyi Spring of Bidzhan River basin (Amur River basin), N 48°37' 810'' , E 131°39' 114'', 7. IV. 2014, leg. E. Makarchenko. Paratypes: 4 males, 1 pupa, same data as holotype; 7 mature pupae , same data as holotype except 27.III. 2015 ; 1 pupa, same data as holotype except 31.III. 2015 ; 10 larvae, same data as holotype except 2–6.IV. 2016; leg. E. Makarchenko.

Larvae were associated with pupae and adults by DNA.

Adult male (n=3). Total length 2.0– 2.9 mm. Wing length 1.96–2.20 mm. Total length/wing length 1.02–1.32. Colouration brown to dark brown.

Head. Eyes pubescent, without dorsomedian prolongations or sometimes only with weak extensions. Temporal setae (from one side): 7 verticals and 2–5 postorbitals. Clypeus with 4–6 setae. Antenna with 13 flagellomeres and well developed plume; AR 1.04–1.18. Lengths of palpomeres 2–5 (in µm): 48–60: 124–132: 112–120: 156–200. Third palpomere with 5–6 sensilla clavata subapically.

Thorax chaetotaxy. Antepronotum with 5–7 lateral setae. Ac 14–18, beginning close to antepronotum; Dc 7– 11; Pa 4–5; Scts 6–8, in 1 row.

Wing. Halteres dark. R with 13–17 setae, R1 with 2 setae, R4+5 with 0–1 seta subapically. Costa extension 48–64 µm. Apex of R4+5 distal of apex M3+4. Cu1 curved in apical quarter. Anal lobe developed, rectangular-rounded. Squama with 6–8 setae.

Legs. Spur of fore tibia 56–60 µm. Spurs of mid tibia 28–32 µm and 24 µm long, of hind tibia 56–64 µm and 20–24 µm long. Hind tibial comb with 14 setae. Pulvilli small. Length (in µm) and proportions of leg segments as in Table 1 .

continued.

Hypopygium ( Figs. 1–2 ). Tergite IX with 18–21 long setae and narrowly triangular anal point 60–72 µm long and 16–20 µm wide in base. Anal point in base with microtrichia, the remaining part naked. Laterosternite IX with 7–9 setae on each side. Transverse sternapodeme rounded, 108–112 µm long, with short rounded oral projections. Virga 72–80 µm long, consisted of several setae. Gonocoxite 212 µm long; inferior volsella as in Figs. 1–2 . Gonostylus 88–92 µm long, with small subapical crista dorsalis in form of tooth, megaseta 8–12 µm long.

Pupa (n=2). Total length 3.0–3,75 mm.

Cephalothorax. Frontal apotome with 2 setae 36–60 µm long. Thorax light brown and smooth. Antepronotum with 2 median and 1 lateral antepronotals 72–80 µm long. Thoracic horn 104 µm (females) or 108–160 µm long (males) and 16–20 µm wide, tapering to pointed apex, with small spinules in distal part ( Figs. 3–5 ). Precorneal setae hair-like, arranged as triangle or one after the other, 60–84 µm long. Distance between Pc1 and Pc 2 8–12 µm; distance between Pc2 and Pc3 8 µm. Dorsocentrals hair-like, 48–60 µm long. Distance between Dc1 and Dc2 44–64 µm; between Dc2 and Dc3 108 µm; between Dc3 and Dc 4 24–28 µm.

Abdomen. Tergite I without shagreen and only with not numerous spinules on each side along posterior edge. Tergites II–VIII uniformly covered with shagreen spinules of one size and with 1–2 rows of larger spines near posterior edge; anal lobes with not numerous spinules ( Fig. 6 ). Sternites I–III without shagreen of spinules; sternite IV with small spinules in distal half; sternites V–VIII covered with small spinules of one size; sternite IX without shagreen. Segment I with 2 pair of hair-like lateral setae 60–100 µm long. Segments II–VII with 4 pairs of lateral setae: 2 pairs of seta-like setae on small tubercles (LS1 and LS3) and 2 pairs of hair-like setae (LS2 and LS4). Segment VIII with 3 pairs of hair-like lateral setae. Anal lobe 2 28–240 µm long, with 3 spine-like macrosetae 40– 56 µm long and ca 8 µm wide. Distance from base of anal lobe to anterior macroseta (AM1) 0.45–0.50 (males) or 0.57 (female) of anal lobe length. Location of anal megasetae illustrated in Figs. 6 , 35 . Male genital sac extending 64–72 µm beyond anal lobe.

Forth instar larva (n=3). Total length 4.9–5.6 mm.

Head. Head capsule brown, more light in lateral parts; 270 µm long and 230–240 µm wide. S I of labrum branched into 3–4 short and pointed branches, sometimes serrated laterally ( Figs. 12–13 ), S II–S IV simple. Labral lamella paired, high triangular shape ( Fig. 12–13 ). Pecten epipharyngis consisted of 3 scales which sometimes stick together and look like a plate. Premandible with two apical teeth and one inner tooth, with brush ( Fig. 11 ). Antenna 56–60 µm long, with 5 segments; one large and one small ring organs in proximal half of basal segment, third ring organ little distal of large organ; segment 2 on apex with large lauterborn organs and its tip reaches middle of segment 4; longest branch of blade ending about apex of segment 4 ( Fig. 7 ); AR 1.33–1.50. Mandible with 4 teeth, apical tooth shorter to combined width of 3 inner teeth; seta subdentalis tapering to pointed apex ( Fig. 10 ); seta interna with 7 simple plumose branches. Pecten galearis weakly developed and very often invisible. Mentum with 1 median tooth and 5 pairs of lateral teeth; middle tooth almost 4 times wider than first lateral tooth; middle tooth of one larva with notch in middle ( Fig. 8 ). Ventromental plate large and elongate, extends beyond the lateral teeth ( Fig. 9 ). Anal tubules shorter of posterior parapods. Procercus 28 µm long and 20 µm wide, bearing 7 apical anal setae of different length, namely 3 setae 180–240 µm long and 4 setae 108–160 µm long; 2 lateral setae short and thin.

Diagnostic characters. Adult male of the new species is close related to C. longivirgatus Stur et Spies but virga of hypopygium C. egorych sp. nov. consisted of several not fused setae about the same length and gonostylus slightly expanded distally. Virga of C. longivirgatus with up to 5 long, thin spines and 6–16 shorter spines near base; gonostylus without significant expansions ( Stur & Spies 2011). Also see the key and results of barcoding ( Fig. 45 ).

Etymology. The species is named in memory of our friend, Russian hydrobiologist Sergey Egorovitch Sirotsky, often called by us Egorych . The name is a noun in apposition.

Figures

FIGURE 45. Phylogenetic tree of the fifteen Chaetocladius species and one out-group, Hydrobaenus majus Makarchenko et Makarchenko (Orthocladiinae), based on the mitochondrial cytochrome c oxidase I (COI) barcode gene sequences (658 bp). The numbers are support values for 500 bootstraps. The specimens obtained in this study are in bold.

FIGURES 1 – 13. Chaetocladius egorych sp. nov., adult male (1 – 2), pupa (3 – 6) and fourth instar larva (7 – 13). 1 – 2, hypopygium in dorsal view; 3 – 5, thoracic horn; 6, tergite VIII and anal segment of male; 7, antenna; 8, median teeth of mentum; 9, mentum; 10, mandible; 11, premandible; 12 – 13, S I and labral lamellae. AM 1 — anterior anal macroseta, AM 2 — middle anal macroseta, AM 3 — posterior anal macroseta. Scale bars—Figs. 1 – 5 — 50 µm; Fig. 6 — 200 µm; Figs. 7 – 13 — 20 µm.

FIGURES 34 – 39. Chaetocladius egorych sp. nov. (34 – 38) and Chaetocladius fedotkin Makarchenko et Makarchenko (39), pupa (34 – 35, 39) and fourth instar larva (36 – 38). 34, tergite IV; 35, tergite VIII and anal segment of male; 36 – 38, mentum; 39, anal segment of male.

Tables

TABLE 1. Lengths (in µm) and proportions of leg segments of Chaetocladius egorych sp. nov., male (n = 3).

	fe	ti	ta1	ta2	ta3	ta4	ta5
P1	768–832	928–1040	560–640	320–368	240	144–160	112–120
P2	784–896	848–960	384–432	224–256	176–192	112–144	112–120
P3	896–992	992–1152	576–656	304–368	264–288	160–176	112–128