Chaetocladius yavorskayae 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 : 323-327

Chaetocladius yavorskayae Makarchenko et Makarchenko , sp. nov.

( Figs. 29–33 , 42–44 )

Chaetocladius sp.1 Makarchenko et al. 2014: 424.

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'', 31.III. 2015, leg. E. Makarchenko . Paratypes: 1 mature pupa of male, the same data as holotype, 31.III. 2015, leg. E. Makarchenko ; 3 males, the same data as holotype except, Fedotkin Spring of Bidzhan River basin, N 48°38' 409'', E 131°37' 217'', 6. IV. 2014, leg. E. Makarchenko ; 2 males, the same data as holotype except, Kolgaevskiy Spring of Bidzhan River basin, N 48°38' 522'', E 131°54' 788'', 6. IV. 2014, leg. E. Makarchenko .

Adult male (n=3). Total length 3.2–3.7 mm. Wing length 2.32–2.56 mm. Total length/wing length 1.38–1.45. Colouration brown to dark brown.

continued.

Head. Eyes bare, without dorsomedian prolongations. Temporal setae include (from one side) 7–8 verticals and 5–6 postorbitals. Clypeus with 6–8 setae. Antenna with 13 flagellomeres and well developed plume; AR 1.91–2.38. Lengths of palpomeres 2–5 (in µm): 48–52: 144–168: 128–176: 252–296. Third palpomere in distal part with 8– 10 sensilla clavata.

Thorax. Brown. Antepronotum with 5–6 lateral setae. Acrostichals 15–21, beginning close to antepronotum; dorsocentrals 11–16; prealars 3–4; scutellum with 7–8 setae in 1 row.

Wing. Greyish, with more dark veins and good visible microtrichia. Halteres brownish-yellow. R with 10–11 setae, R1 and R4+5 without setae. Costa extension 56–80 µm. Apex of R4+5 distal of apex M3+4. Cu1 curved in apical part. Anal lobe developed, rectangular-rounded. Squama with 9–13 setae.

Legs. Spur of fore tibia 76–80 µm. Spurs of mid tibia 24–32 µm and 28–32 µm long, of hind tibia 60–68 µm and 16–28 µm long;ta1 and ta2 of mid leg 2 pseudospurs, ta3 with 1–2 pseudospurs; ta1–ta3 of hind leg with 2 pseudospurs. Hind tibial comb with 15–19 setae. Pulvilli small. Length (in µm) and proportions of leg segments as in Table 4 .

Hypopygium ( Figs. 29–33 , 42 ). Tergite IX without anal point, trapezoidal,densely covered with microtrichia, its free edge as it is curled inwards, in inner side and on the edge with middle and long 11–19 setae ( Fig. 31 ). Laterosternite IX with 8–9 setae on each side. Transverse sternapodeme rounded, 108–112 µm long, with weak oral projections. Virga 40–48 µm long, consists of 2–3 colorless setae. Gonocoxite 260 µm long; inferior volsella as a rounded projection located in distal half of gonocoxite, covered with microtrichia and setae ( Figs. 29–30 ). Gonostylus bifurcate, inner branch 104–108 µm long, with megaseta 14–20 µm long ( Figs. 29–30, 32 , 42 ).

Pupa (n=1). Cephalothorax was destroyed and we had chance to study only abdomen.

Abdomen. Tergite I without shagreen. Tergites II–VIII uniformly covered with shagreen spinules of one size and with larger long spinules in 2–3 rows along posterior edge, behind long spinules on tergites III–VII located small spinules tops of which are directed forward ( Fig. 44 ). Sternites I–III, VII–VIII without shagreen of spinules; sternite IV with row of small spinules near posterior edge; sternites V–VI with small spinules on surface. Segment I with 2 pairs of hair-like lateral setae. Segments II–VII with 2 pairs of seta-like lateral setae on tubercles and 2 pairs of hair-like setae. Segment VIII with 3 hair-like setae. Anal lobe 284 µm long, with 3 spine-like macrosetae; anterior macroseta (AM1) 80 µm long and 8 µm wide; middle macroseta (AM2) 76–80 µm long and 6 µm wide; posterior macroseta (AM3) 116 µm long and 8 µm wide. Distance from base of anal lobe to AM1 0.49 of anal lobe length. Distance between AM1 and AM2 68 µm; between AM2 and AM3 20 µm. Location of anal megasetae illustrated in Figs. 33 , 43 . Male genital sac extending 32–36 µm beyond anal lobe.

Diagnostic characters. A new species is separate from all known species of Chaetocladius s. str. by absence of anal point and bifurcate gonostylus. See also the results of barcoding ( Fig. 45 ) and key.

Etymology. The species is named in honour of Dr. N.M. Yavorskaya from the Institute of Water and Ecological Problems FEB RAS (Khabarovsk), the hydrobiologist who collected the more specimens of chironomids in the Amur River basin for describing of a new species.

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 29 – 33. Chaetocladius yavorskayae sp. nov., adult male (29 – 32) and pupa (33). 29, hypopygium in dorsal view; 30, gonocoxite and gonostylus; 31, tergite IX; 32, gonostylus; 33, tergite VIII and anal segment of male. Scale bars: Figs. 29 – 32 — 50 µm; Fig. 33 — 200 µm.

FIGURES 40 – 44. Chaetocladius lopatinskiy sp. nov. (40 – 41) and Chaetocladius yavorskayae sp. nov. (42 – 44), adult male (40, 42) and pupa (41, 43 – 44). 40, 42, hypopygium in dorsal view; 41, 43, anal segment of male; 44, spinules of tergite IV.

Tables

TABLE 4. Lengths (in µm) and proportions of leg segments of Chaetocladius yavorskayae sp. nov., male (n = 3).

	fe	ti	ta1	ta2	ta3	ta4	ta5
P1	944–1024	1088–1200	720–752	304–400	272–288	192	128–144
P2	976–1056	992–1088	448–512	280–288	192–208	128–144	128
P3	1088–1168	1232–1344	720–768	384–416	320–336	176–192	144