Pseudokiefferiella matafonovi Makarchenko et Semenchenko, 2023

Makarchenko, Eugenyi A. & Semenchenko, Alexander A., 2023, Two new chironomid species of the genus Pseudokiefferiella Zavřel (Diptera: Chironomidae: Diamesinae) from the Amur River basin of Russia, Zootaxa 5339 (5), pp. 481-491 : 482-487

Pseudokiefferiella matafonovi Makarchenko et Semenchenko , sp. nov.

http://zoobank.org/NomenclaturalActs/ 69AA60DC-3129-41FA-9A7F-6CE7F1D20E09

( Figs. 1–18 )

Type material. Holotype: adult male, Russia: Trans-Baikal Territory , environs of the Chita Сity, Kaydalovka River, upper stream, N 52.039058, E 113.560243, 18.VIII 2003, leg. P. Matafonov. Paratypes: 1 adult male, 1 pupa (male), 4 pupal exuviae, 7 larvae, the same data as holotype, 18.VIII 2003, leg. P. Matafonov ; 8 larvae, the same data as holotype, except 31. V. 2022, N 52.039988, E 113.562473, leg. P. Matafonov ; 1 larva, the same data as holotype, except Karpovskyi Stream , 2.VII.2004, leg. O. Klishko.

Derivatio nominis. The species is named in honour of the Russian hydrobiologist Dr. Pyotr Viktorovich Matafonov (Institute of Natural Resources, Ecology and Cryology of the Siberian Branch of the Russian Academy of Sciences) who collected material in type locality.

Description

Adult male (n = 2, except when otherwise stated). Total length 3.6–3.9 mm. Total length/wing length 1.06– 1.16.

Coloration. Brown, dark brown. Head, thorax and abdomen with hypopygium brown or dark brown. Legs yellowish brown. Wings greyish.

Head. Eyes pubescent, slightly elongate dorsomedially. Temporal setae including 13–19 verticals and 12–13 postorbitals. Clypeus with 2–5 setae. Antenna with 13 flagellomeres and well developed plume of setae; maximal length of these setae on flagellomeres 540 μm; terminal flagellomere with 1 subapical seta, 60–64 μm long; pedicel with 2 setae, 60–72 μm long. AR 1.35–1.57. Palpomere length (μm) (n=1): 44, 84, 156, 120, 156. Palpomere 3 in distal part with sensilla capitata with diameter 8 μm. Head width/palpal length 1.0.

Thorax.Antepronotum with 7 ventrolateral setae. Dorsocentrals 12–13, prealars 5–6. Scutellum with 9–18 setae in 1 row.

Wing. Length 3.3–3.4 mm, width 0.92 mm. Anal lobe developed and rounded. Squama with 30–46 setae, 75–100 μm long. R and R 1 with 18–20 setae, R 4+5 with 4–5 setae in distal part. RM/MCu 2.3–2.5.

Legs. Spur of front tibia 76–84 µm long. Spurs of mid tibia 60–64 µm and 64 µm long. Spurs of hind tibia 84–96 µm and 60–64 µm long. Hind tibial comb with 16 setae. Length (μm) and proportions of leg segments are as in Table 1 .

Hypopygium ( Figs 1–6 ). Tergite IX with 17–18 setae from one side, 32–36 µm long and with anal point, 80 µm long and 16 µm wide in base, apically with 3 setae, 24–26 µm long ( Figs 1–3 ). Laterosternite IX with 8 setae, 64–76 µm long. Transverse sternopodeme consisting of a narrow arch 216–240 µm long. Aedeagal lobe 116–132 µm long, wide in basal third and narrow finger-shaped in distal two-thirds ( Fig. 6 ); phallapodeme 120 µm long. Gonocoxite 308–310 µm long, with basal plate in the form of two rounded lobelike projections, lower of which is covered with microtrichia and numerous long setae, upper without microtrichia and setae ( Fig. 4 ). Gonostylus massive, 168–176 µm long and 56–60 µm wide, with long crista dorsalis; apex with short macroseta, 16 µm long ( Figs 1, 5 ); HR 1.75–1.76.

Pupa (n=4). Total length ca 6 mm. Abdomen length 4.28–5.44 mm. Coloration brownish. Exuviae white and transparent, sometimes yellowish.

Cephalothorax. Frontal apotoma with 2 setae 152–160 μm long. Thorax in anterodorsal part smooth or slightly wrinkled. Thoracic horn absent. Precorneal setae lengths (μm): Pc 1 – 48–60, Pc 2 – 180–256, Pc 3 – 56–104. Pc 1 and Pc 3 weak and pale, Pc 2 strong and brown ( Figs. 7–8 ). Antepronotum with 1 median seta, 180–236 μm long and 1 lateral antepronotals, 64–152 μm long. Dorsocentrals absent.

Abdomen. Apophyses distinct. Tergite I without shagreen and posterior transverse row of spines. Tergite II with shagreen in anterior third, tergites III–VIII almost completely covered in shagreen. Sternites I and IX without shagreen; II–VIII with median and lateral shagreen. Tergites II—VIII with posterior transverse row of strong, brown or dark brown elongated spines, maximum length 72–80 μm and width 20–24 μm; sternites without spines. Number of these spines on tergites II–VIII accordingly – 34–40: 30–33: 27–34: 29–32: 22–33: 22–35: 16–25 ( Figs 9–12 ). Segment I with 1 pair of lateral setae. Segments II–VIII with 3 pairs of brouwn lateral setae 240–288 μm long. The setae extension is shown in Figs 8, 12 . Segments II –VIII with spine-like process on posterolateral corner, 28–40 μm long. Anal lobe with 3 anal macrosetae, 300–388 μm long, slightly curved in distal part; apical tubercle pointed, 48–52 μm long. Male genital sac not extended beyond anal lobe ( Fig. 12 ).

Fourth instar larva (n = 6). Coloration greenish. Total length 6.4–7.1 mm. Head capsule 460–514 µm long and 420–429 µm wide; brown or dark brown, postoccipital margin black and narrow. S I short, seta-like; S III simple. Labral lamellae consisting of 2 pectinate lobes. Premandible broad apically with 6 teeth ( Fig. 16 ). Antenna with 5 segments, length of antennal segments (µm): 40, 10, 7, 3, 3. Lauterborn organs small, often invisible; style 13 µm long, reaches the middle of the fourth segment; longest branch of antennal blade 35 µm long and reaches the apex of the fourth segment, shorter branch 33 µm long; ring organ 7–8 µm diameter located in basal quarter of first segment. AR 1.60–1.74. Mandible dark brown, with apical tooth and 4 inner teeth; apical tooth same length as first inner tooth but inner tooth slightly wide than apical tooth; seta subdentalis minute; seta interna with 18–20 simple branches ( Fig. 14 ). Mentum with 1 median and 6 pairs of lateral teeth; median tooth not much larger than first lateral tooth and together with two pairs of lateral teeth lighter than other lateral teeth; ventromental plate small ( Fig. 13 ). Abdominal setae dark brown 164–295 µm long; ratio of length of abdominal segment to length of setae 2.22–2.53 ( Fig. 18 ). Procercus dark brown, 48 µm long and 40 µm wide, bearing 7 dark brown anal setae 340–356 µm long and 2 subapical setae from which proximal subapical seta strong and dark brown, 284 µm long, distal seta pale and short. Last abdominal segment with 3 pairs of supraanal setae, from which middle setae most long – 276–280 µm ( Fig. 17 ). Posterior parapods 400 µm long. Dorsal pair of anal tubulus 128 µm long, ventral pair 156 µm long.

Diagnosis. Total length of adult male 3.6–3.9 mm. Wing length 3.3–3.4 mm AR 1.35–1.57. Dorsocentrals 12–13, prealars 5–6, scutellars 9–18. LR 1 0.71, BV 1 3.53–3.56, SV 1 2.43–2.46. Anal point apically with 3 setae. Aedeagal lobe wide in basal third and narrow finger-shaped in distal two-thirds. Gonocoxite with basal plate in the form of two rounded lobelike projections, lower of which is covered with microtrichia and numerous long setae, upper without microtrichia and setae. Gonostylus massive, with long crista dorsalis. HR 1.75–1.76. Pupa without thoracic horn. Pc 1 and Pc 3 weak and pale, Pc 2 strong and brown. Tergites II—VIII with posterior transverse row of strong, brown or dark brown elongated spines. Segment I with 1 pair of lateral setae. Segments II–VIII with 3 pairs long brown lateral setae. Segments II —VIII with spine-like process on posterolateral corner. Anal lobe with 3 anal macrosetae, slightly curved in distal part; apical tubercle pointed. Male genital sac not extended beyond anal lobe. Total length of larva 6.4–7.1 mm. Premandible broad, apically with 6 teeth. Antenna with 5 segments, Lauterborn organs small, often invisible; style reaches middle of fourth segment; longest branch of antennal blade reaches the apex of the fourth segment; ring organ located in basal quarter of first segment. AR 1.60–1.74. Mandible dark brown, with apical tooth and 4 inner teeth; apical tooth same length as first inner tooth but inner tooth slightly wide than apical tooth; seta interna with 18–20 simple branches. Mentum with 1 median and 6 pairs of lateral teeth; median tooth with two pairs of lateral teeth lighter than other lateral teeth. Abdominal setae dark brown, ratio of length of abdominal segment to length of setae 2.22–2.53. Procercus dark brown, little longer than wide, bearing 7 strong dark brown anal setae and 2 subapical setae from which proximal subapical seta is strong dark brown.

Remarks. Unfortunately, due to the uninformative description of the adult male holotype of Ps. parva ( Edwards 1932) and often other conflicting descriptions of adults, pupa and larvae of this species ( Pagast 1947; Wülker 1959; Zavřel 1941; Oliver 1959; Pankratova 1970; Schmid 1993 and other), it is impossible to make an objective and reliable comparison of this species with Ps. matafonovi sp. nov. The most complete and correct description of the imago and pupa of Ps. parva is given only in the work of Serra-Tosio (1971), according to which the gonocoxite of the male in dorsolateral position at the base of the gonostylus has a rounded-triangular protrusion, which is absent in the male Ps. matafonovi sp. nov. Also that the shape and structure of anal point and the aedeagal lobes differ in both species. Pupa of the new species without thoracic horn and tergites II–VIII with posterior transverse row of strong, brown or dark brown elongated spines, segments II–VIII with 3 pairs of lateral setae while pupa of Ps. parva with thoracic horn and tergites II–VIII with transverse row of thorn-like spines, segments II–VIII with 4 pairs of lateral setae.

Ecology. Larvae and pupae were collected in the upper reaches of the Kaydalovka River, at an altitude of 960– 980 m above sea level, among the fouling of small boulders with moss and yellow-green algae Vausheria geminata f. geminata and Tribonema sp. , at a depth of about 10 cm at a water temperature of 3.5–4.5 ºС.

Distribution. Known only from the type locality in upstream of Amur River basin.

Figures

FIGURES 1–6. Adult male of Pseudokiefferiella matafonovi sp. nov. 1, hypopygium in dorsal view; 2–3, anal point; 4, basal plate of gonocoxite; 5, gonostylus; 6, transverse sternapodeme, aedeagal lobes and phallapodeme. Scale bars: 50 μm.

FIGURES 7–12. Pupa of Pseudokiefferiella matafonovi sp. nov. 7–8, precorneals; 9, tergite IV; 10, tergite V; 11, tergites V–VI; 12, tergites VII–VIII and anal segment. Scale bars: 50 μm.

FIGURES 13–18. Fourth instar larva of Pseudokiefferiella matafonovi sp. nov. 13, mentum; 14, mandible; 15, antenna; 16, distal part of premandible; 17, anal segments in dorsal view; 18, anal segments in lateral view. SaS – supraanal setae. Scale bars: Fig. 4 – 50 μm; Figs. 15–16 – 20 μm.