Thalassomya paraskevae Makarchenko, Semenchenko et Palatov, 2024

Makarchenko, Eugenyi A., Semenchenko, Alexander A., Palatov, Dmitry M. & Lisanovskaya, Elena A., 2024, Morphological description and DNA barcoding of Thalassomya paraskevae sp. nov. (Diptera: Chironomidae: Telmatogetoninae) from coast of the Black Sea, Zootaxa 5501 (4), pp. 524-530 : 525-528

Thalassomya paraskevae Makarchenko, Semenchenko et Palatov , sp. nov.

http://zoobank.org/NomenclaturalActs/ ED222392-FC41-44C4-BCA1-0E74C1AB7640

( Figs. 1 –11)

Type material. Holotype, adult male, ABKHAZIA: Gudautra District , New Athos Town, breakwater near the pier on the beach of the village, 01.0 I.2024, 43.083339 N, 40.816681 E, leg. D. Palatov. Paratypes: 6 adult males, the same data as holotype ; 3 adult males, RUSSIA: Krasnodar Territory, Tuapse District, Cape Kadosh cliffs on the Black Sea coast, near the village of Agoy , south of the mouth of the river of the same name, 25.04.2024, 44.132806 N, 39.026056 E, leg. D. Palatov.

Derivatio nominis. The species is named in honour of Bulgarian chironomidologist Dr. Paraskeva Mikhailova (Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia) who studied Thalassomya frauenfeldi from Bulgaria’s Black Sea coast.

Description

Adult male (n = 5, except when otherwise stated). Total length 3.4–4.2 mm. Total length/wing length 0.98–1.0.

Coloration. Dark brown. Wings grey, with brownish veins.

Head ( Fig. 1 ). Eyes bare, rounded, without dorsomedial projections. Temporal setae strong and numerous— 75–108. Clypeus with 49–58 strong setae. Antenna with scape covered ca 30 strong setae and 6 flagellomeres with reduced plume of setae ( Fig. 2 ); number and length of these setae on 1–5 flagellomeres respectively: 5–6 (44–68 μm), 4 (60–68 μm), 4 (44–52 μm), 4 (48–56 μm), 4 (44–68 μm); terminal flagellomere with 4 setae, 48–60 μm long in basal part and with 1 subapical setae, 32–40 μm long. Length of 1–6 flagellomeres (μm): 96–112, 52–56, 44–52, 40–48, 40–44, 96–120; terminal flagellomere with a distinct nipple-like apex. AR 0.35–0.39. Palpomere length (μm): 40–42, 32–44, 80–88, 136–188, 208–252. Palpomere 1 without setae, palpomeres 2–3 with setae 68–96 μm long, palpomeres 4–5 with setae 24–32 μm long; palpomere 3 in distal part with sensilla capitata with diameter 16 μm. Head width/palpal length 1.12–1.26. Antennal length/palpal length 0.74–0.75.

Thorax. Antepronotum with 37–40 ventrolateral setae, 148–256 μm long. Acrostichals 30–32, 104–128 μm long, in anterior part in 1 row, in posterior part in 2 rows; dorsocentrals 23–39, 156 μm long; humerals 5–6, 100–104 μm long; prealars 16–21, 100–112 μm long (in 2 groups). Scutellum with 30–34 setae. Preepisternum without setae.

Wing ( Fig. 3 ). Length 3.44–4.08 mm, width 1.08–1.28 mm. R 2+3 absent. Rand R 1 with 62–68 setae, R 4+5 with 35–38 setae. fCu well beyond base of r-m. Anal lobe rounded-angular. Squama with 31–45 setae, 100–120 μm long.

Legs. Spur of front tibia 80–100 µm long. Spurs of mid tibia 76–80 µm and 96–120 µm long. Spurs of hind tibia 92 µm and 92–100 µm long. Anterior tarsal claws on front and middle legs pectinate at tip, other claws sharp ( Figs. 4–5 ). Length (μm) and proportions of leg segments are as in Table 1 .

Hypopygium ( Figs. 7 –11). Tergite IX reduced, with 25–29 setae in two groups. Laterosternite IX with 10– 11 setae. Gonocoxite 304–308 µm long, broad at base, rounded laterally, abruptly narrowed on distal half; dorsobasal lobe triangle rounded or rounded, with 4–5 setae 32–40 µm long and in subapical part with group of very short setae; on ventral side at base with a patch of strong and long (112–128 µm) setae. Gonostylus 144–156 µm long, broadest medially, tapering apically to 2 setae, 24–44 µm long, with some setae 72–88 µm along the outer edge. Endomere yellow and with setae, 6–8 µm long in distal part. Phallapodeme dark brown, 184–188 µm long. HR 1.93–2.17.

Pupa and larva unknown.

Diagnosis and comments. Adult male total length 3.4–4.2 mm. Eyes bare, without dorsomedial projections. Temporal setae strong and numerous. Clypeus with 49–58 strong setae. Antenna with 6 flagellomeres and reduced plume of setae; terminal flagellomere with a distinct nipple-like apex; AR 0.35–0.39. Palpomere 3 in distal part with sensilla capitata. Head width/palpal length 1.12–1.26. Antennal length/palpal length 0.74–0.75. Antepronotum with 37–40 ventrolateral setae. Acrostichals 30–32, in anterior part in 1 row, in posterior part in 2 rows; dorsocentrals 23–39; humerals 5–6; prealars 16–21 (in 2 groups). Scutellum with 30–34 setae. Preepisternum without setae. Wing length 3.44–4.08 mm, R 2+3 absent. Anal lobe rounded-angular. Squama with 31–45 setae. Anterior tarsal claws on front and middle legs pectinate at tip, other claws sharp. LR 1 0.45–0.55, BV 1 4.69–4.99, SV 1 3.39–3.81. Tergite IX reduced, with 25–29 setae in two groups. Gonocoxite broad at base, rounded laterally, abruptly narrowed on distal half; dorsobasal lobe triangle rounded or rounded, with 4–5 setae and in subapical part with group of very short setae; on ventral side at base with a patch of strong and long setae. Gonostylus broadest medially, tapering apically to 2 setae, with some setae along outer edge. Endomere yellow and with setae in distal part. HR 1.93–2.17.

As noted above, the new species is most closely related to T. frauenfeldi and is poorly distinguished from the latter in morphological features. The matter is further complicated by the fact that T. frauenfeldi was described by Schiner (1856) from adult female and for comparison we can use only the description by Wirth (1947), which is based on an adult male, a pupa and a larva from San Remo in Italy. This description is not complete enough. However, it can be noted that structure of the male hypopygium of these two species do not differ as well as value of AR, wing venation, shape of terminal flagellomere and some other features. There are differences in the number of ventrolateral setae on the antepronotum and the values of LR, BV and SV. Thus, a male T. paraskevae sp. nov. with 37–40 ventrolateral setae on the antepronotum, LR 1 0.45–0.55, BV 1 4.69–4.99, SV 1 3.39–3.81, while male T. frauenfeldi with 8–10 ventrolateral setae, LR 1 0.57, BV 1 4.53, SV 1 3.25. It is also possible that there will be a different number of acrostichals, dorsocentrals and other setae of mesonotum but unfortunately there is no such data in the description of T. frauenfeldi ( Wirth 1947) . Most likely, we are dealing with cryptic species, which can be reliably distinguished only by molecular methods. The use of this method will also allow in the future to analyze the species of Thalassomya from the Bulgarian Black Sea coast, which was recorded as T. frauenfeldi ( Valkanov 1949; Valkanov & Michailova 1974; Michailova 1976) and may be T. paraskevae sp. nov.

Ecology. Like other species of Thalassomya , the new species is associated with algal fouling on rocks or similar artificial structures such as breakwaters located along the coastal area. Adult individuals actively moved along the rocks at the waterline, in the splash zone, occasionally flying from one place to another. The highest locomotor activity of imago was observed during daytime hours, correlated with maximum air temperature. However, the activity of some individuals had been also noted at night. The species cohabits with Telmatogeton sp. and Clunio sp.

Distribution. Known only from the type locality in coast of the Black Sea ( Figs. 12–15 ).

Figures

FIGURES 1–8. Adult male of Thalassomya paraskevae sp. nov. 1, head; 2, antenna; 3, wing; 4, claws of mid leg; 5, claws of hind leg; 6, endomeres and phallapodemes; 7–8, hypopygium, in dorsal view; 9, part of hypopygium, in ventral view; 10, dorsobasal lobe of gonocoxite; 11, gonostylus.

FIGURES 12–15. Habitats of Thalassomya paraskevae sp. nov. on the coast of the Black Sea near New Athos (Abkhazia) (12– 13, type locality) and Cape Kadosh in the vicinity of Tuapse (Krasnodar Territory, Russia) (14–15). Arrows indicate collection points.