Coelosynapha Kjaerandsen, Polevoi & Salmela, 2020

Kjaerandsen, Jostein, Polevoi, Alexei & Salmela, Jukka, 2020, Coelosynapha, a new genus of the subfamily Gnoristinae (Diptera: Mycetophilidae) with a circumpolar, Holarctic distribution, Biodiversity Data Journal 8, pp. 54834-54834 : 54834

Coelosynapha Kjaerandsen, Polevoi & Salmela, 2020 gen. n.

Coelosynapha Coelosynapha loici Kjaerandsen, Polevoi & Salmela Status: new species described in this paper.

Description

A Gnoristinae genus, as presently known with moderately slender and quite small, down to 3 mm body length, species (Figs 3, 5 ). Colouration uniformly brown on head and body, darker preterminal segments, mostly yellow on legs and terminalia. Head (Fig. 4) round, eyes kidney-shaped with tendency of dorsal eye-bridge expansion (like in Synapha Meigen, 1818, unlike in Coelosia Winnertz, 1864 and Austrosynapha Tonnoir, 1929), interommatidia pubescent. Antenna moderately slender, with 16 segments, large, semi-globular pedicel and flagellar segments 2-3 times as long as wide (shorter in Synapha , distinctly longer in Coelosia and Austrosynapha ). Mouth parts average, with five, gradually longer palpal segments, no clear sensory pit discernible in third segment (without slide mounting). Clypeus bud-shaped, shorter than face. Three ocelli in a near straight line (Fig. 4 b, c), lateral ocellus more than two times its diameter from eye. Antepronotum with pair of strong antepronotal setae arching over the head (Fig. 4 a, c). Mesonotum with setae in acrostichal and dorsocentral rows, devoid of setulae in between but rich in setae laterally (Fig. 4 c). Meso- and metapleurites all without setae (Figs 4 a, 5 ). Wings (Figs 6, 7) hyaline, unpatterned, wing membrane with irregularly arranged microtrichia. Costa produced more than half way between R4+5 and M1, subcosta long, ending in C proximal to crossvein Rs (Fig. 6 a), usually without, occasionally with crossvein sc-r (Fig. 7 d). Radial sector variable, usually with R2+3 present (Fig. 6 d), sometimes with R2 and R3 separate (Fig. 6 b), occasionally with only crossvein Rs (Fig. 7 b). Anterior fork with stem more than 2 × longer than r-m. Posterior fork short, rather widely divergent. All veins anterior of iCu with setae on dorsal surface except for basal transversal crossvein tb and M -stem. Legs with irregularly arranged setulae. Fore tarsus subequal in length to fore tibia. No sense organ discernible on mid tibia.

Female terminalia (Fig. 8 ) rather truncated, with only hypoproct/sternite 10 and cerci somewhat elongated. Tergite 8 short, wide rectangular. Tergite 9 wide, subrectangular, with some setae extending towards epiproct dorsally. Cercus with first segment more than 2 × as long as wide, second segment small, ovate. Gonocoxite 8 moderately split ventrally, with free, sclerotised, semicircular lamellae. Sternite 9 small, retracted.

Male terminalia (Figs 9, 10) with tergite 9 long and apically tapered. Cerci and epiproct usually partly retracted under tergite 9, but can be exposed (Fig. 9 a). Gonocoxite open, semicircular with deep ventral cleft (Fig. 10 a). Gonostyles large, elongated, exposed, apically with three, sclerotised, blunt, digitate projections and pair of long setae on inner surface (Fig. 10 b). Aedeagal apparatus inconspicuous, tiny, elongated, framed within a small, pentagonal parameral structure (Fig. 10 a).

Diagnosis

A Gnoristinae genus similar to Austrosynapha Tonnoir, 1929, Coelosia Winnertz, 1864 and Synapha Meigen, 1818 in general appearance, but with very characteristic and unique male terminalia with three blunt, digitate processes apically on the gonostyles (Figs 9 a, b, 10 a, b). It can be separated from the three genera by the wing venation having the combination of 1) extension of C long, ending more than half way between R4+5 and M1 (Fig. 6 a, like in Coelosia , shorter in Austrosynapha and Synapha ); 2) Sc ending in C at level of Rs (Fig. 6 a, shorter in Austrosynapha which is variable for this character), usually without, but occasionally with sc-r present (Fig. 7 d, always absent in Coelosia ); 3) anterior fork petiole more than 2 × length of crossvein r-m (Fig. 6 a, like in most Austrosynapha and all Synapha , unlike in Coelosia ); 4) short and wide posterior fork (Fig. 6 a, like in all Coelosia and some Austrosynapha , unlike in Synapha and some Austrosynapha ).

Etymology

The generic name is feminine gender and put together by the two genus names Coelosia Winnertz, 1864 and Synapha Meigen, 1818, indicating the affinity to and intermediate position between those two genera.

Distribution

Records of the new genus display a circumpolar distribution pattern from Fennoscandia to Far East Russia in the Palaearctic Region and across Canada in the Nearctic Region (Fig. 2 ).

Figures

Figure 2. The circumpolar distribution of Coelosynapha gen. n. visualised on Google Earth. Green plots across the Palaearctic region display records of Coelosynapha loici sp. n., yellow plots across the Nearctic region display records of Coelosynapha heberti sp. n.

Figure 5. Holotype of Coelosynapha heberti sp. n., in 95 % ethanol (CC- 0, CBG Photography Group, Centre for Biodiversity Genomics).

Figure 8. Terminalia of female paratype of Coelosynapha heberti sp. n. (A = dorsal view. B = lateral view). Abbreviations: C 1 = cercus 1; C 2 = cercus 2; G 8 = gonocoxite 8; HP / S 10 = hypoproct and sternite 10; S 9 = sternite 9; T 8 = tergite 8; T 9 = tergite 9.