Trouessartia mugimaki Mironov & Dmitryukov, 2025, sp. nov.

Trouessartia mugimaki sp. nov. Zoobank: 94FFFBF3-98D5-473F-9DFD-6F78DC0D3671 (Figs 5–8, 14A, B) Type material. Holotype male (ZISP 23703), 13 male and 15 female paratypes (ZISP 23704–23731) from Ficedula mugimaki (Temminck, 1815) (Passeriformes: Muscicapidae), SVM-22-0531-1(2), Russia, Buryatia, Kabansky District, Mishikha, 51°38’36”N, 105°31’20”E, 31 May 2022, coll. S.V. Mironov. Description. MALE (holotype, ranges for 13 paratypes in parentheses) (Figs 5, 7A, 8A–D, F). Idiosoma, length × width, 455 (420–470) × 215 (205–225), length of hysterosoma 305 (280–315). Prodorsal shield: length along midline 140 (125–145), greatest width 145 (140–155), anterior part at level of trochanters II not narrowed, anterolateral extensions elongated, with a small hook-shaped projection directed forward and not extending to epimerites Ia between legs I and II, lateral margins not fused with scapular shields, posterior margin slightly sinuous, surface with poorly distinct reticular ornamentation. Setae si spiculiform, 42 (38–43) long, separated by 52 (48–53); setae se separated by 102 (92–107). Setae c2 spiculiform, 55 (55–68) long, situated in anteromedian angles of humeral shields. Setae c3 narrowly lanceolate with subapical denticle, 30 (22–31) long (Fig. 8F). Prohysteronotal and lobar parts of the hysteronotal shield connected, delimited by large lateral incisions encompassing bases of setae e2, total length of hysteronotal shield from anterior margin to lobar apices excluding terminal lamellae 305 (280– 305), width at anterior margin 155 (135–155). Lateral margins at level of trochanters III with small incisions, more heavily sclerotized patch at margin of these incisions without a well-defined border, surface with poorly distinct circular lacunae in median area. Dorsal setae d1, d2, e2 present, setae f2 absent. Opisthosoma attenuate posteriorly; opisthosomal lobes fused with each other along midline forming a heavily sclerotized median septum, only apical parts of lobes posterior to level of setae h2 separated by narrow parallel-sided terminal cleft. Length of terminal cleft from anterior end to lobar apices 24 (21–24); length from anterior end to posterior margins of terminal lamellae 42 (40–47), width of cleft 3 (3–4). Terminal lamellae semi-ovate, with smooth margins, length from bases of setae h3 to lamellar apices 30 (25–33), greatest width 31 (25–32). Distances between dorsal setae: c2:d2 72 (66–72), d2:e2 95 (85–97), e2:h2 93 (80–93), h2:h3 26 (23–26), h2:h2 35 (35–38), h3:h3 30 (26–30), e1: e2 37 (37–45), ps1:h3 10 (10–11). Epimerites I free. Rudimentary sclerites rEpIIa minute or indistinct. Genital apparatus: long and narrow, length excluding epiandrum 45 (38–45), greatest width 8 (8–10); epiandrum roughly ovate; distal ends of parameres without denticles; aedeagus shaped as a long, narrow cone not extending beyond apices of parameres; latigenital sclerites absent, basal sclerite almost extending to level of setae 4a (Fig. 7A). Anterior and posterior pairs of genital papillae similar in size, anterior papillae more distant from midline. Genital shield represented by small sclerites at bases of setae g. Setae g filiform, about 1/3 the distance between setae g and ps3, with bases not adjacent to each other. Postgenital plaque small semicircular. Apophyses of adanal apodemes represented by longitudinal ridges behind the level of the adanal suckers. Lateral margins of opisthosoma without membranes. Translobar apodeme of medium width. Adanal shields represented by small ovate or teardrop-shaped sclerites bearing setae ps3. Adanal suckers 11 (11–12) in diameter. Anterior ends of epimerites IIIa anterior to level of setae 4b, without distinct angular extensions on inner margins. Epimerites IVa as plates of irregular form, with anterior ends not extending to level of setae g. Setae 4b situated anterior to level of setae 3a, both pairs anterior to genital apparatus apex; setae g posterior to level of setae 4a. Distances between ventral setae: 4b:3a 10 (6–12), 4b:4a 78 (70–81), 4a:g 7 (5–7), g:ps3 56 (50–58), ps3:h3 106 (96–106). Leg. Setae cG, mG of genua I, II filiform. Genual solenidia σ I and σ II situated at midlength of corresponding genua (Fig. 8A, B). Trochanteral setae sR III narrowly lanceolate, with subapical denticle, 22 (19–23) long. Legs IV with ambulacral disc extending to level of setae h3. Tarsus IV 35 (31–38) long; modified setae d barrel-shaped with discoid cap, situated in distal one third of this segment; modified setae e hemispheroid, without cap, situated apically (Fig. 8D). Lengths of solenidia: σ I 63 (48–63), σ II 28 (28–37), σ III 26 (22–29), φ IV 46 (45–56). FEMALE (range for 10 paratypes) (Figs 6, 7B, C, 8E, 14A, B). Idiosoma, length × width, 520–560 × 220–240, length of hysterosoma 365–390. Prodorsal shield: shape as in male, surface with faint net-like ornamentation, 145–155 × 150–160. Setae si spiculiform, 42–48 long, separated by 50–55; setae se separated by 103–110. Setae c2 spiculiform, 63–67 long, situated in anteromedial angle of humeral shields. Setae c3 lanceolate, with subapical denticle, 28–33 long. Hysteronotal shield: length from anterior margin to posterior tips 330–355, width at anterior margin 150–170; lateral margins at level of trochanters III shallowly concave; sclerotization at margin of this incision barely distinct; surface in posterior 1/3 with clear rounded and ovate lacunae, anterior 2/3 with poorly distinct ornamentation of ovate lacunae (Figs 7B, 14B). Dorsal setae d1, d2, e2 present. Setae h1 narrowly lanceolate, 21–23 long, situated anteromesal to setae h2 on non-sclerotized areas of roughly ovate form, 22–25 from corresponding lateral margins of hysteronotal shield. Width of opisthosoma at level of setae h2 90–94. Setae ps1 equidistant from margins of opisthosomal lobes or slightly closer to outer margins. Supranal concavity open posteriorly into terminal cleft. Length of terminal cleft from anterior end of supranal concavity to lobar apices 138–143, length from free margin of interlobar membrane to lobar apices 85–86, greatest width of cleft 28–35. Interlobar membrane occupying anterior 1/3 of terminal cleft. External copulatory tube absent, copulatory opening situated ventrally on minute nipple-like tubercle near free margin of interlobar membrane. Primary spermaduct guide present. Distances between dorsal setae: c2:d2 72–81, d2:e2 90–96, e2:h2 73–78, h2:h3 62–63, h2:h2 65–70, h3:h3 48–50, d1:d2 38–45, e1: e2 38–41, h1:h2 5–7, h1:h1 35–39, ps1:h3 10–12. Epimerites I free. Epigynum 46–48 long, 96–103 wide. Inner margins of epimerites IIIa with acute extension. Epimerites IVa present. Adanal sclerites absent. Setae f2 indistinct, setae ps2 short setiform. Head of spermatheca with short smooth collar; proximal end of primary spermaduct inside head of spermatheca inflated and with numerous longitudinal folds; distal part of primary spermaduct without enlargements; secondary spermaducts 45–50 long (Fig. 7C). Legs I–III as in males. Trochanteral setae sR III narrowly lanceolate, with truncate apex and subapical denticle, 23–26 long. Legs IV with ambulacral disc not extending to level of setae ps1. Length of solenidia: σ I 57–65, σ II 26–43, σ III 24–42. Barcoding data. Genbank accession number of the COI sequence is PV370490. Etymology. The specific epithet is taken from the species name of the type host and is a noun in apposition. Differential diagnosis. Trouessartia mugimaki sp. nov. belongs to the grouping of species associated with Muscicapidae and most clearly characterized by setae h1 situated on large desclerotized areas (windows) of the hysteronotal shield and by the absence of the external copulatory tube, e.g. T. swidwiensis Jablonska, 1968, T. simillima Gaud, 1957, and T. calliope Mironov, 2021 (Santana 1976; Mironov 2021b; Dmityukov and Mironov 2023). Among species of this group, T. mugimaki is most similar to T. simillima from Muscicapa striata (Pallas) in having the following features: in males, the genital apparatus is narrow and almost parallel-sided, the prohysteronotal shield bears ornamentation of ovate lacunae, setae g are short filiform and surrounded by the semicircular subgenital plaque, and rudimentary sclerites rEpIIa are minute, barely distinct; in females, the posterior half or 1/3 of the hysteronotal shield bears numerous large lacunae mostly of ovate form, the non-sclerotized lacunae surrounding bases of setae h1 are large and extend to bases of macrosetae h2, and the copulatory opening is distant from the free margin of interlobar membrane. Trouessartia mugimaki differs from T. simillima in the following features: the tips of adanal apodemes are narrow and bent medially with a distinct blunt angle; the apophyses of adanal apodemes are shaped as longitudinal ridges; genital setae g are situated posterior to the level of setae 4a; in females, the terminal cleft is narrow (28–35 wide), setae h1 are 21–24 long and distinctly longer than half the distance between their bases, and the opisthosoma is narrower, with the width at the level of setae h2 90–94 (Figs 6A, 7B, 14A). In males of T. simillima, the anterior ends of adanal apodemes are thick and slightly curved, the apophyses of adanal apodemes are shaped as tubercles, genital setae g are situated at the level of setae 4a; in females, the width of terminal cleft is 40–50, setae h1 are 18–20 long and barely extend to the midline of idiosoma, and the width of opisthosoma at the level of setae h2 is 100–110 (Fig. 13D).