Trouessartia locustellae, Mironov & Dmitryukov, 2025

Mironov, Sergey V. & Dmitryukov, Arsenii V., 2025, Three new species of the feather mite genus Trouessartia (Acariformes: Trouessartiidae) from passerines (Passeriformes) in the Asian part of Russia, Zootaxa 5661 (2), pp. 178-200 : 180-185

Trouessartia locustellae sp. nov.

Zoobank: 0F8C9A5B-5FDF-43B3-915A-73FFC7F41BF3

( Figs 1–4 , 13A, B )

Type material. Holotype male ( ZISP 23662 ) , 11 male and 7 female paratypes ( ZISP 23663–23680 ) from Helopsaltes certhiola (Pallas, 1811) ( Passeriformes : Locustellidae ), SVM-12-0820-2, Russia, Primorsky Krai, Spasski District, 5 km E of Stepnoe, 44°42’27.3”N, 132°40’06.8”E, 20 August 2012, coll. S.V. Mironov; 8 male and 9 female paratypes ( ZISP 2368 –23697 ), same host species, SVM-19-0811-1, Russia, Primorsky Krai, Spasski District, 15 km NW of Spasskoe, Khanka Lake coast, 44º40'04" N, 132º35'34" E, 11 August 2019, coll. S.V. Mironov.

Additional material. 4 males and 1 female ( ZISP 23698–23702) from Helopsaltes ochotensis (Middendorff, 1853) ( Passeriformes : Locustellidae ), SVM-11-0917-1, Russia, Sakhalin Island, 1 km S of Shebunino, 46°24'53"N, 141°51'05"E, 17 September 2011, coll. S. V. Mironov.

Description. MALE (holotype, ranges for 10 paratypes in parentheses) ( Figs 1 , 3A , 4 AD, G). Idiosoma, length × width, 520 (485–520) × 255 (245–255), length of hysterosoma 350 (315–350). Prodorsal shield: length along midline 160 (145–160), greatest width 170 (150–170), anterior part at level of trochanters II not narrowed, anterolateral extensions pointed, almost extending to rudimentary epimerites Ia between legs I and II, lateral margins not fused with scapular shields, posterior margin almost straight, surface without ornamentation. Internal scapular setae si spiculiform, 42 (30–42) long, separated by 63 (59–63); external scapular setae se separated by 120 (105– 120). Setae c2 spiculiform, 70 (62–75) long, situated in anteromedian angles of humeral shields. Setae c3 narrowly lanceolate with pointed apex, 25 (22–25) long ( Fig. 4G ). Prohysteronotal and lobar parts of the hysteronotal shield completely separated by narrow transverse band of soft tegument; total length of hysteronotal shield from anterior margin to lobar apices excluding terminal lamellae 325 (300–325), width at anterior margin 174 (158–174). Length of prohysteronotal part along midline 220 (200–220), lateral margins at level of trochanters III with deep incisions, margin of incision with heavily sclerotized C-shaped patch, surface without ornamentation. Dorsal setae d1, d2, e2 present, setae f2 absent. Length of lobar shield 100 (100–105). Opisthosoma strongly 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 22 (20–22); length from anterior end to posterior margins of terminal lamellae 48 (41–48), lateral margins of cleft almost touching. Terminal lamellae semi-ovate, with one angular denticle at level of setae h2 and with 15–18 rounded denticles along lateral and posterior margins, slightly overlapping by inner margins, length from bases of setae h3 to lamellar apices 25 (22–25), greatest width 33 (30–33). Distances between dorsal setae: c2:d2 82 (73–82), d2:e2 120 (110–120), e2:h2 85 (80–85), h2:h3 25 (21–25), h2:h2 45 (38–45), h3:h3 33 (30–33), e1:e2 63 (55–63), ps1:h3 12 (8–12).

Epimerites I free. Rudimentary sclerites rEpIIa small ovate. Genital apparatus: narrow, slightly enlarged posteriorly; intermedial sclerite with trapezoidal lateral projections, length excluding epiandrum 75 (70–75), greatest width (excluding projections) 30 (28–30); epiandrum ovate; distal ends of parameres, each with one denticle; aedeagus long but not extending beyond ends of parameres; basal sclerite roughly quadrangular, extending beyond level of setae g; latigenital sclerites absent ( Fig. 3A ). Small paragenital apodemes flanking genital apparatus at level of lateral projections. Anterior and posterior pairs of genital papillae similar in size, anterior papillae slightly more distant from midline than posterior ones. Genital shield absent. Setae g short filiform, about 1/8 the distance between setae g and ps3, with bases distant from each other. Postgenital plaque absent. Apophyses of adanal apodemes represented by two pairs of acute and flat spines at the level of adanal suckers. Lateral margins of opisthosoma without membranes. Translobar apodeme of medium width. Adanal shields represented by small ovate sclerites bearing setae ps3. Adanal suckers 22 (20–22) in diameter. Anterior ends of epimerites IIIa not extending to level of setae 4b, without angular extensions on inner margins. Epimerites IVa as plates of roughly ovate form, with anterior ends not extending to level of setae g. Setae 4b situated anterior to level of setae 3a, both these pairs anterior to genital apparatus apex; setae g slightly anterior to level of setae 4a. Distances between ventral setae: 4b:3a 20 (20–23), 4b:4a 111 (106–111), 4a:g 5 (5–6), g:ps3 80 (75–80), ps3: h3 107 (97–107).

Legs. Setae cG, mG of genua I, II filiform. Genual solenidia σ I and σ II situated at midlength of corresponding genua ( Fig. 4A, B ). Trochanteral setae sR III narrowly lanceolate, with acute apex, 20 (16–20) long. Legs IV with ambulacral disc not extending to posterior margin of terminal lamellae. Tarsus IV 42 (40–42) long; modified setae d barrel-shaped with discoid cap, situated in distal one third of this segment; modified setae e cylindrical, without cap, situated apically ( Fig. 4D ). Lengths of solenidia: σ I 48 (48–50), σ II 20 (15–20), σ III 26 (25–26), φ IV 48 (43–48).

FEMALE (range for 7 paratypes) ( Figs 2 , 3B–D , 4E, F , 13A, B ). Idiosoma, length × width, 555–603 × 228–256, length of hysterosoma 390–420. Prodorsal shield: shape as in male, surface without ornamentation, 148–155 × 148– 160. Setae si spiculiform, 25–30 long, separated by 60–62; setae se separated by 108–113. Setae c2 spiculiform, 60– 65 long, situated in anteromedial angle of humeral shields. Setae c3 narrowly lanceolate, with pointed apex, 24–26 long. Hysteronotal shield: length from anterior margin to posterior tips 350–375, width at anterior margin 165–170; lateral margins at level of trochanters III shallowly concave, margin of concavity without noticeable sclerotization; surface with 3-4 pairs of poorly distinct lacunae arranged in a bow-shaped row between levels of trochanters III and IV, remaining area without ornamentation ( Figs 2A , 3B , 13B ). Dorsal setae d1, d2, e2 present. Setae h1 filiform, 12– 14 long, situated anteromesal to setae h2, 25–26 from corresponding lateral margins of hysteronotal shield. Width of opisthosoma at level of setae h2 105–115. Setae ps1 situated equidistant from margins of opisthosomal lobes. Supranal concavity open posteriorly into terminal cleft, but clearly demarcated by narrow subtegumental bridge supporting primary spermaduct. Length of terminal cleft from anterior end of supranal concavity to lobar apices 155–165, length from free margin of interlobar membrane to lobar apices 105–117, greatest width of cleft 20–25. Interlobar membrane occupying anterior 1/5–1/6 of terminal cleft. External copulatory tube short and thin, situated on free margin of interlobar membrane, 11–12 long; basal guides of copulatory tube absent, primary spermaduct guide short. Distances between dorsal setae: c2:d2 77–92, d2:e2 90–96, e2:h2 75–85, h2:h3 62–65, h2:h2 78–90, h3:h3 48–55, d1:d2 33–41, e1: e2 41–42, h1:h2 20–21, h1:h1 47–51, ps1:h3 22–30.

Epimerites I free. Epigynum 38–40 long, 89–100 wide. Inner margins of epimerites IIIa without acute extension. Epimerites IVa present. Adanal sclerites absent. Setae f2 short setiform, setae ps2 minute. Head of spermatheca with short smooth collar; primary spermaduct strongly expanded except the part in terminal cleft, with heavily sclerotized bend near the entrance into supranal concavity; secondary spermaducts 10–12 long ( Fig. 3C, D ).

Legs. Setae cG, mG of genua I, II filiform. Trochanteral setae sR III narrowly lanceolate, with pointed apex, 16–18 long. Legs IV with ambulacral disc extending to level of setae ps1. Lengths of solenidia: σ I 49–51, σ II 14–15, σ III 22–26, φ III 63–68, φ IV 23–25.

Barcoding data. Genbank accession numbers for COI sequences from samples from Helopsaltes certhiola (SVM-12-0820-2 and SVM-19-0811-1) are PV370494 and PV370492, respectively. The accession number for the sample from H. ochotensis is PV370493.

Etymology. The specific epithet is taken from the host family Locustellidae and is a noun in the genitive case.

Differential diagnosis. The new species, Trouessartia locustellae sp. nov. is close to T. mironovi Constantinescu, 2013 from Acrocephalus melanopogon (Temminck) ( Acrocephalidae ) in having the following features in males: the lateral margins of lobar region are strongly convex, the margins of terminal lamellae have numerous festoonlike denticles, and the laterial incisions of hysteronotal shield are much deeper than those in females. Trouessartia locustellae differs from T. mironovi in the following characters: in both sexes, epimerites I are free, the posterior corners of the prodorsal shield are roughly rectangular, and setae c3 are narrowly lanceolate; in males, the genital apparatus has a pair of lateral trapezoidal projections, the paragenital apodemes are free from epimerites IVa, the anterior ends of epimerites IIIa do not extend to level of setae 4b, and the terminal lamellae are ovate in shape; in females, the external copulatory tube is 10–12 long. In both sexes of T. mironovi , the tips of epimerites I are connected by a narrow transverse bridge, the posterior corners of the prodorsal shield are pointed, and setae c3 are spiculiform; in males, the genital apparatus lacks lateral trapezoidal projections, the paragenital apodemes are fused with epimerites IVa, the anterior ends of epimerites IIIa extend to the level of setae 4b, and the terminal lamellae are circular in shape; in females, the external copulatory tube is extremely short, about 5 long.

Figures

FIGURE 1. Trouessartia locustellae sp. nov., male. A—dorsal view, B—ventral view.

FIGURE 2. Trouessartia locustellae sp. nov., female. A—dorsal view, B—ventral view.

FIGURE 3. Trouessartia locustellae sp. nov., details. A—genital apparatus and opisthosoma of male, ventral view, B— opisthosoma of female, dorsal view, C—spermatheca, D —supranal concavity and distal part of primary spermaduct. Abbreviations: ad—adanal apodeme, ap—apophyses of adanal apodeme, bs—basal sclerite, ct—external copulatory tube, ea— epiandrum, hs—head of spermatheca, is—intermedial sclerite, lp—lateral projection, pa—paragenital apodeme, pd—primary spermaduct, pg—primary spermaduct guide, pm—paramere, sd—secondary spermaduct, sp—spermatheca, tl—terminal lamella.

FIGURE 4. Trouessartia locustellae sp. nov., details. A, B—legs I, II of male, C, D—tibiae and tarsi III, IV of male, E, F— tibiae and tarsi III, IV of female, G—setae si, c2, c3 and sRIII of male.

FIGURE 13. Trouessartia females, dorsal shields.A—Trouessartia locustellae sp. nov., prodorsal shield, B—same, hysteronotal shield, C—T. simillima Gaud, 1957, prodorsal shield, D—same, hysteronotal shield.