Trouessartia seiurus Mironov and Chandler, 2020

Mironov, Sergey V. & Chandler, C. Ray, 2020, Feather mites of the genus Trouessartia (Acariformes: Trouessartiidae) from passerines (Aves: Passeriformes) in Georgia, USA, Zootaxa 4860 (1), pp. 1-54 : 19-23

Trouessartia seiurus Mironov and Chandler , sp. n.

( Figs. 11–13 )

Type material. Holotype male ( BMOC 20-0303 - 008 ), 14 male and 18 female paratypes from Seiurus aurocapilla (Linnaeus, 1766) ( Passeriformes : Parulidae ) ( SVM 18-0530 - 8 /2), USA, Georgia, Statesboro, Georgia Southern University Campus , 32°25’15”N, 81°47’22”W, 1 May 2018, coll. C. R. Chandler.

Depositories. Holotype, 5 male and 5 female paratypes— UMMZ, remaining paratypes—ZISP.

Description. MALE (holotype, ranges for 10 paratypes in parentheses) ( Figs. 11 , 13 A–D, G). Idiosoma, length × width, 435 (425–450) × 210 (205–220), length of hysterosoma 290 (270–290). Prodorsal shield: length along midline 135 (125–140), greatest width posterior to level of scapular setae 150 (145–155), anterior part at level of trochanters I, II not narrowed, anterolateral extensions angular, almost reaching bases of epimerites Ia, lateral margins not fused with scapular shields, posterior margin almost straight, surface without ornamentation. Internal scapular setae si thin spiculiform, 25 (25–30) long, separated by 62 (60–64); external scapular setae se separated by 100 (95–100). Setae c2 long spiculiform, 38 (37–50) long, situated in anteromedian angle of humeral shields. Setae c3 narrowly lanceolate, with blunt apex, 23 (22–25) long. Hysteronotal shield completely separated into prohysteronotal and lobar parts, total length 275 (250–280). Prohysteronotal shield: length along midline 175 (170–180), width at anterior margin 145 (135–145), lateral margins at level of trochanters III with small incision, flanked by C-shaped sclerotized patch, DHA absent, central area bear faint reticular ornamentation. Dorsal setae d1, d2, e2 present. Setae f2 absent. Length of lobar shield excluding terminal lamellae 97 (88–105). 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 cleft from anterior end to lobar apices 23 (22–28); length from anterior end to posterior margin of terminal lamellae 58 (55–62), width 8 (7.5–9). Terminal lamellae semi-ovate, with slightly attenuate apices, with smooth margins; length from bases of setae h3 to apices 33 (30–38), greatest width 25 (22–25). Distance between dorsal setae: c2: d2 70 (68–73), d2:e2 90 (87–93), e2:h2 75 (67–78), h2:h3 22 (20–25), h2:h2 42 (37–43), h3:h3 33 (28–33), d1:d2 45 (42–45), e1: e2 40 (35–40).

Epimerites I free. Rudimentary sclerites rEpIIa shaped as inverted teardrop with a small circular lacuna. Genital apparatus: length excluding basal sclerite 45 (45–48), greatest width 20 (19–20), epiandrum roughly ovate, latigenital sclerites absent, distal ends of parameres without denticles, aedeagus short finger-shaped. Anterior genital papillae distinctly larger and situated more distant from midline than posterior papillae. Postgenital plaque large semicircular. Setae g long, noticeably enlarged in basal 2/3rd, with bases clearly separated and surrounded by small and sclerotized areas weakly connected to each other (rudimentary genital shield). Apophyses of adanal apodemes represented by narrow ridges with rounded tubercle at anterior end. Lateral margins of opisthosoma with barely distinct lateral membranes. Translobar apodeme present. Adanal shields shaped as small triangles bearing setae ps3. Adanal suckers 15 (13–15) in diameter. Inner ends of epimerites IIIa with apices extending to level of setae 4b, and without extensions on inner margins. Epimerites IVa short and wide, with anterior ends barely reaching level of basal sclerite and setae g. Setae 4b situated anterior to level of setae 3a; setae g slightly posterior to level of setae 4a. Distance between ventral setae: 4b:3a 7 (7–10), 4b:g 82 (82–88), g:g 12 (8–12), g:ps3 55 (50–55), ps3: h3 95 (90–105).

Setae cG, mG of genua I, II filiform. Genual solenidia σ I and σ II situated slightly closer to distal margin of corresponding genu ( Fig. 13A, B ). Trochanteral setae sR III narrowly lanceolate with blunt apex, 15 (13–15) long. Legs IV with ambulacral disc extending slightly beyond level of h3. Tarsus IV 35 (35–38) long; modified setae d barrel-shaped, with discoid cap, situated in distal one third of this segment; modified setae e button-like, without cap, situated apically ( Fig. 13C ). Length of solenidia: σ I 45 (42–55), σ II 10 (10–13), σ III 25 (25–28), φ IV 35 (32–38).

FEMALE (range for 10 paratypes) ( Figs. 12 , 13E, F ). Idiosoma, length × width, 500–520 × 210–220, length of hysterosoma 345–365. Prodorsal shield: shaped as in male, 135–140 long, 155–160 wide, surface without ornamentation. Setae si thin spiculiform, 25–28 long, separated by 65–68; setae se separated by 105–110. Setae c2 spiculiform, 40–45 long, situated in anteromedian angle of humeral shields. Setae c3 narrowly lanceolate, with blunt apex, 20–24 long. Hysteronotal shield: length from anterior margin to tips of shield 315–330, width at anterior margin 150–160, lateral margins at level of trochanters III with incision flanked by bean-shaped sclerotized patch, DHA absent, anterior half from margin to level of trochanters IV with weakly pronounced small ovate lacunae, posterior half from trochanters IV to level of setae h2 with narrowly ovate lacunae. Dorsal setae d1, d2, e2 present. Setae h1 narrowly lanceolate, extending to free margin of interlobar membrane, 28–30 long, situated anteromesal to bases of setae h2, 22–24 from corresponding lateral margins of hysteronotal shield. Width of opisthosoma at level of setae h2 95–100. Setae ps1 situated equidistant from margins of opisthosomal lobes. Supranal concavity open posteriorly into terminal cleft. Length of terminal cleft including supranal concavity to lobar apices 135–140, length from free margin of interlobar membrane to lobar apices 100–110, width of cleft at level of setae h3 42–50. Interlobar membrane occupying anterior 1/8th of terminal cleft. External copulatory tube straight stylet-like with acute apex, situated on free margin of interlobar membrane, 24–26 long; basal guide of external copulatory tube weakly sclerotized, primary spermaduct guide in supranal concavity tube-like with basal enlargement. Distance between dorsal setae: c2:d2 75–60, d2:e2 85–88, e2:h2 57–60, h2:h3 65–68, h2:h2 77–85, h3:h3 57–63, d1:d2 47–53, e1: e2 28–32, h1: h2 15–22, h1:h1 42–48, ps1:h3 14–16.

Epimerites I free. Epigynum 40–43 long, 92–98 wide ( Fig. 12B ). Inner margins of epimerites IIIa with small blunt-angular extension. Epimerites IVa short and wide.Anal opening with small adanal sclerites. Setae f2, ps2 present. Head of spermatheca with semi-ovate peak, primary spermaduct without enlargement and with S-shaped bend or loop before entering into external copulatory tube, secondary spermaducts 22–28 long ( Fig. 13E ).

Legs I, II as in males ( Fig. 13A, B ). Trochanteral setae sR III narrowly lanceolate with blunt apex, 17–18 long. Legs IV with ambulacral disc extending to midlength between levels of setae h2 and h3. Length of solenidia: σ I 50–62, σ II 14–16, σ III 25–28.

Differential diagnosis. Among previously described species of the capensis group, the new species, Trouessartia seiurus sp. n., is closest to T. basileuteri Hernandes, 2014 in having setae h 1 in females not extending beyond the margin of the interlobar membrane and the stylet-like external copulatory tube approximately reaching the midlength between the levels of setae h2 and h 3 in females. Trouessartia seiurus differs from T. basileuteri in having the following features: in males, the prohysteronotal shield has a faint reticulate ornamentation, the rudimentary sclerites rEpIIa are teardrop-shaped with a small lacuna in centre, and the bases of setae g are surrounded by noticeable sclerotized areas; in females, the anterior half of the hysteronotal shield bears poorly distinct lacunae (in contrast to well outlined lacunae in the posterior part), the external copulatory tube is shorter (28–30) and does not extend to the midlength between the levels of setae h2 and h3, and the distal part of the primary spermaduct has a Sshaped bend or loop. In males of T. basileuteri , the prohysteronotal shield lacks any ornamentation, the rudimentary sclerites rEpIIa are shaped as small ovals without a lacuna, and the bases of setae g are not surrounded by sclerotized areas; in females, the small ovate lacunae on the anterior and posterior parts of the hysteronotal shield are equally well-distinct, the external copulatory tube is longer (36–42) and extends beyond the midlength between the levels of setae h2 and h3, and the distal part of the primary spermaduct is straight.

Etymology. The specific epithet is taken from the generic name of the type host and is a noun in apposition.

Figures

FIGURE 11. Trouessartia seiurus sp. n., male. A—dorsal view, B—ventral view.

FIGURE 12. Trouessartia seiurus sp. n., female. A—dorsal view, B—ventral view.

FIGURE 13. Trouessartia seiurus sp. n., details. A, B—genu, tibia and tarsus I, II of male, respectively, C—tibia and tarsus IV of male, D—setae si, c2, c3 and sRIII of male, E—spermatheca and spermaducts, F—opisthosoma of female, dorsal view, G—opisthosoma and genital apparatus of male, ventral view.