Hemialges mimus (Trouessart, 1919) Mironov, 2021

Mironov, Sergey V., 2021, The identity of Plesialges mimus Trouessart, 1919 and taxonomic notes on the feather mite genus Hemialges Trouessart, 1895 (Acariformes: Analgidae), Acarologia 1895 (3), pp. 626-640 : 632-638

Hemialges mimus (Trouessart, 1919) comb. n.

( Figures 1-6)

Plesialges mimus Trouessart, 1919: 336-337 ; Trouessart and Berlese 1921: 4; Mironov 2019:

30.

Material examined — Male lectotype and female paralectotype ( MNNH, Trouessart collection, # 30B1) from Pomatostomus superciliosus (Vigors & Horsfield, 1827) ( Passeriformes : Pomatostomidae ) [= Pomathorhinus superciliosus ], Australia, no date, E. Trouessart. (Lectotype and paralectotype designated here).

Description — Heteromorph male (lectotype) ( Figures 1, 2, 5, 6A, B). Idiosoma, length

× width, 365 × 245, moderately widened, humeral areas blunt-angular. Hysterosoma length 265. Subcapitulum with lateral spines. Prodorsal shield: shaped as almost rectangular plate, posterior margin almost straight, posterior corners with roughly rounded extensions bearing setae se, median ridges not developed, posterior suprategumental processes absent, greatest length 82, width at posterior margin 88, surface of median area shaped as narrow trapezoid with dense and strongly pronounced punctuation, lateral areas almost smooth ( Figure 1). Setae vi about 1.5 times longer than prodorsal shield. Setae se separated by 75, almost extending to posterior margin of opisthosoma; setae si not extending to level of setae d2. Supracoxal setae scx absent. Posteromesal corners of scapular shields with triangular suprategumental extensions. Humeral shields without lateral spines. Hysteronotal shield: roughly rectangular in shape, anterior margin straight, anterior angles acute, lateral margins posterior to level of trochanters IV slightly convex, greatest length of shield 215, width at anterior margin 87, anterior part with barely distinct transverse striae, remaining surface without ornamentation. Opisthosoma gradually attenuate posteriorly, posterior margin almost straight, opisthosomal lobes and lamellae not developed. Bases of macrosetae h2, h3 close to each other and situated in posterolateral corners of opisthosoma. Supranal concavity 43 long. Setae c2 situated in anteromesal extensions of humeral shields, extending beyond level of setae e2. Setae d 2 in anterior angles of hysteronotal shield, extending beyond posterior margin of opisthosoma, setae e2 on lateral margins of this shield, with distal half extending beyond posterior margin of opisthosoma. Short setae d1 on striated tegument, near anterior margin of hysteronotal shield. Setae e1 and hysteronotal gland openings gl slightly anterior to level of setae e2. Setae f2 about

10 long, situated laterally at level of setae ps2. Setae ps1 about 10 long, slightly anterior to level of setae h2 and h3. Macrosetae h2 subequal in length to idiosoma, both macrosetae h 3 in lectotype broken. Distances between dorsal setae and openings: c2: e2 62, d2: e2 93, e2: h3 105, d1: d2 20, e1: e2 15, e2: gl 10, h2: h2 75, h3:h3 58.

Epimerites I fused as a Y, length of sternum approximately equal to free parts of epimerites, posterior end of sternum acute ( Figure 2). Coxal fields I sclerotized in anterolateral part, coxal fields II entirely sclerotized. Inner margins of coxo-humeral shields rounded. Genital apparatus

23 × 26; aedeagus narrow cone-shaped, half as long as genital apparatus. Epiandrum absent. Paragenital apodemes (sclerites) small, flanking genital apparatus laterally. Genital papillae on each side fused to each other, situated at midlevel of genital apparatus, off paragenital apodemes. Coxal setae 1a, 4a, 4b 35–40 long. Setae 4a at level of genital apparatus base; genital setae g minute, situated posterior to setae 4a ; setae 3a and 4b at same transverse level. Adanal shield represented by a pair of small elongated sclerites with uneven margins, about

20 long ( Figure 2, 6B). Adanal suckers with smooth corolla 20 in diameter. Cupules ih absent. Distances between ventral setae: 4b: g 38, 4b:4a 32, g: ps 3 88, ps 3: h3 70, ps 3: ps3 15.

Ventral cuff-like processes of tarsi I, II with minute denticles and striations on margins.

Femur II with rounded lateral margin ( Figure 5B). Legs III strongly widened and roughly chela-shaped, femur especially strongly widened and bearing large bidentate extension on inner margin, genu and tibia shaped as truncated cones (frustums); tarsus with large claw-like apical process bearing setae e, d and f and with basal angular process on inner margin bearing setae w and s. All setae of tarsus III filiform, not longer than this segment; ambulacral stalk cylindrical, not extending beyond tip of apical claw; ambulacral disc reduced, small ovate and partly retracted into ambulacral stalk. Legs IV with distal part of tarsus extending beyond posterior margin of opisthosoma; tarsus IV 45 long, with small bidentate apical process; modified setae

d and e small button-like, situated at midlength and apical process of this segment, respectively. Tibial solenidion φ III slightly shorter than tarsus III, solenidion φ IV about 1.5 times longer than tarsus IV. Length of genual solenidia: σ2 I 45, σ II 10, σ III 35.

Female (paralectotype) ( Figures 3, 4, 6C, D). Idiosoma, length × width, 435 × 220, length of hysterosoma 310. Prodorsal shield shaped almost as in male, except posterior margin slightly convex; greatest length 98, width at posterior margin 100. Setae se separated by 88, extending to level of setae e2. Scapular shields as in male, except suprategumental processes more rounded. Opisthosoma widely rounded posteriorly, nearly semicircular. Hysteronotal shield absent. Idiosomal setae c2, d2, and e2 represented by macrosetae. Setae c2 about 120, extending beyond bases of setae d2 ; setae d2 about 150, extending to midlength between bases of setae e2 and h2 ; setae e2 about 180, with distal one third extending past end of opisthosoma. Setae f2 about 15 long. Hysteronotal gland openings gl situated immediately anterior to bases of setae e2. Setae d1, e1 as microsetae. Distance between dorsal setae: c2: d2 70, d2: e2 95,

e2: h3 105, d1:d2 30, e1: e2 35, h2: h2 110, h3:h3 98.

Epimerites I fused in a Y as in male. Coxal fields I, II without extensive sclerotization. Epigynum bow-shaped, without suprategumental processes, 25 long and 65 wide ( Figure 4). Apodemes of oviporus not sclerotized. Genital papillae of each side fused to each other, situated posterior to setae g. Setae 1a short, not reaching epigynum. Setae 4b 55 long, situated on tips of epigynum, and extending to midlength between levels of setae g and 4a ; setae g 55 long, situated at posterior ends of oviporus flaps extending slightly beyond level of setae 4a ; setae

4a 120–130 long not extending to anterior end of anus. Setae ps3 about 60 long, extending slightly beyond posterior margin of opisthosoma. Distances between ventral setae: 4b: 3a 17,

4b: g 42, g: 4a 55. Copulatory opening situated asymmetrically, at level of posterior end of anus. Spermatheca and spermaducts in paralectotype specimen indistinct.

Legs I, II as in male. Legs IV with pretarsus not reaching posterior margin of opisthosoma. Tarsi III, IV 50 and 58 long, respectively ( Figure 6C, D). Length of solenidia: σ2 I 42, σ II 10,

σ III 35, φ III 43, φ IV 28.

Differential diagnosis — Based on the subdivision of the genus Hemialges by Trouessart (1920) into species groups ( Table 1), H. mimus (Trouessart, 1919) should be placed in the furcula group, the males of which are characterized in having femur III with two large spines and the posterior end of opisthosoma without distinct opisthosomal lobes. These two features clearly discriminate the furcula group from remaining species groups of Hemialges , always having well developed triangular lobes with variously shaped terminal lamellae, and femora III with one spine or without it. Hemialges furcula was described from a single heteromorph male without any illustrations and was the only species previously constituting the furcula group.

The male of H. mimus differs from that of H. furcula in having the following features: in H. mimus , the large extension of the inner margin of femur III bears two relatively short spines similar in shape and size, and the posterior end of opisthosoma is trapezoidal in form, with almost straight posterior margin. According to the brief description H of. furcula , femur III bears two unequal spines situated one after another, among which the posterior one is smaller and shaped as a claw, and the posterior end of opisthosoma is slightly concave. Additionally, H. mimus is much smaller, with idiosoma 365 long; while H. furcula is a very large species, about 800 long (Trouessart 1920).