Protolichus casuarinus Trouessart, 1884

Mironov, Sergey V. & Dabert, Jacek, 2010, Systematic revision of the feather mite genus Protolichus Trouessart, 1884 (Astigmata, Pterolichidae), Zootaxa 2526, pp. 1-36 : 27-31

Protolichus casuarinus Trouessart, 1884

( Figs 16–18 , 21 A)

Pterolichus (Protolichus) casuarinus Trouessart 1884: 529 ; Trouessart and Mégnin 1885: 54; Canestrini and Kramer 1899: 57; Dubinin 1956: 152.

Protolichus casuarinus: Gaud and Atyeo 1996: 132 .

Protolichus (s. str.) brachiatus pugilator Trouessart 1899: 43 (nom. n. pro P. casuarinus ).

Protolichus (s. str.) pugilator: Favette and Trouessart 1904: 137, Pl. VI (part; fig. 5, male; not fig. 6 = female of brachiatus group).

Material examined. Heteromorph male holotype ( TRT 35E4) ex Casuarius unappendiculatus Blyth, 1860 (Casuariidae) , New Guinea, Salwatty Island, no other data. 17 heteromorph males, 4 homeomorph males, 8 females (12 slides TRT 34H15, 5 slides TRT 34F16, labeled as P. pugilator ) ex Pseudeos fuscata, New Guinea, Yule Island; 8 heteromorph males, 1 female ( TRT 34H16), same host, New Guinea, no other data; 2 heteromorph males and 1 female ( TRT 34F3, 3 slides, labeled as P. pugilator ) ex Chalcopsitta atra, New Guinea, no other data.

Description. Heteromorph male (10 specimens from Pseudeos fuscata ). Idiosoma, length x width, 600– 640 x 360–420 (idiosomal size of poorly preserved holotype of P. casuarinus with missing distal parts of lobes 560 x 365). Subcapitulum with strong bow-shaped transverse fold in widest part and a pair of small curved folds posterolateral to setae subc, posterior margin slightly convex ( Fig. 17 E). Prodorsal shield with posterior margin straight in median part, length along midline 180–200, surface monotonously punctate, transverse bar across scapular setae poorly sclerotized. Setae si spiculiform, 50–60 long. Distance between scapular setae: se:se 72–78, si:si 35–42. Hysterosoma 410–435 long. Hysteronotal shield: length 395–430, width 280–300, anterior margin straight, surface monotonously punctate. Opisthosomal lobes with obliquely cut apex, with transverse crest posterior to bases of setae h3 ( Fig. 17 G). Supranal concavity ovate, poorly expressed. Terminal cleft as a U, posterior half slightly wider than anterior one, length 68–72, width in anterior part 10–12, width posterior to setae e 1 14 –25. Setae c2 spiculiform, 50–55 long; setae d2 setiform, 30–35 long; setae e2 thickened, not reaching the lobar apices, 90–100 long; setae e1 situated on margin of terminal cleft, slightly posterior to level of macrosetae h2; setae f2 spatuliform, with bidentate apices. Distance between dorsal setae: c2:d2 135–152, d2:e2 160–170, e2: e1 72 (70), e2:e2 110–125, h2:h2 70–72, h3:h3 68–72, ps1:ps1 42–50, e2:h2 55–60, h2:h3 190–21, h2: e 1 10–11, ps1:h 3 10–11. Genital apparatus at level of anterior margin of trochanters IV, 28– 32 x 20–22. Paragenital apodemes with anterior ends extended to midlevel of coxal fields III, not connected to epimerites IIIa, posterior parts of apodemes connected by narrow transverse bridge ( Fig. 16 B). Distance between ventral setae: 3b:3a 20–22, 3 a:g 26–32, g:4a 70–85, 4 a:ps3 105–110. Diameter of anal suckers 21–22.

Legs II 1.3–1.4 times longer and much thicker than legs I. Tarsus I with crest-like ventral extension stretching along entire segment, proximal end of this extension widely rounded ( Figs17 A, B). Tibia and genu I without ventral apophysis. Genual seta cG I setiform, noticeably thickened in basal half. Femur I with longitudinal ventral crest bearing seta vF ( Fig. 17 B). Tarsus II with large semi-ovate ventral extension bearing setae wa on its apex, with wide indented and verrucous dorsal crest between solenidion ω 1 and seta d, and with narrow smooth dorsal crest between solenidion ω 1 and lyrifissure ( Figs 18 A, B). Tibiae II with large claw-like apophysis on antaxial surface and with wide longitudinal dorsal crest ( Fig. 18 A). Genu II with small blunt-angular ventral apophysis at base of seta mG II, with wide longitudinal dorsal crest; seta cG II as wide blade, strongly curved in basal part, 1.4–1.5 times longer than segment. Solenidion φ of tibiae I, II with verrucae in basal parts. Tarsus IV slightly longer than corresponding tibia; setae d, e spiculiform with distinct basal ring ( Fig. 17 C).

Homeomorph male (2 specimens from Pseudeos fuscata ). Subcapitulum with short transverse fold at midlevel and with numerous interrupted transverse striae ( Fig. 17 F). Terminal cleft as a narrow U, variable in shape: from cleft with posterior half slightly larger than anterior one (about 3 times longer than wide in posterior half) to one with almost straight and parallel margins (about 5 times longer than wide) ( Fig. 17 H). Transverse bridge between middle parts of paragenital apodemes absent.

Legs II slightly longer than legs I. Tarsi I, II with blunt-angular extensions on ventral margin ( Fig. 18 C). Tibiae and femora I, II not modified. Genua I, II with small tubercle-like extensions near bases of setae mG. Setae cG of genu II thickened, dagger-shaped, not longer than segment ( Fig. 18 D).

Measurements: Idiosoma, length x width, 520–530 x 310–315. Prodorsal shield 150–158 long. Setae si 48–40 long. Distance between scapular setae: se:se 75–78, si:si 42–45. Hysterosoma 372–375 long. Hysteronotal shield: greatest length 360–365, greatest width 240–250. Terminal cleft 57–63 long, width in anterior part 11– 15, width in posterior part 11–24. Length of lateral setae: c2 40–45, d 2 25–28, e2 90 –100. Distances between dorsal setae: c2:d2 125–130, d2:e2 140–150, e2:e2 110–120, h2:h2 68–70, h3:h3 60–65, ps1:ps1 40–41, e2:h2 50–52, h2:h 3 19–20, h2: e 1 9–10, ps1:h 3 12–15. Genital apparatus 28–30 x 20 –22. Distance between ventral setae: 3b:3a 18–20, 3 a:g 20–25, g:4a 65–70, 4 a:ps3 95–100. Diameter of anal suckers 20.

Female (7 specimens). Subcapitulum as in homeomorph male. Idiosoma, length x width, 480–525 x 285– 315. Prodorsal shield with posterior margin straight, length along midline 140–145, most of surface monotonously punctate, transverse bar across scapular setae poorly sclerotized, lateral area at level of trochanters I may bear transverse wavy striae. Setae si spiculiform, 32–38 long. Distance between scapular setae: se:se 95–105, si:si 58–65. Hysterosoma 335–375 long. Hysteronotal shield: length 320–350, width 240–265, anterior margin straight, surface monotonously punctate, with poorly pronounced transverse wavy striation; subtegumental sclerotized bands posterior to setae e2 slightly enlarged ( Fig. 21 A). Setae c2 spiculiform, seta d2 setiform, setae e2 thick setiform, setae f2 setiform or with narrow membranous expansion and additional spine on margin; setae ps2 setiform, subequal in length to f2, setae e1 situated approximately at level of cupules im, setae ps1 much shorter than half-width of idiosoma. Length of lateral hysteronotal setae: c 2 28–35, d 2 20–25, e2 85 –100, f2 35–40. Distance between hysteronotal setae: c2:d2 120–145, d2:e2 145– 155, e1: e2 70–85, e2:h3 62–78, e2:e2 172–185, h2:h2 90–100, ps1:ps1 35–48. Epigynum bow-shaped, 20 x 60. Seta mG of genu I, II setiform.

Type host and locality. Casuarius unappendiculatus (Casuariidae) , New Guinea (accidental contamination).

Remark. Protolichus casuarinus was described based on a sole male from the northern cassowary, Casuarius unappendiculatus (Casuariidae) , by Trouessart (1885). Since the finding of this species on the cassowary was the obvious result of accidental contamination in the course of museum collecting, Trouessart (1899) renamed this species (against taxonomic rules) P. brachiatus pugilator . Trouessart had apparently considered the epithet “ casuarinus ” to be misleading. Further, Favette and Trouessart (1904) elevated “ P. b. pugilator ” to the specific rank and redescribed it based on the specimens collected from three parrot species, Chalcopsitta atra , Pseudeos fuscata and Trichoglossus rubiginosus (Bonaparte, 1850) (Loriidae) . These authors also mentioned “ P. pugilator ” as occurring on hosts from various genera of lories “Trichoglossidae”. Gaud and Atyeo (1996) restored the valid name, P. casuarinus , for this species.

The holotype (by monotypy) of P. c a s u a r i n u s is poorly preserved and quite unsuitable for a full redescription (both pairs of posterior legs and distal halves of opisthosomal lobes are lost), although main diagnostic structures of this species retained: a large claw-like apophysis of tibia II and blade-shaped genual seta cG II ( Fig. 18 A). Favette and Trouessart (1904) considered the specimens collected from three parrot species to be conspecific to this sole specimen of P. casuarinus from the cassowary. However, it was not true, because that material actually represents a mixture of species. Even in the photos given by Favette and Trouessart (1904: Pl. VI, figs 5, 6), it is clearly visible that the female has saber-shaped setae e2, which means that the displayed female belongs to the brachiatus rather than to the crassior species group. Examination of this material also showed that mites from T. rubiginosus with certainty represent a undescribed species of the crassior group. Heteromorph males from Ch. atra and Ps. fuscata correspond well to the description of “ P. pugilator ” given by Favette and Trouessart (1904) with regard to the above diagnostic features of this species.

We did not find reliable differences between specimens from Ps. fuscata and Ch. atra , except for more divergent opisthosomal lobes in males from the latter host. Since there are only 2 males from this host, this difference may be an artifact of slide mounting. It is impossible to prove exactly, which of these two parrot species was the natural host of the holotype of P. casuarinus . Taking into consideration that the structure of opisthosomal lobes in males from Ps. fuscata look slightly more similar to those in the holotype of P. casuarinus , and that these males also correspond better to the photo of the “ P. pugilator ” heteromorph male ( Favette and Trouessart 1904: Pl. VI, fig. 5), we have chosen the material from this host for redescription. This means that we conclude that the natural host of P. c a s u a r i u s is Pseudeos fuscata . We should keep in mind that mites from Ps. fuscata and Ch. atra might potentially be two different cryptic species.

Figures

FIGURE 16. Protolichus casuarinus, heteromorph male. A—dorsal view, B—ventral view.

FIGURE 17 Protolichus casuarinus, details of males. A—leg I of heteromorph male, dorsal view, B—leg I of heteromorph male, ventral view, C—tarsus IV of heteromorph male, dorsal view, D—tarsus IV of heteromorph male, ventral view, E—gnathosoma of heteromorph male, ventral view, F—gnathosoma of homeomorph male, ventral view, G—opisthosoma of heteromorph male, dorsal view, H—opisthosoma of homeomorph male, dorsal view.

FIGURE 18. Legs of male Protolichus casuarinus. A—leg II of heteromorph male, dorsal view, B—leg II of heteromorph male, ventral view, C—leg I of homeomorph male, dorsal view, D—leg II of homeomorph male, dorsal view.

FIGURE 21. Protolichus females, dorsal view. A— Protolichus casuarinus, B— P. gratus.