The cockatiel Nymphicus hollandicus (Kerr, 1792) (Psittaciformes: Cacatuidae) is native to Australia but owing to maintaining as a household pet it distributed worldwide (Engebretson, 2006). The only other feather mite species previously described from this host is Nymphicilichus perezae Mironov & Galloway, 2002 (Astigmata: Pterolichidae) in New Zealand.

Pterolichid feather mites associated with parrots (Aves: Psittaciformes) are represented by three morphologically distinct generic groups: Psittophagus (4 genera), Rhytidelasma (12 genera), and Protolichus (24 genera) (Gaud and Mouchet, 1959; Gaud, 1980; Atyeo and Pérez, 1982, 1990; Atyeo et al. , 1984; Atyeo, 1985, 1988, 1989a, b, c; Atyeo and Gaud, 1987; Gaud and Atyeo, 1996; Mironov and Galloway, 2002, Mironov and Pérez, 2003; Mironov et al., 2003a,b, 2005, 2011, 2014; Dabert et al., 2004, 2006, 2008; Mironov and Dabert, 2007, 2010). From these, the Psittophagus generic group is the least diverse, comprising currently 9 species (including the new one described herein) in four genera: Nymphicilicus Mironov & Galloway, 2002, Micropsittophagus Mironov & Pérez, 2003, Psittaculobius Mironov, Dabert & Ehrnsberger, 2003, and Psittophagus Gaud & Atyeo, 1996; the three former genera include only one species each.

To date, the genus Psittophagus has included five species associated with Old World parrots of the family Cacatuidae (Psittaciformes) from the Australasian region: Psittophagus ornatus (Mégnin & Trouessart, 1884) (type species), P. obsoletus (Mégnin & Trouessart, 1884), P. galahi Mironov, Dabert & Proctor, 2003, P. calyptorhynchi Mironov, Dabert & Ehrnsberger, 2003, and P. lacunosus Dabert, Badek & Skoracki 2007 (Mégnin and Trouessart, 1884; Mironov et al., 2003a, b; Dabert et al., 2007). A table summarizing the mite-host relationships of the Psittophagus generic group, in addition to a key to genera and species of this group, were provided by Mironov et al. (2003a). In this paper, a new species of Psittophagus is described from the cockatiel in Brazil.

The material was collected from a specimen of Nymphicus hollandicus which died in captivity and sent to the laboratory of Acari of the Department of Zoology, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil. The bird specimen was placed in a freezer and then washed with water containing detergent; the liquid was then filtered and mites were collected with a fine brush from the filter papers under stereomicroscope, cleared in 30% lactic acid for 24 h at 50°C, and mounted in Hoyer’s medium (Krantz and Walter, 2009). After five days at 50 °C, the slides were sealed with varnish. Drawings and measuring of mites were made with a Leica DM3000 microscope equipped with differential interference contrast (DIC) optics and a camera lucida. Pencil sketches were scanned at 300 dpi and grayscale mode; line drawings were created with Adobe Illustrator CS6 and a Wacom Bamboo Create tablet. The idiosomal and leg chaetotaxies follow Griffiths et al. (1990) and Atyeo and Gaud (1966), respectively, with corrections for coxal setae proposed by Norton (1998). Type specimens are deposited at DZUnesp-RC — Collection of Acari of Department of Zoology of the Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil.

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Type material: holotype ♂ (DZUnesp-RC3759), paratypes 10 ♂ and 4 ♀ (3760–3773) ex Nymphicus hollandicus (Kerr, 1792) (Psittaciformes: Cacatuidae), captivity specimen from Pedreira, São Paulo State, BRAZIL, 17 August 2007, col. David V. Boas Filho (203).

Differential diagnosis — The new species is morphologically close to P. lacunosus Dabert, Badek & Skoracki, 2007 in having, in males, setae e2 thick spiculiform, and the hysterosomal shield reaching to or close to the level of setae c1. Psittophagus hollandicus n. sp. is distinguished from that species in having, in males, the dorsal shields with weak ornamentation, the prodorsal shield split transversally at the level of scapular setae and free from the scapular shields, solenidion σ of genu III about half as long as the segment (Fig. 3C), setae si, c2 filiform, and the anal suckers without indentations. Females of the new species have piliform setae d2 and e2, setae d2 being 30μm long and barely reaching the halfway to bases of piliform setae e2. In contrast, males of P. lacunosus have the dorsal shields covered with numerous rounded lacunae, the prodorsal shield entire and fused with the scapular shields, solenidion σ of genu III equal to or even longer than the segment, setae si, c2 spiculiform, and the suckers with indentations; females of P. lacunosus have setae d2 and e2 long spiculiform, the former setae are much longer ( 100μm) and distinctly surpass the bases of corresponding setae e2.

Description

Male (Figures 1, 3A–E) (holotype, range for 6 paratypes in parenthesis) — Idiosoma short and wide, 252 (241–260) in length, 171 (174–190) in width. Gnathosoma 41 (41–43) × 52 (50–56). Prodorsal shield split into two pieces at the level of scapular setae, length of the anterior part along midline 47 (40–47), maximum width of posterior part 76 (74–80) (Fig. 1A). Distance between scapular setae se-se 58 (57–61). Setae si thin piliform. Scapular shields present, with poorly distinct borders, not fused with prodorsal shield. Humeral shields small, setae c2 on soft tegument, mesal to these shields. Hysteronotal shield: greatest length 148 (142–149), width at anterior margin 110 (107–116), anterior end almost extending to level of setae c1, anterior margin roughly convex, surface with faint circular ornamentation. Hysteronotal gland openings gl situated at half distance between setae d2 and e2. Setae c3 long, about half the idiosomal width. Subtegumental sclerotized structures in sejugal area absent. Opisthosomal lobes roughly rounded, with small extensions bearing bases of setae h2, h3. Terminal cleft small, as a wide-based triangle with rounded anterior end, 14 (10–14) in length. Supranal concavity semi-ovate. Setae e2 spiculiform, noticeably thickened in distal third (somewhat shaped as baseball bat), 30 (28–32); setae ps1 small, narrowly lanceolate, 15 (14–16) long. Dorsal measurements (distances between setal rows and seta bases): c1-c1 41 (40–46), d2-d2 86 (86–94), e2-e2 49 (49–54), c1-d2 66 (65–71), d2-e2 63 (61–63), h2-h2 51 (50–54), ps1-ps1 23 (23–26).

Epimerites I, II with inflated and heavily sclerotized bases, epimerites I free. Genital apparatus 15 (14–16) × 11 (9–12), aedeagus slightly shorter than genital arch. Setae 4a at base of genital arch. Setae 4b anterior to level of inner tips of epimerites IIIb. Adanal shields absent. Opisthoventral shields large, with projection towards anal suckers, carrying cupules ih and bases of setae ps2 (Fig. 2B). Ventral measurements: 4b-3a 10 (7–10), 3a-g 31 (29–38), g-4a 34 (28–34), 4a-ps3 22 (22–24), ps3-ps3 18 (15–19).

Legs IV extending beyond opisthosoma by entire tarsus. Tarsus I with three long setae (f, la, ra), exceeding length of solenidion ω3, tarsus II with one long seta (d). Legs IV with tarsus entirely extending beyond level of lobar apices. Solenidion Φ of tibia IV about ¾ the length of tarsus IV. Length of tarsi: I 30 (30–35), II 40 (39–43), III 34 (33–37), IV 37 (32–37).

Female (Figures 2, 3F–G) (range for 4 paratypes) — Idiosoma 350–386 in length, 224–250 in width. Gnathosoma 58–60 × 76–80. Prodorsal shield present only anterior to scapular setae, length along midline 54–61. Setae si thick spiculiform, 48–58 long. Distance between scapular setae se-se 76–83. Setae si thick spiculiform, 48–58 long. Scapular and humeral shields absent. Setae c2 on striated tegument, slightly shorter than humeral seta cp. Setae c3 long, about 1/2 of idiosomal width. Hysteronotal shield: occupying posterior half of hysterosoma, anterior margin convex, extending slightly anterior to level of setae d2, posterior margin indistinct, greatest length 139–148, surface with faint ornamentation. Setae d2 piliform, about 30 long, situated on striated tegument, barely extending to level ofopenings gl; setae e2 piliform, 20 long. Subtegumental sclerotized structures in sejugal region very large, ball-shaped, and dark-coloured; subtegumental structures of opisthosoma roughly rectangular and less sclerotized. Hysteronotal gland openings gl on soft tegument at level of trochanters IV. Setae c3 long, about 1/2 of idiosomal width. Posterior end of opisthosoma wide and bluntly rounded. Dorsal measurements: c1-c1 62–65, d2-d2 110–125, e2-e2 108–115, c1-d2 85–89, d2-e2 65–72, h2-h2 66–76.

Epimerites I, II as in the male. Oviporus anterior to level of trochanters III, folds of this opening not sclerotized, epigynum absent. Legs IV with entire tarsus extending beyond posterior margin of opisthosoma. Length of tarsi: I 41–48, II 53–57, III 61–64, IV 74–77.

Etymology — The species name is taken from the specific epithet of the type host.

Remarks — 1) In addition to Nymphicilicus perezae from the cockatiel in Brazil, Albuquerque et al. (2012) reported an undetermined Psittophagus species quite probably corresponding to the new species described herein. However, the SEM photo of the female applied to that undetermined species (Albuquerque et al., 2012: page 577, figure 7B) seemingly depicts the female of N. perezae, rather than that of Psittophagus species. This is suggested based on the length of setae si and the ornamentation of the hysteronotal shield. 2) The illustrations of P. galahi and N. perezae females in Mironov et al. (2003) were accidentally mixed up. The correct legend for figure 9 in that paper should actually be: Fig. 9, a – N. perezae, b – P. galahi.

The author thanks David Vilas Boas Filho (Faculdade Jaguariúna, Jaguariúna, São Paulo State, Brazil) for collecting the dead specimen of cockatiel. The study was funded by FAPESP—São Paulo Research Foundation (2011/50145-0).

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