Two new feather mites of the subfamily Proctophyllodinae (Acariformes: Proctophyllodidae) from the Yellow-bellied Flycatcher Empidonax flaviventris (Passeriformes: Tyrannidae) in Canada

Two new feather mite species, Nycteridocaulus sulcatus sp. n. and Tyranniphyllodes empidonicus sp. n. (Astigmata: Proctophyllodidae), are described from the Yellow-bellied Flycatcher, Empidonax flaviventris (Passeriformes: Tyrannidae), in Canada. The clearest distinguishing characteristic of N. sulcatus is the structure of the supranal concavity in males, which is parallel-sided, heavily sclerotized and opened posteriorly. Tyranniphyllodes empidonicus readily differs from the only previously known species, T. pitangi Hernandes et al. 2007, by the absence of setae d1 in both sexes and in having strongly elongated epimerites IVa and the genital sheath in males not extending to the tip of the aedeagus, and long anterolateral extensions of the prodorsal shield in females. This is the first record of the genus Tyranniphyllodes in North America.


Introduction
Feather mites (Astigmata: Analgoidea and Pterolichoidea) are permanent and highly specialized commensals and parasites of birds living mainly on the plumage of their hosts and also on the skin and in the respiratory tracts (Gaud and Atyeo 1996; Dabert and Mironov 1999; Proctor and Owens 2000; Proctor 2003. These mites are known from all extant orders of birds, including penguins, as recently determined (Mironov and Proctor 2008). Owing to their high degree of specialization to particular microhabitats on the host body, one species of host may often be infested by a complex of specific feather mite species.
In terms of global biogeography, diversity of feather mites has been explored quite unequally. Most extensively, with examination of the majority of potential avian hosts, these mites have been well studied only in Europe and to lesser extent in Africa, while the fauna of other continents has been explored significantly less intensively (for major references, see: Gaud and Atyeo 1996). In Canada, diversity of feather mites from birds inhabiting the grassland biomes (Alberta, Saskatchewan, and Manitoba) has been recently summarized  where 135 described and about 40 undescribed species of 20 families were reported. Beaulieu The present paper continues the series of our taxonomic work on feather mites in Canada (Mironov and Galloway 2002, 2003, 2006, 2014, and we present descriptions of two species of the family Proctophyllodidae found on the Yellowbellied Flycatcher, Empidonax flaviventris (Baird & Baird, 1843) (Passeriformes: Tyrannidae). Mites of the family Procto phyllodidae are predominantly distributed on passerine birds, although members of the tribe Rhamphocaulini (Pterodectinae) are also widely distributed on hummingbirds (Apodiformes: Trochilidae), and a few species have been recorded from hosts of nonpasserine orders (Atyeo and Braasch 1966; Park and Atyeo 1971a, 1971b; Gaud and Atyeo 1996; Mironov 2009; Hernandes and Valim 2014. The new species coinfesting Yellowbellied Flycatcher represent two different phylogenetic lineages of the subfamily Proctophyllodinae, the Nycteridocaulus and Platyacarus generic groups (Klimov et al. 2017), which are almost exclusively associated with suboscine passerines.

Materials and methods
Bird specimens were obtained from the Wildlife Haven (Manitoba Wildlife Rehabilitation Organization, MWRO, Île des Chênes, Manitoba) and the Prairie Wildlife Rehabilitation Centre (PWRC, St. Adolphe, Manitoba). All birds from the MWRO and PWRC were casualties of various accidents or infections and died at the rehabilitation hospitals. Laboratory techniques for collection of feather mites from frozen bird corpses and preparation of feather mites during this study were described by Mironov and Galloway (2002). Drawings and measurements were made with Leica microscopes (DM2500, Leica Microsystems, Inc.) equipped with differential interference contrast optics (DIC) and a camera lucida.
Descriptions of new species follow the modern format and measuring techniques proposed for mites of the family Proctophyllodidae (Hernandes et al. 2007; Mironov & GonzálezAcuña 2011; Mironov 2012, 2017; Hernandes 2014; Mironov et al. 2017. General morphological terms and idiosomal chaetotaxy are those of Gaud and Atyeo (1996) with minor corrections by Norton (1998), and the leg chaetotaxy is after Grandjean (1939). All measurements are in micrometres (μm).
Scientific names of birds and supraspecific classification follow Gill and Donsker (2020 Genus Nycteridocaulus Atyeo, 1966 Type species: Nycteridocaulus tyranni Atyeo, 1966, by original designation. Nycteridocaulus is the most speciesrich genus within the Nycteridocaulus generic group, one of two major phylogenetic lineages of the subfamily Proctophyllodinae associated with suboscine passerines in the New World (Klimov et al. 2017; Mironov and Bermúdez 2018. Prior to the present study, the genus Nycteridocaulus included 15 species mainly associated with suboscine passerines. Of them, 12 species are distributed on tyrant flycatchers and allies (Tyrannides: Thamnophilidae, Tyrannidae, and Tytyridae); one species is known from ovenbirds (Furnariides: Furnariidae) and two on oscine passerines of the families Parulidae and Troglodytidae (Atyeo 1966; Atyeo and Gaud 1968; De Alzuet and Brandetti 1986; Hernandes 2014; Mironov et al. 2017. Nycteridocaulus tyranni commonly infests tyrant flycatchers, and two records on birds of the families Passerellidae and Vireonidae by Atyeo (1966), based on collections from museum skins, are questionable and require verification.
The clearest diagnostic feature of the genus Nycteridocaulus is the genital arch in males shaped as a recurved bow and the whole genital apparatus resembling a flying bat, the basis for the name of the genus. Among proctophyllodines of the Nycteridocaulus group, this genus is the most diverse in the structure of the opisthosomal lobes and terminal lamellae, varying from short rectangular membranes, as in the new species described below, to long leaflike projections. A key to most presently known species was provided by Mironov et al. (2017).
Epimerites I free, close to each other, posterior tips divergent; epimerites I, II with narrow surface fields; epimerites IVa absent. Rudimentary sclerite rEpIIa barely distinct. Trochanters III flanked by sclerotized bands going from bases of epimerites IIIa. Epimerites IIIa with sclerotized areas around their inner tips with acute extensions directed anteromediad. Trochanters IV flanked by sclerotized bands stretching from bases of epimerites IV. Genital apparatus situated at level of trochanters IV. Genital arch shaped as recurved bow, 8 (7-8) in length and 45 (45-48) in width. Aedeagus styletlike, 17 (17-18) in length, reaching level of setae g ( Figure 3G). Genital papillae of each side on small oval plates at level of genital arch  (4) Femora I, II with ventral crest. Solenidion σ of genu I approximately 1.5 times longer than this segment and situated at its midlevel ( Figure 3A). Solenidion σ of genu III situated at midlevel of this segment. Legs III, IV subequal in size, legs IV with ambulacral discs extending beyond posterior margin of terminal lamellae.  in length, with longitudinal dorsal ridge and with triangular ventral process bearing seta w; modified setae d and e buttonlike, setae d situated at midlength of segment ( Figure 3D). Epimerites I as in male; epimerites I, II with narrow surface fields. Epimerites IVa large, roughly triangular, with heavily sclerotized margins. Epigynum horseshoeshaped, thick, lateral margins without extensions, tips acute, not extending to level of setae g, 40-45 in length, 55-67 in width. Genital papillae of each side on small, ovate sclerotized plate. Setae ps2 situated at midlevel of anal opening. Translobar apodemes not fused to each other anterior to terminal cleft. Copulatory opening situated on anterior end of terminal cleft. Head of spermatheca short; proximal part of primary spermaduct with ampuliform enlargement 20-25 long ( Figure 3F). Distance between pseudanal setae: ps2:ps2 43-45, ps3:ps3 19-21, ps2:ps3 13-15.
Legs I, II as male. Legs IV with ambulacral disc extending beyond level of setae h2. Solenidion σ of genu I about 1.5 times longer than this segment and situated at its midlevel. Solenidion σ of genu III in proximal half of this segment. Solenidion φ of tibia IV equal to corresponding tarsus ( Figure 3E (Figure 2A), and setae h3 are 75-85 long, about 3/4 the length of the terminal appendages. In males of N. guaratubensis, the supranal concavity is closed posteriorly and shaped as a long teardrop, pregenital apodemes are absent, and tarsus IV does not have a dorsal ridge; in females, the entire surface of the hysteronotal shield bears small circular lacunae and the posterior part has a pair of longitudinal rows consisting of 3 to 4 large ovate lacunae, and setae h3 are 66-72 long, about 1/2 the length of terminal appendages.
Etymology -The specific epithet sulcatus (from sulcus, groove, L.) is an adjective referring to the distinct groovelike supranal concavity in males.
Legs I noticeably thicker and slightly longer than legs II; femur II with noticeable bluntly rounded ventral extension. Solenidion σI about 1.5 times longer than genu I and situated closer to base of this segment. Solenidion σ of genu III slightly closer to base of this segment. Legs IV with ambulacral disc extending to midlength of terminal lamellae.  long, with clawlike apical process; setae d, e buttonlike, setae d situated at midlength of this segment, seta e on apical clawlike process. Solenidion φ of tibia IV not extending to apex of tarsus IV. Length of solenidia: σI [30][31][32].
Differential diagnosis -Tyranniphyllodes empidonicus sp. n. differs from T. pitangi in a number of characters. In both sexes of T. empidonicus, setae d1 are absent; in males, the posterior piece of the prodorsal shield is trapezoidal in shape with acute posterior corners, epimerites I are fused into a Y, epimerites IVa are strongly elongated and encompass bases of setae 4a, the genital sheath is strongly narrowed in the distal half and does not extend to the tip of aedeagus, the genital shield is shaped as a small transverse oval bearing setae g, and the adanal shield is represented by a pair of longitudinal sclerites laterally flanking the anal field; in females, the anterolateral extensions of the prodorsal shield are fused with epimerites Ia, the posterior corners of this shield are directed posterolaterally, the posterior margin is almost straight, and setae se are on this shield and distant from its lateral margins. In both sexes of T. pitangi, setae d1 are present; in males, the posterior piece of the prodorsal shield is shaped as a narrow transverse plate with bluntangular posterior margin, epimerites I are fused into a V, epimerites IVa are short and not extending beyond the level of genital arch apex, the genital sheath is bifurcate apically and extends beyond the tip of aedeagus, the genital and adanal shields are fused into the entire Hshaped opisthogastric shield; in females, the anterolateral extensions of the prodorsal shield are absent, the posterior corners of this shield are directed laterally, the posterior margin is strongly convex, and setae se are situated on the lateral margins of this shield.
Etymology -The specific epithet is derived from the generic name of the type host.