Two new species of feather mites of the subfamily Pterodectinae (Analgoidea: Proctophyllodidae) from Indonesia

Two new pterodectine feather mite species collected in Indonesia (Kalimantan) are described: Montesauria indonesiana sp. n. from the Asian glossy starling Aplonis panayensis (Scopoli, 1786) (Passeriformes, Sturnidae), and Proterothrix murariui sp. n. from the White-rumped woodpecker Meiglyptes tristis (Horsfield, 1821) (Piciformes, Picidae). Males of M. indonesiana have adanal and opisthoventral circular shields, surrounding the base of setae g and ps3, respectively, and females have the anterior and lobar parts of hysteronotal shields well delimited from each other by a transverse groove. The new species of Proterothrix described here is the first species of this genus discovered on a host of the family Picidae. This species has unique character states and cannot be included in any of the species groups defined so far within the genus. In both sexes, dorsal hysterosomal setae c1 are absent and hysterosomal setae cp are spiculiform. Males of P. murariui have a pregenital sclerite (epiandrum), the aedeagus is band-shaped, thickened in the anterior half and narrowed in the posterior half, the terminal lobes have two pairs of trapezoidal membranous extensions, coxal fields I are almost closed, and coxal fields III are open. Females have a narrow terminal cleft, parallel-sided in the anterior 2/3, large and with oblique margins in the posterior 1/3.


Introduction
The subfamily Pterodectinae is one of the two subfamilies currently recognized within the family Proctophyllodidae, and is divided into two tribes: Rhamphocaulini and Pterodectini. Representatives of the tribe Rhamphocaulini occur exclusively on hummingbirds (Apodiformes: Trochilidae), while the Pterodectini occur mostly on passerines (Passeriformes), in addition to other scattered bird orders. In the host birds' plumage, pterodectines mainly inhabit the primaries and secondaries of the wings, where they are located in corridors on the ventral surface of the vane (Mironov et al. 2012).
According to modern concepts, the genus Montesauria belongs to the Pterodectes generic group, characterized by the posterior or postero-lateral position of setae ps3 in relation to the anal suckers in the male. Along with four other genera it belongs to the Montesauria generic complex, whose representatives have the genital papillae situated at level of the genital arch or posterior to it in the male (Mironov et al. 2012). Based on morphology, the genus Montesauria was divided into nine species groups and its species were revised (Mironov, 2006). Later, an additional species group, macronoi, was proposed (Mironov et al. 2012). This is the species-richest genus of the subfamily Pterodectinae currently including 64 species distributed mostly in the Old World (Till 1954, Gaud 1957, Gaud and Mouchet 1957, Mironov and Kopij 1996a, 1996b, 1997, Mironov and Fain 2003, Mironov 2006, 2008, Kuroki et al. 2006, Hernandes et al. 2010, 2012, Mironov and Tostenkov 2013, Hernandes and OConnor 2017, Constantinescu et al. 2018b. To date, 14 species of Montesauria have been described from Asia: 8 from Vietnam (Gaud and Petitot 1948, Mironov et al. 2012, Mironov and Tostenkov 2013, 2 from Japan (Kuroki et al. 2006), 2 from India (Constantinescu et al. 2018b), 1 from Taiwan (Sugimoto 1941) and 1 from Indonesia (Mironov 2006). Atyeo (in: McClure and Ratanaworabhan 1973), reported 81 supposedly new species of this genus from Southeastern Asia; unfortunately, new species from this material have never been described.
The present paper describes two new feather mite species of pterodectines belonging to the genera Montesauria and Proterothrix, collected from birds in Indonesia (Kalimantan).

Materials and methods
Mites were collected by the authors from museum specimens of birds preserved in ethanol, from the Ornithological Collection of "Grigore Antipa" National Museum of Natural History (Bucharest, Romania). The ethanol in which the birds were preserved was filtered through filter paper, then the mite specimens were collected manually with a fine needle placed in vials filled with 96% ethanol. Then mite specimens were cleared in 90% lactic acid for 24 hours, and mounted on microscope slides in Hoyer's medium. Drawings were made using an Olympus CX21 compound microscope, equipped with a camera lucida drawing device. The taxonomy of birds follows Lepage et al. (2019). The body setation of mites follows that of Griffiths et al. (1990) with the modifications by Norton (1998) concerning coxal setae, while the leg setation follows Gaud and Atyeo (1996). Species redescriptions follow the standard style accepted in taxonomic works describing pterodectine mite species (Mironov and Fain 2003, Mironov 2006, Valim and Hernandes 2006); we measured a set of standard morphological diagnostic features following Mironov and Proctor (2009). Measurements are given for the holotype (male) and followed by ranges for paratypes. All measurements are in micrometers (μm). The mite specimens studied herein are deposited in the Acari Collection of "Grigore Antipa" National Museum of Natural History, Bucharest, Romania (MGAB) and in the Acari Collection of the Department of Zoology of the Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil (DZUnesp-RC).  Type deposition -Holotype male (ANA 801), 6 male (ANA 802-807) and 8 female (ANA 808-815) paratypes in MGAB collection, 1 male and 1 female paratypes in DZUnesp-RC collection.
Etymology -The specific name indonesiana refers to the name of the country (Indonesia) where the mite was collected.
Differential diagnosis. The new species, Montesauria indonesiana sp. n., belongs to the pachypa species group. This new species is most similar to M. mainati (Trouessart, 1885), which was originally described from Common hill myna Gracula religiosa Linnaeus, 1758 (Passeriformes, Sturnidae) in Indonesia (Trouessart 1885) and later redescribed (Mironov 2006). Both species have similar ornamentation of the dorsal shields and setae cGI and cGII are spiniform in male and female. In males of both species, setae h3 are lanceolate, setae ps2 are thickened in the basal part and filiform in apical part, and epimerites IVa are present. In females, the terminal cleft is extended beyond the level of setae h2. M. indonesiana sp. n. clearly differs from M. mainati by the following character states in males (corresponding character states of M. mainati are in parentheses): the prodorsal and hysteronotal shields are separated by a narrow band of soft tegument (vs. both shields almost touching), the terminal cleft has a triangular anterior end (vs. round), the rudimentary sclerites rEpIIa are present (vs. absent), the adanal shields are present (vs. absent), the opisthoventral shields are small, circular, surrounding the base of setae ps3 (vs. narrow, with short extension bearing setae ps3). In females of the new species, the anterior and lobar parts of hysteronotal shields are well delimited from each other by a transverse groove (vs. poorly delimited by a pair of thin striae on the sides of the opisthosoma), the dorsal crest of genu IV has a round angle (vs. acute angle), the dorsal crest of tibia I has its proximal margin rounded, with indentations (vs. sharp and without indentations), the dorsal crest of genu IV has a round angle (vs. acute angle).
Genus Proterothrix Gaud, 1968 Proterothrix murariui Constantinescu sp. n. Etymology -This species is named in honour of Dr. Dumitru Murariu, mammologist, correspondent member of the Romanian Academy, who led the expedition organized by "Grigore Antipa" National Museum of Natural History in the islands of the Indonesian archipelago in 1991, and collected himself some of the bird specimens on which the new species of feather mite was identified.
Remarks -Proterothrix murariui Constantinescu, sp. n. is the first species of the genus discovered on a host of the family Picidae. This species has unique combination of character states and does not resemble any of the species of Proterothrix described so far. It cannot be included in any of the species groups defined so far within the genus. Males of Proterothrix murariui have three morphological character states within are unique in Proterothrix: a pregenital sclerite (epiandrum) present; the aeadegus is band-shaped, thickened in the anterior half and narrowed in the posterior half; and the terminal lobes have two pairs of trapezoidal, membranous extensions. In both sexes, dorsal setae c1 are absent, and setae cp are spiculiform. Females have the terminal cleft narrow, parallel-sided in the anterior 2/3, and large with oblique margins in the posterior 1/3. The presence of epiandrum in males is a rare occurrence among mites of the subfamily Pterodectinae, encountered only in some species of the genus Anisodiscus (Hernandes and OConnor 2013). The absence of dorsal setae c1 is a character also found to some species of the Proterothrix megacaula species group. It is too premature to define a new group of species within the genus Proterothrix, based only on this species described here, but maybe the discovery of other species of the genus from woodpeckers, sharing common morphological characters, will make this possible in the future.