Sternostoma gallowayi, Knee, Wayne, 2018

Knee, Wayne, 2018, New species of parasitic nasal mites infesting birds in Manitoba, Canada (Mesostigmata, Rhinonyssidae), ZooKeys 786, pp. 1-17 : 3-4

Sternostoma gallowayi sp. n. Figs 1, 2, 3, 4, 5

Material examined.

Type material. Holotype: female (CNC535681) from horned lark (WK357), Eremophila alpestris , Winnipeg, Manitoba, Canada, 22.x.2011, coll: T.D. Galloway. Paratypes: female (CNC991940) same collection information as holotype. Two females (CNC991941, CNC991942) from horned lark (WK625), Winnipeg, Manitoba, Canada, 5.viii.2014, coll. TD Galloway.

Diagnosis female. Dorsum with two shields, podosomal shield large, covering most of podosoma with eight pairs of minute setae and two pairs of pore-like structures, opisthosomal shield medium-sized with two pairs of minute setae and four pairs of pore-like structures. Two pairs of minute setae in dorsal opisthosomal unsclerotised integument. Paranal setae on anal shield level with anus, postanal seta absent. Sternal shield longer than wide, three pairs of sternal setae (st1-3) on shield. Genital shield slightly reticulated lengthwise, broadly rounded posteriorly, seta st5 on genital shield. Four pairs of minute setae in ventral opisthosomal unsclerotised integument. Ventral subcapitulum without setae. Ventrolateral and apical setae on tarsus II–IV thickened, baculiform and slightly curved distally.

Description female. Dorsal idiosoma (Figs 1-2). Idiosoma 427 (387-468) long excluding gnathosoma 267 (260-274) wide. Podosomal shield 205 (201-212) long, 202 (193-217) wide covering most of podosoma, with eight pairs of minute setae with rounded tips 1.9 (1.8-2) long in alveoli, and two pairs of pore-like structures in alveoli on shield. Podosomal shield rounded anteriorly, slightly convex lateral margins, posterior margin straight, plate with granular texture and vacuolate areas (Figure 2). Opisthosomal plate quadrangular 150 (148-153) long and 159 (155-161) wide at widest point, slightly wider than long, narrowing posteriorly. Plate with granular texture and vacuolate areas, two pairs of minute setae with rounded tip in alveoli, and four pairs of pore-like structures in alveoli. Dorsal integument finely striated, two pairs of minute setae with rounded tip in unsclerotised integument lateral and posterolateral of opisthosomal shield. Stigmata 11 (9-12) wide, without peritreme, situated near posterior corners of podosomal shield. Anal shield dorsoterminal 60 (56-65) long and 48 (45-51) wide, thickened well sclerotised lateral margins, cribrum present, paranal setae minute with rounded tip 1.8 (1.5-2.1) level with anus, postanal seta absent.

Ventral idiosoma (Figure 3). Sternal shield poorly sclerotised, with weak punctation, slightly wider towards posterior, longer than wide, 124 (120-128) long and 76 (73-79) at widest point, setae st1 (1.6), st2 (1.5), st3 (1.5) in alveoli on shield. Genital shield large, 124 (121-126) long and 76 (73-82) wide level with st5, seta st5 (2.1) on shield, slight reticulations lengthwise, and posterior broadly rounded, pair of lyrifissures iv5 off genital shield. Cuticle finely striated, four pairs of minute setae with rounded tips in ventral opisthosomal unsclerotised integument.

Gnathosoma (Figure 4). Gnathosoma ventral in position, ventral length including palps 77 (69-82), maximum width 70 (68-73). Deutosternal groove present, deutosternal teeth absent, and subcapitulum without setae. Palps five-segmented, chaetotaxy of palps 0 –3–3–2– 5, all setae with rounded tips, palp apotele absent. Chelicerae widest proximally and tapering distally, 60 (57-63) long and 19 (18-20) at widest point, with small pointed fixed and moveable digits.

Legs (Figure 5). Excluding ambulacra, length of leg I 257 (226-283), leg II 206 (175-228), leg III 215 (196-243), and leg IV 263 (260-266). Setation of legs I–IV: coxae 2 –2–2– 1; trochanters 3 –3–4– 4; femora 8 –6–5– 4; genua 9 –6–6– 6; tibiae 8 –6–5– 6; tarsi 19 –17–17– 17. Most leg setae simple, minute, with rounded tip, a few apical tarsal setae filamentous. Ventrolateral and apical setae on tarsus II–IV (7.5) thickened, baculiform and slightly curved distally.

Male and immatures. unknown

Etymology.

This species is named after Dr. Terry D Galloway, who has tirelessly collected nasal mites and other bird-associated arthropods for many years, and has given me the opportunity to continue my studies of these unique mites.

Remarks. The female of Sternostoma gallowayi sp. n. is most similar to those of S. sialiphilus Hyland and Ford, and S. loxiae Fain. These species each have two dorsal shields which are similar in extent and shape, enlarged and elongated ventrolateral and apical setae on tarsus II–IV, no setae in the unsclerotised dorsal podosomal integument, four pairs of setae in the ventral opisthosomal integument, two or less pairs of setae in the dorsal opisthosomal integument, and lack a postanal seta. Sternostoma sialiphilus has been collected from the bank swallow ( Riparia riparia ) in Canada, and the eastern bluebird ( Sialia sialis ) in the United States ( Hyland and Ford 1961, Knee et al. 2008). Sternostoma loxiae has been collected from the red crossbill ( Loxia curvirostra ) in Canada and Belgium, from the American yellow warbler ( Dendroica petechia ), and mountain bluebird ( Sialia currucoides ) in Canada ( Fain 1965, Knee et al. 2008, Knee and Galloway 2017).

Female S. gallowayi can be distinguished from that of S. sialiphilus and S. loxiae by having eight pairs of setae and two pairs of pores on the podosomal shield, S. sialiphilus has nine pairs of setae, S. loxiae has seven pairs of setae; two pairs of setae and four pairs of pores on the opisthosomal shield, S. sialiphilus has one pair of setae and three pairs of pores, S. loxiae has three pairs of setae and two pairs of pores on the shield; two pairs of setae in the dorsal opisthosomal unsclerotised integument, S. sialiphilus and S. loxiae have one pair; paranal setae level with anus, S. sialiphilus and S. loxiae the paranal setae are posterior to the anus; baculiform ventrolateral and apical setae on tarsus II–IV which are not distally inflated, S. sialiphilus and S. loxiae have distally inflated ventrolateral and apical setae on tarsus II–IV. Sternostoma gallowayi differs specifically from S. sialiphilus by the presence of seta st5 on the genital shield, which is absent in S. sialiphilus , and the absence of contiguous alveoli between the podosomal and opisthosomal shields which are present in S. sialiphilus . Sternostoma gallowayi differs specifically from S. loxiae by having slight reticulation lengthwise on the genital shield, this reticulation is well-developed in S. loxiae ( Fain 1966a). Comparisons were made using species descriptions from the literature and examining voucher material.

Horned larks are not commonly submitted to wildlife rehabilitation hospitals in Manitoba. Only six specimens have been submitted since 1994, five of which were examined for nasal mites. Of these, two were infested with S. gallowayi .