Ixodes robbinsi D. Apanaskevich & Edgy, 2022

Apanaskevich, Dmitry A., Apanaskevich, Maria A., Klimov, Pavel B., Edgy, Brett M., Bermúdez, Sergio E., Labruna, Marcelo B., Korzeev, Andrei I. & Barker, Stephen C., 2022, Description of eight new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. auritulus Neumann, 1904, parasites of birds in the Australasian, Nearctic and Neotropical Regions, Zootaxa 5173 (1), pp. 1-73 : 53-64

Ixodes robbinsi D. Apanaskevich & Edgy n. sp.

Type-host: American robin— Turdus migratorius Linnaeus ( Passeriformes : Turdidae ).

Other hosts: Ruffed grouse— Bonasa umbellus (Linnaeus) ( Galliformes : Phasianidae ), black-headed grosbeak— Pheucticus melanocephalus (Swainson) ( Passeriformes : Cardinalidae ), dark-eyed junco— Junco hyemalis (Linnaeus), song sparrow— Melospiza melodia (Wilson) , Savannah sparrow— Passerculus sandwichensis (Gmelin) , sooty fox sparrow— Passerella unalaschensis (Gmelin) , golden-crowned sparrow— Zonotrichia atricapilla (Gmelin) , white-crowned sparrow— Zonotrichia leucophrys (Forster) ( Passeriformes : Emberizidae ), purple finch— Haemorhous purpureus (Gmelin) ( Passeriformes : Fringillidae ), black-capped chickadee— Poecile atricapillus Linnaeus ( Passeriformes : Paridae ), house sparrow— Passer domesticus (Linnaeus) ( Passeriformes : Passeridae ), Bewick’s wren— Thryomanes bewickii (Audubon) , Pacific wren— Troglodytes pacificus Baird ( Passeriformes : Troglodytidae ).

Type-locality: USA: Oregon: Tillamook County: Netarts.

Other localities: Canada: British Columbia: Vancouver Island, Rocky Point, Rocky Point Bird Observatory ; USA: Alaska: Alexander Archipelago, Wrangell Island; Juneau, Gold Creek , Salmon Creek ; California: Mendocino County, Ten Mile River; Napa County , Mead Ranch ; Oregon: Curry County, near Brookings, Goat Island ; Tillamook County : Hebo , Tillamook ; Washington: Kitsap County: Hansville Road c. 8 km north of junction with Highway 104; Olympic Mountains .

Type-material: Holotype female, from T. migratorius, Netarts (~ 45°26’N, 123°56’W), Tillamook County, Oregon, USA, 3.iii.1930, A. Walker ( AW) and R. Walker ( RW); deposited in the USNTC ( USNMENT 00987201 ) . Paratypes: 10 females. USA: Oregon: Tillamook County, Hebo (~ 45°13’N, 123°51’W) : 1 female, from P. domesticus , 25.viii.1932, USNMENT 00987238 ; Tillamook County, Netarts : 1 female, from P. unalaschensis , 5.iii.1930, AW and RW, USNMENT 00987204 ; same locality : 1 female, from T. migratorius , 21.iii.1930, AW and RW, USNMENT 00987239 ; same locality : 1 female, from M. melodia , 16.xi.1930, RW, USNMENT 00987207 ; same locality : 1 female, from M. melodia , 25.xi.1930, AW and RW, USNMENT 00987218 ; Tillamook County, Tillamook (~ 45°27’N, 123°50’W) : 1 female, from J. hyemalis, 10.xii.1930, AW and RW, USNMENT 00987205 ; same locality : 1 female, from J. hyemalis, 24.ii.1930, AW, USNMENT 00987223 ; same locality : 1 female, from T. migratorius , 15.iii.1930, AW and RW, USNMENT 00987222 ; same locality : 1 female, from H. purpureus , 24.iii.1930, AW and RW, USNMENT 00987195 ; Washington: Kitsap County, Hansville Road c. 8 km north of junction with Highway 104 (~ 47°52’N, 122°32’W) : 1 female, from P. atricapillus , 30.ix.2000, H. Kaster, USNMENT 00988219 . All paratypes are deposited in the USNTC .

Other material: 11 nymphs and 17 larvae. Canada: British Columbia: Vancouver Island, Rock Point (~ 48°19’N, 123°32’W), Rocky Point Bird Observatory: 1 nymph, from T. bewickii , 18.viii.2001, G. Gibson, USNMENT 00988214 . USA: Alaska: Alexander Archipelago, Wrangell Island (~ 56°17’N, 132°10’W): 1 nymph, from P. unalaschensis , 22.iv.1946, J. D. Webster, USNMENT 00987221 ; Juneau, Gold Creek (~ 58°17’N, 134°25’W): 7 larvae, from P. sandwichensis , 10.v.1945, R . B. Williams ( RBW), USNMENT 00987209 ; Juneau, Salmon Creek (~ 58°20’N, 134°24’W): 9 larvae, from Z. atricapilla , 5.v.1953, RBW, USNMENT 00987180 ; California: Mendocino County, Ten Mile River (~ 39°33’N, 123°46’W): 1 nymph, from Z. leucophrys , 10.v.1959, R . C. Banks , USNMENT 00987197 ; Napa County, Mead Ranch (~ 38°23’N, 122°14’W): 1 nymph, from P. melanocephalus , 25.viii.1970, R. T . Mead , USNMENT 00987224 ; Oregon: Curry County, near Brookings, Goat Island (~ 42°3’N, 124°19’W): 2 nymphs, from M. melodia , 16.ix.1967, E. Easton ( EE), USNMENT 00987210 ; same locality: 1 nymph, from M. melodia , 22.vi.1968, Clifford, Corwin and EE, USNMENT 00987230 ; same locality: 1 larva, from M. melodia , 8.ix.1971, EE, USNMENT 01481795 ; Tillamook County, Tillamook : 1 nymph, from M. melodia , 19.iii.1930, AW and RW, USNMENT 00987237 ; same locality: 1 nymph, from J. hyemalis, 6.xi.1930, RW and AW, USNMENT 00987213 ; same locality: 1 nymph, from T. pacificus , 27.ii.1931, AW, USNMENT 00987203 ; Washington: Olympic Mountains (~ 47°49’N, 123°49’W), Spruce: 1 nymph, from B. umbellus , 20.iv.1933, H. H. Stage, USNMENT 00987150 . All specimens are deposited in the USNTC.

ZooBank registration: The Life Science Identifier (LSID) for Ixodes robbinsi n. sp. is urn:lsid:zoobank.org:act:0F514D22-818B-4951-B436-FF95A14A2B24 .

Etymology: The species is named after Richard George Robbins, a United States acarologist and colleague who has contributed much to our knowledge on the systematics, distribution and ecology of ticks, especially those of the Americas, East and Southeast Asia.

Description. Female [Based on 11 specimens; Figs. 30 , 31 .] Idiosoma ( Fig. 30A, F ) of medium- to largely engorged specimens broadly suboval. Scutum ( Fig. 30B, C ) length 1.24–1.36 (1.29 ± 0.05; n = 11), width 1.05–1.26 (1.11 ± 0.06; n = 11), ratio 1.08–1.25 (1.16 ± 0.05; n = 11); lateral margins diverging for approximately 1/2 of scutal length, then converging to broadly rounded posterior margin; lateral carinae absent; cervical grooves very shallow reaching posterior quarter of scutal length; relatively sparse very fine punctations evenly distributed throughout scutum; very slight rugosity may be discernible in central field of scutum; setae ( Fig. 30B, C ) relatively sparse, very short (c. 0.03 in anterolateral margin of scutum). Alloscutum ( Fig. 30A ) as illustrated; setae ( Fig. 30A, D, E ) numerous, evenly distributed, very short in center of alloscutum: c. 0.02–0.03 (avg. 0.02) and long in area medial to marginal grooves: c.0.04–0.05 (avg. 0.05), setae in area medial to marginal grooves 1.83-3.00 (avg. 2.65) times longer than setae in center of alloscutum; ratio scutal length to length of setae in area medial to marginal grooves 24.60–30.00 (26.93 ± 1.51; n = 11). Venter ( Fig. 30F ) as illustrated; genital aperture ( Fig. 30F ) medial to coxae III; genital groove ( Fig. 30F ) well developed; anal groove ( Fig. 30F ) oval with open posterior margin; ventral setae ( Fig. 30F ) numerous, length of preanal setae c. 0.04, evenly distributed. Spiracular plates ( Fig. 31A ) length 0.30–0.37 (0.33 ± 0.02; n = 11), width 0.31–0.39 (0.35 ± 0.03; n = 11), ratio 0.88–0.97 (0.92 ± 0.03; n = 11); broadly suboval to subcircular.

Gnathosoma ( Fig. 31B–D ) length from palpal apices to cornual apices dorsally 0.68–0.73 (0.69 ± 0.02; n = 11), width of basis capituli dorsally 0.53–0.60 (0.56 ± 0.03; n = 11), ratio 1.15–1.29 (1.22 ± 0.05; n = 10). Dorsal basis capituli ( Fig. 31B ) length from medial insertion of palpal segment I to cornual apices 0.23–0.25 (0.24 ± 0.01; n = 11), ratio width to length 2.21–2.47 (2.34 ± 0.07; n = 11), subrectangular, lateral margins slightly convex, without lateral projections, posterior margin nearly straight or very slightly convex; cornua short, length 0.03–0.06 (0.04 ± 0.01; n = 11), ratio total length of basis capituli, including cornua, to cornual length 4.00–8.00 (5.84 ± 1.05; n = 11), triangular with broadly rounded apex; transversally suboval porose areas large, width 0.18–0.21 (0.20 ± 0.01; n = 11), ratio width of basis capituli dorsally to width of porose area 2.63–3.03 (2.83 ± 0.12; n = 11), clearly distinct, slightly indented, separated by distance of nearly 1/3 of their own width, openings discrete. Ventral basis capituli ( Fig. 31C, D ) pentagonal; auriculae moderately long, length 0.04–0.05 (0.05 ± 0.004; n = 11), ratio length of gnathosoma dorsally to length of auriculae 13.24–16.18 (14.59 ± 1.08; n = 11), broad, nearly as long as wide, directed posteriorly or very slightly posterolaterally, with broadly rounded apex. Lateral surface of basis capituli concave ( Fig. 31C, D ). Palpi ( Fig. 31B, C, E ) moderately long, length dorsally (segments II and III) 0.35–0.40 (0.38 ± 0.02; n = 11), maximum width (in dorsolateral plane) 0.14–0.16 (0.16 ± 0.01; n = 11), ratio 2.31–2.52 (2.41 ± 0.07; n = 11), length of medial margin of palpal segment I ventrally 0.14–0.18 (0.17 ± 0.01; n = 11); segment I with moderately long internal projection directed anteriorly and giving L-shape to segment I dorsally and ventrally; length of internal projection ventrally from base of palpal segment II to anterior apex 0.10–0.14 (0.13 ± 0.01; n = 11), ratio combined length of palpal segments II and III to length of internal projection on palpal segment I ventrally 2.68–3.43 (3.02 ± 0.25; n = 11); dorsally segment I with slight transversal ridge at base, mesodorsal spur indistinct, dorsoapical denticle indistinct, as small blunt projection; segments II and III fused with indistinct or barely discernible (mostly medially) suture between them, narrow proximally and gradually widening to broadly rounded apex. Hypostome ( Fig. 31C, F ) length 0.40–0.43 (0.41; n = 3), width 0.15 (n = 3), ratio 2.67–2.78 (2.71; n = 3); base of hypostome nearly at same level as base of palpal segments II, club-shaped, widest close to mid-length; dental formula mostly 4/4, proximal rows 2/2 and then 3/3, distal rows 5/5; denticles sharply pointed; proximal part of hypostome without denticles moderate in length.

Legs moderately long, slender. Coxae ( Fig. 31G, H ): coxae I-III with internal and external spurs, coxae II and III may be with poorly distinct or indistinct internal spur, coxa IV with external spur only; external spur on coxae I-IV moderately long, subequal or spur on coxa I slightly longer than spur on other coxae, narrow, narrowly rounded at apex, directed slightly posteromedially; internal spur on coxae I-III short, decreasing in size from coxa I to III, narrow on coxa I and broader on coxae II and III, narrowly rounded at apex, spur on coxa I directed slightly posteromedially or posteriorly, spur on coxae II and III directed posteriorly; external spur on coxa I at least twice as long as internal spur; no syncoxae. Distally trochanters I-IV ( Fig. 31G, H ) with moderate ventral spur with narrowly rounded apex. Tarsus I length 0.86–0.94 (0.90 ± 0.03; n = 9); tarsus IV length 0.75–0.84 (0.80 ± 0.03; n = 9).

Nymph [Based on 11 specimens; Figs. 32 , 33 .] Idiosoma ( Fig. 32C ): broadly suboval, widest posterior to midlength. Scutum ( Fig. 32A ) length 612–672 (634 ± 15; n = 11), width 553–621 (583 ± 24; n = 11), ratio 1.00–1.15 (1.09 ± 0.04; n = 11); lateral margins diverging for approximately half of scutal length, then converging to broadly rounded posterior margin; posterolateral margins nearly straight; lateral carinae lacking; cervical grooves shallow; setae ( Fig. 32A ) relatively sparse, short: length in posterocentral field of scutum 5–13 (9 ± 2; n = 8), shorter than those on alloscutum, distributed as figured. Alloscutum ( Fig. 32B ) as illustrated; setae ( Fig. 32B ) numerous, evenly distributed, short in center of alloscutum: 13–18 (16 ± 1; n = 10) and long in area medial to marginal grooves: 34–40 (36 ± 2; n = 10), setae in area medial to marginal grooves 2.00–2.67 (2.28 ± 0.22; n = 10) times longer than setae in center of alloscutum; ratio scutal length to length of setae in area medial to marginal grooves 15.94–19.00 (17.55 ± 0.93; n = 10). Anal groove ( Fig. 32C ) oval with open posterior margin; ventral setae ( Fig. 32C ) numerous, evenly distributed. Spiracular plates ( Fig. 32D ) broadly oval; length 136–196 (160 ± 18; n = 11), width 153–196 (171 ± 14; n = 11), ratio 0.84–1.05 (0.94 ± 0.07; n = 11).

Gnathosoma ( Fig. 33A, B ) length from palpal apices to posterior margin of basis capituli ventrally 387–417 (402 ± 11; n = 9), width at dorsal cornua apices 272–306 (291 ± 9; n = 11), ratio 1.36–1.40 (1.37 ± 0.01; n = 9). Basis capituli ( Fig. 33A, B ): dorsally subtriangular, posterior margin slightly convex with long posterolaterally directed cornua; ventrally pentagonal; auriculae moderately long: length 21–30 (26 ± 2; n = 11), ratio gnathosoma length to auriculae length 13–20 (16 ± 2; n = 9), triangular, directed slightly posterolaterally. Palpi ( Fig. 33A, B ): elongate, length dorsally (segments II and III) 162–187 (175 ± 7; n = 9), width 77–85 (82 ± 4; n = 9), ratio 2.10–2.22 (2.14 ± 0.05; n = 9); segment I well developed, with moderately long internal projection directed anteriorly and giving L-shape to segment I dorsally and ventrally; length of internal projection ventrally from base of palpal segment II to anterior apex 43–57 (50 ± 5; n = 11), ratio combined length of palpal segments II and III to length of internal projection on palpal segment I ventrally 2.98–4.00 (3.42 ± 0.31; n = 9); segments II and III fused with indistinct suture between them, narrower proximally and gradually widening to broadly rounded apex. Hypostome ( Fig. 33B ) length 179–193 (187 ± 6; n = 6), width 72–85 (79 ± 5; n = 6), ratio 2.24–2.51 (2.37 ± 0.12; n = 6); widest at approximately its mid-length; base of hypostome approximately at same level as base of palpal segment II; proximal portion of hypostome without denticles short, then dental formula 2/2 for approximately 2 or 3 rows, 3/3 for approximately 4–8 rows, 4/4 for 0–3 rows; apex broadly rounded with irregular smaller denticles.

Legs moderately long. Coxae ( Fig. 33C ): coxae I-III with well-developed internal and external spurs, coxa IV with well-developed external spur and indistinct internal spur; external spur on coxae I-IV moderately long, narrow, narrowly rounded at apex, curved slightly posteromedially; external spur on coxae I-IV nearly subequal; internal spur on coxae I-III short, broad and narrowly to broadly rounded at apex, shorter than external spur; no syncoxae. Trochanters I-IV ( Fig. 33C ) with short ventral spur. Tarsus I length 434–476 (451 ± 15; n = 10); tarsus IV length 366–400 (385 ± 11; n = 9).

Larva [Based on 17 specimens; Figs. 34 , 35 .] Idiosoma ( Fig. 34B ): broadly suboval, widest close to midlength. Scutum ( Fig. 35A ) length 305–365 (328; n = 3), width 375–390 (383; n = 3), ratio 0.81–0.95 (0.86; n = 3); hexagonal, lateral margins diverging for slightly more than 1/2 of scutal length, then converging to broadly rounded or nearly straight posterior margin; posterolateral margins with very slight depressions; lateral carinae absent; cervical grooves faint, shallow depressions. Setae 5 pairs, length of Sc 2 18 (n = 1); length of Sc 3 15 (n = 2); alloscutum ( Fig. 34A ) as illustrated. Dorsal setae approximately 15–17 pairs; approximately 3–5 pairs of central dorsals, length of Cd 1 22–25 (24; n = 3), length of Cd 2 20–21 (20; n = 3); approximately 11–13 pairs of marginal dorsals combined with supplementaries, length of Md 1 19–22 (20; n = 3). Venter ( Fig. 34B ) as illustrated; anal groove indistinct anteriorly and open posteriorly. Ventral setae approximately 14–16 pairs plus 1 pair on anal valves; 3 pairs of sternals, length of St 1 20–22 (21; n = 3); 2 pairs of preanals, length of Pa 1 24–25 (25; n = 3), length of Pa 2 28–30 (29; n = 3); approximately 6–8 pairs of premarginals; 3 pairs of marginal ventrals, length of Mv 1 18–21 (20; n = 3).

Gnathosoma ( Fig. 35B–D ): length from hypostomal apex to posterior margin of basis capituli ventrally 240– 275 (254; n = 3), width at dorsal cornual apices 164–185 (172; n = 3); ratio 1.43–1.51 (1.48; n = 3). Basis capituli ( Fig. 35B–D ): dorsally subtriangular, posterior margin slightly convex with long posterolaterally directed cornua; ventrally pentagonal with relatively short, triangular auriculae, directed posterolaterally. Post-hypostomal setae 2 pairs. Palpi ( Fig. 35B, C ): elongate, length (segments II and III) 101–105 (103; n = 3), width 48–50 (48; n = 3), ratio 2.10–2.13 (2.12; n = 3); segment I well developed, with moderately long internal projection directed anteriorly and giving L-shape to segment I dorsally and ventrally; length of internal projection ventrally from base of palpal segment II to anterior apex 23–25 (23; n = 3), ratio combined length of palpal segments II and III to length of internal projection on palpal segment I ventrally 4.05–4.67 (4.41; n = 3); segments II and III fused, suture between them indistinct; segment I lacking setae, 10 dorsal and 3 ventral setae on segments II and III combined. Hypostome ( Fig. 35C ): length 100–103 (101; n = 3), width 50–53 (51; n = 3), ratio 1.95–2.00 (1.97; n = 3); base of hypostome nearly at same level as articulation of palpal segments I and II; proximal portion without denticles short, then dental formula 1/1 for 1 row, 2/2 for 3 or 4 rows and 3/3 for approximately 4 or 5 rows; apex broadly rounded with irregular small denticles.

Legs moderately long. Coxae ( Fig. 35E ): coxa I with well-developed internal and external spurs, coxae II and III each with well-developed external spur and indistinct internal spur; external spur on coxae I-III moderately long, narrow, narrowly rounded at apex, curved slightly posteromedially; external spur on coxa I slightly longer than spur on other coxae; external spur on coxa III slightly shorter than on coxa II; internal spur on coxa I short, broad, narrowly rounded at apex, shorter than external spur; posteromedian angle of coxa II forming slight, broadly rounded projection; no syncoxae; coxae I and III with 3 setae each, coxa II with 2 setae. Trochanters I and II with short ventral spur; trochanter III lack of ventral spur ( Fig. 35E ). Tarsus I length 238–268 (251; n = 3); tarsus III length 208–245 (230; n = 3).

Remarks. Apparently, the male of this species was described in Gregson (1956). Descriptions of the female were partially or entirely based on specimens of I. robbinsi n. sp. in Nuttall (1916), Cooley and Kohls (1945), Gregson (1956), Arthur (1960), Furman and Loomis (1984) and Lindquist et al. (2016). Descriptions of the nymph were seemingly, partially or entirely, based on specimens of I. robbinsi n. sp. in Nuttall (1916), Cooley and Kohls (1945), Gregson (1956), Furman and Loomis (1984) and Lindquist et al. (2016). Descriptions of the larva were seemingly, partially or entirely, based on specimens of I. robbinsi n. sp. in Nuttall (1916), Furman and Loomis (1984), Webb et al. (1990) and Lindquist et al. (2016).

By having a distinct, anteriorly directed internal projection on palpal segment I, the female of I. robbinsi n. sp. most closely resembles the following Ixodes (Multidentatus) spp.: I. auritulus , I. brevisetosus n. sp., I. contrarius n. sp., I. cornuae , I. guglielmonei n. sp., I. insulae n. sp., I. kerguelenensis , I. moralesi n. sp., I. paranaensis , I. percavatus , I. rio n. sp., I. tinamou n. sp. and I. zealandicus .

The female of I. robbinsi n. sp. can be distinguished from the female of I. cornuae by having short cornua (vs very long cornua in that species); from females of I. kerguelenensis and I. percavatus by having the indistinct mesodorsal spur on palpal segment I (vs large, distinct spur in those species); from the female of I. paranaensis by having longer auriculae (vs very short auriculae in that species) (see Arthur 1960; Wilson 1970; Barros-Battesti et al. 2003).

The female of I. robbinsi n. sp. can be distinguished from females of other species by the broad scutum: mean ratio length to width 1.16 (vs narrower scutum: mean ratio 1.44 in I. brevisetosus n. sp., 1.45 in I. contrarius n. sp., 1.35 in I. insulae n. sp., 1.41 in I. rio n. sp. and 1.37 in I. zealandicus ); short setae in center of alloscutum and moderately long setae in alloscutal area medial to marginal grooves: mean ratio length of setae in alloscutal area medial to marginal grooves to length of setae in center of alloscutum 2.65 (vs longer setae in alloscutal area medial to marginal grooves: mean ratio 3.40 in I. auritulus , 3.75 in I. contrarius n. sp., 3.68 in I. moralesi n. sp. and 4.00 in I. rio n. sp.; shorter setae in alloscutal area medial to marginal grooves: mean ratio 1.58 in I. brevisetosus n. sp.; longer setae in both center and area medial to marginal grooves of alloscutum: mean ratio 1.09 in I. guglielmonei n. sp. and 1.14 in I. zealandicus ); moderately long setae of alloscutum medial to marginal grooves: mean ratio length of scutum to length of alloscutal setae medial to marginal grooves 26.93 (vs longer setae of alloscutum medial to marginal grooves: mean ratio 12.88 in I. auritulus , 15.03 in I. contrarius n. sp., 15.16 in I. guglielmonei n. sp., 17.20 in I. insulae n. sp., 15.18 in I. rio n. sp., 17.40 in I. tinamou n. sp. and 16.22 in I. zealandicus ; shorter setae of alloscutum medial to marginal grooves: mean ratio 45.62 in I. brevisetosus n. sp.); broad gnathosoma: mean ratio length of gnathosoma to width of basis capituli 1.22 (vs narrower gnathosoma: mean ratio 1.33 in I. brevisetosus n. sp. and I. zealandicus and 1.34 in I. insulae n. sp.); basis capituli slightly convex dorsolaterally (vs basis capituli with angular dorsolateral projections in I. brevisetosus n. sp. and I. rio n. sp.); lateral surface of basis capituli concave (vs lateral surface flat in I. brevisetosus n. sp.); posterior margin of basis capituli slightly convex (vs sinuously concave in I. guglielmonei n. sp. and straight to very slightly concave in I. zealandicus ); long cornua: mean ratio length of basis capituli to cornual length 5.84 (vs shorter cornua: mean ratio 14.00 in I. contrarius n. sp.); broad porose areas: mean ratio width of basis capituli to width of porose area 2.83 (vs narrower porose areas: mean ratio 3.61 in I. brevisetosus n. sp. and 3.47 in I. rio n. sp.); auriculae moderately long: mean ratio length of gnathosoma dorsally to length of auriculae 14.59, broad, directed posteriorly, with broadly rounded apex (vs longer auriculae: mean ratio 9.74 in I. auritulus , 8.97 in I. brevisetosus n. sp. and I. insulae n. sp., 9.50 in I. contrarius n. sp. and 9.65 in I. rio n. sp.; shorter auriculae: mean ratio 28.15 in I. guglielmonei n. sp., 40.07 in I. tinamou n. sp. and 19.54 in I. zealandicus ; auriculae distinctly narrower, with narrowly rounded apex in I. auritulus , I. brevisetosus n. sp., I. contrarius n. sp., I. insulae n. sp. and I. rio n. sp.); moderately long internal projection on palpal segment I: mean ratio length of palpal segments II and III to length of projection on palpal segment I 3.02 (vs longer projection: mean ratio 1.88 in I. contrarius n. sp.; shorter projection: mean ratio 4.94 in I. guglielmonei n. sp., 3.55 in I. insulae n. sp. and 4.50 in I. zealandicus ); lacking spur at base of palpal segment I dorsally (vs short mesodorsal spur at base of palpal segment I dorsally in I. insulae n. sp., I. moralesi n. sp. and I. zealandicus ); indistinct dorsoapical spur on palpal segment I (vs moderate spur in I. auritulus , I. brevisetosus n. sp., I. insulae n. sp. and I. zealandicus ; large, hook-like spur in I. moralesi n. sp.); moderately broad palpal segments II and III: mean ratio length to width 2.41 (vs narrower segments: mean ratio 2.82 in I. brevisetosus n. sp., 2.64 in I. insulae n. sp. and 2.87 in I. rio n. sp.; broader segments: mean ratio 2.16 in I. guglielmonei n. sp.); external spur on coxae I-IV relatively long, narrow, sharper at apex (vs shorter, broader spur with broadly rounded apex in I. tinamou n. sp. and I. zealandicus ); generally moderately large species: see description for measurements (vs noticeably smaller species: I. contrarius n. sp., I. rio n. sp. and I. zealandicus ; noticeably larger species: I. guglielmonei n. sp. See descriptions for measurements).

The nymph of I. robbinsi n. sp. can be distinguished from nymphs of I. auritulus , I. brevisetosus n. sp., I. guglielmonei n. sp. and I. tinamou n. sp. by its moderately long and broad scutum (vs shorter and narrower scutum in I. auritulus ; narrower scutum in I. brevisetosus n. sp.; broader scutum in I. guglielmonei n. sp.; shorter scutum in I. tinamou n. sp.), shorter setae in posterocentral field of scutum (vs longer setae in I. guglielmonei n. sp.), short setae on alloscutum in area medial to marginal grooves (vs longer setae in I. auritulus , I. guglielmonei n. sp. and I. tinamou n. sp.; shorter in I. brevisetosus n. sp.), short setae in center of alloscutum (vs longer setae in I. auritulus , I. guglielmonei n. sp. and I. tinamou n. sp.), setae on alloscutum in area medial to marginal grooves at least twice longer than setae in center of alloscutum (vs subequal setae in I. guglielmonei n. sp.), relatively large spiracular plate (vs smaller spiracular plate in I. tinamou n. sp.), moderately long and narrow gnathosoma (vs longer and broader gnathosoma in I. guglielmonei n. sp.; shorter gnathosoma in I. tinamou n. sp.), relatively short auriculae (vs longer auriculae in I. auritulus and I. brevisetosus n. sp.; shorter auriculae in I. tinamou n. sp.), relatively short and moderately broad palpal segments II and III (vs narrower segments in I. auritulus and I. brevisetosus n. sp.; longer and broader segments in I. guglielmonei n. sp.), relatively long internal projection on palpal segment I (vs shorter projection in I. guglielmonei n. sp. and I. tinamou n. sp.), moderately long and broad hypostome (vs shorter hypostome in I. auritulus ; longer and broader hypostome in I. guglielmonei n. sp.; shorter and narrower hypostome in I. tinamou n. sp.), moderately long tarsus I (vs shorter tarsus in I. auritulus ; longer tarsus in I. guglielmonei n. sp.) and moderately long tarsus IV (vs shorter tarsus in I. auritulus and I. brevisetosus n. sp.; longer tarsus in I. guglielmonei n. sp.).

The larva of I. robbinsi n. sp. can be distinguished from larvae of I. auritulus , I. brevisetosus n. sp. and I. guglielmonei n. sp. by the distinctly sculptured surface of scutum (vs sculpturing of scutum usually poorly distinct in I. brevisetosus n. sp.); smaller dimensions of the following characters: width of scutum, length of gnathosoma, length and width of palpal segments II and III, length and width of hypostome, length of tarsi I and III (vs longer hypostome in I. brevisetosus n. sp.; larger size of the characters listed in I. guglielmonei n. sp.); shorter setae Sc 2, Sc 3, Md 1, St 1, Pm 1 and Mv 1 (vs longer setae in I. auritulus and I. guglielmonei n. sp.); moderately short setae Cd 1 and Cd 2 (vs longer setae in I. auritulus and I. guglielmonei n. sp.; shorter setae in I. brevisetosus n. sp.); shorter setae Pa 1 and Pa 2 (vs longer setae in all other species); shorter auriculae (vs longer auriculae in I. auritulus and I. brevisetosus n. sp.); moderately long anterior projection on palpal segment I (vs longer projection in I. auritulus ; shorter projection in I. guglielmonei n. sp.) and poorly distinct internal spur on coxa II (vs well-developed spur in I. guglielmonei n. sp.).

Collection data for I. robbinsi n. sp. are listed in the material above. Collections of this species were made in Canada (British Columbia Province) and the United States (Alaska, California, Oregon and Washington States) ( Fig. 10F ). All stages of this species were collected from various, mostly passeriform, birds. Females, nymphs and larvae of this species were collected from the song sparrow, M. melodia ( Passeriformes : Emberizidae ). Both females and nymphs were collected from the dark-eyed junco, J. hyemalis and the sooty fox sparrow, P. unalaschensis ( Passeriformes : Emberizidae ). Only females of I. robbinsi n. sp. were collected from the purple finch, H. purpureus ( Passeriformes : Fringillidae ), the black-capped chickadee, P. atricapillus ( Passeriformes : Paridae ), the house sparrow, P. domesticus ( Passeriformes : Passeridae ) and the American robin, T. migratorius ( Passeriformes : Turdidae ). Only nymphs of I. robbinsi n. sp. were collected from the ruffed grouse, B. umbellus ( Galliformes : Phasianidae ), the white-crowned sparrow, Z. leucophrys ( Passeriformes : Emberizidae ), the black-headed grosbeak, P. melanocephalus ( Passeriformes : Cardinalidae ), the Bewick’s wren, T. bewickii and the Pacific wren, T. pacificus ( Passeriformes : Troglodytidae ), while only larvae were taken from the Savannah sparrow, P. sandwichensis and the golden-crowned sparrow, Z. atricapilla ( Passeriformes : Emberizidae ). Females were collected during February, March, August, September, November and December, nymphs during February-June, August, September and November, and larvae during May and September.

The record of I. auritulus from Florida, USA ( Durden & Keirans 1996) is based on a misidentified nymph. Examination of this specimen ( USA: Florida: Brevard County [~ 28°18’N, 80°42’W]: 1 nymph, from the great shearwater, Puffinus gravis (O’Reilly) [ Procellariiformes : Procellariidae ], 17.vi.1993, G. Foster, USNMENT 00987227) revealed that it belongs to one of the Multidentatus species parasitizing sea birds, possibly I. kerguelenensis or a closely related species.

Figures

FIGURE 10. Map showing the known geographical distribution of Ixodes auritulus Neumann, 1904, I. brevisetosus n. sp., I. contrarius n. sp., I. guglielmonei n. sp., I. insulae n. sp., I. moralesi n. sp., I. rio n. sp., I. robbinsi n. sp. and I. tinamou n. sp. A, Filled star shows the type-locality and filled circles show confirmed localities of I. auritulus; B, Filled asterisk shows the type-locality and filled circles show confirmed localities of I. brevisetosus n. sp., filled star shows the type-locality of I. insulae n. sp.; C, Filled triangle shows the type-locality of I. contrarius n. sp., filled cross shows the type-locality and filled circle shows confirmed locality of I. moralesi n. sp.; D, Filled star shows the type-locality and filled circles show confirmed localities of I. guglielmonei n. sp.; E, Filled star shows the type-locality and filled circle shows confirmed locality of I. rio n. sp., filled asterisk shows the type-locality of I. tinamou n. sp.; F, Filled star shows the type-locality and filled circles show confirmed localities of I. robbinsi n. sp.

FIGURE 30. Ixodes robbinsi n. sp., scanning electron micrographs of female (Tillamook, Tillamook County, Oregon, USA, USNMENT 00987222, paratype).A, Idiosoma, dorsal view; B, Scutum, dorsal view; C, Scutum, dorsolateral view; D, Alloscutal setae in central area of alloscutum; E, Alloscutal setae in area of alloscutum medial to marginal grooves; F, Idiosoma, ventral view. Scale-bars: A, F, 0.5 mm; B, C, 0.2 mm; D, E, 0.05 mm. SEMs by D.A. Apanaskevich

FIGURE 31. Ixodes robbinsi n. sp., hypostome and scanning electron micrographs of female (Tillamook, Tillamook County, Oregon, USA, A–E, G, H, USNMENT 00987222, paratype; F, USNMENT 00987223, paratype). A, Spiracular plate (arrows show orientation of spiracular plate: a, anterior; d, dorsal); B, Gnathosoma, dorsal view; C, Gnathosoma, ventral view; D, Gnathosoma, anteroventral view; E, Palpal segment I, medial view; F, Hypostome; G, Coxae I–III and trochanters I–III; H, Coxa IV and trochanter IV. Scale-bars: A–D, F, 0.1 mm; E, 0.05 mm; G, H, 0.2 mm. SEMs by D.A.Apanaskevich; D.A.Apanaskevich del.

FIGURE 32. Ixodes robbinsi n. sp., scanning electron micrographs of nymph (Brookings, east side of Goat Island, Curry County, Oregon, USA, USNMENT 00987210). A, Scutum; B, Alloscutum; C, Idiosoma, ventral view; D, Spiracular plate (arrows show orientation of spiracular plate: a, anterior; d, dorsal). Scale-bars: A, D, 0.1 mm; B, C, 0.2 mm. SEMs by D.A. Apanaskevich.

FIGURE 33. Ixodes robbinsi n. sp., scanning electron micrographs of nymph (Brookings, east side of Goat Island, Curry County, Oregon, USA, USNMENT 00987210). A, Gnathosoma, dorsal view; B, Gnathosoma, ventral view; C, Coxae and trochanters. Scale-bars: 0.1 mm. SEMs by D.A. Apanaskevich

FIGURE 34. Ixodes robbinsi n. sp., scanning electron micrographs of larva (Salmon Creek, Juneau, Alaska, USA, USNMENT 00987180). A, Alloscutum; B, Idiosoma, ventral view. Scale-bars: 0.2 mm. SEMs by D.A. Apanaskevich

FIGURE 35. Ixodes robbinsi n. sp., scanning electron micrographs of larva (Salmon Creek, Juneau, Alaska, USA, USNMENT 00987180). A, Scutum; B, Gnathosoma, dorsal view; C, Gnathosoma, ventral view; D, Gnathosoma, anteroventral view; E, Coxae and trochanters. Scale-bars: A, E, 0.1 mm; B–D, 0.05 mm. SEMs by D.A. Apanaskevich