Tetranychus canadensis , Pritchard & Baker 1952, new combination
Creators: name: Liu, Man
name: Yi, Tian-Ci
name: Gulbronson, Connor
name: Bauchan, Gary R.
name: Ochoa, Ronald
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Prostigmata
Tetranychidae
Tetranychus
Tetranychus canadensis

description: Tetranychus canadensis (McGregor, 1950) (Figs 1–35)
Septanychus canadensis, McGregor 1950: 319, original description.
Tetranychus canadensis, Pritchard & Baker 1952: 267, new combination; Baker & Pritchard, 1953: 221; Pritchard & Baker 1955: 393; Tuttle & Baker 1964: 41; Baker & Tuttle 1994: 289; Seeman & Beard 2011: 24.
Description
Measurements are given based on the specimens ex. Liriodendron tulipifera, from 49 th Place, College Park City, Maryland, U.S.A.
Female (n = 10)
Dorsum (Figs 1–3). Idiosomal length from v 2 to h 2 380 (317–424), width from c 3 to c 3 282 (244–311). Propodosoma with broadly truncate anterior margin, with longitudinal medial lobed striae anteriorly and posteriorly flanked by a narrow strip of transverse lobed striae (Fig. 1). Prodorsum with three pairs of barbed setae. Length of prodorsal setae: v 2 68 (64–73), sc 1 118 (114–123), sc 2 88 (79–96). Distance between setal bases: v 2 – v 2 67 (60–73), sc 1 – sc 1 78 (72–82), sc 2 – sc 2 193 (169–210).
Hysterosoma with transverse striae between c 1 – f 1, longitudinal between f 1 – f 1 followed by transverse (Fig. 2, 3C), arched (Figs 3B, D) or irregular striae (Fig. 3A). Length of longitudinal striae between f 1 – f 1 varies among female mites ex. Liriodendron tulipifera (Magnoliaceae), usually ending at the level of f 2 - f 2 (Fig 3D), sometimes not reaching the level of f 2 - f 2 (Figs 2, 3B, C). Dorsal setae on hysterosoma similar to prodorsal setae. Para-anal setae h 2 sub-terminal, h 3 terminal, located ventrally. Length of setae: c 1 108 (101–114), c 2 106 (100–111), c 3 96 (88–103), d 1 106 (91–113), d 2 107 (100–112), e 1 106 (101–110), e 2 106 (98–114), f 1 94 (85–100), f 2 85 (78–98), h 2 33(28–38), h 3 35 (25–40). Distances between setal bases: c 1 – c 1 69 (62–79), c 2 – c 2 143 (129–154), c 3 – c 3 282 (244–311), d 1 – d 1 80 (76–90), d 2 – d 2 107 (100–112), e 1 – e 1 51 (45–56), e 2 – e 2 157 (131–151), f 1 – f 1 51 (45–58), f 2 – f 2 94 (84–113). Three pair of lyrifissures (ia, im, ip) visible.
Venter (Figs 4–6). Ventral striae without lobes, transverse except for pregenital region with longitudinal broken (Figs 5, 6A, C, D, E) or, in other populations, weakly broken or entire striae (Figs 6B, F). Genital flap with transverse fine striae. Coxal setal chaetotaxy 2-2-1-1. Three pairs of intercoxal barbed setae 1a, 3a and 4a. Setae 1a 45 (43–47) longer than distance 1a–1a 34 (32–36). Setae 3a 51 (47–53) shorter than distance 3a–3a 69 (66–74). Setae 4a 72 (62–79) as long as distance between 4a–4a 72 (66–78). Two pairs of barbed genital setae (g 1 & g 2), subequal in length, g 1 43 (39–47) and g 2 40 (37–42). Two pairs of anal setae (ps) nude, subequal in length, ps 1 18 (15–20) and ps 2 17 (16–19).
Gnathosoma (Figs 7–8). Stylophore with longitudinal striae only. Peritreme groove hook-like; four or five peritrematal septa visible (Fig.7A, arrows a, b). Subcapitular setae m smooth, subequal in length [46 (44 – 47)] to distance m–m 48 (46–51). Three pairs of adoral setae (or 1–3) conspicuous, or 1 dorsal, spine-like; or 2 lateral, leaf-like, or 3 ventral, leaf-like. Hole-like rostral fossette visible on ventral subdistal rostrum (Fig. 7B arrow e).
Palp striate dorsally and ventrally, but membranes between palpal segments punctate ventrally. Dorsal surface of palp base with supracoxal seta (ep), eupathidial form. Setae d PFe and l″ PGe barbed. All three palptibial setae finely barbed; l′ PTi located near base of tibial claw. Tibial claw each side with lateral hole (Fig. 7B, arrows c) and lateral spur (Fig. 7B, arrows d). Terminal eupathidium (suζ) sub-conical, 6.7 (6.0–7.0) long and 3.6 (3.1–3.8) in diameter at widest level. Two lateral eupathidia (ul′ζ and ul″ζ) subequal in length, ul′ζ 6.9 (6.5–7.4), ul″ ζ 7.3 (7.1– 7.6). Solenidion (ω) 4.6 (4.3–5.0) long, about twice as long as wide 1.7 (1.5–1.8). Three normal setae (a, b, c) nude (Figs 8A, B).
Legs (Figs 9, 10). Coxa I dorsally with a supracoxal seta (el), eupathidial form (Fig. 7A). Claws of I–IV pad like, each with a dorsal spur (Fig. 9A, arrow a) and a pair of tenet hairs. Empodia I–IV each with a small dorsal spur and three pairs of proximoventral hairs (Figs 9 A–D, arrows b–e). Tarsus I with two pairs of duplex setae; tarsus II with one pair of duplex setae; tarsus III and IV each with a solenidion. Dorsal seta on tibia I (db) with trichobothridial aspect (Fig. 10A).
Male (n =10)
Dorsum (Figs 11–13). Length of idiosoma (v 2 – h 2) 202 (190–217); width of idiosoma (c 3 – c 3) 151 (134–160). Prodorsal striae longitudinal, with lobes; hysterosomal striae transverse, without lobes. Shape of dorsal setae as in female, h 2 dorsal, h 3 laterodorsal (Figs 13 & 14A). Length of setae: v 2 51 (46–56), sc 1 91 (82–101), sc 2 65 (54–75), c 1 77 (69–85), c 2 77 (67–85), c 3 71 (63–78), d 1 75 (69–80), d 2 76 (66–91), e 1 72 (67–78), e 2 74 (66–81), f 1 59 (52–63), h 2 19 (16–23), h 3 15 (13–17). Distances between setal bases: v 2 – v 2 51 (46–56), sc 1 – sc 1 61 (54–65), sc 2 – sc 2 121 (110–129), c 1 – c 1 54 (49–59), c 2 – c 2 94 (80–97), c 3 – c 3 151 (134–160), d 1 – d 1 53 (47–56), d 2 – d 2 101 (93–107), e 1 – e 1 31 (27–33), e 2 – e 2 76 (67–83), f 1 – f 1 30 (24–34), f 2 – f 2 46 (41–50).
Venter. Ventral striate including pregenital region transverse, without lobes; ventral setae barbed excepting smooth ps 1 and ps 2 (Fig. 14A): 1a 35 (30–39), 3a 37 (33–41), 4a 50 (45–55), ag 41 (33–47), g 1 16 (14–17), g 2 14 (14–15), ps 1 9 (8–10), ps 2 9 (8–10). Distances between setal bases: 1a–1a 23 (21–26), 3a–3a 45 (40–49), 4a–4a 49 (41–67).
Gnathosoma (Figs 14B, 15A, B, 16). Peritreme groove hook-like (Figs 15A, 16A); sometimes hook bifurcate (Fig. 15A). Subcapitular setae m smooth, length 36 (30 – 41) subequal with distance m–m 36 (34–41). Three pairs of adoral setae (or 1–3) conspicuous, or 1 dorsal, spine-like; or 2 lateral, leaf-like, or 3 ventral, leaf-like.
Palp (Figs 14B, 15A). Supracoxal seta (ep) eupathidial form. Seta d PFe peg-like. Palpal tarsus with coneshaped spinneret (suζ) slightly thinner than female, 5.8 (5.4–6.5) in length, 2.1 (1.9–2.2) in diameter at base; single solenidion 4.4 (4–4.7) in length and 1.4 (1.3–1.5) width; two eupathidia, ul′ζ 5.5 (5.1–5.9), ul″ζ 6.5 (5.7–7.2) and three normal setae (a, b, c).
Legs (Figs 17–18). Coxa I dorsally with a supracoxal seta (el), eupathidial form (Figs 15A, C). Empodium I with one dorsal spur and two pairs of ventral spurs. Empodia II–IV with one dorsal spur and three pairs of proximoventral hairs. Tarsus I with two pairs of duplex setae (Fig. 17A) and tarsus II with one pair of duplex setae; tarsus III and IV each with one solenidion. Dorsal seta on tibia I, a trichobothrium, with cup shaped base and broken striae on inner integument (Fig. 17B).
Aedeagus (Figs. 19–21). Dorsal margin of knob of aedeagus convex, anterior projection shorter than posterior.
A thin, long ejaculatory duct connecting aedeagus to a cup-shaped seminal vesicle.
Deutonymph (n =5)
Dorsum (Fig.22). Length of idiosoma (v 2 – h 2) 259 (240–277); width of idiosoma (c 3 – c 3) 204 (198–214). Prodorsal striae longitudinal and without lobes, posteriorly flanked by a narrow strip of transverse lobed striae or smooth striae; Hysterosoma with transverse striae between c 1 – e 1, arched between f 1 – f 1 following by transverse striae. Hysterosomal striae smooth except for lobed striae between c 1 – c 1. Length of setae: v 2 54 (50–57), sc 1 98 (96–100), sc 2 69 (66–73), c 1 81 (66–92), c 2 82 (75–86), c 3 57 (69–81), d 1 84 (81–87), d 2 88 (85–89), e 1 83 (79–87), e 2 81 (79–83), f 1 70 (64–74), f 2 57 (55–59), h 2 29 (28–30), h 3 25 (24–27). Distances between setal bases: v 2 – v 2 56 (54–58), sc 1 – sc 1 67 (65–69), sc 2 – sc 2 159 (152–164), c 1 – c 1 61 (58–62), c 2 – c 2 118 (114–122), c 3 – c 3 204 (198–214), d 1 – d 1 68 (65–73), d 2 – d 2 142 (137–148), e 1 – e 1 40 (38–43), e 2 – e 2 110 (104–121), f 1 – f 1 32 (29–35), f 2 – f 2 64 (61–69).
Venter (Fig. 23). Most ventral striae transverse except for pregenital region with longitudinal entire striae. Ventral setae: 1a 34 (34–35), 3a 38 (37–39), 4a 45 (38–52), ag 54 (53–56), g 1 25 (23–29), ps 1 14 (13–15), ps 2 14 (13–15). Distances between setal bases: 1a–1a 23 (21–26), 3a–3a 52 (47–55), 4a–4a 52 (50–55), ag–ag 46 (46– 47).
Gnathosoma (Figs. 24C, D). Subcapitular setae m length 36 (33–39) slightly shorter than distance m -m 39 (35–43). Spinneret (suζ) 5.8 (5.5–6.1) in length and 2.2 (2–2.4) in diameter; single solenidion 4.4 (4–4.8) in length and 1.5 (1.4–1.5) in diameter, and two eupathidia ul′ζ 5.7 (5.2–6.1), ul″ζ 6.5 (6.4–6.5).
Legs (Fig. 25). Coxa I dorsally with a supracoxal seta (el), eupathidial form. Claws of I–IV pad-like, each with a dorsal spur and a pair of tenet hairs. Empodia I–IV each with a small dorsal spur and three pairs of proximoventral hairs. Tarsus I with two pairs of duplex setae; tarsus II with one pair of duplex setae; tarsus III with a solenidion and tarsus IV without solenidion.
Protonymph (n=2)
Dorsum (Fig. 26). Length of idiosoma (v 2 – h 2) 184 (183–184); width of idiosoma (c 3 – c 3) 170 (165–174). Prodorsal striae longitudinal and without lobes, posteriorly flanked by a narrow strip of transverse striae. Hysterosoma with transverse striae. Length of setae: v 2 51 (49–53), sc 1 81 (80–82), sc 2 58 (57–58), c 1 70 (68–71), c 2 63 (61–65), c 3 60 (57–62), d 1 62 (57–66), d 2 67 (65–69), e 1 59 (58–59), e 2 65 (61–69), f 1 56 (55–56), f 2 47 (44–49), h 2 22 (20–24), h 3 22 (21–22). Distances between setal bases: v 2 – v 2 51 (50–52), sc 1 – sc 1 63 (62–64), sc 2 – sc 2 126 (115–137), c 1 – c 1 58 (57–59), c 2 – c 2 110 (109–111), c 3 – c 3 170 (165–174), d 1 – d 1 60 (58–62), d 2 – d 2 123 (118–128), e 1 – e 1 35 (34–35), e 2 – e 2 84 (82–85), f 1 – f 1 20 (18–21), f 2 – f 2 42 (41–42).
Venter (Fig. 27). Venter with transverse striae except for pregenital region with longitudinal entire striae. Ventral setae: 1a 30 (29–30), 3a 35 (32–38), ps 1 12 (11–12), ps 2 13 (12–13). Distances between setal bases: 1a–1a 27 (26–28), 3a–3a 48 (47–49).
Gnathosoma (Figs. 28, 29). Subcapitular setae m length 30 (29–31) subequal to distance m -m 32 (31–33). Spinneret (suζ) 4.6 (4.5–4.6) in length and 1.9 (1.8–2.0) in diameter; single solenidion 3.9 (3.8–4.0) in length and 1.3 (1.2–1.3) in diameter, and two eupathidia ul′ζ, 4.5 (4.4–4.6), ul″ζ 5.7 (5.6–5.7).
Legs (Fig. 30). Claws of I–IV pad like, each with a dorsal spur and a pair of tenet hairs. Empodia I–IV each with a small dorsal spur and three pairs of proximoventral hairs. Tarsus I with two pairs of duplex setae; tarsus II with on pair of duplex setae; tarsus III and IV without solenidion.
Larva (n = 5)
Dorsum (Figs 31, 32A, B). Length of idiosoma (v 2 – h 2) 140 (127–157); width of idiosoma (c 3 – c 3) 147 (133–157). Doral striae and shape of dorsal setae similar to that of protonymph. Length of setae: v 2 46 (38–55), sc 1 68 (67–68), sc 2 56 (45–70), c 1 51 (50–53), c 2 48 (47–49), c 3 47 (45–51), d 1 48 (47–51), d 2 48 (47–49), e 1 45 (41–47), e 2 45 (43–48), f 1 41 (41–41), f 2 35 (33–38), h 2 22 (18–24), h 3 22 (21–25). Distances between setal bases: v 2 – v 2 41 (37–44), sc 1 – sc 1 56 (53–61), sc 2 – sc 2 99 (89–108), c 1 – c 1 45 (43–50), c 2 – c 2 87 (77–93), c 3 – c 3 147 (133–157), d 1 – d 1 42 (39–46), d 2 – d 2 95 (84–102), e 1 – e 1 24 (28–31), e 2 – e 2 67 (57–75), f 1 – f 1 12 (10–13), f 2 – f 2 37(33–41).
Venter (Fig. 32C). Ventral striae entirely transverse. Ventral setae: 1a 30 (28–32), 3a 26 (26–27), ps 1 12 (12–13), ps 2 12 (12–13). Distances between setal bases: 1a–1a 26 (26–27), 3a–3a 34 (31–36).
Gnathosoma (Figs. 33B, C). Spinneret (suζ) 5.4 (4.9–5.8) in length and 1.4 (1.4–1.4) in diameter; single solenidion 3.9 (3.7–4.2) in length and 1.2 (1.1–1.3) in diameter, and two eupathidia ul′ζ 4.2 (3.9–4.5), ul″ζ acuminate, 5.0 (4.6–5.7).
Legs (Fig. 34). Claws of I–IV pad-like, each with a dorsal spur and a pair of tenet hairs. Empodia I–IV each with a small dorsal spur and three pairs of proximoventral hairs. Tarsus I and II each with one pair of duplex setae; tarsus III and IV without solenidion.
Ontogenetic development of leg setae
Larva. Setae counts: femora, 3-3-2; genua, 4-4-2; tibiae, 5(1 ω)-5-5; tarsi, 6(1 ω)(2 ζ)-6(1 ω)(2 ζ)-6. Trochanters I–III nude, without seta. Femora I–II with three setae (d, v′, bv″), one dorsal and two ventral, respectively, and femur III with two setae (d, ev′). Genua I–II with four setae (l′, l″, v′, v″) respectively, and genu III with two setae (l′, v′). Tibiae I–III with five tactile setae (d, l′, l″, v′, v″), tibia I with solenidion (φ). Tarsus I with six tactile setae, unguinals (u′, u″), primiventrals (pv′, pv″) and fastigials (ft′, ft″), one solenidion (ω″), two eupathidial prorals (p′ζ, p″ζ). One fastigianl ft″ and solenidion (ω″) forming duplex setae.
Protonymph. A total of seven setae added on leg I–III in protonymph— tc′, tc′′ and v′ 1 on tarsus I, tc′ and tc′′ on tarsus II and III. Leg IV with a total 16 tactile setae: femur with 2, genu 2, tibia 5 and tarsus 6. Setal counts: femora, 3-3-2-2; genua, 4-4-2-2; tibiae, 5(1 ω)-5-5-5; tarsi, 8(2 ω)(3 ζ)-7(1 ω)(2 ζ)-6-6.
Deutonymph. A total of 20 setae and solenidia added on leg I–IV in deutonymph— v′ on trochanters I–III; l′, l″, v″ on femur I; d on genua I–IV; l′ 1, l″ 1 on tibia I; l′ 1, l″ 1, v″ 1, ω″ 1 on tarsus I; v′ 1 on tarsus II; ω′ on tarsus III; tc′, tc″ on tarsus IV. Setal counts: trochanters, 1-1-1-0, femora, 6-3-2-2; genua, 5-5-3-3; tibiae, 7(1 ω)-5-5-5; tarsi, 11(3 ω)(3 ζ)- 8(1 ω)(2 ζ)-6(1 ω)-6.
Female. A total of 28 tactile setae and two solenidia added on legs I–IV— l′ 1, l″ 1, v′ 1, v″ 1 on femur I; v′ 1, v″ 1 on tibia I; v′ 2 on tarsus I; l′ 1, l″ 1, v″ 1 on femur II; v′ 1, l′ 1 on tibia II, l′ 1, v″ 1, v′ 2 and one solenidia on tarsus II; l′ 1, v′ on femur III; v″ on genu III; v″ 1 on tibia III; v′ 1 on tarsus III; v′ on trochanter IV; l′ 1, v′ on femur IV; v″ on genu IV; l″ 1, v′ 1 on tibia IV; v′ 1, v″ 1 and one solenidia on tarsus IV. Setal counts: trochanters, 1-1-1-0, femora, 10-6-4-4; genua, 5-5-4-4; tibiae, 9(1 ω)-7-6-7; tarsi, 12(3 ω)(3 ζ)-11(1 ω)(2 ζ)-9(1 ω)-10(1 ω).
Male. A total of 28 tactile setae and seven solenidia added on legs I–IV— l′ 1, l″ 1, v′ 1, v″ 1 on femur I; v′ 1, v″ 1 and three solenidia on tibia I; v′ 2 and two solenidia on tarsus I; l′ 1, l″ 1, v″ 1 on femur II; l′ 1, v′ 1 on tibia II, l′ 1, v″ 1, v′ 2 and one solenidia on tarsus II; l′ 1, v′ on femur III; v″ on genu III; v″ 1 on tibia III; v″ 1 on tarsus III; v′ on trochanter IV; l′ 1, v′ on femur IV; v″ on genu IV; l″ 1, v′ 1 on tiba III; v′ 1, v″ 1 and one solenidia on tarsus IV. The male of spider mites has extra solenidia normally on tarsus I and tibia I and rarely in femora I and II, genua I and II (Zhang & Jacobson 2010; Yi & Ochoa 2018). In T. canadensis, two extra solenidia added on tarsus I and two or three on tibia I. Setal counts: trochanters, 1-1-1-0, femora, 10-6-4-4; genua, 5-5-4-4; tibiae, 9(3-4 ω)-7-6-7; tarsi, 12(5 ω)(3 ζ)-11(1 ω)(2 ζ)-9(1 ω)- 10(1 ω).
description: Published as part of Liu, Man, Yi, Tian-Ci, Gulbronson, Connor, Bauchan, Gary R. & Ochoa, Ronald, 2020, Ontogenetic and morphological studies on Tetranychus canadensis (Acari: Tetranychidae), pp. 215-250 in Zootaxa 4857 (1) on pages 221-237, DOI: 10.11646/zootaxa.4857.1.11, http://zenodo.org/record/4396392