Austrostigmaeus walteri sp. n.

(Figs. 1–12; Plates 1–2)

Diagnosis

Adult female. Ratio vi: vi–vi = 3.9 (3.3–3.9), ve: ve–sci = 2.2 (1.8–2.2); central area of hysterosoma striated, c1–c1: d1–d1: e1–e1: f1–f1 = 1.1: 1.1: 1.0: 1.2, c1: c1–c1 = 0.6, d1: d1–d1 = 0.2, e1: e1–e1 = 1.0; 3 pairs of aggenital setae each on a platelet; tarsi 13 + 1, 9 + 1, 7

, 7.

Adult male. Palptarsus basally angled; subcapitulum broadly expanded, nearly as wide as idiosoma; vi: vi–vi = 1.9 (1.9–2.6), ve: ve–sci = 2.0, c1–c1: d1–d1: e1–e1: f1–f1 = 1.4 (1.3–1.4): 1.2: 1.0: 1.0, c1: c1–c1 = 0.5, d1: d1–d1 = 0.2 (0.2–0.3), e1: e1–e1 = 0.8; aggenital setae situated on an undivided shield; tarsi 13 + 2, 9 + 2, 7, 7.

Material examined

Holotype adult female: Australia: Western Australia, Kimberley Region, Galvan's Gorge, 16°47'55"S, 125°50'39"E, 30 Oct 2000, J.J. Beard, small shrub with lightly pubescent leaves, 1 female on a slide.

Paratypes: 2 adult females each on 1 slide, 4 adult males on 3 slides, 2 deutonymph females each on 1 slide; same data as holotype.

Description

ADULT FEMALE (n = 3)

Yellow to dark orange in life.

Gnathosoma (Figs. 1–2). Chelicera slender, 77 (77–83) long; movable digit less than 1/2 of chelicera, 34 (33–35) long. Palp 60 (58–66) long; accessory claw seta­like; setation from palptrochanter to palptarsus: 0, 3, 1, 3 + 1 claw, 4 + 1 + 1 subterminal spine­like eupathidium + 3 basally fused eupathidia; palptarsus normal, not basally angled; setae ba, bp and lp simple, setiform; solenidion more than 1/2 of palptarsus, 10 (10–11) long. Subcapitulum normal, not broadly expanded as in adult male, subcapitular setae n 2.6 (2.1–2.6)x length of m, m = 23 (23–25), n = 60 (53–61); distance m–m about 1.4 (1.3–1.4)x distance n–n, m–m = 30 (29–31), n–n = 22 (22–23), m–n = 7 (7–9).

Idiosoma (Figs. 1–2; Plates 1–2). Oval, 293 (279–292) long, 191 (162–192) wide. Dorsal idiosomal setae sparsely barbed. Prodorsum with a small plain shield bearing 2 pairs of setae (vi and ve) and a pair of eyes; setae sci on platelets; pob not observed; sce absent; eye 7 (7–8) in diameter, ratio vi: vi–vi = 3.9 (3.3–3.9), ve: ve–sci = 2.2 (1.8–2.2); setal lengths: vi 27 (26–27), ve 48 (44–49), sci 40 (36–41); distances: vi– vi 7 (7–8), vi–ve 20 (20–21), ve–sci 22 (22–25), ve–ve 31 (31–32), sci–sci 66 (66–74). Central area of hysterosoma striated, without obvious shield; setae c1, c2, d1, d2, e1, e2 and f1 situated on small platelets, c2, d1, d2, e2 and f1 much shorter than others; ratio c1–c1: d1–d1: e1–e1: f1–f1 = 1.1: 1.1: 1.0: 1.2, c1: c1–c1 = 0.6, d1: d1–d1 = 0.2, e1: e1–e1 = 1.0 (0.9–1.0); setal lengths: c1 33 (31–33), c2 20 (20–24), d1 13 (13–14), d2 13 (13–14), e1 47 (43–47), e2 15 (14–15), f1 13 (13–14); distances: c1–c1 54 (54–56), c1–c2 62 (62–67), c1–d1 50 (45–51), d1–d1 54 (54–61), d1–d2 47 (46–47), d1– e 1 47 (45–53), e1– e 1 47 (47–50), e1– e 2 30 (30–36), e1–f1 22 (16–22), f1–f1 56 (56–64). Suranal shield entire, bearing 2 pairs of barbed setae, h1 = 32 (32–33), h2 = 24 (24–26), h1–h1 = 22 (22–25), h1–h2 = 20 (19–20). Ventral setae 4a situated posterior to coxae IV, 1a 27 (24–27), 3a 23 (22–25), 4a 21 (18–21). Aggenital area with 3 pairs of subequal setae, each on a platelet, ag3 thicker than other two pairs, ag1 13, ag2 12 (12–13), ag3 11; distances ag1–ag2 = 15 (13–16), ag2–ag3 = 15 (15–21); genital opening with a pair of setae (g), 14 long; pseudanal setae ps3 14 (14–15), ps2 14 (14–16), ps1 12 (12–13).

Legs (Figs. 2–3; Plate 2). Length: leg I 146 (146–153), leg II 115(111–121), leg III 118 (114–120), leg IV 138 (138–147). Setae d of femur I and genu I sparsely barbed, 21 (21–23) and 20 (20–25) long, respectively. Leg tarsal claw absent; membranous arolium developed; empodium rod­like, arising from arolium and bearing 3 Y­shaped tenent hairs. Setae v on leg I and II, v and v” on leg III and IV very long and barbed. Counts of setae and solenidia on legs I–IV: coxae 2 + 1 elc I, 1, 2, 2; trochanters 1, 1, 1, 1; femora 5, 4, 2, 2; genua 3 + 1, 1, 0, 0; tibiae 5 + 1 p, 5 + 1 p, 5 + 1 p, 5 + 1 p; tarsi 13 + 1, 9 + 1, 7

, 7. Lengths of solenidia: I 17 (17–19), II 20 (15–20), III 10 (9–10), IV 6 (6–8).

ADULT MALE (n = 3)

Gnathosoma (Figs. 4–5; Plate 2). Chelicera slender, 78 (76–81) long; movable digit less than 1/2 of chelicera, 36 (34–36) long. Palp very strong, 93 (93–105) long; accessory claw seta­like; setation from palptrochanter to palptarsus: 0, 3, 1, 3 + 1 claw, 4 + 1 + 1 subterminal spine­like eupathidium + 3 basally fused eupathidia; palptarsus basally angled as members of Summersiella; setae ba, bp and lp simple, setiform; solenidion more than 1/2 of palptarsus, 13 long. Subcapitulum broadly expanded, nearly as wide as idiosoma, subcapitular setae n 2.3 x length of m, m = 23 (22–24), n = 53 (51–54); distance m–m about 1.6x distance n–n, m–m = 50 (44–50), n–n = 31 (31–33), m–n = 10 (10–11).

Idiosoma (Figs. 4–5; Plate 1). Oval, 237 (228–240) long, 118 (118–120) wide. Dorsal idiosomal setae sparsely barbed. Prodorsum with a small plain shield bearing 2 pairs of setae (vi and ve) and a pair of eyes; setae sci on platelets; pob not observed; sce absent; eye 7 (7–8) in diameter, ratio vi: vi–vi = 1.9 (1.9–2.6), ve: ve–sci = 2.0; setal lengths: vi 25 (23–25), ve 44 (36–44), sci 31 (28–31); distances: vi– vi 13 (9–13), vi–ve 24 (23–25), ve–sci 22 (21–23), ve–ve 36 (35–37), sci–sci 64 (64–70). Hysterosoma with a pair of small shields between setae d2; setae c1, d1, d2, e1, e2 and f1 situated on small platelets, c2, d1, d2, e2 and f1 much shorter than others; ratio c1–c1: d1–d1: e1–e1: f1–f1 = 1.4 (1.3–1.4): 1.2: 1.0: 1.0, c1: c1–c1 = 0.5, d1: d1–d1 = 0.2 (0.2–0.3), e1: e1–e1 = 0.8; setal lengths: c1 27 (24–28), c2 22 (21–24), d1 13 (12–13), d2 13 (12–13), e1 36 (36–37), e2 13 (12–13), f1 14 (13–14); distances: c1–c1 60 (53–60), c1–c2 35 (33–38), c1–d1 40 (39–41), d1–d1 53 (48–53), d1–d2 30 (27–32), d1– e 1 30 (29–31), e1– e 1 45 (43–45), e1– e 2 21 (17–21), e1–f1 17 (16–17), f1–f1 44 (41–44). Suranal shield entire, bearing 2 pairs of barbed setae; h1 thin, much shorter than h2, h1: h2 = 0.5 (0.4–0.5); h1 = 8, h2 = 17 (17–19), h1–h1 = 10, h1–h2 = 12 (12–13). Ventral setae 4a situated posterior to coxae IV, 1a 22 (20–22), 3a 23 (20–23), 4a 20 (17–20). Aggenital area with 3 pairs of setae, all on an undivided shield, ag3 thicker than other two pairs, lengths: ag1 12 (12–13), ag2 12 (12–14), ag3 13 (13–14); distances ag1–ag2 = 15 (12–15), ag2–ag3 = 10 (10–15); genital setae absent; pseudanal setae ps1 small, 6 (5–6), ps2 12 (12–13), ps1 12.

Legs (Figs. 5–6). Length: leg I 152 (139–155), leg II 108 (103–111), leg III 109 (106–109), leg IV 136 (131–141). Setae d of femur I and genu I sparsely barbed, 23 (20–23) and 16 (16–21) long, respectively. Leg tarsal claw absent; membranous arolium developed; empodium rod­like, arising from arolium and bearing 3 Y­shaped tenent hairs. Setae v on leg I and II, v and v” on leg III and IV very long and barbed. Counts of setae and solenidia on legs I–IV: coxae 2 + 1 elc I, 1, 2, 2; trochanters 1, 1, 1, 1; femora 5, 4, 2, 2; genua 3 + 1, 1, 0, 0; tibiae 5 + 1 p, 5 + 1 p, 5 + 1 p, 5 + 1 p; tarsi 13 + 2, 9 + 2, 7

, 7. Lengths of solenidia: I 1 23 (20–24), I 2 34 (33–34), II 1 28 (27–29), II 2 32 (29–33), III 12, IV 12.

DEUTONYMPH FEMALE (n = 2)

Gnathosoma (Figs. 7–8). Chelicera slender, 66 (63–66) long; movable digit 27 (27–28). Palp 42 (42–44) long; accessory claw seta­like; setation from palptrochanter to PLATE 1. Austrostigmaeus walteri sp. n. (A–B, adult female; C, adult male). A, prodorsum; B, hysterosoma; C, idiosoma.

palptarsus: 0, 3, 1, 3 + 1 claw, 4 + 1 + 1 subterminal spine­like eupathidium + 3 basally fused eupathidia; palptarsus not basally angled; setae ba, bp and lp simple, setiform; solenidion more than 1/2 of palptarsus, 7 long. Subcapitulum not broadly expanded as adult male, subcapitular setae n 2.3 x length of m, m = 16 (16–18), n = 36 (33–36); distance m–m about 1.3x distance n–n, m–m = 23 (23–24), n–n = 18 (18–19), m–n = 4.

Idiosoma (Figs. 7–8). Oval, 224 (218–224) long, 137 (122–137) wide. Dorsal idiosomal setae sparsely barbed. Prodorsum with a small plain shield bearing 2 pairs of setae (vi and ve) and a pair of eyes; setae sci on platelets; pob not observed; sce absent; eye PLATE 2. Austrostigmaeus walteri sp. n. (A–C, adult female; D–E, adult male). A, genito­anal area; B, leg II; C, pretarsus II; D, palpi; E, subcapitulum.

7 in diameter, ratio vi: vi–vi = 3.3, ve: ve–sci = 1.8; setal lengths: vi 23 (23–30), ve 42 (42–43), sci 28 (27–28); distances: vi– vi 7, vi–ve 18, ve–sci 23 (21–23), ve–ve 30 (30–32), sci–sci 66 (66–67). Central area of hysterosoma faintly straited; setae c1, c2, d1, d2, e1, e2 and f1 situated on separate small platelets, c2, d1, d2, e2 and f1 much shorter than others; ratio c1–c1: d1–d1: e1–e1: f1–f1 = 1.3 (1.2–1.3): 1.3 (1.2–1.3): 1.0: 1.2, c1: c1–c1 = 0.6 (0.5–0.6), d1: d1–d1 = 0.2, e1: e1–e1 = 1.0; setal lengths: c1 24 (23–24), c2 27 (25–27), d1 9, d2 10, e1 38 (37–38), e2 10, f1 10; distances: c1–c1 53 (44–53), c1–c2 59, c1–d1 40 (36–40), d1–d1 50 (43–50), d1–d2 37 (34–37), d1– e 1 37 (37–39), e1– e 1 40 (37–40), e1– e 2 28 (27–28), e1–f1 17 (12–17), f1–f1 46 (45–46). Suranal shield entire, bearing 2 pairs of barbed setae, h1 = 23 (23–24), h2 = 16 (16–18), h1–h1 = 18 (15–18), h1–h2 = 11 (10–11). Ventral setae 1a 18 (18–19), 3a 19 (18–19), 4a 13 (13–15). Aggenital area with 3 pairs of subequal setae, each on a separate platelet, ag3 thicker than other two pairs, ag1 10, ag2 10, ag3 11; distances ag1–ag2 =12 (12–14), ag2–ag3 = 8 (7–8); genital setae absent; pseudanal setae ps3 12 (11–12), ps2 12 (10–12), ps1 10.

Legs (Fig. 9). Length: leg I 105 (105–114), leg II 76 (76–80), leg III 78 (78–86), leg IV 91 (91–95). Setae d of femur I and genu I sparsely barbed, 11 (11–13) and 13 (13–14) long, respectively. Leg tarsal claw absent; membranous arolium developed; empodium rod­like, arising from arolium and bearing 3 Y­shaped tenent hairs. Setae v on leg I and II, v and v” on leg III and IV very long and barbed. Counts of setae and solenidia on legs I–IV: coxae 2 + 1 elc I, 1, 2, 2; trochanters 1, 1, 1, 0; femora 5, 4, 2, 2; genua 3 + 1, 1, 0, 0; tibiae 5 + 1 p, 5 + 1 p, 5 + 1 p, 5 + 1 p; tarsi 13 + 1, 9 + 1, 7, 7. Lengths of solenidia: I 14 (13–14), II 16 (14–16), III 7 (6–7), IV 6 (5–6).

Etymology

The species is named after Dr David Evans Walter (University of Alberta, Canada) who has broadened our knowledge of acarology.