Neonidulus tereotus, Beard, Jennifer & Walter, David Evans, 2010

Beard, Jennifer & Walter, David Evans, 2010, New spider mite genus (Prostigmata: Tetranychidae) from Australia & New Zealand, with a discussion of Yezonychus Ehara, Zootaxa 2578, pp. 1-24 : 8-19

Neonidulus tereotus sp. nov. Beard & Walter

( Figs 7–22 )

Material examined. Holotype. Ψ. Australia, ex. Weeping Lillypilly, Waterhousea floribunda (Myrtaceae) , The University of Queensland St Lucia campus, Brisbane, Queensland, 27°30’ S 153°00’ E, 11.xi.2000, D.E. Walter (QM). Paratypes. 10 Ψ, ɗ, 1 deutonymph, same data as holotype (one slide); 2 ɗ, same data as holotype except 12.xii.2000 (one slide); 8 Ψ, 5 ɗ, deutonymph, 4 protonymphs, 4 larvae, same data as holotype except 05.xii.2001, J.J. Beard (all on separate slides, QM); 4 Ψ, ɗ, protonymph, larva, same data (all on separate slides, USNM).

Other material examined: 10 Ψ, 5 ɗ, pharate Ψ, 9 deutonymphs, 2 pharate deutonymphs, 3 protonymphs, 1 larva, Gap Creek Road, Kenmore, Brisbane, 27°28’51” S 152°55’39” E, 19.xii.2004, ex. Brush Box, Lophostemon confertus (Myrtaceae) , J.J. Beard and P.I. Forster (all separate slides; QM); 4 Ψ, 3 ɗ, deutonymph, protonymph, same data ( USNM); 2 Ψ, 2 ɗ, 2 deutonymphs, protonymph, same data ( NZAC); 2 Ψ, ɗ, 2 deutonymphs, 2 protonymphs, 2 larvae (separate slides), protonymph 3 larvae (on same slide), ex.

Brush Box, Lophostemon confertus , 6 km WNW Orchid Beach, Great Sandy National Park, Fraser Island, 24°56’56” S 153°15’40” E, 04.ix.2004, P.I. Forster & J.J. Beard (QM).

Diagnosis. Prodorsum with three pairs of setae, two pairs of eyes; opisthosoma with nine pairs of setae (c1, c2, c3, d1, d2, e1, e2, f1, h1); setae h2–3 present (para-anal setae); two pairs of ps setae (anal setae); ventral setae 2c absent; entire dorsum plicate, with distinct regular polygonal reticulate pattern medially on prodorsum; peritreme with short distal hook like a golf-club (sometimes hook not apparent, appears as a distal expansion); tarsus I with two pairs of duplex setae, distal and adjacent; tarsus II with one pair duplex setae; female empodia I–IV and male empodia II–IV consisting of a pair of three-pronged structures, each prong thickened basally and strongly tapering distally; male empodium I consisting of a pair of three-pronged structures, each prong short, stout and subequal in length, median prong slightly larger than other prongs ( Fig. 16).

As for genus in addition to: dorsal setae long, thin, obviously barbed; male leg I enlarged, elongate; male femur I with two adaxial setae and one ventral seta modified into thickened spines; female with spinneret (suζ) obviously swollen; female pregenital striae longitudinal, becoming broken towards setae ag and forming a distinct cresentic pattern between setae ag; male body strongly diamond shaped; female body strongly rounded.

Female. Dorsum. ( Fig. 7 ) Body measurements: v2 –h1 290–320, c1–c 1 15–26, c3–c3 222–264, d1–d 1 17– 26, d1–d2 61–73, e1– e 1 25–33, e1– e2 45–61, f1–f 1 18–31, h1–h 1 26–51. Prodorsum distinct, with regular polygonal reticulate pattern mesally, fine striate pattern laterally and anteriorly; series of small pores visible in row medad setae sc1 (6-8); opisthosoma transversely striate, with striae forming an arch between setae e2–e2; lateral opisthosomal striae longitudinal. Dorsum with 14 pairs of finely barbed setae, mostly longer than the distance to the next setal base; v2 32 –38, sc1 63–73, sc2 56–71, c1 64–85, c2 50–67, c3 74–92, d1 66–78, d2 47–67, e1 63 –78, e2 55 –73, f1 56–75, h1 58–71, h 2 22–43, h 3 31–37. Setae h2 and h3 usually inserted ventrally.

Ve n te r. ( Fig. 8 ) Body finely striate, striae mostly transverse with longitudinal striae between setae 3a–4a and laterad pregenital region; coxal bases III–IV smooth; coxal bases I–II smooth or with light, fine striae; small lobes present on striae between setae 1a–3a, and between setae 4a–ag; distinct pattern in striae between setae ag–g1 — female pregenital striae longitudinal, becoming broken towards setae ag and forming a distinct cresentic pattern between setae ag ( Fig. 9); genital flap small; all ventral setae thin, smooth: 1a 21–32, 1 b 42– 64, 1 c 23–42, 2 b 23–34, 3 a 23–32, 3 b 33–39, 4 a 22–28, 4 b 27–37, ag 17–35, g 1 23–27, g 2 27–34, ps 1 13–28, ps 2 15–21.

Gnathosoma . Palp tarsus with short, broad, swollen spinneret (su ζ) (6–7 wide, 4–7 long) ( Fig. 10 A); single solenidion (3–5) and two eupathids (ul’ 3–5, ul” 6–7) ( Fig. 10 A). Peritreme ending in small expansion or short hook ( Fig. 10 B).

Legs. ( Fig. 11 ) Tarsus I with two duplex setae (solenidia: proximal ω ' 39–50, distal ω " 49–64), proximal solenidion (ω " 1 26–38) and three distal eupathidia (pv’ ζ 12–18), tibia I with one solenidion (φ 33–49), tarsus II with one duplex seta (solenidion ω " 40–54), proximal solenidion (ω " 1 24–41) and three distal eupathidia (pv’ ζ 15–20), tarsus III with solenidion (ω ’ 31–38), tarsus IV with solenidion (ω ’ 30–38); all leg setae finely barbed. Number of setae on legs I–IV respectively: coxae 2, 1, 1, 1; trochanters 1, 1, 1, 1; femora 9, 6, 3, 3; genua 5, 4, 3, 3; tibiae 8(1+0), 5, 5, 5; tarsi 15(3+3), 12(2+3), 8(1+0), 8(1+0). Aberrant setal counts: femur I: 1/ 12 females with 8 setae — one dorsal distal seta absent; femur II: 1/ 12 females with 7 setae — extra dorsal seta, 1/12 with 5 setae — one ventral proximal seta absent; genu II: 1/ 12 females with 3 setae — one dorsal seta absent; genu III: 1/ 12 females with 2 setae — one dorsal seta absent; tibia I: 1/ 12 females with 9(2+0) setae — extra solenidion (male chaetotaxy); tarsus I: 1/ 12 females with 17(5+3) setae — two extra solenidia (male chaetotaxy); tarsus III with 9(1+0) setae — extra ventral seta; tarsus IV: 1/ 12 females with 7(1+0) setae — one dorsal seta absent.

Colour. Pale olive green with red eyes; eggs are pale yellow to green and rounded.

Male. Dorsum. ( Fig. 12 ) Body measurements: v2 –h1 238–287, c1–c 1 13–20, c3–c3 173–221, d1–d 1 13– 21, d1–d2 46–71, e1– e 1 23–31, e1– e2 32–41, f1–f 1 11–18, h1–h 1 22–35. Prodorsum distinct, with fine regular polygonal reticulate pattern mesally, fine striate pattern laterally and anteriorly; series of small pores (8) visible in row medad setae sc1; opisthosoma transversely striate. Dorsum with 14 pairs of barbed setae, mostly longer than the distance to the next setal base; v 2 28–46, sc1 48–75, sc2 60–91, c1 53–72, c2 44–73, c3 68–96, d1 49–70, d2 43–63, e1 42 –64, e2 42 –64, f1 42–57, h1 43–61, h 2 22–33, h 3 25–37. Setae h2 and h3 usually inserted posterodorsally.

Ve n te r. Body finely striate with large areas of smooth cuticle around coxal bases; striae between setae 3a and 4a with lobes; all ventral setae thin, smooth: 1a 22–30, 1 b 49–76, 1 c 30–45, 2 b 27–39, 3 a 25–36, 3 b 33– 46, 4 a 21–32, 4 b 31–40, ag 13–20, g 1 13–17, g 2 14–17, ps 1 13–16, ps 2 15–18.

Gnathosoma . Palp tarsus with cone-shaped spinneret (su ζ) smaller than female (3–4) with nipple-like tip; single solenidion (4–5) and two eupathids (ul’ 4–5, ul” 5–7) ( Fig. 13). Peritreme ending in small expansion or short hook (see Fig. 10 B).

Aedeagus. ( Fig. 14 ) Long, thin and tapering to finger-like tip (see Fig. 14 for measurements, a: 3–4, b: 20–27, c: 6, d: 47–62.

Legs. ( Figs 15–17 ) Tarsus I with two duplex setae (solenidia: proximal ω ' 39–50, distal ω " 47–65), three solenidia (proximal–distal 20–28, 20–30, ω " 1 28–37) and three distal eupathidia (pv’ ζ 12–17); tibia I with two solenidia (proximal 21–29, φ distal 34–41); tarsus II with one duplex seta (solenidion ω " 41–51), single proximal solenidion (ω " 1 20–28) and three distal eupathidia (pv’ ζ 14–20); tarsus III with solenidion (ω ’ 26– 40); tarsus IV with solenidion (ω ’ 26–36); all leg setae barbed; femur I with two thickened spine-like setae (l’ 17–34, v’ 10–19), barbed or smooth ( Fig. 17 ), and one thickened seta (v” 1 26–36). Number of setae on legs I– IV respectively: coxae 2, 1, 1, 1; trochanters 1, 1, 1, 1; femora 9, 6, 3, 3; genua 5, 4, 3, 3; tibiae 9(2+0), 5, 5, 5; tarsi 17(5+3), 12(2+3), 8(1+0), 8(1+0). Aberrant setal counts: femur I: 1/ 13 males with 10 setae — extra spurlike seta, 1/ 13 males with 8 setae – one dorsal seta absent; tarsus I: 3/ 13 males with 16(5+3) setae – one ventral seta absent. Empodia II–IV consisting of a pair of three-pronged structures, each prong thickened basally and strongly tapering distally; empodium I consisting of a pair of three-pronged structures, each prong short, stout and subequal in length, median prong slightly larger than other lateral prongs ( Fig. 16).

Colour. Yellow-green, red eyes, and legs I and II becoming orange distally.

Deutonymph. Dorsum. Body measurements: v2 –h1 206–271, c1–c 1 16–21, c3–c3 177–210, d1–d 1 17– 22, d1–d2 49–60, e1– e 1 23–33, e1– e2 39–46, f1–f 1 12–21, f1–h 1 16–24. Prodorsum distinct, with fine regular polygonal reticulate pattern mesally, fine striate pattern laterally and anteriorly, weaker than that of adult.

Dorsum with 14 pairs of lightly barbed setae — v 2 27–37, sc1 42–60, sc2 55–71, c1 43–66, c2 37–56, c3 68– 99, d1 43–68, d2 37–57, e1 38 –61, e2 41 –64, f1 38–67, h1 47–60, h 2 22–34, h 3 22–35; setae h2, h3 usually ventral.

Ve n te r. Venter almost entirely transversely striate, striae between setae 3a and g1 with small lobes; ventral setae thin, smooth or lightly barbed: 1a 19–26, 1 b 41–50, 1 c 21–33, 2 b 20–33, 3 a 26–32, 3 b 28–33, 4 a 19–27, 4 b 23–28, ag 20–27, g 1 15–25, ps 1 11–18, ps 2 11–17.

Gnathosoma . The sexually dimorphic spinneret (su ζ), clearly visible in the adult stage, is also apparent in the deutonymph: spinneret broad rounded (5 wide, 5 long) to short thin (2 wide, 3 long); single solenidion (3– 5) and two eupathids (ul’ 4–5, ul” 5–6). Peritreme ending in small expansion or short hook.

Legs. ( Fig. 18 ) Tarsus I with two duplex setae (solenidia: proximal ω ' 28–40, distal ω " 45–51), single proximal solenidion (21–28), three distal eupathidia (pv’ ζ 13–15); tibia I with solenidion (φ 31–38); tarsus II with one duplex seta (solenidion ω " 38–44), three distal eupathidia (pv’ ζ 13–15); tarsus III with single solenidion (ω ’ 24–31); all leg setae lightly barbed except a few smooth setae distally on tarsi. Number of setae on legs I–IV respectively: coxae 2, 1, 1, 1; trochanters 1, 1, 1, 0; femora 6, 3, 2, 2; genua 5, 4, 3, 2; tibiae 8(1+0), 5, 5, 5; tarsi 15(3+3), 11(1+3), 8(1+0), 7.

Protonymph. Dorsum. ( Fig. 19 ) Body measurements: v2 –h1 155–223, c1–c 1 17–25, c3–c3 145–203, d1– d 1 17–22, d1–d2 42–47, e1– e 1 21–26, e1– e 2 22–32, f1–f 1 11–18, f1–h 1 12–24. Prodorsum distinct, with fine regular polygonal reticulate pattern mesally, fine striate pattern laterally and anteriorly, weaker than that of adult. Dorsum with 14 pairs of lightly barbed setae — v 2 23–31, sc1 38–50, sc2 41–70, c1 43–57, c 2 30–43, c3 64–86, d1 37–57, d2 36–50, e1 32 –51, e2 32 –58, f 1 31–52, h1 34–54, h 2 20–33, h 3 22–32; setae h2, h3 usually ventral.

Ve n te r. Venter mostly transversely striate, striae with small lobes; ventral setae thin, smooth or lightly barbed: 1a 17–24, 1 b 38–43, 1 c 20–26, 2 b 21–24, 3 a 24–29, 3 b 22–30, g 1 17–22, ps 1 8–16, ps 2 7–15.

Gnathosoma . The sexually dimorphic spinneret (su ζ), clearly visible in the adult stage, is also apparent to a lesser degree in the protonymph: spinneret broad rounded (4 wide, 3 long) to thin (2–3 wide, 4 long); single solenidion (3–4) and two eupathids (ul’ 4, ul” 5–6). Peritreme ending in small expansion or short hook, like a golf-club.

Legs. ( Fig. 20 ) Tarsus I with two duplex setae (solenidia: proximal ω ' 27–33, distal ω " 39–51) and three distal eupathidia (pv’ ζ 11–18); tibia I with single solenidion (φ 27–31); tarsus II with one duplex seta (solenidion ω " 31–42) and three distal eupathidia (pv’ ζ 11–18); all leg setae lightly barbed except a few smooth setae distally on tarsi. Number of setae on legs I–IV respectively: coxae 2, 1, 1, 0; trochanters 0, 0, 0, 0; femora 3, 3, 2, 2; genua 4, 3, 2, 2; tibiae 6(1+0), 5, 5, 5; tarsi 13(2+3), 11(1+3), 7, 5.

Larva. Dorsum. ( Fig. 21 ) Body measurements: v2 –h1 120–187, c1–c 1 22–29, c3–c3 127–145, d1–d 1 16– 24, d1–d 2 29–36, e1– e 1 17–25, e1– e 2 21–26, f1–f 1 6–12, f1–h 1 9–15. Prodorsum distinct, with small patch of fine regular polygonal reticulate pattern mesally, fine striate pattern laterally and anteriorly, weaker than that of adult. Dorsum with 14 pairs of lightly barbed setae — v 2 21–28, sc 1 30–42, sc 2 31–61, c1 37–50, c 2 24– 34, c3 47–76, d1 36–46, d 2 30–42, e1 32 –41, e2 37 –52, f 1 30–46, h1 45–64, h2 33–41, h3 42–52; setae h2, h3 usually ventral.

Ve n te r. Venter mostly transversely striate, striae with lobes; ventral setae thin, smooth or lightly barbed: 1a 16–24, 1 b 36–40, 3 a 25–33, ps 1 7–13, ps 2 9–16.

Gnathosoma . Palp tarsus with rounded spinneret (3–4) (su ζ), single solenidion (3–4) and single eupathid (ul’ 3–4). Peritreme ending in small expansion or short hook like golf club.

Legs. ( Fig. 22 ) Tarsus I with one set of duplex setae (solenidion ω ' 43–56) and two distal eupathids; tibia I with single solenidion (φ 20–31); tarsus II with one duplex seta (solenidion ω " 34–44) and two distal eupathids; all leg setae lightly barbed except a few smooth setae distally on tarsi. Number of setae on legs I– III respectively: coxae 1, 0, 0; trochanters 0, 0, 0; femora 3, 3, 2; genua 4, 3, 2; tibiae 6(1+0), 5, 5; tarsi 9(1+2), 9(1+2), 5.

Remarks. Ontogeny for leg setae and solenidia for nymphs and adult female given in Table 1 . Individuals of N. tereotus feed on the underside of the leaves of their host plants, are dorsoventrally flattened, and spin strong, thick, sheets of webbing to form their nests, i.e. they have the life type known as the woven nest (WN) type sensu Saito (1983; 1985; 2009; pers. com. Saito 2009). Thick silk sheeting is woven along the midrib on the underside of the leaves, from the top of the midrib down to the surface of the leaf blade, forming a tent, that can be as long as 40 mm along the midrib. Females also begin new nests in natural depressions present on the leaf blade, weaving thick silken covers over the depression, usually forming a circular nest. Faecal material appears to be placed amongst the feeding areas within the nests, whereas the eggs are kept away from such areas (pers. com. Saito 2009). Individual females are able to start new nests, but it appears that males are unable to do so. Males use their enlarged forelegs to guard quiescent female deutonymphs prior to mating them, and males have been observed to pick up quiescent female deutonymphs and move them to a new position (pers. obs. D. Walter). We have not observed males attempt to defend the nest when it is broken open, nor male-to-male aggression behaviour like that displayed by males of Stigmaeopsis miscanthi (Saito) , also a life type WN species ( Saito 1995; Saito & Sahara 1999). Feeding within the nests causes the part of the leaf blade directly under the webbing to turn yellow-orange, and then brown in older nests. This discolouration can be clearly seen from the other side of the leaves, and as it persists long after the mites have died off, even in herbarium specimens (pers. obs. J. Beard), it is a good indication that the mites are present or have been in the past.

While there is a broad range in the length of setae for this species, the range is not related to differences in the host plant, as setal lengths are equally variable on both recorded host plant species.

The spinneret, suζ, in this species is sexually dimorphic, being enlarged in females and reduced in males. This morphological difference in the spinneret is also apparent in the deutonymphs and to a lesser extent in the protonymphs. The range in lengths of setae on the deutonymphs is also explained by differences in sexes, as female deutonymphs are larger than male deutonymphs.

An examination of plant specimens located in the Queensland Herbarium (BRI) indicates the presence of this mite on both recorded hosts, most commonly on W. floribunda , since the earliest record in 1932. Etymology. The name is derived from the Greek word “tereo” meaning “to watch over or guard”, in reference to body form of the male.

Figures

FIGURE 7. Neonidulus tereotus sp. nov. adult female dorsum. Scale bar = 100 μm.

FIGURE 8. Neonidulus tereotus sp. nov. female venter. Scale bar = 100 μm.

FIGURE 10. Neonidulus tereotus sp. nov. female, A. palp, with detail of spinneret (suζ); B. variation in peritreme. Scale bar = 50 μm.

FIGURE 11. Neonidulus tereotus sp. nov. female legs I – IV, chaetotaxy indicated (I-II right abaxial, III-IV right adaxial aspect). Scale bar = 100 μm.

FIGURE 12. Neonidulus tereotus sp. nov. adult male dorsum. Scale bar = 100 μm.

FIGURE 14. Neonidulus tereotus sp. nov. adult male, details and variation in aedeagus, (i-iii) lateral aspect, (iv-v) dorsal aspect; a-d indicate measurements taken. Scale bar = 25 μm.

FIGURE 15. Neonidulus tereotus sp. nov. adult male legs I – IV, chaetotaxy indicated (I, III-IV left adaxial, II right abaxial aspect). Scale bar = 100 μm.

FIGURE 17. Neonidulus tereotus sp. nov. adult male, detail of spurs on femur I. Scale bar = 25 μm.

FIGURE 18. Neonidulus tereotus sp. nov. deutonymph legs I-IV, chaetotaxy indicated (I, III-IV left abaxial, II right abaxial aspect). Scale bar = 50 μm.

FIGURE 19. Neonidulus tereotus sp. nov. protonymph posterior dorsum. Scale bar = 100 μm.

FIGURE 20. Neonidulus tereotus sp. nov. protonymph legs I-IV, chaetotaxy indicated (left abaxial aspect). Scale bar = 50 μm.

FIGURE 21. Neonidulus tereotus sp. nov. larva dorsum (n. b. seta h 3 inserted ventrally). Scale bar = 100 μm.

FIGURE 22. Neonidulus tereotus sp. nov. larva legs I-III, chaetotaxy indicated (right legs). Scale bar = 50 μm.