Acaricis scleriae, Beard & Seeman, 2025

Beard, Jennifer J. & Seeman, Owen D., 2025, A new flat mite genus and five new species (Tetranychoidea: Tenuipalpidae) from native Australian sedges (Cyperaceae), Zootaxa 5637 (1), pp. 1-56 : 2-9

Acaricis scleriae sp. nov. Beard & Seeman

( Figs 1–5)

Material examined. Holotype. Female, Australia, Queensland, Rungulla National Park, along a wooded rocky ridgeline near a creek, Rungulla National Park, 32.1 km SSE from the Ranger Station and airstrip, 19°24’21’’ S 143°34’32” E, ex. Scleria sphacelata F. Muell. ( Cyperaceae ), 11.v.2022, J.J. Beard ( QM). Paratypes. 1 deutonymph, 1 larva, same data as holotype ( QM).

Diagnosis. As per genus in addition to: body 3 times longer than wide; anterior margin of prodorsum with moderately long median forked projection; most dorsal setae short (almost minute) weakly lanceolate; trochanters 1-1-1-0; femora 4-4-2-2; genua 2-2-1-0; dorsal leg setae strong, smooth, weakly to strongly lanceolate, in contrast to fine ventral setae; tectal setae on tarsi strongly barbed.

Description

Adult female (1 measured)

Dorsum. ( Fig. 1) Body measurements: v2–h1 332, sc2–sc2 105, c3–c3 107, f3–f3 60. Body mostly smooth, with prodorsal and opisthosomal shields not developed. Prodorsum with few longitudinal plicae in line with sc1 and sc2; eyes large and prominent; anterior margin with elongate median forked projection with notch (20); pair minute pores posterior to sc1. Opisthosoma with few longitudinal plicae anteriorly between cx III–IV; pair of large pores present (mesad c3, posteromesad d3); pair minute pores present anterior to e1. Dorsal setae mostly short, smooth, blunt, except setae h2 finely elongate. Setal measurements: v2 5–6, sc1 5–6, sc2 6, c3 5–6, d1 6, d3 4–5, e1 5, e3 5 –6, f2 5–6, f3 5–6, h1 8–9, h2 72–73.

Infracapitulum. Palps 3-segmented; palp tarsus with two phaneres (not measurable), femur-genu-tibia with single barbed dorsal seta and single barbed ventral seta.

Venter. ( Fig. 2A ) Ventral cuticle entirely finely plicate. With longitudinal plicae between setae 1b to 1a; with transverse plicae from 1a to ag setae, with a narrow band of widely spaced transverse plicae between setae 2c–2c; plicae between 3a and 4a1–2 with fine granulate texture; with longitudinal plicae laterally from coxae III to level with anus; genital flap with irregular plicae between ag–g1, and longitudinal from g1 to posterior margin; narrow band of oblique plicae flanking anal opening, and smooth cuticle laterad genitoanal region. Setae g1 inserted anterior to g2 on genital flap; setae ps3 inserted on anal valves far anterior to ps2. Ventral setae mostly short, fine, smooth, except setae 1a, 4a1, 4a2 finely elongate. Setal measurements: 1a 62–112, 1b 15–17, 1c 13–15, 2b 16–20, 2c 16–19, 3a 16, 3b 16–17, 4a1 84–90, 4a2 80–103, 4b 17, g1 15, g2 15, ps2 10–11, ps3 12–13.

Spermathecal apparatus. ( Fig. 2B ) A moderately elongate, coiled, membranous duct terminating in a narrow, elongate vesicle (11); appears broken or folded distally.

Legs. ( Fig. 3 ) Setal formulae for legs I – IV: cx 2-2-1-1, tr 1-1-1-0, fe 4-4-2-2, ge 2-2-1-0, ti 5-5-3-3, ta 7(1)-7(1)- 4-4. Leg chaetotaxy: cx I 1b, 1c; cx II 2b, 2c; cx III 3b; cx IV 4b; tr I–III v′; fe I–II d, l′, v′, bvʺ; fe III–IV d, ev′; ge I–II l′, lʺ; ti I–II d, l′, lʺ, v′, vʺ; ti III–IV d, v′, vʺ; ta I–II ft′, tc′, p′ζ, pʺζ, u′, uʺ, ωʺ (ft″, tc″ absent); ta III–IV ft′, tc′, tcʺ, u′, uʺ. Tarsi I and II each with one abaxial solenidion ωʺ (8 and 7–8, respectively); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ inserted on small tubercles (both 7). Femur II with bv″ broadly lanceolate (13).

Deutonymph (1 measured).

Dorsum. Body measurements: v2–h1 218, sc2–sc2 98, c3–c3 82, f3–f3 41. Smooth prodorsal and pygidial shields indicated by cuticle pattern; broad band of widely spaced transverse plicae anterior to c3–d1; cuticle smooth posterior to d1–d3. Anterior margin prodorsum with elongate median forked projection forming a notch (10). Dorsal setae mostly short, smooth, blunt, except setae h2 fine, elongate. Setal measurements: v2 3–4, sc1 4–5, sc2 3–4, c3 4, d1 5, d3 3–4, e1 3 –4, e3 3 –4, f2 4, f3 4–5, h1 5–6, h2 67–70.

Infracapitulum. Palps 3-segmented; palp tarsus with two phaneres (not measurable), femur-genu-tibia with single barbed dorsal seta (6) and single barbed ventral seta (6).

Venter. Ventral cuticle entirely plicate. With longitudinal and oblique plicae between setae 1b to just posterior to 1a; with transverse plicae from 1a to coxae IV, becoming wavy to ag setae; central cuticle from g1 to ps2 with fine longitudinal plicae, smooth laterally; setae ps3 inserted on anal valves far anterior to ps2. Ventral setae mostly short, fine, smooth, except setae 1a, 4a1 fine, elongate. Setal measurements: 1a -, 1b 8, 1c 7–10, 2b 8–10, 2c 8–13, 3a 10–12, 3b 8, 4a1 36–42, 4b 8, g1 10–12, ps2 8–9, ps3 6.

Legs. Setal formulae and chaetotaxy for legs I – IV as in adult female. Tarsi I and II each with one abaxial solenidion ωʺ (both 6); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ inserted on small tubercles (both 6). Femur II with bv″ strong, smooth, blunt (7).

Larva (1 measured).

Dorsum. ( Fig. 4 ) Body measurements: v2–h1 188, sc2–sc2 72, c3–c3 68, f3–f3 28. Cuticle pattern as in deutonymph; anterior margin with single short median projection (14); dorsal setae short, smooth, blunt, except setae h2 finely elongate. Setal measurements: v2 3–4, sc1 3, sc2 3–4, c3 3, d1 4, d3 2–3, e1 4, e3 2 –3, f2 3, f3 4, h1 4–5, h2 33–41.

Infracapitulum. Palps 3-segmented ( Figs 5A–D ); palp tarsus with two phaneres (5, 2–3), femur-genu-tibia with single barbed dorsal seta (6) and single barbed ventral seta (6).

Venter. Ventral cuticle with almost entirely weak fine transverse plicae from 1a to just posterior coxae III, where small central region of broadly U-shaped plicae becomes oblique to ps3. Setal measurements: 1a 68–87, 1b 9, 3a 9–10, ps2 6–7, ps3 6.

Legs. ( Fig. 5 ) Setal formulae for legs I – III: cx 1-0-0, tr 0-0-0, fe 3-3-2, ge 1-1-1, ti 5-5-3, ta 6(1)-6(1)-3. Leg chaetotaxy: cx I 1b; fe I–II d, v′, bvʺ; fe III d, ev′; ge I–III l′; ti I–II d, l′, lʺ, v′, vʺ; ti III d, v′, vʺ; ta I–II ft′, p′ζ, pʺζ, u′, uʺ, ωʺ; ta III ft′, u′, uʺ. Tarsi I and II each with one abaxial solenidion ωʺ (6 and 5, respectively); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (all 5).

Colour. These mites were yellowy-green when alive.

Host. Scleria sphacelata F. Muell. ( Cyperaceae ).

Distribution. This mite is so far known only from Rungulla National Park in northern Queensland, Australia. Although the host plant was collected at three different sites within the park, only three specimens of the mite were collected at one location where Scleriacarus gilbert i sp. nov. Beard & Seeman was also collected.

Etymology. This species is named for the sedge host genus, Scleria .

Remarks. Host plant identification made by Queensland Herbarium (BRI vouchers: RNP68).

As seta d is not a larval seta on the genua, we feel the setae on genua I–IV are a combination of l′ and l″, not d and l″ as they are named in Xu et al. (2013) and Castro et al. (2018).

Both genera Prolixus and Acaricis have only a single fastigial (ft) seta present on tarsi I–II, and over the years it has been labelled as ft′ on species of Prolixus ( Xu & Zhang 2014; Xu et al. 2017; Xu et al. 2018) and as ft″ on species of Acaricis ( Xu & Zhang 2013; Castro et al. 2018). Here, we designate this seta as ft′ in both genera (and in Scleriacarus gen. nov.), and we feel that in the absence of the companion seta ft″, ft′ has moved to be more central or even somewhat abaxial on the segment.

Figures

FIGURE 2. Acaricis scleriae sp. nov. Beard & Seeman adult female—A. posterior venter; B. spermatheca (tip assumed to be either broken or folded).

FIGURE 3. Acaricis scleriae sp. nov. Beard & Seeman adult female legs I–IV (right side), with detail of both surfaces of tibiatarsus I and II (n.b. details of setae on tarsus III–IV are obscured).

FIGURE 4. Acaricis scleriae sp. nov. Beard & Seeman larva, dorsum, with detail of leg III.

FIGURE 5. Acaricis scleriae sp. nov. Beard & Seeman larva, detail of legs I–II and palps—A. left palp dorsal aspect; B. left palp ventral aspect; C. right palp dorsal aspect; D. right palp ventral aspect.