Prolixus asperus, 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 : 22-30

Prolixus asperus sp. nov. Beard & Seeman

( Figs 15–20 )

Diagnosis. Adult female: as per genus, in addition to: body four times longer than wide; anterior margin of prodorsum smooth; seta e1 present; seta f2 absent; setae sc1, sc2 strongly pilose, thickened; sc1 (length 15–20) shorter than sc2 (length 23–31); setae c3, f3 setae strongly pilose, similar in form to sc1–2; 1c, 3b, 4b, ag absent; setae 2b, 2c present; seta 3a not flagellate (length 14–31); trochanters 0-0-0-0; femora 4-4-2-2; genua 2-1-0-0 (occasional losses on both genua); tarsi 8(1)-8(1)-4-4; spermathecal calyx cylindrical. Adult male: as per genus and female in addition to: trochanters 1-0-0-0, genua 2-2-0-0, tarsi 9(2)-9(2)-4-4.

Material examined. Holotype. Female, Australia, Queensland, Rungulla National Park, Marta Logo Spring , 3.3 km NE of the Ranger Station and airstrip , 19°07’33”S 143°30’02”E, ex. Gahnia aspera (R.Br.) Spreng. ( Cyperaceae ), 03.v.2022, J.J. Beard ( QM). Paratypes. 20 females, 8 males, 4 deutonymphs, 3 protonymphs, 2 larvae, same data as holotype ( QM).

Other material examined. 18 females, 11 males, 2 protonymphs, 5 larvae, along creek line, 16.3 km NNW of the Ranger Station and airstrip, 18°59’59”S 143°24’24”E, Rungulla National Park, ex. Gahnia aspera , Queensland, Australia, 06.v.2022, J.J. Beard ( QM); 23 females, 14 males, 12 nymphs, 1 km along tributary of Gilbert River, 19.1 km NNW of the Ranger Station and airstrip, 18°59’01”S 143°22’53”E, Rungulla National Park, Queensland, Australia, ex. Gahnia aspera , 09.v.2022, J.J. Beard ( QM) .

Description

Adult female (8 measured).

Dorsum. ( Fig. 15 ) Body measurements: v2–h1 336–398 [386], sc2–sc2 74–87 [78], c3–c3 75–85 [78], f3–f3 32–40 [40]. Body entirely membranous and plicate, prodorsal and opisthosomal shields not developed. Prodorsum with longitudinal plicae v2 to sc1 and between sc1 to sc2 surrounding eyes, becoming transverse centrally; anterior margin without projections. Opisthosoma with transverse plicae from level with sc2 to d1–c3; central plicae from d1 to h1 V-shaped to U-shaped, becoming longitudinal towards lateral margins. Dorsal setae barbed, variable in length; setae h2 finely elongate, often broken and difficult to determine full length. Setal measurements: v2 3–5 [4], sc1 16–20 [16], sc2 23–31 [28], c3 18–23 [19], d1 5–8 [8], d3 4–6 [5–6], e1 4 –8 [8], e3 5 –9 [6], f3 13–20 [17–20], h1 5–6 [6], h2 82–110 [104].

Infracapitulum. ( Fig. 15 ) Cuticle on dorsal infracapitulum with longitudinal plicae. Palps 3-segmented; palp tarsus with two elongate narrow phaneres (4–5 [4–5]; 6–7 [6–7]), femur-genu-tibia with single barbed dorsal seta (8–12) [12] and single smooth ventral seta (6–8) [7].

Venter. ( Fig. 16A ) Ventral cuticle entirely plicate. With longitudinal and oblique plicae between setae 1b to just posterior to 1a; with transverse wavy plicae from coxae II to 4a setae, becoming broadly U-shaped level with coxae III, often with small central region of irregular plicae between 3a and 4a1–2; between coxae III–IV, central cuticle broadly U-shaped becoming longitudinal laterally; posterior to coxae IV, central cuticle becoming arched to setae g2; between g2–g2 with longitudinal plicae along posterior margin of genital flap; with oblique plicae surrounding anal valves. Setae g1 inserted anterior to g2 on genital flap; setae ps3 inserted far anterior to ps2 on anal valves. Ventral setae mostly short, fine, smooth, except setae 1a, 1b, 4a1, 4a2 finely elongate, often broken and difficult to determine full length. Setae 1c, 3b, 4b, ag absent. Setae ps3 often obscured within membranous folds. Setal measurements: 1a 83–117 [94], 1b 41–65 [62], 2b 8–14 [11], 2c 10–15 [12], 3a 14–31 [23–31], 4a1 47–82 [77], 4a2 45–62 [45], g1 8–14 [12], g2 8–13 [12], ps2 8–11 [11], ps3 5–7 [6].

Spermathecal apparatus. ( Fig. 16B ) A moderately elongate, coiled, membranous duct terminating in a short, narrow, cylindrical vesicle (8–10).

Legs. ( Fig. 17 ) Setal formulae for legs I – IV: cx 1-2-0-0, tr 0-0-0-0, fe 4-4-2-2, ge 2-1-0-0, ti 5-5-3-3, ta 8(1)- 8(1)-4-4. Leg chaetotaxy: cx I 1b; cx II 2b, 2c; cx III 3b; cx IV 4b; 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′, tc″, p′ζ, pʺζ, u′, uʺ, ωʺ; ta III–IV ft′, tcʺ, u′, uʺ. Tarsi I and II each with one abaxial solenidion ωʺ (5–7 [6–7], 4–6 [5], respectively); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ inserted on small truncate tubercles (all 6–7). Seta d on tibiae I with enlarged socket (20–25 [22]); seta d on tibiae II (13–17 [14]). Genua I–II have 1–2 setae present, often asymmetrically. Genu I most commonly has 2 setae (l′, l″) and genu II most commonly with 1 seta (l′) present. We note that because males have 2-2 on ge I–II, and seta l″ is apparently inconsistently added to ge I–II in deutonymph, it follows that the sex of the deutonymph can likely be determined by the number of setae on genu II.

Adult male (8 measured).

Dorsum. ( Fig. 18 ) Body measurements: v2–h1 257–283, sc2–sc2 68–77, c3–c3 63–72, f3–f3 36–40. Body entirely membranous and plicate, prodorsal and opisthosomal shields not developed. Prodorsum with mostly longitudinal plicae, becoming oblique to transverse posteromedially between setae sc2–sc2; anterior margin without projections. Opisthosoma with broad band of transverse plicae between sc2 to c3; central plicae from level with c3 to h1 mostly longitudinal with some oblique plicae in region between c3 to d1, and narrow band of mostly transverse plicae between coxae IV. Dorsal setae barbed, variable in length; setae h2 finely elongate, often broken and difficult to determine full length; setal measurements: v2 5–8, sc1 22–30, sc2 32–39, c3 24–31, d1 7–10, d3 11–19, e1 8 –11, e3 20 –23, f3 21–27, h1 6–9, h2 93–138.

Infracapitulum. ( Fig. 18 ) Cuticle on dorsal infracapitulum with longitudinal plicae. Palps 3-segmented; palp tarsus with two elongate narrow phaneres (both 5–7), femur-genu-tibia with single barbed dorsal seta (9–10) and single smooth ventral seta (7–8).

Venter. ( Fig. 19A ) Ventral cuticle entirely plicate; from seta 1b to level with coxae II with longitudinal plicae; with a band of transverse plicae just posterior to coxae II, becoming longitudinal to 3a and oblique laterally; narrow band of transverse plicae just posterior to 3a, then longitudinal to 4a; small region of arching plicae just posterior to 4a that becomes a narrow band of transverse plicae between coxae IV; posterior to coxae IV with fine longitudinal plicae to a band of transverse to arching plicae around genitoanal region. Setae ps3 modified to form short narrow accessory genital stylets, often obscured within membranous folds. Ventral setae mostly short, fine, smooth, except setae 1a, 1b, 4a1, 4a2 finely elongate, often broken and difficult to determine full length. Setae 1c, 3b, 4b, ag absent. Setal measurements: 1a 70–108, 1b 30–71, 2b 15–20, 2c 15–20, 3a 17–30, 4a1 62–87, 4a2 24–60, g1 11–15, g2 9–14, ps2 12–14, ps3 7. One male has seta 3b asymmetrically present.

Aedeagus. ( Fig. 19B ) Sclerotised, elongate, narrowly subulate (34–38), with narrow membranous tube emerging from sclerotised section terminating in a broad V-shaped calyx and rounded membranous vesicle.

Legs. ( Fig. 20 ) Setal formulae and chaetotaxy same as adult female except tr I–II with 1 seta (v′), ge I–II with 2 setae present, ta I–II with additional solenidion ω′ present; ω′ inserted proximally on segment. Tarsi I and II each with two solenidia (ta I adaxial ω′ 8–9, abaxial ωʺ 7–8; ta II adaxial ω′ 6–9, abaxial ωʺ 7–8); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ inserted on small truncate tubercles (all 6–7). Seta d on tibiae I with enlarged socket (23–27); seta d on tibiae II (16–17). Form of leg setae similar to that of female, except d setae on femora are longer and thicker—fe I 16–21, fe II 14–20, fe III 17–20, fe IV 18–22. Seta bv″ on femur II 19–24 long.

Deutonymph (3 measured).

Dorsum. Body measurements: v2–h1 314–321, sc2–sc2 67–76, c3–c3 62–66, f3–f3 26–29. Body entirely membranous and plicate. Central cuticle on prodorsum between v2 to sc1 with chevron-shaped plicae, flanked by longitudinal plicae; small region between sc1 to sc2 with longitudinal striae surrounding eyes; sc1 to just posterior to setae d3 with wavy transverse plicae; posterior to d3 with arching striae becoming longitudinal; longitudinal plicae from level with coxae IV to h1. Dorsal setae similar in form to adults. Setal measurements: v2 4–5, sc1 16–17, sc2 23–26, c3 16–19, d1 8–9, d3 5–6, e1 3 –4, e3 5 –9, f3 9–11, h1 4–5, h2 72–78.

Infracapitulum. Cuticle as in adults. Palps 3-segmented; palp tarsus with two narrow phaneres (4–5, 5–6); femur-genu-tibia with single barbed dorsal seta (8–10), and single smooth ventral seta (6–7).

Venter. With longitudinal plicae from 1b to just posterior 1a, then wavy transverse plicae to 4a1; with V-shaped plicae 4a1 to g1; with a band of transverse plicae at g1; anal flaps with longitudinal plicae, and oblique plicae laterad anal flaps. Form of ventral setae as in adults. Setal measurements: 1a 88, 1b 37–39, 2b 8–10, 2c 8–10, 3a 16–18, 4a1 32–41, g1 8–10, ps2 5–7, ps3 3–4.

Legs. Setal formulae for legs I–IV as in adult female except (differences in bold): cx 1-2- 0-0, fe 3-3 -2-2. Tarsi I and II each with one abaxial solenidion ωʺ (both 4–5); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (all 5–6). Genua I–II have 1–2 setae present, sometimes asymmetrically, with 1 seta (l′) present being most common. We note that it is seta d that is inconsistently added to ge I–II in the deutonymph, with all larvae and protonymphs examined having 1 seta (l′) symmetrically present on ge I–II.

Protonymph (3 measured).

Dorsum. Body measurements: v2–h1 231–255, sc2–sc2 61–70, c3–c3 53–57, f3–f3 21–22. Body entirely membranous and plicate. Central cuticle on prodorsum between v2 to sc1 with chevron-shaped plicae, flanked by longitudinal plicae; small region between sc1 to sc2 with longitudinal striae surrounding eyes; sc1 to just posterior to setae d1 with transverse plicae; plicae between d1 to h1 longitudinal to oblique, with small patches of irregular plicae. Dorsal setae similar in form to adults. Setal measurements: v2 4–5, sc1 10–13, sc2 17–20, c3 8–11, d1 5–6, d3 3–5, e1 3 –4, e3 4 –5, f3 4–5, h1 4–5, h2 68–89. One individual with an aberrantly long seta f3, 11 long.

Infracapitulum. Cuticle as in adults. Palps 3-segmented; palp tarsus with two narrow phaneres (4; 5); femur-genu-tibia with single barbed dorsal seta (7–8), and single smooth ventral seta (5–6).

Venter. With longitudinal to oblique plicae from 1b to posterior margin coxae II; transverse plicae from coxae II to anterior margin anus; longitudinal plicae around anal flaps. Setal measurements: 1a 43–58, 1b 26–36, 2 c 7–9, 3a 13–21, ps2 4–5, ps3 3–4.

Legs. Setal formulae for legs I – IV: cx 1-1-0-0, tr 0-0-0-0, fe 3-3-2-2, ge 1-1-0-0, ti 5-5-3-3, ta 8(1)-8(1)-4-3. Leg chaetotaxy same as larva except: 2c added to cx II; tc′ and tc″ added to ta I–II; tc″ added to ta III. Tarsi I and II each with one abaxial solenidion ωʺ (both 3–4); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (both 4–5).

Larva (2 measured).

Dorsum. Body measurements: v2–h1 183–185, sc2–sc2 55–62, c3–c3 48–52, f3–f3 20–22. Body entirely membranous and plicate. Prodorsum similar to protonymph; opisthosoma with transverse plicae to just anterior to e1; with broad V-shaped plicae from e1 to h1. Dorsal setae as in adults. Setal measurements: v2 3–4, sc1 8–9, sc2 9–12, c3 6–7, d1 5–6, d3 4–5, e1 3 –4, e3 3 –4, f3 4–5, h1 4–5, h2 98.

Infracapitulum. Palps 3-segmented; palp tarsus with two narrow phaneres (4–5 seta-like; 5–6 blunt); femur-genu-tibia with single barbed dorsal seta (8–9) and single smooth ventral seta (6–7).

Venter. Ventral cuticle the same as protonymph. Setal measurements: 1a 30–33, 1b 18–27, 3a 11–12, ps2 4–5, ps3 4.

Legs. Setal formulae for legs I – III: cx 1-0-0, tr 0-0-0, fe 3-3-2, ge 1-1-0, 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–II 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 (3; 2–3); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (all 5).

Colour. These mites were translucent orange when alive.

Host. Rough saw-sedge, Gahnia aspera (R.BR.) Spreng. ( Cyperaceae ). Host plant identification was made by Queensland Herbarium (BRI vouchers: RNP01, RNP27, RNP64).

Distribution. This mite is so far known only from Rungulla National Park in northern Queensland, Australia, where it and its host plant were collected at three different sites within the park—two along creek-lines and one near a spring.

Etymology. This species is named for the sedge species it was collected from, Gahnia aspera .

Remarks. The new species is remarkably close to Prolixus corruginus Beard, Fan & Walter, 2005 , which was collected on the same host species approximately 2000 km to the south, from the Wondul Range in southern Queensland. The main feature separating these species is that P. asperus sp. nov. has four setae on femur II ( P. corruginus has three setae, with l′ absent). Apart from this, the species are remarkably close, suggestive of a sistergroup relationship. We note that there are some minor setal length differences between the two species also, see below.

The measurements of dorsal setae provided in Beard et al. (2005) for P. corruginus are not all accurate. The following are some noted differences (although often with minor overlap) in length of setae on P. asperus sp. nov. vs P. corruginus .

Male. Dorsal body setae: sc2 33–39 vs 38–54; c3 24–31 vs 30–35; e1 8 –11 vs 10–16; f3 21–27 vs 25–34. Seta d on legs: femur I 16–21 vs 15–24, femur II 14–20 vs 14–22, femur III 17–20 vs 16–23, femur IV 18–22 vs 18–25; tibia I 23–27 vs 17–23, tibia II 16–17 vs 15–18; seta bv″ on femur II 18–24 vs 26–30.

Female. Dorsal body setae: sc1 16–20 vs 21–28; sc2 23–31 vs 32–40; c3 18–23 vs 24–29; e1 4 –8 vs 8–10; f3 13–20 vs 19–24. Seta d on legs: femur I 8–11 vs 15–16; femur II 8–10 vs 10–12; femur III 8–12 vs 11–12; femur IV 8–12 vs 12–13; tibia I 20–25 vs 23–25; tibia II 13–17 vs 14–18; femur II seta bv″ 11–14 vs 13–21.

Figures

FIGURE 15. Prolixus asperus sp. nov. Beard & Seeman adult female dorsum (n.b. the section of dorsal cuticle pattern not illustrated has transverse plicae).

FIGURE 16. Prolixus asperus sp. nov. Beard & Seeman adult female—A. posterior venter; B. spermatheca.

FIGURE 17. Prolixus asperus sp. nov. Beard & Seeman adult female legs (right side), with detail of ventral aspect of tarsus I and II.

FIGURE 18. Prolixus asperus sp. nov. Beard & Seeman adult male dorsum.

FIGURE 19. Prolixus asperus sp. nov. Beard & Seeman adult male—A. posterior venter; B. aedeagus.

FIGURE 20. Prolixus asperus sp. nov. Beard & Seeman adult male legs I and III (right side), with detail of ventral aspect of tarsus I.