Prolixus insignis, 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 : 30-42

publication ID	https://doi.org/10.11646/zootaxa.5637.1.1
publication LSID	lsid:zoobank.org:pub:B743993E-AF9C-4A08-9EEC-B8199D1AA343
DOI	https://doi.org/10.5281/zenodo.15561976
persistent identifier	https://treatment.plazi.org/id/03E1AB02-FF85-357B-9AB6-C367FCF4FD91
treatment provided by	Plazi
scientific name	Prolixus insignis
status	sp. nov.

Treatment

Prolixus insignis sp. nov. Beard & Seeman

( Figs 21–29 View FIGURE 21 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 View FIGURE 26 View FIGURE 27 View FIGURE 28 View FIGURE 29 )

Diagnosis. Adult female: as per genus, in addition to: body four times longer than wide; anterior margin with greatly reduced broadly rounded projection medially; seta e1 present; seta f2 absent; setae sc1, sc2 strongly pilose, thickened, subequal in length (respective lengths 25–37, 28–44); setae c3, d1, e1 of similar form to sc1–2; 2c absent; seta ag absent; 1c, 2c, 3b, 4b present; seta 3a not flagellate (length 17–29); trochanters 0/1-0/1-0-0 (i.e. unstable v′ on tr I–II (added in adult)); femora 4-4-2-2; genua 1-1-0-0; tarsi 8(1)-8(1)-4-4; spermathecal calyx cylindrical. Adult male: as in genus and female in addition to: f2 present; 2b, 2c present; trochanters 1-1-1-0 (with v′ present (all added in deutonymph), thick and barbed on tr III; genua 2-2-0-0. Deutonymphs: female trochanters 0-0-0-0; f2 absent; 2b absent, 2c present; femur II 3 setae; genua 1-1-0-0; male trochanters 1-1-1-0; f2 present; 2b, 2c present; femur II 4 setae; ge 2-2-0-0.

Material examined. Holotype. Female, Australia, Queensland, Dave’s Creek, Binna Burra, Lamington National Park , ex. Gahnia insignis S.T.Blake ( Cyperaceae ), 28°13’28”S 153°12’16”E, 18.iii.2008, J.J. Beard and P.I. Forster ( QM; BRI voucher PIF33440 ). GoogleMaps Paratypes. 11 females (incl. 2 pharate), 6 males (incl. 1 pharate), 8 deutonymphs (5 female, 3 male), 3 protonymphs, 1 larva, same data as holotype ( QM).

Description

Adult female (8 measured).

Dorsum. ( Fig. 21 View FIGURE 21 ) Body measurements: v2–h1 376–411 [376], sc2–sc2 77–91 [83], c3–c3 82–93 [84], f3–f3 29–34 [29]. Body entirely membranous and plicate; plicae with minute lobes; prodorsal and opisthosomal shields not developed. Prodorsum with almost diamond-shaped region of longitudinal plicae between v2 to sc1, becoming oblique between sc1 to sc2 surrounding eyes; anterior margin with greatly reduced broadly rounded projection medially. Opisthosoma with transverse to somewhat wavy plicae from level with sc2 to level with d1–c3; central plicae from d1 to e1 forming fine chevrons, becoming longitudinal and granulate towards lateral margins; plicae between e1 and h1 mostly longitudinal to oblique with a small central region of transverse plicae. Dorsal setae barbed, variable in length; setae h2 finely elongate, often broken and difficult to determine full length. Setal measurements: v2 4–7 [5–6], sc1 25–37 [25–29], sc2 28–44 [32–33], c3 21–26 [22–23], d1 17–24 [20–21], d3 7–10 [7–8], e1 13 –21 [17–19], e3 7 –10 [7–9], f3 6–11 [7–8], h1 4–7 [6–7], h2 77–121 [77–92].

Infracapitulum. ( Figs 21 View FIGURE 21 , 22B View FIGURE 22 ) Cuticle on dorsal infracapitulum with fine longitudinal plicae. Palps 3- segmented; palp tarsus with two elongate narrow phaneres (6 [6]; 6–7 [7]), femur-genu-tibia with single barbed dorsal seta (11–14) [11–12] and single barbed ventral seta (7–10) [8–9].

Venter. ( Fig. 22A View FIGURE 22 ) Ventral cuticle entirely plicate. With longitudinal to oblique plicae between setae 1b to just posterior to 1a; coxae I and II with fine longitudinal to oblique plicae; cuticle between coxae II and level with c3 with mixed plicae, oblique laterally becoming wavy transverse centrally with small central diamond shaped region of longitudinal plicae; transverse wavy plicae from level with c3 to just anterior to cx III; plicae broadly Vshaped centrally between setae 3b, becoming longitudinal laterally between cx III–IV; plicae from setae 4a1–2 to g1 irregular; g1 inserted anterior to g2 on membranous flap with plicae forming a distinct triangle pattern; plicae laterad genital region longitudinal and granulate; setae ps3 inserted 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, 2b, ag absent. Setae ps2–3 often obscured within membranous folds. Setal measurements: 1a 53–98 [74–85], 1b 37–51 [37–44], 2c 13–19 [19], 3a 17–29 [20–24], 3b 10–13 [11–12], 4a1 47–78 [51], 4a2 46–67 [51], 4b 9–12 [9–10], g1 9–12 [10–11], g2 9–11 [9–10], ps2 5–6 [5], ps3 9–12 [12].

Spermathecal apparatus. ( Fig. 22C View FIGURE 22 ) An elongate, membranous duct terminating in a narrow, elongate vesicle (12–14) [12].

Legs. ( Fig. 23 View FIGURE 23 ) Setal formulae for legs I – IV: cx 2-1-1-1, tr 0/1-0/1-0-0, fe 4-4-2-2, ge 1-1-0-0, ti 5-5-3-3, ta 8(1)-8(1)-4-4. Leg chaetotaxy: cx I 1b, 1c; cx II 2c; cx III 3b; cx IV 4b; fe I–II d, l′, v′, bvʺ; fe III–IV d, ev′; ge I–II l′; 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. The seta on trochanters I–II is unstable with various patterns observed: some females with v′ symmetrically present, females with v′ asymmetrically present, females with no setae present, females with a seta present on tr I but not tr II and vice versa. Aberrations: one individual with l′ absent on both fe I; one with d absent on single fe I; one with d absent on single fe IV; one with ev′ absent on single fe IV. Tarsi I and II each with one abaxial solenidion ωʺ (5–7 [6], 4–5 [4], respectively); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ inserted on small truncate tubercles (all 6–8). Seta d on femora: I 18–24, II 8–15, III 9–12, IV 8–11. Femur II with seta bv″ 14–17. Seta d on tibiae I with enlarged socket (23–27 [23]); seta d on tibiae II (14–18 [17]).

Adult male (5 measured).

Dorsum. ( Fig. 24 View FIGURE 24 ) Body measurements: v2–h1 276–297, sc2–sc2 68–74, c3–c3 64–73, f3–f3 34–38. Body entirely membranous and plicate, prodorsal and opisthosomal shields not developed. Prodorsum with region of longitudinal plicae between v2 to sc1, becoming oblique between sc1 to sc2 surrounding eyes; with central band of longitudinal plicae between sc2 and c3 flanked by transverse plicae; anterior margin without projection medially. Prodorsum and opisthosoma separated by narrow band of fine transverse plicae. Opisthosoma with narrow waist level with cx IV; narrow central band of transverse plicae between c3 and d3 flanked by longitudinal plicae laterally; plicae posterior to waist longitudinal, granulate laterally. Dorsal setae strongly barbed, variable in length but mostly longer and thicker than those of female; setae h2 finely elongate, often broken and difficult to determine full length; setal measurements: v2 5–7, sc1 28–37, sc2 37–48, c3 25–32, d1 16–18, d3 22–29, e1 17 –19, e3 30 –36, f2 33–38, f3 25–29, h1 7–10, h2 70–107.

Infracapitulum. ( Fig. 24 View FIGURE 24 ) Cuticle on dorsal infracapitulum with fine longitudinal plicae. Palps 3-segmented; palp tarsus with two elongate narrow phaneres (6–7; 7), femur-genu-tibia with single barbed dorsal seta (10–12) and single barbed ventral seta (7–10).

Venter. ( Fig. 25 View FIGURE 25 ) Ventral cuticle entirely plicate; from seta 1b to 1a with longitudinal plicae; with transverse plicae from level with 2c to posterior to 3a, becoming longitudinal to 4a1–2; narrow band of transverse plicae between coxae IV; posterior to coxae IV with fine longitudinal plicae to a band of widely spaced 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, ag absent. Setal measurements: 1a 63–98, 1b 42–57, 2b 11–17, 2c 16–21, 3a 19–30, 3b 13–20, 4a1 48–73, 4a2 38–62, 4b 11–18, g1 14–17, g2 10–16, ps2 15–18, ps3 7–8.

Aedeagus. ( Fig. 26 View FIGURE 26 ) Sclerotised, elongate, narrowly subulate (38–40), with narrow membranous tube emerging from sclerotised section terminating in a broad V-shaped calyx with a basal granulate region.

Legs. ( Fig. 27 View FIGURE 27 ) Setal formulae and chaetotaxy same as adult female except tr I–III with 1 seta (v′), cx II with 2 setae (2b, 2c), ge I–II with 2 setae consistently present (l′, l″), 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′ 9, abaxial ωʺ 9–10; ta II adaxial ω′ 7, 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 femora longer and thicker than those on female: I 20–24, II 13–17, III 16–23, IV 21–24. Femur II with seta bv″ 17–19. Seta d on tibiae I with enlarged socket (22–25); seta d on tibiae II (15–18).

Deutonymph (4 F, 3 M measured).

Dorsum. ( Figs 28A–B View FIGURE 28 ) Body measurements: v2–h1 F 346–377 M 242–325, sc2–sc2 F 63–73 M 70–75, c3–c3 F 64–73 M 64–74, f3–f3 F 26–29 M 26–27. Body entirely membranous and plicate, with similar plicate patterns. Central cuticle on prodorsum between v2 to sc1 with longitudinal plicae; wavy transverse plicae from sc1 to d3, transverse plicae becomes central elongate diamond shaped region of longitudinal plicae just anterior to e1, flanked by transverse plicae laterally; setae d3 surrounded by small region longitudinal plicae; posterior to e1 with mixed mostly oblique plicae to h1. Dorsal setae shorter and finer than those of adults. Setal measurements for female and male deutonymphs combined when ranges overlap: v2 4–6, sc1 21–27, sc2 22–27, c3 11–16, d1 11–14, d3 6–9, e1 9 –11, e3 F 6–7 M 7–10, f 2 male only 8–12, f3 F 4–7 M 8–11, h1 3–5, h2 62–87.

Infracapitulum. Cuticle as in adults. Palps 3-segmented; palp tarsus with two narrow phaneres (F 4–5, 5–6; M 5, 6); femur-genu-tibia with single barbed dorsal seta (10–11 9–11), and single smooth ventral seta (6–8 7–9).

Venter. With longitudinal plicae from 1b to just posterior 1a, then wavy transverse plicae to level with coxae III where plicae become V-shaped to 4a1; 4a1 to ag with transverse plicae with central region between coxa IV with V-shaped plicae; plicae arch around and flank anal opening becoming longitudinal laterally. Form of ventral setae as in adults. Setal measurements: 1a 49–53 58, 1b 31–43 40–48, 1c 9–11 10–11, 2b male only 7–11, 2c 11–16 12–13, 3a 15–21 13–19, 3b 7–10 8–12, 4a1 27–30 38–42, 4b 7–9 9–10, g1 7–8 7–9, ps2 6–8 8–11, ps3 4–4 5–6.

Legs. Setal formulae and chaetotaxy for legs I–IV as in adult female and male respectively (note sexual dimorphism in additions—male adds 2b on coxa II, l″ on genua I–II. Female deutonymphs have seta l′ variously symmetrically or asymmetrically absent on femora II, but more often absent than present. Tarsi I and II each with one abaxial solenidion ωʺ (F 4–5, 3–4; M 4, 3); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (all 5–6). Seta d on femora: I 15–17 15–19, II 6–9 8, III 6–9 7–9, IV 6–8 7–8. Femur II with seta bv″ 11–14 11. Seta d on tibiae I with enlarged socket (23–25 22–24); seta d on tibiae II (13–16 15–16).

Protonymph (3 F measured).

Dorsum. Body measurements: v2–h1 251–254, sc2–sc2 63–67, c3–c3 53–58, f3–f3 19–24. Body entirely membranous and plicate; cuticle patterns as in deutonymph.Dorsal setae similar in form to adults.Setal measurements: v2 4–5, sc1 19–21, sc2 17–19, c3 8–9, d1 9–10, d3 5–6, e1 5 –7, e3 4 –5, f3 3–5, h1 3–4, h2 53–66.

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 (9–11), and single smooth ventral seta (3–4).

Venter. With longitudinal plicae from 1b to just posterior 1a with oblique plicae around 1a, then wavy transverse plicae to level with coxae IV where plicae become longitudinal to ps3. Setal measurements: 1a 36–39, 1b 30–32, 1c 7–8, 2 c 8–9, 3a 16–20, 3b 7–8, ps2 4–5, ps3 3–4.

Legs. Setal formulae for legs I – IV: cx 2-1-0-0, 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: 1c, 2c, 3b added to relative coxae; 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 (all 5).

Larva (1 M measured).

Dorsum. ( Fig. 29 View FIGURE 29 ) Body measurements: v2–h1 175, sc2–sc2 54, c3–c3 47, f3–f3 12. Body entirely membranous and plicate. Prodorsum with longitudinal to oblique plicae from v2 to sc1; with mostly oblique plicae between sc1 to sc2 surrounding eyes; with transverse plicae from level with sc1 to e1; posterior to e1 with irregular but mostly broadly V-shaped plicae. Dorsal setae short, fine, barbed; except h2 fine, elongate. Setal measurements: v2 4, sc1 15, sc2 11–12, c3 8, d1 7, d3 6–7, e1 5 –6, e3 4, f 2 male only 4, f3 4–5, h1 3–4, h2 56–61.

Infracapitulum. ( Fig. 29 View FIGURE 29 ) Palps 3-segmented; palp tarsus with two narrow phaneres, one long one short (3, 5); femur-genu-tibia with single barbed dorsal seta (9) and single barbed ventral seta (6).

Venter. Ventral cuticle the same as protonymph, except longitudinal plicae posterior to coxae III. Setal measurements: 1a 33, 1b 27, 3a 18–21, ps2 3, ps3 2.

Legs. ( Fig. 29 View FIGURE 29 ) 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 (both 2–3); companion seta ftʺ absent; pair proral setae p′ζ, pʺζ (all 4–5).

Colour. These mites were orange-red in colour when alive.

Host. Gahnia insignis S.T.Blake ( Cyperaceae ). Host plant identification was made by Queensland Herbarium (BRI voucher PIF33440).

Distribution. This mite is so far known only from Lamington National Park. The host plant was growing in a low mallee woodland on rhyolite. The host leaves are smooth and shiny, with narrow and shallow grooves on the dorsal surface in which the mites live.

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

Remarks. Prolixus insignis sp. nov. is distinguished from all other species of Prolixus by the pattern of larger modified dorsal setae on the female (sc1, sc2, c3, d1, e1 all thick and barbed, versus other combinations in other species). Prolixus is unusual in the sexually dimorphic expression of some idiosomal and leg setae. In P. insignis sp. nov., only the male has setae f2, 2b, vʹ on trochanter III, lʹʹ on genua I–II, as well as expressing vʹ on trochanters I–II (unstable in females). The sexual dimorphism of setae f2 is unique, and being a larval seta, allows sexes to be identified throughout their life cycle. The other sexually dimorphic setae are added in the deutonymph, of which seta lʹʹ on genua I–II is atypically delayed from the larva to this stage.