Extenuipalpus situngu Beard & Ueckermann, 2024

Beard, Jennifer J., Ueckermann, Edward A., Castro, Elizeu B. & Seeman, Owen D., 2024, A revision of the genus Extenuipalpus Reck, 1959 (Trombidiformes: Tetranychoidea: Tenuipalpidae), with description of a new species, Zootaxa 5417 (1), pp. 1-62 : 49-60

Extenuipalpus situngu Beard & Ueckermann sp. nov.

( Figs 40–48 )

Type material. Holotype: female ex Rhoicissus rhomboidea (E.Mey ex Harv.) Planch. ( Vitaceae ), Gonubie (written incorrectly as Gunubie on slide), East London , Eastern Cape Province, South Africa, 26.ix.2014, S. Situngu (one slide with 2 females, 1 deutonymph; ARC-PHP; X15/36 ) ; paratypes: 1 female, 1 deutonymph, same data as holotype (same slide as holotype) ; 1 male ex R. rhomboidea, Somerset East (renamed KwaNojoli in 2023), Eastern Cape Province, South Africa, 08.x.2014, S. Situngu ( ARC-PHP; X15/94 ).

Diagnosis. Female. Prodorsal setae sc1 short, obovate, one third size of elongate lanceolate to weakly falcate setae sc2; mid-prodorsum with transverse folds. Opisthonotal setae c1, d1, e1 large, obovate with basal stalks. Cuticle finely punctate on coxal fields I–II. Ventral opisthosoma with small region of colliculate cuticle laterad anterior corners genital flap. Femora IV with two setae (d, evʹ). Genua I–II with three setae (d, lʹ, lʺ). Tibiae II with five setae (d, lʹ, lʺ, vʹ, vʺ). Male. Setae v2 long, ligulate, more than twice size of oblanceolate setae sc1.

Deutonymph. Setae sc2 elongate falcate, c3 ovate; femur II seta d orbicular.

Description. Adult female. (2 measured). Dorsum. ( Figs 40 , 41 ). Body measurements: v2–h1 300–327 [327], sc2–sc2 208–209 [208], c3–c3 237–244 [237], f3–f3 92–95 [92]. Anterior margin of prodorsum with broad median forked projection forming a central notch 27–30 [27], with a pair of smaller lateral notches, and triangular projections extending between coxae I–II. Prodorsum with central band of short, fine transverse folds centrally, widening towards posterior margin, flanked by region of smooth cuticle sublaterally; and with region of fine oblique folds in posterior lateral corner. Prodorsum wider than long; setae sc1 and sc2 inserted in transverse row along anterior margin, slightly posterior to setae v2. Opisthosoma with central band of transverse folds between setae c1–c1 and e1–e1; folds become longitudinal and irregular and rugose between and just posterior to setae e1–e1; with band of fine longitudinal folds around posterior margin between setae e1–e1 and row of posterior setae (h1, h2, f3, e3); lateral region of smooth cuticle mesad setae c3 and d3 with two pairs minute pores. Dorsal setae of various forms, finely barbed. Setae v2, sc1, c3, d3 much smaller than other setae (v2 lanceolate; sc1, c3, d3 obovate); sc2 large, elongate lanceolate to weakly falcate; setae c1, d1, e1 large, flat, obovate with elongate basal stalks; posterior row of setae (h1, h2, f3, e3) large, flat, narrowly to broadly lanceolate. Most dorsal setae inserted on small rounded tubercles. Setal measurements: v2 28–31 [28–29], sc1 20–22 [22], sc2 58–66 [60–66], c1 45–47 [47], c3 30–38 [31–32], d1 53–59 [53–59], d3 17–18 [18], e1 46 [46], e3 50 –54 [50–54], f3 53–57 [57], h1 44–46 [45–46], h2 45–54 49–54].

Gnathosoma . ( Fig. 42 ). Ventral cuticle posterad infracapitular setae m 10 [10] with fine transverse striae/plicae. Palp tarsus with solenidion 2–3 [2], eupathidium 6 [6]; tibiogenu with 2 setae 11–12 [12], 14–15 [14–15].

Venter. ( Fig. 42 ). Ventral cuticle variously ornamented. Cuticle finely punctate anteriorly on coxal fields I–II; with broad band of fine longitudinal striae/plicae laterally, and broad band of smooth cuticle centrally; cuticle laterad 4a–ag with short, fine mostly longitudinal folds, with small region of colliculate cuticle laterad anterior corners genital flap. Weakly formed genital flap, with sparse transverse folds; setae g1–g2 inserted in almost transverse row on flap. Setae ps2–3 inserted in almost transverse row posterior, in finely striate cuticle around posterior margin. All setae short, fine, finely barbed, except setae 1a elongate, flagellate (difficult to measure full length). Setal measurements: 1a 107–162 [107], 1b 20–25 [20–23], 1c 16–21 [16], 2b 23–28 [23], 2c 21–26 [26], 3a 17 [17], 3b 20–22 [22], 4a 15–20 [20], 4b 15–25 [25], ag 20 [20], g1 28–29 [29], g2 21–23 [23], ps2 28–31 [28–29], ps3 24–26 [25–26].

Spermathecal apparatus. Not visible.

Legs. ( Fig. 43 ). Setal formulae and chaetotaxy for legs I – IV as in the type species, E. quadrisetosus . Tarsi I and II each with one abaxial solenidion ωʺ (both 11–12 [11–12, 12]), companion seta ftʺ (both 5–7 [6–7]), and one pair eupathidia p′ζ–pʺζ (all 7–8 [7–8]). Seta ft′–ftʺ inserted on small tubercles. Companion seta ftʺ inserted adjacent and just proximal to ft′. Femora I–IV setae d thickened and heavily barbed; seta l′ on femora I–II and genu III thickened and heavily barbed; seta bvʺ on femur II much thicker and more heavily barbed than on femur I; tarsi III–IV with setae tc′–tcʺ inserted on short projections.

Adult male. (1 measured). Dorsum. ( Fig. 44A ). Body measurements: v2–h1 283, sc2–sc2 202, c3–c3 177, f3–f3 69. Anterior margin of prodorsum with broad median forked projection forming a central notch 24. Prodorsum with some transverse and weakly arching striae/plicae centrally and region of oblique arching striae/plicae laterally. Dorsal opisthosoma weakly divided into mesonotal region and pygidial region by narrow band of weak transverse striae/plicae; mesonotum with few weak mostly transverse striae/plicae; pygidial region with fine longitudinal striae/ plicae. Posterior margin of opisthosoma with short triangular projection extending between setae h1. Prodorsal setae similar in form to those of female; dorsal opisthosomal setae generally smaller than those of female, and central setae much smaller. Most dorsal setae inserted on small rounded tubercles. Setal measurements: v2 43–45, sc1 24–25, sc2 42–45, c1 17, c3 30–32, d1 8, d3 27–28, e1 9, e3 30 –31, f3 34, h1 32, h2 31–35.

Gnathosoma . ( Fig. 44B ). Ventral cuticle posterad infracapitular setae m 9–10 with fine transverse striae/plicae. Palp tarsus with solenidion 6–7, eupathidium 7–8; tibiogenu with 2 setae 13–14, 15–17.

Venter. ( Fig. 45A ). Ventral cuticle mostly smooth anteriorly, and with various patterns of fine striae/plicae posteriorly. Anterior venter and coxae I–II smooth, with fine oblique striae laterad setae 3a between 3a and coxae II; with a square-shaped region of smooth cuticle between setae 3a and 4a; with narrow band of strong transverse striae level with coxae IV just posterior to setae 4a, becoming weaker fine transverse striae to setae ag; with fine, broken, oblique striae/plicae laterad to ag, becoming transverse just anterior to genital opening; striae/plicae surrounding g1–g2 and ps2 longitudinal; projections holding modified ps3 with fine longitudinal striae/plicae. All setae short, fine, smooth to finely barbed, except setae 1a elongate, flagellate (difficult to measure full length), and ps3 modified as finely tapered accessory genital stylets inserted distally on tapered projection from genitoanal region ( Fig. 45A ). Setae g1, g2, ps2 inserted together in a row on paired flaps flanking genitoanal projection. Setal measurements: 1a 134–151, 1b 23–28, 1c 18–20, 2b 28–32, 2c 22–27, 3a 17, 3b 19–25, 4a 15–16, 4b 15–16, ag 16–18, g1 17–19, g2 18–19, ps2 27–29, ps3 24–25.

Aedeagus. ( Fig. 45B ). Sclerotised, extremely elongate, finely tapering (approx. 160), difficult to measure full length, with narrow membranous tube emerging basally, tube apparently ending in blunt bulb.

Legs. ( Fig. 46 ). Setal formulae same as adult female except solenidion ω′ present on ta I–II. Tarsi I and II each with two solenidia (ta I adaxial ω′ 13, abaxial ωʺ 16; ta II adaxial ω′ 13, abaxial ωʺ 15), companion seta ftʺ (all 8–9), and pair eupathidia p′ζ–pʺζ (ta I 9–10; ta II 8–9). Seta ft′–ftʺ inserted on small tubercles. Femora I–IV setae d thickened and heavily barbed. Femora I is assumed to have 4 setae, with the specimen examined here having 5 setae on one side ( Fig. 46 , n. b. the large barbed seta marked with an * in an lʺ position is assumed to be an asymmetrical aberration).

Deutonymph. (1 measured). Dorsum. ( Fig. 47 ). Body measurements: v2–h1 252, sc2–sc2 180, c3–c3 228, f3–f3 77. Anterior margin of prodorsum with median forked projection forming a central notch 22. No dorsal shields developed, but with central regions of smooth cuticle in prodorsal and pygidial regions; setae v2, sc1, sc2 inserted in transverse row across anterior prodorsum. Posterior margin of opisthosoma with short rounded projection extending between setae h1. Dorsal setae of various forms, finely barbed. Setae sc2 elongate falcate; c3 ovate; setae e3, f3, h1, h2 broadly lanceolate; setae v2, c1, d1, e1 all small to minute; setae sc1, d3 missing. Setal measurements: v2 6–7, sc1 missing, sc2 100, c1 5–7, c3 32–35, d1 6–7, d3 missing, e1 3 –4, e3 47, f3 45, h1 31, h2 37–40.

Gnathosoma . Palp tarsus with solenidion 1 and eupathidium 6; tibiogenu with 2 setae 7–8, 9.

Venter. Ventral cuticle almost completely finely striate/plicate, with various patterns of fine striae/plicae. With weak fine longitudinal striae 1b–1a; fine strong transverse striae 1a–ag; with chevron shaped striae ag–g1; fine longitudinal striae on anal valves from g1–ps2. Coxae I–II appear smooth, but weak extremely fine longitudinal striae difficult to discern. All setae short, fine, smooth to finely barbed, except setae 1a elongate, flagellate (difficult to measure full length). Setal measurements: 1a 117–126, 1b 17, 1c 12–14, 2b 13–20, 2c 20–23, 3a 12–13, 3b 18–19, 4a 57–77, 4b 14–15, ag 12–13, g1 11, ps2 12, ps3 14–15.

Legs. ( Fig. 48 ) Setal formulae for legs I – IV the same as the female except tr IV nude. Tarsi I and II each with one abaxial solenidion ωʺ (both 7–8), with distant companion seta ftʺ (both 5–6), and one pair of ventral eupathidia p′ζ–pʺζ present (all 6–7). Seta ft′ inserted on small tubercle; eupathidia p′ζ–pʺζ inserted on small, distinctly shaped projections closely flanking pretarsus. Seta bvʺ on femur II much longer than on femur I.

Protonymph & Larva. Unknown.

Host. Glossy forest grape, Rhoicissus rhomboidea (E.Mey ex Harv.) Planch. ( Vitaceae ).

Distribution. South Africa: Eastern Cape Province.

Etymology. This species is named for the collector, Dr Sivuyisiwe Situngu, currently at the School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg.

Remarks. The new species is closest to E. niekerkae due to the short prodorsal setae sc1 and folded midprodorsal cuticle. The females of these species differ in the ornamentation of the coxal fields (punctate in E. situngu , smooth to plicate in E. niekerkae ) and the mid-opisthosomal patterning (rugose in E. situngu , with few folds in E. niekerkae ). Males of these species differ in the shape of setae v2 and c1 (distinctly smaller in E. situngu ) and deutonymphs in the form of setae c1 (minute in E. situngu , larger and obovate in E. niekerkae ).

These mites were collected from the leaves of their host plant.

Figures

FIGURE 40. Extenuipalpus situngu sp. nov., adult female holotype dorsum.

FIGURE 41. Extenuipalpus situngu sp. nov., adult female paratype dorsum. A—photographed using differential interference contrast (DIC), and B—phase contrast.

FIGURE 42. Extenuipalpus situngu sp. nov., adult female holotype venter.

FIGURE 43. Extenuipalpus situngu sp. nov., adult female legs I–IV (right side; legs I–III dorsal aspect, leg IV abaxial aspect); with detail of ventral aspect tarsi I–III, and adaxial aspect tarsus IV.

FIGURE 44. Extenuipalpus situngu sp. nov., adult male. A—dorsum; B—detail of palp (dorsal and ventral aspect) and basal insertion of solenidion.

FIGURE 45. Extenuipalpus situngu sp. nov., adult male. A— posterior venter; B—detail of aedeagus.

FIGURE 46. Extenuipalpus situngu sp. nov. adult male legs I and III (right side, dorsal to adaxial aspect), with detail of abaxial aspect of tarsi (n. b., the seta * on femur I is an asymmetrical aberration).

FIGURE 47. Extenuipalpus situngu sp. nov., deutonymph dorsum.

FIGURE 48. Extenuipalpus situngu sp. nov., deutonymph legs I–IV (right side, dorsal aspect); with detail of ventral aspect all tarsi, and left tarsus I (dorsal and ventral aspects) (n. b. several setae are missing: ft′ is missing on both tarsi I, l″ is missing on genu I and tibiae I–II; and ft′ illustrated separately on tarsi III–IV).