Eutarsopolipus walteri, Seeman & Katlav, 2024

Seeman, Owen D. & Katlav, Alihan, 2024, Podapolipid mites (Acari: Heterostigmata): key to genera, biogeographical history and description of four new Australian species of Eutarsopolipus, Zootaxa 5448 (3), pp. 301-347 : 335-340

Eutarsopolipus walteri sp. nov.

( Figs 19– 22 , 3E , 6E , 9E )

Diagnosis. Solenidion on tarsus II present. Female: plates C, D entire, plate H weakly expressed, setae h developed, length 10; dorsal setae (except for sc2) small, thorn-like; coxal setae 1a, 2a, 3a thickened, blunt, 3b slender; pretarsus I with single strong claw; femur I seta lʹ short, 2. Male: pretarsus I with weak claws, II–III lacking claws; opisthonotal setae minute. Larva: pretarsi II–III lacking claws; plate CD incised; coxal setae 1a, 2a minute, 3a, 3b slender; setae h1 60–65, h2 20–23.

Type material. All ex Chlaenius ophonoides Fairmaire. Holotype female ( QMS 117057 ). 15 miles SW Normanton, 17°50′S, 140°55′E, 25 May 1972, GB & SR Monteith, beetle #10. Paratypes. 5 males, 34 larvae, as follows. 9 larvae ( QMS 117061-66 ), same data as holotype. 5 males ( QMS 117058-60 , 67 ), 21 larvae ( QMS 117068-78 ), Toowoomba, 27°33′S, 151°58′E, 25 Apr 1960, beetle #5. 4 larvae ( QMS 117079-81 ), Homestead at Silver Plains via Coen , 13°58′S, 143°36′E, 11 Dec 1964, beetle #8. All in QM except 1 male, 1 larva in ANIC and 1 larva in ZMH .

Description. FEMALE ( Figs 19– 20 , 3E; n = 1). Gnathosoma . Length 48, width 47. Palp without dorsal tibial seta; cheliceral stylets 38, ch 18, su 3.

Idiosoma ( Figs 19 , 3E ). Length 285, width 265, idiosoma moderately expanded between plates C and D. Respiratory system present, atria indiscernible. Setae v1, sc1, c1, c2, d, f thickened, thorn-like. Prodorsal plate with setae v1 3, v2 alveolar remnant, sc1 4, sc2 49. Distance between setae v1–v1 59, sc1–sc1 98, v1–sc1 25, v2–v2 78, sc2–sc2 99, sc1–sc2 32. Plate C setae c1 2, setae c2 3, distance between setae c1–c1 100. Plate D setae d 2, d–d 83, cupuli ia not seen (possibly obscured by internal waste material). Plate EF setae f 2, f–f 62, cupuli im anterolaterad f (obscured on one side). Plate H weak, divided into two small plates, seta h 10. Venter: coxisterna 1 and 3 well defined, coxisterna 2 weakly defined posteriorly; apodemes 1 and appr weakly defined but stronger than apodemes 2, which barely connect with appr, sejugal apodeme absent, apodemes 3–4 weakly defined; coxal setae ( Fig. 3E ) 1a, 2a, 3a peg-like, 3b slender, 1a 2, 2a 2, 3a 4, 3b 6. Alveoli of 1b present, 2b absent or obscured.

Legs ( Fig. 20 ). Setal counts legs I–III, femur-tarsus: 2-0-6(+ φ)-7(+ ω), 0-0-4-7(+ ω), 0-0-4-7. Leg I. Femur, d minute, l′ 3, v″ absent; tibia, d 22, l′ 2, l″ minute, v′ 2, v″ 7, k 4, φ 5 baculiform; tarsus, tc′ 13, tc″ 13, pl′ 7, pl″ absent, pv′ 2, pv″ 2, ω 3 digitiform, s 5, u′′ minute, p′ absent. Leg II. Tibia, d 6, l′ 5, v′ 7, v″ 9; tarsus, tc′ 6, tc ″ 6, pl ″ 13, pvʹ 2, pv″ 4, ω 3 baculiform, u′ 6, u′′ minute. Leg III. Tibia, d 7, l′ 5, v′ 7, v″ 6; tarsus, tc′ 7, tc ″ 6, pl ″ 14, u′ 6, pvʹ 2, pv″ 2, u′′ minute.

Modified setae: tibia I seta k blade-like, lʹ and vʹ small spines; tarsus I seta pvʺ small spine; tarsus I seta s and tarsi II–III seta tcʺ and u′ thickened, large, spine-like, not bifid.

MALE ( Figs 21 , 6E; n = 4). Gnathosoma . Length 20–25, width 22–29. Cheliceral stylets 13–15, ch 3–6, su 1–2.

Idiosoma ( Fig. 21 ). Length 125–140, width 80–95. Prodorsal plate with setae v1 minute, v2 alveolar remnant, sc1 minute, sc2 26–33. Distance between setae v1–v1 19–23, sc1–sc1 39–55, v1–sc1 15–21, v2–v2 27–40, sc2–sc2 52–65, sc1–sc2 24–28. Plate CD setae c1, c2, d minute, distance between setae c1–c1 37–45, c1–c2 16–18, d–d 20–23; cupuli ia anterolaterad setae d (often difficult to see). Plate EF with setae f vestigial, distance f–f 22–25; cupuli im anteriad setae f. Genital capsule length 22–29, width 20–24, setae h minute. Venter: apodemes 1, 2 and appr moderately well defined, apodemes 2 reaching appr, sejugal apodeme absent, apodemes 3–4 well defined. Coxal setae ( Fig. 6E ) 1a, 2a, 3a, 3b minute.

Legs ( Fig. 21 ). Setal counts legs I–III, femur-tarsus: 1-0-6(+ φ)-8(+ ω), 0-0-4-5(+ ω), 0-0-4-5. Compared to female: femur I seta l′ absent, seta pv′ not evident on tarsi I–II; seta u″ not evident on tarsi II–III. Small tarsal setae invisible probably due to small size of males and large tarsal setae tc″ and u′. Leg I. Femur, d minute; tibia, d 13–15, l′ 1, l″ minute, v ′ 1, v ″ 4–6, k 1, φ 3 baculiform; tarsus, tc′ 7–8, tc″ 7–8, pl′ 2, pl″ absent, pv″ minute, ω 2–3 digitiform, s 3–4. Leg II. Tibia, d 2–3, l′ 1, v′ 2–4, v″ 1–2; tarsus, tc′ 3–5, tc ″ 6, pl ″ 8–11, pv″ 2–3, ω 2–3 digitiform, u ′ 4–5. Leg III. Tibia, d 3–4, l′ 1, v′ 1, v″ 1–2; tarsus, tc′ 3–5, tc ″ 4–5, pl ″ 8–10, pv″ 1–2, u′ 5–6.

Modified setae: similar to female except—tibiae II–III setae (v) and lʹ small spines; small size of tarsal setae made them indiscernible/hardly discernible. Claws on leg I paired, rudimentary or absent on legs II–III.

LARVAL FEMALE ( Fig. 22 , 9E ; specimens from Normanton and Coen in ranges – these specimens tended to be smaller than those from Toowoomba; Toowoomba in square brackets if different; n = 35). Gnathosoma . Length 29–37, width 30–41. Cheliceral stylets 20–22, dorsal ch 14–16, su 2–3.

Idiosoma ( Figs 22 , 9E ). Length 130–185, width 88–135. Prodorsal plate expanded, extending over bases of legs I–II and gnathosoma, with setae v1 4–6, v2 alveolar remnant, sc1 5–6, sc2 60–85. Distance between setae v1–v1 16–20 [18–29], sc1–sc1 44–48 [53–61], v1–sc1 14–15 [16–20], v2–v2 34–37 [35–45], sc2–sc2 42–54, sc1–sc2 33–42. Plates C and D fused medially, incised laterally. Plate CD setae c1 4–5, setae c2 5–8, distance between setae c1–c1 58–79, setae d 5–6, d–d 20–34, cupuli ia anteriad to anteromesad d. Plate EF setae f 4–6, f–f 15–26, cupuli im anteriad to anteromesad f. Plate H reduced to caudal cone, 11–15 wide, 13–15 long, bearing setae h1 60–65, h2 20–23. Venter: coxisterna 1–3 poorly defined, almost entirely unsclerotised; apodemes similar to female; coxal setae ( Fig. 9E ) slender, 1a minute, 2a m–2, 3a 5–8, 3b 5–8. Alveoli of 1b, 2b indiscernible or absent.

Legs ( Fig. 22 ). Setal counts legs I–III, femur-tarsus: 2-0-6(+ φ)-7(+ ω), 0-0-4-6(+ ω), 0-0-4-5 (setae pv′ absent on tarsi II–III). Leg I. Femur, d minute, l′ 2–4; tibia, d 19–23, l′ 3–4, l″ 1–2, v′ 3–4, v″ 6–7, k 2–4, φ 4–5 baculiform; tarsus, tc′ 7–8, tc″ 9–10, pl′ 6–8, pl″ absent, pv′ 1–2, pv″ 2, ω 3–4 baculiform, s 5–6, u′′ minute, p′ absent. Leg II. Tibia, d 4–5, l′ 5–6, v′ 6–8, v″ 4–7; tarsus, tc′ 8–9, tc ″ 5–6, pl ″ 11–13, pv″ 3–4, ω 2–4 clavate, u′ 6–7, uʺ minute. Leg III. Tibia, d 6–9, l′ 5–8, v′ 7–9, v″ 5–7; tarsus, tc′ 8–9, tc ″ 6–7, pl ″ 10–14, u′ 6–7, pvʺ 3–5, u′′ minute.

Legs I with two claws; legs II–III without claws.

Modified setae: similar to female except- lʹ slender, not spine-like. One specimen (QM S117068) with asymmetrical addition of small spine-like seta on tibia II in l″ position .

Differential diagnosis. Eutarsopolipus walteri is easily distinguished from all other members of the myzus group by having thorn-like dorsal setae. Males are unique in the myzus group by having paired claws on leg I (single claw in other species). Larvae are more difficult to separate. In having a combination of d well off the margin of shield CD, setae sc2 closer together than sc1, and cheliceral stylets <25 long, E. walteri is similar to E. latus Regenfuss, 1974 and E. steveni Khaustov, 2010 . Larvae of E. steveni have a smaller gnathosoma (21–22 x 22–23) than both E. latus (29–31 x 31–33) and E. walteri (29–37 x 30–41, variation due to intraspecific variation and perhaps some slide-mounting distortion for width). Larvae of E. latus are more difficult to separate from E. walteri due to the limited data provided for E. latus , but we note that Regenfuss (1974) described setae 3b as being much longer and stronger than setae 3a. These setae are subequal in E. steveni and E. walteri .

Etymology. It is with great pleasure that we name this species for Dave Walter, a great acarologist, teacher and friend.

Remarks. Chlaenius is the most common host of the myzus species group with 12 species. However, E. inermis is the only member from another species group ( pterostichi ) found on Chlaenius ( Table 4 ).

The larval specimens vary considerably in size and while there appears to be generally larger specimens from Toowoomba and smaller specimens from Normanton and Silver Plains, small specimens are also present in the Toowoomba population. Thus, despite the remarkable distance between Toowoomba and the other localities (ca. 1600 km), the species is the same in northern and southern populations of Ch. ophonoides . This is not surprising as Chlaenius are highly vagile beetles and thus their species have broad distributions.

Figures

FIGURE 3. Female Eutarsopolipus. (A) E. ampullaceous sp. nov. venter, showing apodemes and (B) coxal setae; (C) E. tripodus, coxal setae; (D) E. vepreculus, coxal setae; (E) E. walteri, coxal setae. Membranous idiosomal cuticle is shaded grey.

FIGURE 6. Male Eutarsopolipus. (A) E. ampullaceous sp. nov. venter, showing apodemes and (B) coxal setae; (C) E. tripodus, coxal setae; (D) E. vepreculus, coxal setae; (E) E. walteri, coxal setae. Membranous idiosomal cuticle is shaded grey.

FIGURE 9. Larval Eutarsopolipus.(A) E. ampullaceous sp. nov. venter, showing apodemes and (B) coxal setae; (C) E.tripodus, coxal setae; (D) E. vepreculus, coxal setae; (E) E. walteri, coxal setae. Membranous idiosomal cuticle is shaded grey.

FIGURE 19. Eutarsopolipus walteri sp. nov. Female, dorsum.

FIGURE 20. Eutarsopolipus walteri sp. nov. Female legs I–III (A–C). Tarsi II–III with seta u″ present but obscured.

FIGURE 21. Eutarsopolipus walteri sp. nov. Male. Tarsi II–III setae pv′ and u″ not seen (possibly because of small mite size and large tc″ obscuring setae).

FIGURE 22. Eutarsopolipus walteri sp. nov. Larva. Minute seta u″ on tarsus III present.