Athyreacarus staturosus, Khaustov & Frolov, 2022

Khaustov, Alexander A. & Frolov, Andrey V., 2022, New taxa of Athyreacaridae (Acari: Heterostigmata) from Neotropical and Afrotropical realms, Zootaxa 5188 (6), pp. 501-520 : 506-513

Athyreacarus staturosus sp. nov.

( Figs 7–13 )

Description. Female. Body broadly oval. Length of idiosoma 635 (565–750), width 360 (330–445).

Gnathosoma ( Fig. 8 ). Gnathosomal capsule, excluding palps, almost round, length 74 (67–79), width 75 (66– 80). Dorsal gnathosomal apodeme not evident. Two pairs of barbed, blunt-tipped cheliceral setae cha 44 (38–56) and chb 33 (27–41). Postpalpal setae (pp) 17 (15–18) blunt-tipped, with some weak barbs in distal half. Setae m 43 (33–44) and n 85 (62–88) pointed; setae m smooth, n weakly barbed. Setae dFe 37 (27–41) and dGe 39 (30– 40) barbed; setae dFe blunt-tipped, dGe pointed. Tibial claw slightly hooked, with distinct subapical projection. Pharynx typical for the genus. Ass short, with small distal projection. Palpal tibiotarsus with short spiniform seta l” anterolaterad palpal solenidion, rather long eupathid-like seta distally and very short setiform structure anteriad ass. Cheliceral stylets 11 (10–13) relatively short and thin.

Idiosomal dorsum ( Figs 7A , 11 , 13A, D ). All dorsal shields with numerous sparsely distributed puncta ( Figs 13A, D ). Prodorsal shield without lateral projections. Setae sc1 completely absent, or in some specimens represented by poorly visible alveolar pits ( Fig. 13D ). All dorsal setae weakly blunt-tipped and weakly barbed. Cupules ia on tergite D, im, ip on tergite EF and ih on tergite H very small, round. Tergites C, D, and EF with pore-like structures typical for the genus. Stigmata round. Pseudanal segment almost completely covered by tergite H. Lengths of dorsal setae: v1 94 (70 – 125), v2 73 (73 – 75), sc2 160 (135 – 175), c1 140 (130 – 185), c2 150 (145 – 195), d 145 (130 – 180), e 120 (105 – 150), f 170 (140 – 180), h1 170 (145 – 195), h2 175 (150 – 200). Distances between setae: v1–v1 58 (55 – 78), v2–v2 85 (80 – 105), sc2–sc2 120 (115 – 145), c1–c1 145 (135 – 180), c1–c2 77 (65 – 87), d–d 180 (145 – 190), e–e 185 (145 – 205), f–f 200 (175 – 245), h1–h1 145 (120 – 150), h1–h2 25 (24 – 35).

Idiosomal venter ( Figs 7B , 112, 13B, C). All ventral plates with numerous puncta ( Figs 13B, C ). Setae ps1 and ps2 weakly barbed; other ventral setae smooth. Setae 1c pointed; other ventral setae weakly blunt-tipped; setae 1a, 1b, 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c, and ag1 swollen basally and attenuate distally ( Figs 13 B, C ). Ap5 long, ap3 and ap4 fused; apsej not evident. Aggenital plate with two pairs of aggenital setae.Anal opening ventral. Pseudanal setae located ventrally Length of mid-sternal plate 128 (96–128), width 145 (120–145); ratio length/width 0.8. Lengths of ventral setae: 1a 39 (34 – 43), 1b 34 (29 – 37), 1c 96 (73 – 99), 2a 45 (43 – 49), 2b 39 (38 – 50), 2c 40 (36 – 53), 3a 29 (27 – 35), 3b 43 (42 – 51), 3c 40 (34 – 46), 4a 44 (38 – 55), 4b 45 (39 – 61), 4c 43 (40 – 52), ag1 41 (40 – 60), ag2 79 (79 – 96), ps1 110 (79 – 140), ps2 125 (105 – 145), ps3 43 (31 – 59).

Legs ( Figs 9 , 10 ). Leg I ( Fig. 9A ): setae v’ of trochanter and d of femur and genu barbed, other setae smooth; setae d of femur, v’ of genu, d, l’, v” of tibia pointed, other leg setae weakly blunt-tipped; lengths of solenidia ω1 15 (13–16), ω2 14 (11–14), φ1 11 (10–11), φ2 12 (10–12); all solenidia digitiform. Tarsal claw very thick and blunttipped. Leg II ( Fig. 9B ): solenidia ω 14 (12–14) and φ 13 (11–14) digitiform; seta d of femur barbed, other setae smooth; seta u” very short, spiniform; seta v’ of trochanter with swollen basal half and attenuate distally; setae (tc) with widened and flattened tips; setae (pv) weakly blunt-tipped, other setae pointed. Tarsal claws distinctly smaller than in other Athyreacarus species. Empodium with distinct dorsal longitudinal striation. Leg III ( Fig. 10A ) similar in shape and length to leg II; solenidion φ 12 (11–14) digitiform; setae d of femur, l” of genu and d of tibia barbed, other setae smooth; seta u” very short, spiniform; seta v’ of trochanter with swollen basal half and attenuate distally; setae (tc) with widened and flattened tips; setae v’ of trochanter, d of femur and (pv) weakly blunt-tipped, other setae pointed. Claws and empodium as on tarsus II. Leg IV ( Fig. 10B ): solenidion φ 14 (14–16) digitiform; setae d of femur, l” of genu, d of tibia and p’ barbed, other setae smooth; seta v’ of trochanter with swollen basal half and attenuate distally; seta v’ of femur thickened in basal half; seta tc’ with widened and flattened tip; setae v’ of trochanter, d of femur, v’ of genu, and p’ weakly blunt-tipped, other setae pointed. Claws and empodium as on tarsi II and III.

Type material. Female holotype, slide No. ZISP T-Ath-012, Argentina, Catamarca Prov., Londres, 7-17.II.2015, G.L. Agnoli, on Zefevazia cantisani Martinez. Paratypes: 7 females, same data ; 17 females, Argentina, Catamarca Prov., Punta de Balasto , II.2015, G.L. Agnoli, on Zefevazia cantisani ; 1 female, Argentina, Catamarca Prov., Belen , II.2013, G.L. Agnoli, on Zefevazia cantisani .

Type deposition. The holotype and five paratypes are deposited in the collection of the Zoological Institute of RAS, Saint Petersburg, Russia ; other paratypes are deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia .

Differential diagnosis. The new species considerably differs from other Athyreacarus species in having very short spiniform setae u” on tarsi II and III (always seta-like in other Athyreacarus ), setae 1a, 1b, 2a, 2b, 2c, 3a, 3b, 3c, 4a, 4b, 4c, and ag1 swollen basally and attenuate distally (not modified in other Athyreacarus ), palp tibiotarsus ventrally with short spiniform seta l” (absent in other Athyreacarus ).

Etymology. The name of the new species is a Latin word staturosus meaning gigantic and refers to extremely large body size.

Remarks. The considerable differences in the new species compared to other Athyreacarus may represent another genus. However, the most sufficient difference (presence of seta l” on palpal tibiotarsus) is a plesiomorphic character state and not useful for creating a new taxon. However, apomorphic characters such as very short spiniform setae u” on tarsi II and III, unusually small cheliceral stylets, and modifications of most ventral idiosomal setae could be helpful. The discovery of other species with similar character states may result in creation of another supraspecific taxon.

Figures

FIGURE 7. Athyreacarus staturosus sp. nov., female: A—dorsum of body, B—venter of body. Legs omitted.

FIGURE 8. Athyreacarus staturosus sp. nov., female: A—gnathosoma, dorsal aspect, B—gnathosoma, ventral aspect.

FIGURE 9. Athyreacarus staturosus sp. nov., female: A—right leg I, dorsal aspect, B—right leg II, dorsal aspect.

FIGURE 10. Athyreacarus staturosus sp. nov., female: A—right leg III, dorsal aspect, B—right leg IV, dorsal aspect.

FIGURE 11. DIC micrograph of Athyreacarus staturosus sp. nov., female (holotype): general aspect dorsally.

FIGURE 12. DIC micrograph of Athyreacarus staturosus sp. nov., female (holotype): general aspect ventrally.

FIGURE 13. DIC micrograph of Athyreacarus staturosus sp. nov., female: A—prodorsum, B—coxisternal fields I and II, C—coxisternal fields III and IV, D—prodorsum with vestigial alveoli of setae sc1.