Athyreacarus similis, Khaustov & Frolov, 2019

Khaustov, Alexander A. & Frolov, Andrey V., 2019, Revision of the genus Athyreacarus (Acari: Athyreacaridae), Zootaxa 4647 (1), pp. 168-225 : 188-196

Athyreacarus similis sp. nov.

( Figs 21–25 )

Description. Female ( Figs 21–25 ). Body broadly fusiform. Length of idiosoma 320 (320–345), width 165 (165– 190).

Gnathosoma . Gnathosomal capsule, excluding palps, almost oval, length 47 (44–47), width 47 (46–53). One pair of barbed, blunt-ended cheliceral setae cha 24 (22–25). Postpalpal setae (pp) 12 (9–12) needle-like. Setae m 16 (12–16) and n 42 (36–44) pointed. Setae m smooth, n barbed. Setae dFe 16 (10–16) and dGe 26 (24–28) weakly barbed; setae dFe blunt-ended, dGe pointed. Tibial claw slightly hooked.

Idiosomal dorsum ( Figs 21A , 24A , 25A, B ). All dorsal shields with numerous sparsely distributed dimples ( Figs 25A, B ). Hysterosomal shields D and EF relatively narrow, not covering approximately 1/3 of hysterosomal dorsum. Prodorsal shield without lateral projections. Setae sc 1 vestigial. All dorsal setae weakly barbed. Setae v 2 and e blunt-ended, other dorsal setae pointed. Cupules ia on tergite D, im, ip on tergite EF and ih on tergite H large, round. Cupules ih located dorsally, anterolaterally to bases of setae h 1. Pseudanal segment much shorter than tergite H. Lengths of dorsal setae: v 1 54 (50–57), v 2 28 (22–32), sc 2 94 (93–96), c 1 61 (60-62), c 2 120 (110–120), d 90 (87–91), e 19 (18–21), f 105 (105–110), h 1 81 (76–85), h 2 49 (48–52). Distances between setae: v 1 –v 1 18 (17–20), v 2 –v 2 49 (48–50), sc 1 –sc 1 59 (58–61), sc 2 –sc 2 47 (43–48), c 1 – c 1 51 (49–52), c 1 – c 2 40 (40–46), d–d 55 (52–57), e–e 46 (43–46), f–f 56 (53–56), h 1 – h 1 37 (32–37), h 1 – h 2 16 (16–18).

Idiosomal venter ( Figs 21B , 24B , 25C, D ). All ventral plates with numerous dimples ( Figs 25C, D ), dimples on aggenital and midsternal plates arranged slightly more densely than on other plates. All ventral setae weakly barbed. Setae 1 b, 2 c, 3 a, ag 1, ps 2, ps 3 blunt-ended, other ventral setae pointed. Ap5 short, located near base of legs IV. Aggenital plate with three pairs of aggenital setae. Anal opening terminal. Length of mid-sternal plate 60 (59–64), width 47 (47–51); ratio length/width 1.2–1.3. Lengths of ventral setae: 1 a 29 (27–31), 1 b 16 (14–17), 1 c 20 (18–21), 2 a 40 (33–41), 2 b 30 (24–30), 2 c 16 (14–19), 3 a 15 (15–18), 3 b 28 (25–29), 3 c 23 (20–25), 4 a 27 (23–28), 4 b 30 (28–32), 4 c 21 (16–22), ag 1 20 (17–21), ag 2 35 (32–37), ag 3 34 (31–37), ps 1 51 (46–52), ps 2 55 (51–57), ps 3 36 (31–37).

Legs ( Figs 22 , 23 ). Length of legs: I 110 (110–115), II 105 (105–110), III 110 (110–115), IV 140 (140–145). Leg I ( Fig. 22A ): setae v’ of femur and k of tibia smooth, other leg setae (except eupathidia) weakly barbed; setae l’, v’ of femur, d, v’ of genu, v’ and k of tibia blunt-ended, other leg setae (except eupathidia) pointed; lengths of solenidia ω 1 12 (11–12), ω 2 8 (8), φ 1 11 (11), φ 2 8 (6–8); ω 1 digitiform, φ 1 weakly clavate, ω 2 and φ 2 baculiform. Leg II ( Figs 22B ): solenidion ω 13 (12–13) digitiform, solenidion φ 8 (7–8) baculiform; all leg setae weakly barbed; seta l’ of femur blunt-ended, other leg setae pointed. Leg III ( Fig. 23A ) similar in shape and length to leg II; solenidion φ 8 (7–8) baculiform; all leg setae pointed and weakly barbed. Leg IV ( Fig. 23B ): solenidion φ 8 (7–8) baculiform; all leg setae weakly barbed; setae l” of genu, and p’ of tarsus blunt-ended, other leg setae pointed.

Type material. Female holotype, slide No. ZISP T-Ath-001, BOLIVIA, Chiquitano [dry forests], 16°24’S 61°11’W, 430 m., human feces, 16.I.2010, Vidaurre et al. leg., on a beetle Neoathyreus centromaculatus (Felsche) . Paratypes: 8 females, same data .

Type deposition. The holotype and two 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 is very similar to A. magnificus sp. nov. and A. variabilis sp. nov. by the absence of setae chb, presence of three pairs of aggenital setae, setae sc 1 vestigial, and setae c 1 well developed.

The new species differs from A. magnificus and A. variabilis by the median ends of apodemes 3 and 4 almost connected (vs. median ends of apodemes 3 and 4 clearly separated in A. magnificus and A. variabilis ). The new species differs from A. magnificus by having a smaller idiosoma (320–345 in A. similis vs 440–465 in A. magnificus ), and setae (pl) on tarsus I, (tc) on tarsi II and III and tc’ on tarsus IV pointed (vs spatulate in A. magnificus ). The new species differs from A. variabilis by the absence of subcuticular reticulation on the prodorsal shield and tergite C (vs weak subcuticular reticulation present on prodorsal shield and tergite C in A. variabilis ), large, sparsely distributed dimples on the idiosomal plates (vs very small, densely distributed dimples on the idiosomal plates in A. variabilis ), and by setae tc” on tarsi II and III and tc’ on tarsus IV pointed (spatulate in A. variabilis ).

Etymology. The name of the new species derives from the Latin word “ similis ” meaning “ similar ” and refers to similarity of the new species to the closely related A. magnificus and A. variabilis .

Figures

FIGURE 21. Athyreacarus similis sp. nov., female: A—dorsum of body, B—venter of body.

FIGURE 22. Athyreacarus similis sp. nov., female: A—right leg I in dorsal view, B—right leg II in dorsal view.

FIGURE 23. Athyreacarus similis sp. nov., female: A—right leg III in dorsal view, B—right leg III in dorsal view.

FIGURE 24. Phase-contrast micrographs of Athyreacarus similis sp. nov., female: A—general aspect dorsally, B—general aspect ventrally.

FIGURE 25. Phase-contrast micrographs of Athyreacarus similis sp. nov., female: A—prodorsal shield, B—tergites D and EF, C—anterior sternal plate, D—aggenital and midsternal plates and part of coxal fields III and IV.