Thyreophagus athiasae ( Fain, 1982 )

Kolesnikov, Vasiliy B., Klimov, Pavel B., Khaustov, Alexander A., Pepato, Almir & Makarova, Olga L., 2024, A new arenicolous species of the genus Thyreophagus (Acari: Acaridae) from the Caspian sea coast: Taxonomy and ecological insights, Zootaxa 5556 (1), pp. 252-267 : 262-264

Thyreophagus athiasae ( Fain, 1982)

( Figs 8 , 9 )

Type material: holotype (female) from Royal Belgian Institute of Natural Sciences, Brussels, Belgium (Institut Royal des Sciences naturelles de Belgique) ( IRSNB): from organic residues found at the bottom of a vase that had contained locally produced lentils, in Algeria . Paratype (female) from IRSNB: on Coccids Lepidosaphes beekii Newm., Rabat in Morocco, 20-7-1949 .

Diagnosis. Prodorsal shield with small flat protrus in posterior part, smoothly punctate except lineate pattern on posterior 1/3 part of shield. Supracoxal seta elcp present. Idiosomal setae h 1, h 2 and h 3 short. Base of spermatheca short, its length is 1.4 times greater than its width, with thickened walls in the conical part where it connects with the inseminatory canal, ½ its part is hidden in the conical base of the sac of spermatheca without “bottleneck” and extended ring. Paired efferent ducts short, their length approximately 1/3 the length of spermatheca base, with short stem.

Re-description.

Female (holotype). Idiosoma elongate, 650 × 250 (holotype), 2.6 times longer than wide. Idiosomal cuticle smooth.

Subcapitular setae (h) long, widened basally; palp tibial setae (a), lateral dorsal palp tibial setae (sup), dorsal palp tarsal seta (cm) filiform; supracoxal seta elcp present; terminal palp tarsal solenidion ω short; external part of terminal eupathidium ul” dome-shaped; terminal eupathidium ul’ small, rounded.

Prodorsal shield ( Fig. 9B ) 130 long, 100 wide, 1.3 times longer than wide, with setae vi (situated at anterior part of shield, alveoli separated at a distance less than their width), rounded anterolateral incisions, and elongate midlateral incisions (insertion points of setae ve). The back of the shield has a small flat protrusion. Prodorsal shield smoothly punctate except lineate pattern on posterior 1/3 part of shield. Grandjean’s organ (GO) with 10 membranous short finger-shaped processes. Supracoxal setae (scx) smooth, sword-shaped, widened and flattened, tapering at tip. Idiosomal setae (vi, se, c p, d 2, e 2, h 1, h 2, h 3, ps 3) smooth, filiform and short (except long se) ( Figs 9A, D ); opisthosomal gland openings slightly anteriad setal bases e 2. Three pairs of fundamental cupules (ia, im and ih) present, ip not observed. Ventral idiosoma with four pairs of coxal setae (1a, 3a, 4a and 4b) and one pair of genital setae (g). Shape of coxal sclerites as in Figures 9C . Genital region situated between coxal fields III and IV ( Fig. 9A ); genital valves form an inverted Y; epigynal and medial apodemes well-developed. Diameter of genital papillae approximately 0.4 the length of genital setae. Anal opening terminal ( Fig. 9D ). Copulatory tube small. Inseminatory canal (ic) of spermatheca long, slender tube-like, uniformly wide.Atrium (hs) ( Figs 8E , 9E ) of spermatheca present, short, its length 1.4 times longer than its width, with thickened walls in the conical part at point of connection with inseminatory canal.Approximately half of atrium enveloped by spermathecal sac. Sac of spermatheca is not forming a short bottleneck with extended rims (flared bottleneck) around atrium ( Fig. 8E ). Paired sclerites of efferent ducts (ed) short, their lengths approximately 1/2 the length of spermathecal atrium, V-shaped, with short stem at base.

Legs short, all segments free. Trochanters I–III each with long, filiform seta, pR I–II, sR III; trochanter IV without setae. Femoral setation 1-1-0-1; setae vF I–II and wF IV long, filiform. Genual setation 2-2-0-0; setae mG and cG I–II long, filiform; seta nG III absent. Tibial setation 2-2-1-1; setae hT I-II absent; setae gT I–II and kT III–IV elongate, somewhat spiniform. Tarsal setation 10-10-10-10; pretarsi consist of hooked empodial claws attached to short paired condylophores. Tarsus I and II ( Figs 8A,B , 9F,G ) with setae ra, la, f and d filiform, e, u, v spiniform (v larger that u), p and q represented by small spines, s small spines (legs I) or flattened, button-shaped (legs II); setae wa present, spiniform. Tarsus III and IV ( Figs 8C,D , 9H,I ) with setae f, d, r, w filiform, e, s, u, v, p, q spiniform (u shorter than other ventral spines). Solenidion ω 1 on tarsus I cylindrical, with clavate apex, straight; solenidion ω 1 on tarsus II simple, cylindrical, with clavate apex, curved, the slightly longer than ω 1 on tarsus I. Solenidion ω 2 on tarsus I shorter than ω 1, cylindrical, with rounded apex, situated slightly distal to ω 1. Solenidion ω 3 on tarsus I cylindrical, with rounded tip, slightly shorter than ω 1 and slightly longer than ω 2. Famulus (ε) of tarsus I wide, short, with broadly rounded apex, widest at middle. Solenidia φ of tibiae I–III elongate, tapering, well extending beyond apices of respective tarsi with ambulacra; solenidion φ IV shorter, shorter than tarsus IV (with ambulacrum). Solenidia σ’ and σ’’ on genu I elongate, tapering, σ’ is longer than σ’’, slightly not reaching base of φ I. Solenidion σ on genu II more than 5–6 times longer than its width, with rounded tip. Solenidion σ of genu III absent.

Male and phoretic deutonymph unknown.

Remarks. The holotype of Th. athiasae was well-illustrated and described in Fain (1982). However, illustration in Fain (1982, fig. 58) show that tarsi I and II lack p and q, while s is spiniform. However, a closer inspection revealed the presence of well-developed, albeit small, p and q spines on tarsi I–II ( Figs 8A, B , 9F, G ). Spine s I is short and spiniform on tarsus I (as originally described), however, on tarsus II s is flattened and button-shaped ( Fig. 8B ).

Figures

FIGURE 8. Thyreophagus athiasae (Fain, 1982), female holotype: A—tarsus I, posterior view; B—tarsus II, anterior view; C—tarsus III, posterior view; D—tarsus IV, posterior view; E—spermatheca.

FIGURE 9. Thyreophagus athiasae (Fain, 1982), female holotype, phase-contrast images: A—ventral view; B—prodorsal shield; C—coxal area I–II, ventral view; D—posterior part of opisthosoma; E—spermatheca; F—tarsus I, posterior view; G— tarsus II, anterior view; H—tarsus III, posterior view; I—tarsus IV, posterior view.