Soricilichus Fain, 1970

Bochkov, Andre V., Mbalitini, Sylvestre G. & Verheyen, Erik, 2016, Review of the fur-mite genus Soricilichus Fain, 1970 (Acariformes: Chirodiscidae) — symbionts of the African shrews of the subfamily Crocidurinae (Soricomorpha: Soricidae), Zootaxa 4072 (2), pp. 235-253 : 236-240

Genus Soricilichus Fain, 1970

Soricilichus Fain, 1970: 300, 1971: 191 , 1981: 41; Bochkov 2010: 132. Type species: Soricilichus scutisorex Fain, 1970 by original designation.

Diagnosis. Both sexes: Idiosoma subcylindrical. Legs I and II with 4 segments (tibia and tarsus fused). Tarsi III with 1 enlarged spur-like seta (w). Ambulacral discs on tarsi IV with terminal projection. Male: setae e2, f2, ps1, ps2, g, and 4b absent. Setae ps3 represented by alveoli. Adanal suckers very small. Tarsi IV with 3 setae (w, r, d). Female: setae ps1, ps2, and 4b absent.

Description. BOTH SEXES. Palpal tibia and tarsus fused. Palpal setae dTi and l”Ti present, seta dTa absent. Palpal tarsus with 2 strongly reduced eupathidia, without apical membranes. Idiosoma subcylindrical, covered by transverse striae. Supracoxal setae absent. Propodonotal shield entire, without dorsal projections. Openings of opisthosomal glands (gl) distinct. Genital papillae indistinct. Apodemes IIIa–IIIa and IVa–IVa fused medially. Apodemes Ia–Ia and IIa–IIa fused in Y-shaped structures. Legs I and II with 4 segments: trochanter without setae, femur with seta vF only on leg II, genu with setae cG, mG, and solenidion σ1, fused tibia and tarsus bearing paired tarsal flaps and solenidia φ and ω1. Tarsal setae w III and w IV with longitudinally striated distinct spurs. Ambulacral discs of legs III and IV transversely striated ventrally.

MALE (Figs. 1–4, 10A, B, D). Idiosomal setation: si, c1, c3, d1, e1, ps3 —represented by alveoli or microsetae; c2 and d2 —short spurs, cp and h2 —distinctly or moderately long, filiform; se, h1, h3, 1a, 3a, and 4a — short filiform. Hysteronotal shield present. Adanal suckers present, weakly developed. Paranal sclerites present. Adanal sclerite unpaired, with or without large concavity (bursa). Opisthosomal lobes distinctly developed. Legs III about twice as long as shortened legs IV. Ambulacral disc of legs III without protrusion, ambulacral disc of legs IV with protrusion. Legs III, IV setation: III— sR, σ, kT, φ, w, r, s, f, e, d; IV— φ, w, r, d.

FUGURE 1. Soricilichus scutisorex Fain, 1970 , male. A—dorsal view; B—ventral view.

FEMALE ( Figs. 5–7 ). Idiosomal setation: si, c1, c3, d1, e1, h1, h3 —represented by alveoli or microsetae; c2, d2, ps3 —short spurs, cp —distinctly or moderately long, filiform; h2 —distinctly or moderately long, filiform or spur-like; se, 1a, 3a, 4a, g —short filiform. Epigynum fused with apodemes IIIa. Legs III and IV subequal. Ambulacral discs on legs III and IV with protrusion. Trochanters III with ventral longitudinal crest. Legs III, IV setation: III— sR, σ, kT, φ, w, r, s, f, e, d; IV— kT, φ, w, r, f, e, d. Ovoviviparous.

LARVA ( Fig. 8 ). Gnathosoma as in adults but its ventro-lateral borders attenuated apically. Idiosoma subcylindrical, 2–2.5 times longer than wide, covered by transverse striae, excluding posterior end of opisthosoma. Propodonotal shield present. Apodemes Ia–Ia and IIa–IIa fused as in adults in Y-shaped structures; apodemes IIIa fused to each other in arch-like structure. Coxal fields I and II striated. Idiosomal setation: si, se, c2, c3, cp, d2, h1, h2, 1a, and 3a. Setae h1 represented by alveoli. Openings of opisthosomal glands (gl) distinct. Anal opening situated ventrally. Legs I and II as in adults. Legs III moderately developed, with full set of articulated segments. Ambulacral discs of legs III striated ventrally, with protrusion. Leg III setation: σ, kT, φ, w, r, f, e, d. Seta w III as in adults.

FEMALE PROTONYMPH ( Fig. 9 A). Idiosoma about 2.5 times longer than wide. Coxal fields I smooth; coxal fields II and III almost completely reduced, their apodemes absent. Idiosomal setae c2, c3, cp, and d2 absent. Legs I shortened comparing to larva, their tarsal flaps narrow and long. Setae mG I and cG I represented by alveoli. Legs II reduced to small tubercles bearing very short solenidia ω 1 II and φ II. Legs III represented by small tubercles bearing very short apical projection (probable remnants of ambulacral stalk). First pair of genital papillae appears.

FEMALE TRITONYMPH ( Fig. 9 B, 10). Idiosoma 3–4 times longer than wide. Second pair of genital papillae added.

MALE PROTONYMPH AND TRITONYMPH. Unknown.

Species included. Soricilichus kivuensis Fain, 1981 , S. scutisorex Fain, 1970 , and S. sylvisorex sp. nov.

Distribution. Africa.

Hosts. African Crocidurinae ( Soricomorpha : Soricidae ) of the genera Crocidura , Scutisorex , and Sylvisorex .

Remarks. Larva hatches from egg in the female (ovoviviparity). Precapulatory male-guarding behavior was observed; males and female postembryonic immature stages (i.e. larva, proto- and tritonymph) are attached to each other in opposite directions by the posterior ends of the opisthosoma (Fig, 10A, B, D).

Figures

FIGURE 5. Soricilichus scutisorex Fain, 1970, female. A—latero-dorsal view; B—latero-ventral view.

FIGURE 6. Soricilichus scutisorex Fain, 1970, details of female. A—posterior end of opisthosoma in lateral view; B—leg III in ventral view; C—leg IV in ventral view.

FIGURE 7. Soricilichus scutisorex Fain, 1970, SEM photos of female. A—dorsal view; B—lateral view; C—posterior end of opisthosoma in frontal view; D—gnathosoma in dorsal view.

FIGURE 8. Soricilichus scutisorex Fain, 1970, larva. A—dorsal view; B—ventral view; C—leg I in ventral view; D—leg II in ventral view; E—tibia-tarsus III in ventral view. Scale bars: A, B = 50 µm; C—E = 25 µm.

FIGURE 9. Soricilichus scutisorex Fain, 1970, nymphs. A—protonymph in dorsal view; B—same in ventral view; Ctritonymph in ventral view. Scale bars: A, B = 50 µm; C = 25 µm.