Papillacarus hirsutus (Aoki, 1961)

Ermilov, S. G., Shimano, S. & Vu, Q. M., 2011, Redescription Of Papillacarus Hirsutus With Remarks On Taxonomic Status Of Papillacarus Arboriseta (Acari: Oribatida: Lohmanniidae), Acarologia 51 (2), pp. 155-163 : 156-161

Redescription of Papillacarus hirsutus

( Figures 1–4 )

Diagnosis

Body size 336 – 360 by 143 – 155; surface of body and legs with dense papillae; rostrum slightly rounded or truncate in dorsal view; rostral (ro), lamellar (le), interlamellar (in) and both pairs of exobothridial (exa, exp) setae branched; sensilli pectinate, with 13 or 14 branches in one side; two pairs of transverse bands well developed (S 3 and S 4), both interrupted medially; notogastral setae multiply branched; two pairs of anal (an 1, an 2) and four pairs of adanal (ad 1 – ad 4) setae setiform, with long cilia; genital plates with branched or heterogeneous (branched and setiform) setae; epimeral setal formula: 8(9)-4-3-4; four or five pairs of hypostomal setae; palps with setation 0-1-0-1-9(+1 ω); leg claws with strong thorn ventrally.

Measurements — Ten specimens from southern Vietnam: body length 336 – 348 (mean 344), body width 143 – 151 (mean 146). Three specimens from central Vietnam: body length 356 – 360 (mean 359), body width 147 – 155 (mean 151).

Integument — Body yellowish to light brown. Surface of body and legs with dense papillae; dorsal papillae rounded (diameter up to 2 µm), lateral papillae conical (length up to 6 µm) (Figures 8, 10).

Prodorsum — ( Figure 1A, C–E ). Roughly triangular in dorsal view, occupying about 1/3 of total body length. Rostrum slightly rounded or truncate in dorsal view, colorless ( Figure 1C ). Rostral (24 – 28), lamellar (20 – 24), interlamellar (20 – 24), anterior (20 – 24) and posterior (20 – 28) exobothridial setae similar in morphology, branched (central core of setae setiform, with long branches) ( Figure 1C–D ). Sensilli (49 – 57) pectinate, with 13 or 14 branches on one side and two or four short cilia on other side ( Figure 1E ).

Notogaster — ( Figure 1A ; Figure 2A–C ). Dorsosejugal suture straight. Two pairs of transverse bands well-developed (S 3 and S 4), both interrupted medially. Band S 2 always absent, but indistinct line rarely present. Only eight pairs of notogastral setae (c 1, c 2, c 3, d 1, d 2, d 3, e 1, e 2) well visible, other notogastral setae are difficult for differentiating between numerous neotrichial setae.

All setae similar in morphology, multiply branched, with short or sometimes very longer thinner tips (in lateral view) and stellate (in dorsal view) ( Figure 2A–C ). Lateral, caudal and ventrolateral setae (24 – 32) longer than dorsal setae (12 – 20).

Anogenital region — ( Figure 1B ; Figure 2D–F ). One pair of ventrolateral bands present. Two pairs of anal (20 – 24) and four pairs of adanal (24 – 28) setae setiform, with long cilia ( Figure 2F ). Genital setae (16 – 20) branched, but four specimens (two from central Vietnam and two from southern Vietnam) with heterogeneous genital setae (seven pairs branched, three pairs setiform, longer, 20 – 24) (Figures 9–11) .

Epimeral region — ( Figure 1B ; Figure 3A–E ). Typical for genus. Epimeres I and II neotrichous, setal formula: 8(seldom 9)-4-3-4. Medial setae 1a, 2a, 3a, 4a and often setae 1d setiform, smooth, other setae branched or setiform, ciliate.

Gnathosoma — ( Figure 3F–H ). Subcapitulum longer than wide, 98 – 106 x 82 – 86. Hypostomal setae a 24 – 26, setiform, thickened, smooth; setae m 1, m 2 and m 3 slightly shorter, 20 – 24, setiform, with cilia; setae h 1 and h 2 (sometimes h 2 absent) shorter than m, 16 – 20, setiform, thickened, with cilia. Three pairs of adoral setae present: or 2 longest, 32 – 36, setiform, thickened, smooth, blunt-ended; or 3 shorter, 22 – 26, setiform, thickened in proximal part and thin tip, smooth; or 1 shortest, 16 – 20, wide, lobe-form. Palps 45 – 49, with setation 0-1-0-1- 9(+1 ω). Distal three setae fused basally. Solenidion long, thick. Chelicerae 123 – 135, chelate-dentate. Cheliceral setae chb long, 32 – 36, setiform, smooth; setae cha minute, thorn-like, thin.

Legs — ( Figure 4A–D ). All claws with strong thorn ventrally. Formulae of leg setation and solenidia: leg I (0-6-3-4-18) [2-1-2], leg II (0-6-3-4-13) [1- 1-2], leg III (2-4-2-3-12) [1-1-0], leg IV (2-3-2-3-12) [1-0-0]; homology of setae and solenidia indicated in Table 1. Most setae with long cilia. Setae it on tarsi II-IV short, thin. Famulus conical, small, thickened. Solenidia ω 1 on tarsi I, ω 1 and ω 2 on tarsi II, σ on tibiae III rod-like, thickened, blunt-ended. Other solenidia long, setiform, with thinner tips.

Figures

FIGURE 1: Papillacarus hirsutus, adult. A – dorsal view; B – ventral view, gnathosoma and legs removed; C – rostrum and rostral setae; D – interlamellar seta; E – sensillus. Scale bar (A + B) 100 µm, scale bar (C, D, E) 10 µm.

FIGURE 2: Papillacarus hirsutus, adult. A – neotrichial seta with short thinner tip and papillae of notogaster, lateral view; B – neotrichial seta with long thinner tip; C – neotrichial setae and papillae of notogaster, dorsal view; D – genital plate with branched setae, right; E – genital plate with heterogeneous (branched and setiform) setae, right; F – anoadanal plates, right. Scale bar (A + B + C) 10 µm, scale bar (D + E) 20 µm, scale bar (F) 50 µm.

FIGURE 3: Papillacarus hirsutus, adult. A – epimera 1 and 2, left; B – epimera 3 and 4, left; C – epimeral seta 3a; D – epimeral seta 3b; E – seta of epimera 1, near subcapitulum; F – subcapitulum; G – palp; H – chelicera. Scale bar (A, B, J) 20 µm, scale bar (C + D + E) 10 µm, scale bar (F, H) 50 µm.

FIGURE 4: Papillacarus hirsutus, adult. A – leg I, without trochanter, right, antiaxial view; B – leg II, without trochanter, right, antiaxial view; C – leg III, left, antiaxial view; D – leg IV, without trochanter, left, antiaxial view. Scale bar (A + B + C + D) 20 µm.