Lasiobelba longisensilla, Ermilov, 2017

Ermilov, Sergey G., 2017, A new species of Lasiobelba (Acari, Oribatida, Oppiidae) from Vietnam, Ecologica Montenegrina 15, pp. 33-39 : 34-38

Lasiobelba longisensilla sp. nov.

( Figs 1–11 )

Diagnosis. Body size: 237–246 × 135–143. Body surface without sculpturing. Rostrum rounded. Interbothridial region with three pairs of muscle sigillae. Prodorsal setae well developed, setiform, slightly barbed; ro and in longer and thicker than le and ex. Bothridial setae very long, spindle-form, with well developed setiform apex, barbed. Nine pairs of notogastral setae (c absent) setiform, barbed; lm, lp longest, p 2, p 3 shortest. Subcapitular setae smooth, a shorter than m and h. Epimeral, aggenital, anal and adanal setae setiform, slightly barbed, genital setae thin, smooth. Discidia present. Leg trochanters III with one posterior tooth.

Description. Measurements. Body length: 246 (holotype), 237–246 (three paratypes); notogaster width: 135 (holotype), 135–143 (three paratypes).

Integument ( Figs 1 , 6 ). Body color light brown. Body surface microfoveolate (visible only under high magnification in dissected specimens, × 1000). Lateral parts of body between bothridia and leg acetabula I–III microgranulate (diameter of granules up to 1).

Prodorsum ( Figs 1 , 6 ). Rostrum rounded. Longitudinal rows comprising several muscle sigillae, present in front of the bothridia. Interbothridial region with three pairs of muscle sigillae. Interbothridial tubercles absent, postbothridial tubercles developed. Rostral (22–24), lamellar (16), interlamellar (24–26) and exobothridial (10–12) setae setiform, slightly barbed, inserted on small tubercles; ro and in thicker than le and ex. Bothridial setae very long (102–110), as long as length of prodorsum, spindle-form, with well developed setiform apex, barbed.

Notogaster ( Figs 1 , 5, 7 ). Anterior border convex medially. Nine pairs of notogastral setae setiform, barbed, lm, lp (49–53) longer than la, h 1 – h 3 (36–41), p 1 (16) and p 2, p 3 (10–12); setae c, even their alveoli absent. Setae lm inserted anteromedial to la. Notogastral lyrifissures (except ip not found) and opisthonotal gland openings well visible, im located anterior to h 3, gla lateral and close to h 3. Circumgastric scissure and circumgastric sigillar band distinct.

Gnathosoma ( Figs 2–4 ). Subcapitulum size: 61–65 × 45–49. Subcapitular setae setiform, smooth, a (12–14) shorter than m and h (18–20). Adoral setae (4–6) setiform, thin, smooth. Length of palps: 41–45. Palpal setal formula: 0–2–1–3–8(+1 solenidion). Solenidion of palptarsi short, bacilliform, connected to one distal seta. Postpalpal setae (2–4) spiniform, smooth. Length of chelicerae: 57–61. Chelicerae with antiaxial ridge and several dorsoparaxial teeth. Cheliceral setae setiform, cha (14–16) shortly ciliate, chb (10) barbed. Trägårdh’s organ of chelicerae elongate triangular.

Epimeral and lateral podosomal regions ( Figs 5–7 ). Sejugal apodeme with one pair of tubercles.

Epimeral setal formula: 3–1–3–3. Epimeral setae setiform, slightly barbed, 3c, 4c (22–24) longer than 1b, 3b, 4a (14–16) and 1a, 1c, 2a, 3a, 4b (10–12). Discidia triangularly pointed.

Anogenital region ( Figs 5, 7 ). Five pairs of genital setae (6–8) setiform, thin, smooth. Anterior pair of genital papillae smallest, posterior pair largest. One pair of aggenital (10–12), two pairs of anal (10–12) and three pairs of adanal (16–18) setae setiform, slightly barbed. Adanal setae ad 1 posterior, ad 2 lateral, ad 3 anterolateral to anal aperture. Adanal lyrifissures located close and parallel to anal plates.

Legs ( Figs 8–11 ). Claw of each leg smooth. Trochanters III with one posterior tooth. Formulas of leg setation and solenidia: I (1–5–2–4–20) [1–2–2], II (1–5–2–4–16) [1–1–2], III (2–3–1–3–15) [1–1–0], IV (1– 2–1–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1 . Setae p setiform on tarsi I, and very short, conical on tarsi II–IV. Famulus of tarsi I short, erect, slightly dilated distally, inserted posterior to solenidion ω 1.

Type deposition. The holotype (in ethanol with drop of glycerol) is deposited in SMNH . Three paratypes (in ethanol with drop of glycerol) are deposited in TSUMZ .

Etymology. The specific name “ longisensilla ” refers to the very long bothridial setae (sensilla).

Remarks. Lasiobelba longisensilla sp. nov. is morphologically most similar to Lasiobelba sculpta Wang, 1993 and L. yunnanensis Wen, 1999 known from Southern China in having very long, spindle-form bothridial setae with well developed setiform apex, and long dorsal notogastral setae. However, the new species differs from both species by the smaller body size (237–246 × 135–143 versus 685–699 × 439–472 in L. sculpta and 610–644 × 386–402 in L. yunnanensis ), notogaster without sculpturing (versus notogaster striate in L. sculpta and granulate in L. yunnanensis ), and lamellar setae shorter than rostral and interlamellar setae (versus lamellar setae not shorter than rostral and interlamellar setae in both L. sculpta and L. yunnanensis ).

Figures

Figure 1–4. Lasiobelba longisensilla sp. nov., adult: 1 – dorsal view (legs not illustrated); 2 –subcapitulum, ventral view; 3 – palp, right, paraxial view; 4 – chelicera, right, antiaxial view. Scale bars 45 μm (1), 17 μm (2–4).

Figure 5–7. Lasiobelba longisensilla sp. nov., adult: 5 – ventral view (gnathosoma and legs not illustrated); 6 – anterior part of body, lateral view (legs, gnathosoma not illustrated); 7 – posterior part of body, lateral view (legs not illustrated). Scale bar 45 μm.

Figures 8–11. Lasiobelba longisensilla sp. nov., adult: 8 – leg I, right, antiaxial view; 9 – trochanter, femur and genu of leg II, right, antiaxial view; 10 – trochanter, femur and genu of leg III, left, antiaxial view; 11 – leg IV, left, antiaxial view. Scale bar 17 μm.