Neoribates striatissimus, Ermilov & Starý, 2017

Ermilov, Sergey G. & Starý, Josef, 2017, New Neoribates (Acari, Oribatida, Parakalummidae) from Vietnam, Zootaxa 4303 (1), pp. 51-72 : 58-59

Neoribates striatissimus sp. nov.

( Figs 14–27 )

Diagnosis. Body size: 514–531 × 332–348. Body surface striate. Rostral setae minute, lamellar and interlamellar setae long, setiform, barbed, le inserted on lamellar ends. Bothridial setae lanceolate, barbed. Ten pairs of notogastral setal alveoli. Epimeral setae thin, slightly barbed, 3с and 4c longest. Anogenital setae short, setiform, smooth, ad 3 inserted in preanal position. Legs tridactylous, lateral claws with one tooth ventrodistally.

Description. Measurements. Body length: 531 (holotype, female), 514–531 (four paratypes: two females and two males); notogaster width: 348 (holotype), 332–348 (paratypes). No clear differences between females and males in the body sizes.

Integument ( Figs 14–18 , 25–27 ). Body color brown. Body surface (including pteromorphs, genital and anal plates, subcapitular mentum and genae and legs) microfoveolate (distinctly visible under high magnification in dissected specimens, ×1000), diameter of foveolae up to 1. Also, prodorsum, notogaster, pteromorphs, ventral side, genital and anal plates and subcapitular mentum striate. Lateral parts (between bothridia and acetabula) microgranulate.

Prodorsum ( Figs 14–16 ). Rostrum broadly rounded. Lobe with projects, creating one inner rostral tooth. Rostrophragmata relatively thick. Lamellae located dorso-laterally, half as long as prodorsum (measured in lateral view), their ends curving anteromedially and directed to insertions of lamellar setae. Sublamellae are two thirds of the lamellae. Sublamellar porose areas oval (16–20 × 10–12), partially covered by sublamellae. Rostral setae minute (4–6), thin, smooth. Lamellar (110–114) and interlamellar (118–127) setae setiform, barbed. Exobothridial setae and their alveoli absent. Bothridial setae (86–94) with long stalks and short, barbed, lanceolate heads. Sejugal porose areas oval, transversely elongated. Anterior and posterior ridges simple, connected, forming T-shaped structure. Lateral ridges poorly visible.

Notogaster ( Figs 14 , 16–18 ). Anterior notogastral margin convex medially. Dorsophragmata comparatively short, longitudinally elongated. Ten pairs of notogastral setae represented by alveoli. Four pairs of sacculi with small openings. Setae lp inserted medially and close to S1. Lyrifissures and opisthonotal gland openings clearly visible.

Gnathosoma ( Figs 15 , 16 , 26 ). Generally, similar to Neoribates pseudojacoti sp. nov. Subcapitulum longer than wide (106–110 × 86–90). Subcapitular setae setiform, slightly barbed, m (20) longer than h (16) and a (12), a slightly thicker than others. Two pairs of adoral setae (12) setiform, heavily barbed. Palps (length 77–86) with setation 0–2–1–3–9(+ω). Postpalpal setae (6) spiniform, smooth. Chelicerae (length 114–123) with two barbed setae, cha (36) longer than chb (24). Trägårdh’s organs long, tapered.

Epimeral and lateral podosomal regions ( Figs 15–17 ). Epimeral setal formula: 3–1–3–3. Setae setiform, thin, slightly barbed, 3с and 4c (32–41) longer than other setae (12–16). Pedotecta I and II small, lamina-like, Pd II rectangular in ventral view, rounded anteriorly. Discidia triangular, broadly rounded distally. Circumpedal carinae long, reaching anterior margin of ventral plate.

Anogenital region ( Figs 15–18 , 27 ). Five pairs of genital (8–10), one pair of aggenital (10–12), two pairs of anal (10–12) and three pairs of adanal (10–12) setae setiform, thin, smooth. Setae ad 3 inserted in preanal position. Adanal lyrifissures located close and parallel to anal plates. Preanal organ slightly bifurcate distally, trapezoid in ventral view. Marginoventral porose area represented by numerous rounded or elongate oval parts.

Legs ( Figs 19–24). Generally, similar to Neoribates pseudojacoti sp. nov. Tridactylous, median claw thicker than laterals, all barbed dorsally. Lateral claws with one tooth ventrodistally. Dorsoparaxial porose areas on femora and trochanters III, IV, posteroventral porose areas on tarsi and anteroventral porose areas on tibiae well visible. Formulas of leg setation and solenidia: I (1–5–3–4–20) [1–2–2], II (1–5–3–4–15) [1–1–2], III (2–3–1–3–15) [1–1– 0], IV (1–2–2–4–12) [0–0–0]; homology of setae and solenidia indicated in Table 1. Solenidia ω1 on tarsi I, ω1 and ω2 on tarsi II and σ on genua II, III thickened, blunt, other solenidia longer, setiform. Famuli short, straight, dilated and truncated distally, inserted between ω2 and ft”. Thick setae on leg segments absent.

Material examined. Holotype (female): Northern Vietnam, Tam Dao National Park , 1200 m a.s.l., primary submontane foggy forest near TV-transmitter, on SE slope of Dinh Mang Chi Mt., leaf litter sample (No. VIE-189), 20.X.1988 (collected by J. Starý & Nguen Tri Tien) . Three paratypes (two females and one male): Northern Vietnam, Tam Dao National Park , 1080 m a.s.l., primary foggy forest between Dinh Thien Thi Mt. and Dính Mang Chi Mt., litter and soil sample (No. VIE-166), 18.X.1988 (collected by J. Starý & Nguen Tri Tien) . One paratype (one female): Northern Vietnam, Tam Dao National Park , 990 m a.s.l., secondary mixed dense bush near artificial pond, litter and soil sample (No. VIE-132), 17.X.1988 (collected by J. Starý & Nguen Tri Tien) .

Type deposition. The holotype is deposited in the collection of the Senckenberg Institute , Görlitz, Germany ; four paratypes are deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia .

Etymology. The specific name striatissimus refers to the striate body surface.

Remarks. Neoribates striatissimus sp. nov. is morphologically most similar to N. similis Fujikawa, 2007 from Japan in general traits (body of medium size; bothridial setae long, with well-developed lanceolate heads; lamellar and interlamellar setae long; adanal setae ad 3 inserted in preanal position). However, the new species differs from both by the presence of striate body surface (vs. without striate surface), minute rostral setae (vs. well-developed) and five pairs of genital setae (vs. four pairs).

Figures

FIGURE 14. Neoribates striatissimus sp. nov., adult: dorsal view. Scale bar 50 µm.

FIGURE 15. Neoribates striatissimus sp. nov., adult: ventral view (legs not shown). Scale bar 50 µm.

FIGURES 16 – 18. Neoribates striatissimus sp. nov., adult: 16 — anterior part of body, lateral view (legs not shown); 17 — posterior part of body, lateral view; 18 — posterior view. Scale bar 50 µm.

FIGURES 25 – 27. Neoribates striatissimus sp. nov., adult, microscope images: 25 — ornamentation on notogaster; 26 — ornamentation on subcapitular mentum (SM) and genae (SG); 27 — ornamentation on anal plates (AP) and in adanal region. Scale bar 20 µm.