Galumna levisensilla, Ermilov, Sergey G. & Anichkin, Alexander E., 2010

Ermilov, Sergey G. & Anichkin, Alexander E., 2010, Three new species of Galumnidae (Acari: Oribatida) from Cat Tien National Park, southern Vietnam, Zootaxa 2681, pp. 20-34 : 25-27

Galumna levisensilla sp. nov.

( Figs. 23–41 )

Diagnosis. With character states of Galumna as summarized by Balogh and Balogh (1992). Distinguished from other species by combination of the following character states: body size 295–328 × 225–246; surface of body smooth; rostrum rounded in dorsoventral view; rostral and lamellar setae (20–24) setiform, slightly barbed; interlamellar setae absent (only alveoli present); sensilli (44–52) with well developed stalk (24–32) and oblong clavate head (20–24), smooth; dorsosejugal suture complete; four pairs of rounded or slightly oval notogastral areae porosae; oval postanal area porosa present.

Description. Measurements. Body length 295 (holotype), 295–328 (paratypes); body width 225 (holotype), 225–246 (paratypes).

Integument. Body color brown. Surface of body smooth.

Prodorsum ( Figs. 23, 25 , 28 ). Rostrum rounded in dorsal view. Lamellar and sublamellar lines well developed. Rostral and lamellar setae (20–24) setiform, slightly barbed, often pressed to surface of prodorsum. Interlamellar setae absent (only alveoli present). Sensilli (44–52) with well developed stalk (24– 32) and oblong clavate head (20–24), smooth. Exobothridial setae not observed. Pair of oval areae porosae Ad present posterior to interlamellar setae.

Notogaster ( Figs. 23, 26, 27 , 29–32 ). Dorsosejugal suture complete. Notogastral setae absent (represented only by 10 pairs of alveoli). Four pairs of rounded or slightly oval areae porosae developed dorsally: Aa 12– 16, A 1 8–14, A 2 8–12; A 3 12–16 × 8–12. Median pore present in all specimens (female and male).

Anogenital region ( Figs. 24 , 33–36 ). Two pairs of anal, three pairs of adanal, one pair of aggenital, six pairs of genital setae very small (2–4). Anterior part of genital plates with three setae (g 1, g 2, g 3). Ovipositor elongate, narrow (110 × 28). Length of lobes 49, length of cylindrical distal part 61. Setae smooth, ψ1 ≈ τ1 (28) longer than ψ2 ≈ τ a ≈ τ b ≈ τ c (16). Setae k short (4). Oval postanal area porosa (12–20 × 8–10) present.

Epimeral region ( Fig. 24 ). Only four pairs of setiform, thin epimeral setae (2–4; 3b 16) observed. Epimeral setal formula: 1–0–2–1.

Gnathosoma ( Figs. 37–39 ). Subcapitulum longer than wide: 77 × 69. Hypostomal setae h absent (only alveoli present); setae h (16) and m (4) and m (24) thin, smooth. Two pairs of short adoral setae (4–16). Palp (length 61) with setation 0–2–1–3–9(+1ω). All setae (except on tarsus) barbed. Chelicera (length 90) with few blunt teeth on fixed and movable digits. Cheliceral setae long, setiform, barbed: cha (32) longer, than chb (20).

Legs ( Figs. 40–41 ). Formulas of leg setation and solenidia: I (1–4–3–4–20) [1–2–2], II (1–4–3–4–15) [1– 1–2], III (1–2–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1. Most setae well barbed; some ventral setae of tarsi and tibiae with long cilia. Solenidia ω1 and ω2 on tarsi II, σ on genua III straight or weakly curved, rod-like. Other solenidia rather long, setiform, with thinner tips.

Material examined. Holotype, paratypes (four specimens). Specimens were obtained from: Asian region, southern Vietnam, 11º26'N, 107º26'E, Cat Tien National Park, 137 m above sea level, in sandy soil of dipterocarp forest, February – March 2009, collected by A.E. Anichkin.

Type deposition. The holotype is deposited in the collection of the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia; three paratypes are deposited in the collection of Siberian Zoological Museum, Novosibirsk, Russia; one paratype are in the personal collection of the first author.

Etymology. The name “ levisensilla ” refers to the smooth sensilli.

Distribution. At present, this species is only known from Cat Tien National Park of southern Vietnam.

Remarks. In having the combination of small body size, lacking interlamellar setae, smooth clavate sensilli with well developed and rounded head distally, complete dorsosejugal suture, four pairs of rounded or slightly oval notogastral areae porosae, and smooth body surface, this species is similar only to Galumna fijiensis Hammer, 1973 from Fiji Islands. It differs from the latter by having rostral and lamellar setae (absent in Galumna fijiensis ). Among species known from the Asian region, Galumna levisensilla sp. nov. is similar in some of these characters to G. flabellifera Hammer, 1958 , G. planiclava Hammer, 1973 and G. granalata Aoki, 1984 , from which it differs by totally lacking interlamellar setae (minute in the others). It also differs from G. flabellifera , G. p l a n i c l a v a in having smooth sensilli (barbed in the others) and from G. granalata by its smooth pteromorphae (with granules in G. granalata ).

Figures

FIGURES 23 – 27. Galumna levisensilla sp. nov.: 23 — dorsal view, 24 — ventral view, legs removed, 25 — dorso-lateral view of prodorsum, 26 — pteromorpha, 25 — caudal view. Scale bar (23 – 24, 27) 100 μm, scale bar (25 – 26) 50 μm.

FIGURES 28 – 36. Galumna levisensilla sp. nov.: 28 — sensillus, 29 — area porosa Aa, 30 — area porosa A 1, 31 — area porosa A 2, 32 — area porosa A 3, 33 — postanal area porosa, 34 — genital plate, left, 35 — anal plate, left, 36 — ovipositor. Scale bar 20 μm.

FIGURES 37 – 41. Galumna levisensilla sp. nov.: 37 — subcapitulum, 38 — palp, 39 — chelicera, 40 — leg I, without trochanter, right, antiaxial view, 41 — leg IV, right, antiaxial view; Ti, Ge – tibiae, genua, accordingly. Scale bar (37 – 39) 20 μm, scale bar (40 – 41) 50 μm.