Perxylobates crassisetosus, Ermilov & Anichkin, 2011

Ermilov, S. G. & Anichkin, A. E., 2011, THREE NEW SPECIES OF HAPLOZETIDAE (ACARI: ORIBATIDA) FROM VIETNAM Sergey G. E and Alexander E. A, Acarologia 51 (1), pp. 43-59 : 44-48

Perxylobates crassisetosus n. sp.

( Figures 1 – 3 )

With characters of Perxylobates as proposed by Hammer (1972), and summarized by Balogh and Balogh (1984, 1992). The diagnostic characters of the genus Perxylobates are: sensilli setiform; dorsosejugal suture absent; notogaster with 10 or 11 pairs of short notogastral setae; three or four pairs of areae porosae; lamellae well-developed, but mostly narrow, no true translamella is present; tutorium present; pteromorphae movable; five pairs of genital setae, one pair of aggenital setae; legs monodactylous.

Diagnosis

Perxylobates crassisetosus n. sp. is distinguished by the following combination of character states. Body size 381 – 448 x 166 – 215; surface of body punctate; rostrum rounded or slightly truncate; rostral and lamellar setae setiform, thickened, with rare cilia dorsally; interlamellar setae setiform, barbed, shorter than rostral and lamellar setae; sensilli setiform, thickened, with 25 –30 cilia on outer margin; ten pairs of short, setiform, straight, smooth notogastral setae; epimeral and anogenital setae setiform, smooth (only one pair of genital setae g 1 barbed).

Description

Measurements — Body length 381 (holotype), 381 – 448 (mean 410, 12 paratypes); body width 166 (holotype), 166 – 215 (mean 190, 12 paratypes). Males slightly smaller than females: body length of males (holotype and seven paratypes) 381 – 415 (mean 396), body width of males 166 – 199 (mean 178); body length of females (five paratypes) 415 – 448 (mean 428), body width of females (five paratypes) 199 – 215 (mean 205).

Integument — Body color light brown to brown. Surface of body punctate.

Prodorsum — ( Figure 1A ; Figure 2A–E ). Rostrum rounded or slightly truncate. Lamellae located dorsolaterally, slightly longer than half of prodorsum. Rostral (ro, 57 – 69) and lamellar (le, 73 – 82) setae setiform, thickened, with rare cilia dorsally; ro inserted on small tubercles. Interlamellar setae (in, 41 – 53) setiform, barbed. Exobothridial setae (ex) short (4), thin, smooth. Sensilli (ss, 90 – 102) setiform, thickened, with 25 – 30 cilia on outer margin. Prodorsum laterally with short tutorium. Sublamellar lines slightly developed. Sublamellar areae porosae absent. Raised line runs between setae ro and acetabulum I (visible in lateral view). Pedotecta I and II small.

Notogaster — ( Figure 1A ). Pteromorphae short, movable, with small concavity in anterior margin. Ten pairs of short (12 – 20), setiform, straight, smooth notogastral setae. Three pairs of circular areae porosae: Aa 10 – 12, A1 6 – 8, A2 4 – 6.

Acarologia 51(1): 43–59 (2011)

Opisthonotal gland opening (gla) and lyrifissures ia, im, ip, ih, ips developed in typical arrangement for genus. Discidia triangular.

Anogenital region — ( Figure 1B ; Figure 2F–H ). Two pairs anal (an 1, an 2, 16 – 20), three pairs adanal (ad 1 – ad 2, 16 – 20) and one pair aggenital (ag, 8 – 12) setae setiform, smooth. Five pairs of genital setae: g 1 (10) setiform, barbed, others shorter and smooth (g 2 – g 5 4 – 6). Lyrifissures iad in typical position for genus. Ovipositor elongate, narrow (143 x 32); length of lobes 61, length of cylindrical distal part (bDp) 82. Lobes with 12 pairs thin, smooth setae: ψ 1 ≈ τ 1 (16) longer than ψ 2 ≈ τa ≈ τb ≈ τc (8 – 10). Coronal setae k absent.

Epimeral region — ( Figure 1B ). Apodemes 1, 2, sejugal, 3 and circumpedal carina well-developed. Epimeral setal formula 3-1-3-3. Setae differ little in length, short (10 – 12), setiform, thin, smooth. Setae 3c and 4c visible only in lateral view.

Gnathosoma — ( Figure 2I–K ). Subcapitulum longer than wide: 94 – 110 x 82 – 94. Hypostomal setae setiform, slightly barbed; a (16 – 20) longer than h (12 – 16) and m (8). Lateral lips with two pairs of adoral setae (12), setiform, straight, with dense cilia. Palps (length 65 – 73) with setation 0-2-1-3-9(+1ω). All setae (except some on tarsi) with cilia (ventral setae on femora and tibiae) or barbs (others). Chelicerae (length 102 – 114) chelate-dentate; cheliceral setae setiform, barbed, cha (41 – 45) longer than chb (16 – 20).

Legs — ( Figure 3 ). All legs with one simple claw. Formulae of leg setation and solenidia: I (1- 5-3-4-19) [1-2-2], II (1-5-3-4-15) [1-1-2], III (2-3-1-3- 15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1. Setae setiform, barbed (except p), some ventral setae of tarsi and tibiae with long spines. Famulus short, straight, slightly dilated distally, blunt-ended. Solenidia ω 1 on tarsi I, ω 1 and ω 2 on tarsi II, σ on genua III thickened, rod-shaped; other solenidia setiform.

Material examined — Holotype (male), paratypes (12 specimens: seven males and five females) were obtained from Cat Tien National Park in southern Vietnam, 11°25’ N, 107°25’ E, 149 m above sea level, in dark loamy soil of Lagerstroemia 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 ; all paratypes are deposited in the collection of the Siberian Zoological Museum , Novosibirsk, Russia .

Etymology — The specific name " crassisetosus " refers to the thickened rostral and lamellar setae.

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

Remarks — Perxylobatescrassisetosus n. sp. is similar to several other species in having thickened lamellar setae: P. paravermiseta Mahunka, 1976 from China, P. vermiseta ( Balogh and Mahunka, 1968) from Antilles, P. vietnamensis ( Jeleva and Vu, 1987) from Vietnam. However, it differs from these and all other species by the thickened rostral setae (thin in the other species). A new species also differs from P. paravermiseta by having rostral setae longer than interlamellar setae (shorter in P. paravermiseta ), short and straight notogastral setae (longer and curved in P. paravermiseta ), epimeral setae 1b and 1c short and smooth (long and barbed in P. paravermiseta ). It differs from P. vermiseta by having greater length (381 – 448 vs. 338 – 363 in P. vermiseta ), body surface not foveolate (foveolate in P. vermiseta ). It differs from P. vietnamensis by the lamellar setae inserted in normal position (very close to each other in P. vietnamensis ), body surface not foveolate (foveolate in P. vietnamensis ).

Figures

FIGURE 1: Perxylobates crassisetosus n. sp. A – dorsal view, legs not shown; B – ventral view, legs, palps and setae of subcapitulum not shown. Scale bar (A + B) 100 µm.

FIGURE 2: Perxylobates crassisetosus n. sp. A – lateral view of prodorsum, legs, gnathosoma and epimeral setae not shown; B – rostral setae; C – lamellar seta; D – interlamellar seta; E – sensillus; F – genital plate, right; G – anal plate, right; H – unextended, partially inverted ovipositor (within body); I – subcapitulum; J – palp; K – chelicera. Scale bars (A, G – I, K) 50 µm, scale bars (B + C + D, E, F, J) 20 µm.

FIGURE 3: Perxylobates crassisetosus n. sp. A – leg I, right, antiaxial view; B – leg II, left, antiaxial view; C – leg III, right, antiaxial view; D – leg IV, left, antiaxial view. Scale bar (A + B + C + D) 50 µm.