Indoribates microsetosus, 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 : 53-57

Indoribates microsetosus n. sp.

( Figures 7 – 9 )

With characters of Indoribates (= Nixozetes Mahunka, 1977 ; = Sundazetes Hammer, 1979 ) as proposed by Jacot (1929), and summarized by Balogh and Balogh (1992) (see also Mahunka (1977) for Nixozetes and Hammer (1979) for Sundazetes ). The diagnostic characters of the genus Indoribates are: sensilli setiform; notogaster with 10 pairs of notogastral setae; four pairs of sacculi; lamellae well-developed, translamella absent or present; tutorium present; pteromorphae movable; dorsosejugal suture complete; five or four pairs of genital setae, one pair of aggenital setae; legs monodactylous or tridactylous.

Diagnosis

Indoribates microsetosus n. sp. is distinguished by the following combination of character states. Body size 431 – 481 x 215 – 249; surface of body punctate (visible under large magnification); rostrum rounded or slightly truncate; rostral, lamellar and interlamellar setae setiform, barbed; sensilli setiform, thickened, with 18 – 24 cilia on its outer margin; sublamellar areae porosae present; dorsosejugal suture slightly convex; ten pairs of very short, setiform, smooth notogastral setae; four pairs of small sacculi present; adanal setae ad 1, ad 2 barbed, considerably longer than smooth ad 3.

Description

Measurements — Body length 481 (holotype), 431 – 481 (mean 447, four paratypes); body width 249 (holotype), 215 – 249 (mean 236, four paratypes).

Integument — Body color light brown to brown. Surface of body punctate (visible only under large magnification). Epimeral region with muscle sigilla.

Prodorsum — ( Figure 7A ; Figure 8A–E ). Rostrum rounded or slightly truncate. Lamellae located dorsolaterally, longer than half of prodorsum. Rostral (41 – 45), lamellar (61 – 69) and interlamellar (77 – 86) setae setiform, barbed. Exobothridial setae minute (1 – 2). Sensilli (82 – 94) setiform, thickened, with 18 – 24 cilia on its outer margin. Lateral parts of prodorsum with short tutorium. Sublamellar lines well-developed. Sublamellar areae porosae present (Al, diameter 14 – 18). Sclerotized line between rostral setae and acetabulum I absent. Pedotecta I and II small.

Ermilov S. G. and Anichkin A. E.

Notogaster — ( Figure 7A ). Dorsosejugal suture slightly convex. Pteromorphae short, movable. Ten pairs of very short (4), setiform, smooth notogastral setae. Four pairs of small sacculi (Sa, S1, S2, S3) present. Opisthonotal gland opening and lyrifissures ia, im, ip, ih, ips developed in typical arrangement for genus. Discidia triangular.

Anogenital region — ( Figure 7B ; Figure 8F, G ). All setae setiform. Two pairs anal setae 20, slightly barbed. Adanal setae ad 1, ad 2 long (49 – 57), straight, barbed. Adanal setae ad 3 (8 – 10) and one pair aggenital setae (6) smooth. Five pairs of genital setae: anterior one pair 16, barbed, others shorter (8) and smooth. Lyrifissures iad in typical position for genus.

Epimeral region — ( Figure 7B ). Apodemes 1, 2, sejugal, 3 and circumpedal carina well-developed. Epimeral setal formula 3-1-3-3. Setae 1a, 1c, 2a short (10 – 12), setiform, smooth. Others setae longer (20 – 36), setiform, slightly barbed. Setae 3c and 4c visible in lateral view.

Gnathosoma — ( Figure 8H–J ). Subcapitulum longer than wide: 106 – 114 x 73 – 94. Hypostomal setae setiform, slightly barbed; h (32 – 36) longer than a (24 – 28) and m (8 – 12). Lateral lips with two pairs of adoral setae (28 – 32), setiform, with dense cilia. Palps (length 61 – 69) with setation 0-2- 1-3-9(+1ω). All setae (except some on tarsi) barbed.

Ermilov S. G. and Anichkin A. E.

Chelicerae (length 127 – 131) chelate-dentate; cheliceral setae setiform, barbed, cha (45 – 53) longer than chb (20).

Legs — ( Figure 9 ). 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, 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 (four specimens, males) were obtained from Cat Tien National Park in southern Vietnam, 11°25’ N, 107°25’ E, Cat Tien National Park, 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 " microsetosus " refers to the very short notogastral setae.

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

Remarks — Among known species of Indoribates microsetosus n. sp. is similar only to I. japonicus ( Aoki, 1988) from Japan, in having short, smooth notogastral setae and long adanal setae ad 1, ad 2. It differs from the latter in the following ways: smaller body (431 – 481, vs. 627 – 777 in I. japonicus ), notogastral setae very short (longer in I. japonicus ), adanal setae ad 1, ad 2 considerably longer than ad 3, 5: 1 (little longer, 2: 1.7 in I. japonicus ), and adanal setae ad 3 thin, smooth (thickened, barbed in I. japonicus ).

The new species differs from I. nobilis (see Golosova 1984), the only other species of Indoribates recorded from Vietnam, by having: lamellar and interlamellar setae with sparse, short barbs (with longer and dense barbs in I. nobilis ), sensilli without flagellate tips (with flagellate tips in I. nobilis ), notogastral setae short and smooth (longer and densely barbed in Indoribates nobilis ), anal and adanal (ad 1, ad 2) setae with sparse barbs (densely barbed in Indoribates nobilis ), aggenital and adanal (ad 3) setae smooth (densely barbed in I. nobilis ), five pairs of genital setae (four pairs in I. nobilis ).

Indoribates was proposed by Jacot (1929) with Protoribates punctulatus Sellnick, 1929 from Java as type species. Since then, two similar genera have been proposed that have been treated by some authors as synonyms of Indoribates . Mahunka (1977) proposed Nixozetes with N. javanus Mahunka, 1977 from Indonesia as type species, but did not compare its diagnostic characters with those of Indoribates . Hammer (1979) proposed Sundazetes with S. crispus Hammer, 1979 from Java as type species, but did not compare the genus with either Indoribates or Nixozetes . As obvious generic distinctions between them are absent, Mahunka (1987) suggested Sundazetes to be a junior synonym of Nixozetes and synonymy of their type species has been suggested ( Balogh and Balogh 2002; Subías 2004, online version 2010). Further, all species of Nixozetes were included in Indoribates by Balogh and Balogh (2002) (see also Subías, 2004, online version 2010). While none of these authors presented supporting discussion for these changes, we agree with them, due to the absence of obvious generic distinctions.

Figures

FIGURE 7: Indoribates microsetosus n. sp. A – dorsal view, legs removed; B – ventral view, legs, palps and setae of subcapitulum not shown. Scale bar (A + B) 100 µm.

FIGURE 8: Indoribates microsetosus 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, and adanal setae; H – subcapitulum; I – palp; J – chelicera. Scale bar (A) 100 µm, scale bars (G, H, J) 50 µm, scale bars (B + C + D, E, F, I) 20 µm.

FIGURE 9: Indoribates microsetosus n. sp. 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, left, antiaxial view. Scale bar (A + B + C + D) 50 µm.