Belba heterosetosa, Bayartogtokh, Badamdorj, 2004

Bayartogtokh, Badamdorj, 2004, Oribatid mites of the genera Belba and Belbodamaeus (Acari: Oribatida: Damaeidae) from Eastern Mongolia, Zootaxa 476, pp. 1-11 : 2-6

Belba heterosetosa sp. nov.

( Figs. 1 & 2 )

Diagnosis. Medium in size, with typical characters of Belba . Propodolateral apophyses absent; prodorsal tubercle Ba well developed, tubercles Bp, Da and Dp absent; sensilli very thin, relatively short, slightly flagellate distally; notogastral setae thin, smooth, seta c1 long, other setae relatively short, about two to three times shorter than seta c1, seta h1 thick, distinctly thicker than other setae; ventral tubercles Va and Vp well developed, E2a and E2p absent, tubercle Sa elongate triangular, Sp small, rounded at tip; epimeral regions III and IV with three and four setae, respectively; apodeme apo.2 distinctly developed; tarsus I with 20, tarsus II with 17, tarsi III and IV with 15 and 13 setae, respectively; setae d on genua I–III and tibiae II–IV slightly shorter than their associated solenidia.

Measurements. Body length 478–547 (507) µm; length of notogaster 338–384 (366) µm; width of notogaster 331–314 (324) µm. In total five specimens were measured.

Integument. Body color reddish to yellowish brown. Surface of body and leg segments with thick granular cerotegument. Mostly without exuvial scalps, but only one paratype carrying exuvial scalps on the notogaster. Leg segments and lateral part of body with dense fungi micelles, but no adherent debris.

Prodorsum. Rostrum rounded in dorsal view, but distinctly projecting anteroventrally in lateral view. Rostral seta (ro) thin, medium in length, smooth. Lamellar seta (le) slightly longer than rostral seta, smooth. Interlamellar seta (in) nearly as long as lamellar seta, thin, smooth, directed posteriorly, slightly flagellate distally. Exobothridial seta (ex) thin, smooth, twice shorter than lamellar seta. Sensillus (ss) relatively short, thin, setiform along its length and flagellate distally. Bothridium irregular funnel­shaped, with large opening, directed posterolaterad. Prodorsal tubercle Ba well developed, situated posteromediad of bothridium. Tubercles Bp, Da, Dp and propodolateral apophysis P absent. A few microtubercles present on the prodorsum, and clustered between interlamellar setae and anteromediad of each bothridium ( Fig. 1 A & C).

Notogaster. Almost circular, slightly longer than wide, robust in lateral view. Setae c1 relatively long and thick, darkly pigmented, about twice to three times as long as other setae. Seta h1 short, but much thicker than other setae of h, p and l series, and darkly pigmented. Lyrifissures ia and im and opisthosomal gland opening (gla) conspicuously developed; lyrifissures ih, ip and ips not evident. Postero­ventral margin of notogaster with small notch on its median part ( Fig. 1 B & C).

Gnathosoma . Infracapitular mentum nearly as long as wide, without noticeable microtubercles. Hypostomal setae h and m of medium length, seta a short, all of them thin, smooth ( Fig. 1 B). Structure of chelicera and palp typical for genus as shown by Bayartogtokh (2000).

Epimeral region. Tectum of podocephalic fossa not projected. Apodeme apo.2 well developed. Ventrosejugal tubercles Va and Vp conspicuously developed; epimeral tubercles E2a and E2p absent. Parastigmatic tubercle Sa long, elongate triangular in shape and sharply projected laterally; tubercle Sp small, subtriangular. Tubercle Vp bearing epimeral seta 3b. Discidium (di) well developed, subtriangular. Epimeral setal formula 3­1­3­4, all setae medium long, thin and smooth ( Fig. 1 B).

Ano­genital region. Structure normal for genus; ano­genital setae medium long, smooth. Adanal lyrifissures (iad) situated obliquely, at a level a little anterior to anal setae an2 ( Fig. 1 B, D & E).

Legs. Trochanter of leg IV with relatively large porose area. Setae d on genua I–III and tibiae II–IV slightly shorter than their associated solenidia. Tarsus I with 20, tarsus II with 17, tarsi III and IV with 15 and 13 setae, respectively. Formula of leg setation (including famulus): I (1­7­4­4­20), II (1­6­4­5­17), III (2­4­3­4­15); IV (1­4­3­4­13); formula of solenidia: I (1­2­2); II (1­1­2); III (1­1­0); IV (0­1­0). Structure and setation of legs I–IV as shown in Fig. 2 .

Material examined. Holotype (male): Northern slope of the Mt. Shiliin Bogd, District Dariganga, Province Suhbaatar, steppe, soils under sweet­brier, 45°28’55’’N, 114°35’03’’E, elevation 1687m a.s.l., 02 June 2003; four paratypes (one female and three males): District Erdenetsagaan, Province Suhbaatar, mountain­steppe, soils 0–5 cm, 46°12’58”N, 116°21’57”E, 31 May 2003, Col. B. Bayartogtokh. The holotype and two paratypes (alcohol preserved) are deposited in the collection of the Department of Zoology, National University of Mongolia, Ulaanbaatar, Mongolia and two paratypes are in the collection of the Zoological Museum of the Moscow State University, Moscow, Russia.

Remarks. The new species, Belba heterosetosa sp. nov. can be readily distinguished form all other known species of Belba by the notogastral setae, which is of different types and sizes, the short, but distally flagellate sensilli, the presence of well­developed apodeme apo.2, and the complete absence of ventral tubercles E2a and E 2p. Among the known species of Belba , only B. meridionalis Bulanova­Zachvatkina , B. sculpta Mihelčič , and B. cornuta Wang & Norton resemble the new species in flagellate sensilli and interlamellar setae and the shape of notogaster. However, B. meridionalis described by Bulanova­Zachvatkina (1962) known from Turkmenistan is different from B. heterosetosa in the much longer notogastral and interlamellar setae, the different number of setae in femur I, and much larger body size.

The second species, B. sculpta described by Mihelčič (1957) and redescribed by Pérez­Iñigo (1970) from Spain is distinguishable from new species by the presence of postbothridial tubercle Bp, the much longer sensilli and interlamellar setae, the very long posterior notogastral setae p1, the long and flagellate anal and adanal setae, and the presence of epimeral tubercle E2a.

The Chinese species, B. cornuta described by Wang and Norton (1995) differs from the new species in the presence of well­developed postbothridial apophysis P, the willow leaf­shaped notogastral setae, the very long notogastral setae p1, and the absence of tubercle Ba.

In spite of the above species, the Mongolian species, B. prasadi Bayartogtokh has some resemblance with B. heterosetosa sp. nov., but it is easily distinguishable from the latter by the far longer sensilli and interlamellar setae, the much longer and flagellate notogastral setae of p series, and the presence of epimeral tubercle E2a.

Etymology. The specific epithet ” heterosetosa ” refers to the character of different size of notogastral setae.

Figures

FIGURE 1. Belba heterosetosa sp. nov. A: Dorsal view; B: Ventral view; C: Lateral view; D: Genital plate; E: Anal plate.

FIGURE 2. Belba heterosetosa sp. nov. A: Leg I (right, antiaxial); B: Leg II (right, antiaxial); C: Leg III (trochanter separately shown; right, antiaxial); D: Leg IV (trochanter separately shown; right, antiaxial).