Trichoribates trimaculatus

Bayartogtokh, B. & Schatz, H., 2008, Trichoribates and Jugatala (Acari: Oribatida: Ceratozetidae) from the Central and Southern Alps, with notes on their distribution, Zootaxa 1948, pp. 1-35 : 21-24

Trichoribates trimaculatus (C. L. Koch, 1836)

(Figs. 11, 12)

Murcia trimaculata C. L. Koch 1836, fasc. 3(21).

Oribates setosus C. L. Koch 1840, fasc. 29(30); Berlese 1889, fasc. 43(4); Oudemans 1896, p. 57.

Oribata notata Thorell 1871, p. 683.

Oribata setosa : sensu Michael 1884, p. 243, figs. 3-12; 1898, p. 17.

Sphaerozetes (Trichoribates) berlesei Jacot 1929, p. 422.

Notaspis trimaculatus : Oudemans 1900, p. 152.

Murcia trimaculata : Sellnick 1928, p. 11, figs. 1-5; Subías 2004, p. 177; 2008, p. 333.

Trichoribates trimaculatus : Willmann 1931, p. 169, fig. 272; Balogh 1943, p. 87, tab. 1; van der Hammen 1952, p. 99; Schweizer 1956, p. 324, fig. 279; Shaldybina 1960, p. 133; 1967, p. 206, fig. 1b, 6, 13; 1975, p. 293, fig. 709; Pérez- 1972, p. 287, fig. 31; 1980, p. 223; Marshall et al. 1987, p. 299; Pavlitshenko 1991, p. 76, fig. 1-2; 1994, p. 70, fig. 21; Bayartogtokh & Aoki 1998, p. 1, figs. 1 & 2; Aoki 2000, p. 3-31; Weigmann 2006, p. 388, fig. 208e.

Diagnosis. Rostrum rounded, mostly with a pair of small lateral dens; rostral, lamellar and interlamellar setae densely barbed; lamella wide, with broad translamella; lamellar cusp with strong lateral and small medial dens; sensillus short, with finely barbed, elongate oval or clavate head; tutorium broad, distally pointed; 11 pairs of notogastral setae long, barbed, dp present; porose areas round to oval; epimeral seta lc and adanal setae barbed, other ventral setae smooth.

Measurements. (n = 8) Body length 562-616 (588) µm; length of notogaster 464-509 (479) µm; width of notogaster 372-464 (404) µm.

Integument. Body colour deep reddish to dark brown. With thick cerotegument, roughened by minute granules. Faintly microtuberculate on cuticle of prodorsum, notogaster, ventral plate, leg segments and subcapitular mentum.

Prodorsum (Figs. 11A, F-K, 12D). Rostrum rounded, with a pair of minute lateral dens, and with a nose-like protuberance dorsally. Rostral and lamellar setae medium long, densely barbed, almost equal in length; seta ro conspicuously thicker than le. Interlamellar seta about 1.5 x longer than ro and le, barbed, not reaching tip of rostrum. Lamella wide, with longitudinal striations along lateral margin; translamella long and wide; lamellar cusp with strong lateral and small medial teeth (Fig. 11F-H). Sensillus medium long, with minutely barbed clavate or elongate oval head. Bothridium small, with pointed bothridial scale svm (12D). Tutorium broad, distally pointed, with oblique striations (11I-K).

Notogaster (Figs. 11A, 12A-C). Oval, about 1.2 - 1.3 x longer than wide. Anterior margin of notogaster arched anteriad, lenticulus well developed. Pteromorph large, curved ventrally, anterior portion not protruding anteriad. Eleven pairs of notogastral setae, dp present, all setae long, barbed. Porose areas oval to round, Aa largest, distinctly larger than other porose areas. Lyrifissures ia, im, ih, ips, ip and opisthosomal gland opening small.

Gnathosoma (Fig. 11B). Subcapitular mentum conspicuously wider than long, without microtubercles. Hypostomal setae a, h, m of medium length, thin, smooth.

Epimeral region (Fig. 11B). Most epimeral setae thin, smooth; setae lb and lc conspicuously longer and thicker than other setae, lc barbed, setal formula 3-1-3-3. Custodium short, not reaching anterior margin of pedotectum II; discidium conspicuously projected laterally.

Ano-genital region (Figs. 11C-E, 12C). Anal aperture larger than genital one, anal and genital plates smooth. All genital, aggenital and anal setae thin, smooth, adanal setae barbed; setal formula same as in the previous species. Some specimens show asymmetrical number and variable placement of genital setae (Fig. HD, E). Postanal porose area narrowly elongate, far longer than distance between bases of adanal setae ad2 (Fig. 12C).

Legs. Formula of leg setation (including famulus): I (1-5-3-4-20); II (1-5-3-4-15); III (2-2-1-3-15); IV (1-2-2-3-12); formula of solenidia: I (1-2-2); II (1-1-2); III (1-1-0); IV (0-1-0). Most leg setae distinctly barbed, except (p) and (u) on tarsi I-IV Setae l" on tibiae and genua I-IV very thick, heavily barbed.

Material examined. Austria, Tyrol, Stamser Eichenwald , leaf litter of Quercus robur and Aegopodium podagraria (690 m a.s.l., 06 March 1987: 11 females, 15 males, leg. Regine Ölz) ; East Tyrol, Kalser Dorfertal , in leaf litter under dwarf shrubs (Vaccinio-Rhododendro-Laricetum) (1770 m a.s.l., 17 July 1988: 1 female, leg. H. Schatz) ; Tyrol, Soelden - Obergurgl, Festkogel , in moss (3030 m a.s.l., 28 October 1995: 1 female, leg. Barbara Knoflach) ; Italy, South Tyrol, Tierser Tal, at Angelbach near Hanicker Schwaige/Malga Costa , in leaf litter (46°28,02'N, 11°36,54'E, 1875 m a.s.l., 24 June 2006: 1 male, 1 female, leg. Yvonne Kiss) ; Schlern/Sciliar massif, calcareous scree around summit Mount Petz , in moss (46°30,67'N, 11°34,49'E, 2550 m, 06 April 2006: 1 female, leg. H. Schatz) .

Remarks. Most character states of the examined specimens agree with those of the specimens studied by Shaldybina (1975), Pavlitshenko (1994), Bayartogtokh et al. (2002), Weigmann (2006). As also observed by Pavlitshenko (1991), the specimens studied by us show some variations in the shape and size of the lamellar cusps, in the shape of notogaster, porose areas and in the placement of notogastral setae.

This species is very similar to T. novus in many character states, but it differs firom the latter in a much shorter stalk of sensilli, the presence of distinctly developed medial dens of the lamellar cusps, and a smaller body size.

Distribution. Trichoribates trimaculatus is one of the most widely distributed species of Trichoribates in the Holarctic Region. In North America it was recorded in the USA and Canada (Marshall et al. 1987), in Europe it can be found almost everywhere (Schatz 1983; Bernini et al. 1995; Luxton 1996; Niemi et al. 1997; Subías & Gil-Martín 1997; Shtanchaeva 2001). In Asia this species is widely distributed in Siberia of Russia, Kyrgyzstan and Mongolia (Golosova et al. 1983; Karppinen et al. 1986; Bayartogtokh & Aoki 1998; Bayartogtokh 2007; Subías 2008).