Trichoribates monticola

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 : 9-13

Trichoribates monticola ( Trägårdh, 1902)

(Figs. 4 – 6)

Notaspis monticola Trägårdh 1902, p. 17, fig. 234.

Trichoribates monticola : Schweizer 1956, p. 329, fig. 289; Shaldybina 1975, p. 292, fig. 704; Pavlitshenko 1994, p. 30, fig. 20.

Murcia monticola : Subías 2004, p. 177; 2008, p. 332.

Diagnosis. Rostrum rounded in dorsal view, without lateral dens, but with a strong nose-like protuberance dorsally; rostral, lamellar and interlamellar setae finely barbed; lamella wide, with long and wide translamella; lamellar cusp broad, broader than basal part of lamella, without lateral or medial dens; lamellar seta curved inward distally; sensillus short, with smooth, club-shaped head; tutorium broad, its dorso-distal end with subterminal shallow concavity, cusp short; 10 pairs of notogastral setae, dp absent, all short, thin, smooth; lenticulus absent; porose areas round to oval; all ventral setae short, smooth; genu I without ventro-distal projection.

Measurements. (n = 6) Body length 384-532 (487) µm; length of notogaster 343-441 (409) µm; width of notogaster 293-372 (351) µm.

Integument. Body colour yellowish brown. Surface of body and leg segments with thick cerotegument, roughened by small granules. Faintly microtuberculate on cuticle of prodorsum, notogaster, ventral plate, leg segments and subcapitular mentum. Microtubercles forming longitudinal Striae on anterior part of pteromorphs.

Prodorsum (Figs. 4A, C-F, 5A). Rostrum rounded in dorsal view, without lateral dens, but with a streng nose-like protuberance dorsally. Rostral seta finely barbed, inserted laterally, underneath of distal end of tutorium, 68-95 µm in length and extending beyond tip of rostrum, directed mediad. Lamella wide, with longitudinal striations, 103-118 µm in length, almost parallel to each other, connected by moderately long and wide translamella, latter nearly straight or very slightly arched anteriorly. Lamellar cusp long and broad, broader than basal part of lamella, without lateral or medial dens, blunt, rounded, base of insertion of lamellar seta sometimes slightly concave (Figs. 4A, D, 5A). Lamellar seta 70-92 µm in length, minutely barbed, distally curved mediad. Interlamellar seta 129-161 µm in length, finely barbed, insertions concealed under anterior margin of notogaster. Sensillus short, exposed portion 38-47 µm in length, with roughened, club-shaped head (Figs. 4A, E, 5A). Bothridium relatively small, irregular funnel-shaped, with a small bothridial scale svm, completely covered by notogaster. Tutorium broad, 86-152 µm in length, its dorso-distal end with subterminal shallow concavity; cusp short, without teeth on distal end (Fig. 4C, F).

Notogaster (Figs. 4A, C, G, 6A). Oval, about 1.2 x longer than wide. Anterior margin of notogaster arched anteriad, lenticulus absent. Pteromorph curved ventrally, anterior portion protruding markedly with rounded margin. Ten pairs of notogastral setae present, dp absent, all setae short (11-15 µm), thin, smooth; seta c slightly longer (length 15-20 µm) than other setae. Porose areas round to oval in shape, Aa largest, others subequal in size. In some specimens Aa divided in two parts, medial area much smaller, sometimes small area appearing only on one side (Fig. 4G). Lyrifissure im clearly visible in dorsal view, ia, ih and ips visible in lateral view, while ip only visible in posterior view. Opisthosomal gland opening located posterior to lyrifissure im.

Gnathosoma (Figs. 4B, 5B). Subcapitular mentum conspicuously wider than long. Hypostomal setae a, h and m short, smooth, attenuated, length of h 7-8 µm, m, a 10-12 µm. Palp and chelicera typical for family as in the previous species; chelicera with strongly sclerotized blunt teeth; setae cha and chb smooth, length 35- 40 µm.

Epimeral region (Figs. 4B, 5B). Epimeral setae short, thin, smooth; setal formula: 3-1-3-3. Custodium almost reaching anterior margin of pedotectum II; discidium conspicuously projecting laterally.

Ano-genital region (Figs. 4B, 5C, D, 6A). Anal aperture larger than genital one, both anal and genital plates smooth. Genito-anal setae short, thin, smooth (length 10-13 µm); setal formula same as in the previous species. Distance between bases of aggenital setae nearly equal to that between setae ad3-ad3. Seta ad3 situated in paranal position. Adanal lyrifissure iad short, situated at same level as setae an2, adjacent and parallel to anterolateral margin of anal aperture. Postanal porose area narrowly elongate, longer than distance between bases of adanal setae ad1 (Fig. 6A).

Legs (Fig. 6B-G). Lateral claws thinner than medial claw. Tibia I with a relatively small, but distinct anterodorsal apophysis, bearing solenidion phi2. Genu I without ventro-distal projection; femora III, IV and trochanter IV with distinct ventral keels or blades, distally rounded. Femora I-IV and trochanters III and IV with large porose areas. Most leg setae distinctly barbed, except (p), (u) and (it) on tarsi I-IV, and ny on trochanter and femur IV. Setae l ” on tibiae I, II, IV and genua I, II very thick, much thicker than other setae. 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).

Material examined. Italy, Provincia di Bolzano, Schlern/Sciliar massif, alpine meadow below rock face (46°30,67'N, 11°35,31'E, 2220 m a.s.l., 04 August 2007: 2 females, leg. Irene Schatz), ibid. , subalpine dwarf-shrubs (46°30,71' N, 11°35,34' E, 2170 m a.s.l., 01 July 2007: 2 females, 2 males, leg. H. Schatz), ibid., summit of Mount Petz (46°20,76' N, 11°34,60' E, 2550 m a.s.l., 01 July 2007: 5 specimens, leg. H. Schatz) .

Remarks. The main characters of our material correspond well with the keys and the figures given in Schweizer (1956), Shaldybina (1975) and Pavlitshenko (1994). In the literature mentioned, only figures of the dorsal view and short descriptions are available, hence the redescription.

Irk (1939) described T. montanus from high mountains of the Central Alps in Tyrol (recorded in the Oetztal and Stubai Alps, 2100-3050 m a.s.l., but also near Umhausen at 1036 m a.s.l.). Subsequently, Franz (1943) and Willmann (1951) recorded this species firom the High Tauern Mountains near the Grossglockner at 2400- 2700 m a.s.l. in high alpine conditions. Later, Niedbała and Olszanowski (1997) reported this species in the checklist of oribatid mites of Poland (without locality data).

According to the figure and description given by Irk (1939), T. montanus is very similar to T. monticola . Moreover, Willmann (1951) and Schweizer (1956) noted that T. montanus has similar characters to T. monticola . Recently, Subías (2004, 2008) considered the former species as a junior synonym of T. monticola . Examination of type material is necessary to clarify this synonymy. However, the type material of T. monticola could not be traced.

It should be mentioned that Janetschek (1957) recorded T. montanus from the Langkofel/Sasso Lungo mountain in the Dolomites, which is close to the Schlern/Sciliar mountains where T. monticola was found. This also indicates a possible synonymy of T. montanus with T. monticola . According to the present knowledge of their distribution, both T. monticola and T. montanus occur in the Alps, mainly in the higher altitudes and seems to have survived the last glaciation on nunataks, but spread into lower habitats during the post-glaciation period (Janetschek 1957).

Distribution. Trichoribates monticola is known from Swedish Lapland (Sarek mountains, original description, Trägärdh 1902), Iceland (several records, listed in Gjelstrup & Solhøy 1994), European Russia (near Pskov: Krivolutsky et al. 1995), Bohemia and Moravia of Czech Republic ( Krkonoše and Hrubý Jeseník mountains, several other records, Franz 1954; Starý 2000a, 2000b), Swiss Alps (Grisons 1780-2950 m a.s.l., Schweizer 1956), Southern Alps (present study), Bulgaria (Balkan, Rila range, 2925 m a.s.l., Csiszár & Jeleva 1962). Shaldybina (1975) and Pavlitshenko (1994) mention a record of this species from the Carpathian mountains in Ukraine, but this record is doubtful and could not be confirmed. Thus, all these records indicate an arctoalpine distribution of T. monticola .