Oribatid mites (Acari: Oribatida) from the Sella massif (Dolomites, Trentino, Italy) with description of Trichoribates valeriae n. sp. (Ceratozetidae)

Results from collections of oribatid mites in the cushion plant belt of Sass Pordoi and Piz Boè in the Italian Dolomites (Prov. Trento) are presented. A total of 10 oribatid species belonging to seven families were found. Most have a wide general distribution, Anachipteria shtanchaevae is restricted to the Alps. Three species are frequently or mainly found in the montane to alpine zone (A. shtanchaevae, Camisia horrida, Oribatula interrupta). Remarkable findings are Camisia foveolata, hitherto only known from the boreal climate zone, which indicates a preglacial relict distribution, and Kunstidamaeus lengersdorfi as highest recorded altitude for this species. Trichoribates valeriae n. sp., found in large numbers on both mountains, is described and compared with other congeners, and its systematic position is discussed. This species is characterized by a lamellar structure with small ridges and widely separated cusps, rounded rostrum with nose-like protuberance, 10 pairs of medium long notogastral setae with short bristles, notogastral porose area A1 divided in two parts, porose areas present on all tibiae and tarsi. Additional morphological information on the presence of porose areas on tarsi of Trichoribates scilierensis Bayartogtokh and Schatz, 2008 is given.


Introduction
The Sella group is a massif in the Dolomites, Northern Italy. The highest elevation is Piz Boè (3152 m a.s.l., Fig. 1A) at the intersection of South Tyrol, Trentino, and Veneto (Prov. Belluno). The Sass Pordoi (2950 m a.s.l., Fig. 1B), a plateaushaped summit, is situated next to and west of Piz Boè. Both mountains are very popular touristic destinations, a funicular from the Pordoi Pass reaches the summit of Sass Pordoi. The isolated mountain ranges are fossil coral reefs of a Middle Triassic carbonate platform from the Raibl formation. It preserves fossils dating back to the Norian Middle Triassic subperiod during the Mesozoic Era (Reithofer 1928, Moroder 2008). Only small vegetation patches are scattered on karstic limestone.
During two excursions in 2017 soil and litter samples were taken on Sass Pordoi and the Piz Boè massif. A commented list of the found oribatid mite species is presented, and a species new to science is described. Results of sampling at the nearby Sella Pass on the edge of the Langkofel group (Gruppo di Sassolungo) are already published (Schatz 2017).

Materials and methods
Material examined Figure 1 The material was collected during two excursions of the author and Irene Schatz on Sass Pordoi (2932 -2940 m a.s.l.) and Piz Boè (2980 -3150 m a.s.l.). A total of 10 soil and litter samples (each ca. 10 x 10 cm, volume ca. 0,5 liter) were taken in vegetation patches within the cushion plant zone, keeping the environmental impact as low as possible. The samples were extracted for 12 days with moderate heating with light, preservation fluid was 75% ethanol. Morphological investigations were carried out in temporary slides in lactic acid. List

Species list
Family Brachychthoniidae Thor, 1934 Taxonomical notes -The three Liochthonius species found on Biz Boè are part of the "Lapponicusgroup" (Moritz 1976) with common features as doublepointed sensillus, small velum on relatively short dorsal setae, and within this group they are separated from other members in having setae c1 -c1 slightly more distant than d1 -d1. They were distinguished by following characters: • L. strenzkei: with small transverse crest anteriorly of setae le, notogastral setae f1, h1 on separate tubercles (not always easily visible).
• thick and continuous transversal line between the apophyses of setae le as in Hammer (1955) (vs. weak or interrupted in Colloff 1993and Seniczak 1991b).
• The asymmetrical number of genital setae as mentioned from Seniczak (1991b) could also be observed in some specimens of protonymphs, tritonymphs and adults.
This mosaic of differences of morphological characters in far distant populations do not justify the status of a separate species for the population in the Dolomites.
Remarks -Schweizer (1956) reported C. horrida frequently from the alpine zone in Switzerland up to 3109 m a.s.l. and considered it as a boreoalpine species. In South Tyrol it was already found in the Dolomites in the nearby Schlern/Sciliar massif at 2200-2560 m a.s.l. (Schatz 2008a), and in the NorthTyrolean Central Alps (Austria) in the alpine grassland up to 2650 m a.s.l. (Schatz 1979). Camisia horrida was also reported from higher altitudes of Central America (Costa Rica: Volcán Irazú, 3400 m, Volcán Chirripó, 3800 m; Panama: Volcán Barú, 3400-3475 m a.s.l., Schatz 2006).
Remarks -The specimens from Piz Boè correspond to the redescription by Miko and Mourek (2008) and are considered conspecific. The relatively short distal parts of spinae adnatae vary. Willmann (1932, fig. 4) drew spinae adnatae with long distal part, apex slightly bent anteriad ("lange, geschweifte Spitze"). In Weigmann (2006, fig. 100a) the spinae adnatae also show a long distal part which is curved outward and directed more than 100°posteriad. In specimens from Harz (Miko and Mourek 2008, fig. 1A) the spinae adnatae are similarly bent as in the figure of Weigmann, in specimens from Slovak Karst) Miko and Mourek (op. cit.), fig. 2A) the spinae adnatae show a short distal part and are bent laterad to different degrees.
General distribution -Central Europe, frequently in caves. New record for the Dolomites and Italy.
Family Tectocepheidae Grandjean, 1954 Tectocepheus sarekensis (Trägårdh, 1910) PérezÍñigo 1997: pp. 276f., fig. 110  Taxonomical and nomenclatorial notes -The specimens from the different samples on Sass Pordoi and Piz Boè show a mosaic of morphological characters between T. velatus and T. sarekensis. But they all are considered to be T. sarekensis based on characters given by Weigmann (2002Weigmann ( , 2006 and Laumann et al. (2007) in having mainly broad and rounded cusp tip (with some exceptions), longitudinal striae on the interlamellar field (all specimens), and 2 -4 pairs of notogastral depressions, the latter sometimes fainter (Table 1). The body length is slightly larger than in most other investigations (250 -390 vs. 302 -349 -Laumann et al. 2007, 312 -374 -PérezÍñigo 1997, 295 -362 -Weigmann 2002. The small granules of the specimen in TN 160 remind of T. alatus Berlese, 1913, but in that species the granules are larger, and small granules on the cerotegument can be found in other Tectocepheus species too. Weigmann (2002Weigmann ( , 2006, Subías (2004) and other authors list T. sarekensis as subspecies of T. velatus (Michael, 1880); I follow Laumann et al. (2007) in considering it a distinct species.

Figures 8 and 9
Measurements - Table 2. Integument -Cuticle pale yellowish in larva, darker greyishyellow in nymphs. Pygidial sclerite (PY ) micropunctate in all nymphal instars. Opisthonotal gland region dark brown. Dorsal part of gastronotum without wrinkles, laterally with small furrows, ventrally with some furrows leading from position of setae la and lm posteriad around anal plates in all immature instars, and around genital plates in nymphs.
Prodorsum -Rostrum broadly rounded. Prodorsal setae setiform with short bristles. Interlamellar setae longest in all instars. Bothridial seta (bo) with clubshaped head and short spines in all instars, size according to the size of the instar (Table 2).
Gastronotic region -Generally weakly sclerotized. Setae of series c without small sclerites in larva, setae of series c, ps2, ps3 on small sclerites in nymphs. Pygidial sclerite in larva indicated by lateral furrows posterior to seta c3. Nymphs with large pygidial sclerite bearing setae of l, d, h series and p1 (latter on edge of the sclerite), anterior region with c series and opisthonotal regions separated. Humeral organ (ho) absent in larva, in nymphs present as protruding papilliform cupule. Larva with 12 pairs of gastronotal setae (c, l, d, h series, seta h3 lateral to medial part of anal plates), nymphs with 15 pairs each (including p series), all setiform with short bristles, most setae of similar length except shorter h2, h3 in larva as well as h2 and p series shorter in nymphs. Lyrifissures expressed as small cupules, ia, im visible on dorsal side, others on ventral side. Lateral sclerite surrounding opisthonotal gland opening dark colored.

Type deposition
The holotype (adult male, TN163) and six paratypes (TN163), preserved in ethanol, are deposited in the collection of the Senckenberg Museum, Görlitz, Germany (SMNG). Additional material is deposited in the collection of the author which will finally also be placed in the Senckenberg Museum, Görlitz. Specimens are preserved in ethanol.
Etymology This species is named in honour of my friend and colleague Dr. Valerie M. BehanPelletier, who has extensively contributed to our knowledge of oribatid mites. She supported my work in many ways.
Remarks 1 • Systematic position. The broad tectum on the anterior margin of the notogaster of the new species and the small banded lamellar complex remind of Jugatala Ewing, 1913. The generic diagnosis of Jugatala (Ewing 1913) underlines the "broad shelflike expansion" (anterior notogastral tectum) as the main trait distinguishing Jugatala species from other genera "except some of the species of the genus Pelops C. L. Koch" (Ewing 1913, p. 131). Sellnick (1923) noted that this character also occurs in other genera as Punctoribates or Trichoribates, and, according to him, the genus Jugatala is generally very close to Trichoribates. A main difference between Trichoribates and Jugatala species is the shape of the pedotectum I which is concave dorsally in Jugatala, but convex in Trichoribates (BehanPelletier 2000, pers. comm.). In Jugatala angulata (C.L. Koch, 1839) the pedotectum I is straight to slightly concave dorsally (Bayartogtokh and Schatz 2008a, additional observations on own material).
The revised generic diagnosis of Trichoribates given by BehanPelletier and Ermilov (2019) lists a number of specific apomorphies for the genus which also pertain to T. valeriae n. sp. This concerns mainly: anterior of notogaster forming tectum, usually covering at least base of bothridium; pedotectum I convex dorsally; pteromorphs without unsclerotized band; octotaxic system with four pairs of porose areas: A1 is divided in two parts of different size; humeral porose areas Ad, Am, Ah, Al present; axillary saccule on mentum present; lateral horizontal folds present dorsal of acetabula I and II; femur III with 2 setae (seta l ′ absent); humeral organ absent in larva, present in nymphs; gastronotal region of nymphs with large pygidial sclerite; larva with 12 pairs of gastronotal setae, nymphs with 15 pairs, adult with ten pairs of notogastral setae (in adult setae c1, c3, da, dm, dp lost).
The new species is also morphologically similar to Trichoribates scilierensis Bayartogtokh and Schatz, 2008 in having a noselike protuberance on prodorsum, lamellar cusps relatively wide apart, bothridium without sharp projection, bothridial setae relatively small, anterior margin of notogaster arched anteriad, 10 pairs of notogastral setae, porose area Aa large, A1 divided in two parts. The species differ in lamellar structure (lamella and cusp wider, well developed teeth on cusp of T. scilierensis), shape of tutorium (part of T. scilierensis specimens with 4-5 small dentations at the dorsodistal end, others without teeth and broader end), epimeral setal formula (3-1-3-2 in T. scilierensis). Trichoribates scilierensis was described from the nearby Sciliar massif in the Italian Dolomites (Bayartogtokh and Schatz 2008a) and later found in further localities in the Italian and Austrian Alps (Fischer and Schatz 2013, Schatz 2018, mainly in alpine and high alpine altitudes. Among all Trichoribates species only T. rausensis Aoki, 1982 has a comparable small lamellar structure. This species differs from T. valeriae n. sp. primarily in having longer cusp with developed outer tooth, shorter notogastral setae, and undivided porose area A1. Trichoribates rausensis was described from mountainous areas in Japan (Aoki 1982) and was also found at the foot of Himalaya in West Bengal, India (Mondal and Kundu 1999).
3 • The fine muscle fibers on pleurophragmata are hitherto only reported in T. biarea (Fig. 3, Gjelstrup and Solhøy 1994) and commented by Beck et al. (2018, p. 161, fig. 17) ("A conspicuous Strahlenfigur [radiating pattern] exists inside behind the front of the notogaster, presumably consisting of fibrillar muscle attachments on apodemal arches"). By checking other species of Trichoribates from my collection I found these muscle fibers invisible or only very weakly visible (e.g. in T. scilierensis). 4 • The frontal view of the retracted male spermatopositor (Fig. 6C) resembles that of Damaeus onustus (Fig. 2 in Grandjean 1956). Only few studies on the male genital morphology of oribatid mites have been conducted (e.g. Alberti and Coons 1999, Grandjean 1955, Warren 1947, Woodring 1970, a comparison with other species was not possible in this context. The ovipositor (Fig. 6D) matches other oribatid species. Among the numerous specimens of this species I found only one female with an everted ovipositor, just releasing an egg. 5 • The presence of porose areas on tibiae and tarsi has not been studied in most Trichori bates species. Beside T. valeriae n. sp. only T. sidorchukae BehanPelletier and Ermilov, 2019 is known to have porose areas distoventrally on all tibiae. Porose areas on tarsi are also known from T. novus Sellnick, 1928, T. sidorchukae, T. striatus (BehanPelletier, 1986 (in these species proximoventrally on tarsi I -IV), and T. zingerlei Bayartogtokh and Schatz, 2008 (on tarsi II, III, see Bayartogtokh and Schatz, 2008b). As BehanPelletier and Ermilov (2019) stated these characters may be more widespread.
A reexamination of Trichoribates scilierensis Bayartogtokh and Schatz, 2008 (specimens from the Dolomites and different places in the Alps) revealed the presence of porose areas on tarsi I -IV, all small and roundish, posterior to seta v ′ on tarsus I, posterior on seta pv" on tarsi I -IV. In that species no porose areas exist on tibiae I -IV. 6 • Trichoribates valeriae n. sp. shares the absence of the humeral organ in the larva and its presence in nymphs with other Trichoribates species examined in this context (T. polaris Hammer, 1953, T. tepetlensis PalaciosVargas and Norton, 1985, T. ocotlicus PalaciosVargas and Norton, 1985, see BehanPelletier and Ermilov 2019. 7 • The setation of legs of immature Trichoribates valeriae n. sp. coincides with T. berlesei (Seniczak 1980, sub T. trimaculatus) and T. polaris (BehanPelletier 1985). Differences with Diapterobates brevidentatus, a wellstudied species regarding immatures (Bayartogtokh and Ermilov 2016), are in tibia II of protonymph (3(1), including l"), tibia I of deutonymph (4(2), including v"), tibia II of deutonymph (4(1), including v"). 8 • Trichoribates valeriae n. sp. is the most frequently recorded species on both mountains of this investigation. It was found in large numbers in Cerastium uniflorum cushions and in moist moss on the plateau of Sass Pordoi and the Piz Boè mountain up to the summit (3150 m a.s.l.). The latter site was chosen as type locality. 9 • Several Trichoribates species and other Ceratozetoidea were found in the high mountains of Europe, Asia, Central and South America or in the Arctic zone. Many seem to be restricted to the harsh environment with short vegetation periods and show adaptations such as cold hardiness (Schatz and Sømme 1981) and prolongation of life cycle (e.g. Schatz 1985, Grishina 1997).

Discussion
A total of ten oribatid species from seven families were found (Table 3). The samples were generally very poor in species, on Sass Pordoi four species were recorded, on Piz Boè nine species. The richest spot in species number was a vegetation patch at the foot of Piz Boè (TN 164, TN 165, 2980 m a.s.l.) with nine species, among them six species found only in this site (Anachipteria shtanchaevae, Camisia horrida, Kunstidamaeus lengersdorfi, Liochthonius lapponicus, L. sellnicki, Oribatula interrupta). Three species were recorded on both mountains (Trichoribates valeriae, Liochthonius strenzkei, Tectocepheus sarekensis), all in more than one sample and most in relatively high abundances. Camisia foveolata was only found in moss on Sass Pordoi.
The individual numbers were not estimated in all samples, especially not in the samples which were rich in individuals, but the results indicate an extreme aggregation of species and individuals wherever a suitable microhabitat exists. Especially the small section at the foot of Piz Boè with cushions of Saxifraga oppositifolia, Cerastium uniflorum, moist moss and a dry to moist underlying humus layer (samples TN 164, TN 165) shows a surprising diversity of species with high abundances. This reflects a new assessment of a possible minimum area for mesofaunal elements (Schatz and Schatz 1991).
The majority of the oribatid species from this study have a wide general distribution (holarctic or semicosmopolitan -7 spp.), one species is known from the Alps, Central, South, Southeast Europe (Anachipteria shtanchaevae), one species is hitherto only known from some sites in Central Europe (Kunstidamaeus lengersdorfi). Trichoribates valeriae is new to science, and until now its known distribution is restricted to the investigation area. Four species were also recorded at the nearby Sella Pass (Liochthonius lapponicus, L. strenzkei, Tectocepheus sarekensis, Oribatula interrupta, Schatz 2017). Three species are new records for the Dolomites and Italy (Camisia foveolata, Kunstidamaeus lengersdorfi; the newly discovered Trichoribates valeriae enlarges the new records for Italy).
These data are snapshots of the investigated vegetation patches. Additional species might possibly occur in the area, but due to conservation considerations only few samples were taken in the scattered vegetation. Despite the small yield, the species spectrum gives an interesting insight into the faunal distribution of high summits. Beside some ubiquitous species three species are frequently or mainly found in the montane to alpine zone (Camisia horrida, Anachipteria shtanchaevae, Oribatula interrupta). Trichoribates valeriae might be added to this "alpine" species group.
Camisia foveolata was hitherto only known from the boreal climate zone in the Northern Holarctic (Subías 2004) and from the Chilean Andean highlands (Covarrubias 2004). The  Thor, 1934-cf. Fischer et al. 2016, Mycobates sarekensis (Trägårdh, 1910) -cf. Schatz 2020). These species are considered as preglacial relicts with a wider geographical extension previous to the last glaciation. They survived in certain habitats and retreats such as unglaciated alpine summits (nunataks), in subterranean niches, or in icefree massifs de refuge along the margins of the Alps, with special adaptations to the extreme conditions in life cycle and development of coldhardiness (Schatz 2008a, b, Fischer et al. 2016. A corresponding explanation is assumed for high alpine endemic species which could have evolved in recent isolation (e.g. Trichoribates valeriae -present study, Kunstidamaeus granulatus (Willmann, 1951), Mycobates alpinus (Willmann, 1951), Oppiella obscura (Mahunka and MahunkaPapp, 2000), Trichoribates scilierensis Schatz, 2008, T. zingerlei Bayartogtokh andSchatz, 2008). Another remarkable finding is Kunstidamaeus lengersdorfi which marks the highest recorded altitude for this species. Kunstidamaeus lengersdorfi is known to be troglobiontic or troglophilic (Miko and Mourek 2008), most records were reported from caves or cave entrances in different parts of Central Europe (Austria, Belgium, Czechia, Germany, Hungary, Slovakia). The Piz Boè massif is a carbonate platform with many smaller and larger synclines, sinkholes, overhangs, and caves. The locality of K. lengersdorfi is situated on a small flat and plant covered section beside an overhanging rock with temporary trickle joining the rank of similar known habitats of that species.