Zootaxa 3620 (3): 483–499 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Article ZOOTAXA Copyright © 2013 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.3620.3.9 http://zoobank.org/urn:lsid:zoobank.org:pub:32043019-C5AA-44A3-875B-1C0059B6B575 A review of the ecology and distribution of Protoribates (Oribatida, Oripodoidea, Haplozetidae) in Alberta, Canada, with the description of a new species DAVID EVANS WALTER1,2 & SARAH LATONAS1 1Royal Alberta Museum 12845 102 Ave., Edmonton, AB, T5N OM6, Canada 2Corresponding author. E-mail: [email protected] Abstract The oribatid mite genus Protoribates Berlese (Haplozetidae) is reviewed for North America and the genus diagnosis is revised to account for the North American species, Protoribates robustior (Jacot, 1937) is redescribed and newly reported from western North America and a new species from Alberta is described. Protoribates haughlandae sp. n. is bisexual, heterotridactylous, and lives primarily in the peat soils of fens and bogs. Protoribates robustior is all-female, monodactylous, and occurs primarily in dry forests or in dry, treeless sites dominated by grasses, sedges, and shrubs. Both species feed on fungal hyphae and spores, but P. haughlandae also is an opportunistic predator and/or necrophage of small arthropods and P. robustior gut contents often include material that resembles plant cell walls. Examination of type specimens confirms that Protoribates prionotus (Woolley, 1968) is a junior synonym of the widespread Protoribates lophotrichus (Berlese, 1904). A key to differentiate Lagenobates from Protoribates and to identify the 7 species of the latter that are known or reported from North America is provided. Key words: Xylobates, Transoribates, Lagenobates, fen, bog, peat soils Introduction Until recently, Protoribates Berlese, 1908, has been a poorly known and taxonomically confusing genus variously treated as a member of the Haplozetidae or as the type genus of Protoribatidae. Weigmann et al. (1993) redescribed the type species (Oribates dentatus Berlese, 1883) and convincingly demonstrated that Xylobates Jacot, 1929, was a junior subjective synonym of Protoribates, as hypothesized by Grandjean in 1936. Miko et al. (1994), Weigmann and Miko (2002), and Weigmann and Monson (2004) further clarified generic concepts in the Haplozetidae for European species. However, many problematic taxa still exist, especially for species described under Xylobates. The purpose of this paper is to review the ecology, distribution, and systematics of Protoribates in North America and describe a new species from Alberta. The Province of Alberta, Canada, covers about 661,000 km2 and stretches approximately 1,223 km from the Northwest Territories south to the state of Montana in the USA (49–60 N latitude) and 660 km from the Canadian province of Saskatchewan in the east (110th meridian) to the crest of the Rocky Mountains on the Alberta-British Columbia border (~120th meridian) in the west. The climate is continental in the south to subarctic in the north. Mixed grasslands cover south eastern Alberta, grading into aspen parkland in central Alberta and the foothills of the Rocky Mountains. Much of the northern two-thirds of the Province is covered by boreal forest (taiga), peatlands, and wetlands. About 330 species of oribatid mites are currently known to occur in Alberta (Walter et al. 2012). For the last five years (2007–2011), adult Oribatida have been used by the Alberta Biodiversity Monitoring Institute (2012) in their Province-wide assessment of the state of biological diversity. In total, 579 sites in Alberta have been sampled for oribatid mites. This survey presents a unique opportunity to assess the ecological and biogeographical distribution of oribatid mites within the Province. Accepted by H. Schatz: 10 Jan. 2013; published: 7 Mar. 2013 483 Material and methods Morphological terminology follows F. Grandjean as summarized by Norton & Behan-Pelletier (2009). This includes notation for prodorsal setae as follows [abbreviation (seta)]: ro (rostral), le (lamellar), in (interlamellar), ex (exobothridial), bo (bothridial seta or sensillus), and the unideficiency nomenclature for notogastral setae. Needle-like setae without obvious ornamentation are referred to as simple, those with small triangular spicules as barbed. Leg setation is presented as the number of setae (including the famulus on tarsus I) with solenidial counts in parentheses for each leg in the order: trochanter-femur-genu-tibia-tarsus. Dactyly is reported separately. Setae on the legs and palps are designated prime (e.g. a’) when on the anterior face of the segment (assuming the leg is perpendicular to the body) and double prime (e.g. a’’) when on the posterior face or by convention for setal pairs on the midline (e.g. ft’’, ft’). Epimeral setation is in sequence for fields I-II-III-IV. Lengths and widths are given as ranges in µm or as approximations for difficult measurements. Body length was measured along the midline from tip of rostrum to posterior edge of notogaster and body width at the greatest width of the hysterosoma (just posterior to the pteromorph) on specimens in cavity slides, except when noted. Summary statistics such as means and standard errors are avoided because when based on small sample sizes they give a misleading impression of precision and are difficult to interpret. Collections with Alberta Biodiversity Monitoring Institute (ABMI) site numbers were obtained by field crews (often helicoptered to locations in Alberta with no road access) and are reported as digital GPS coordinates to within a 5.5 km radius of the site. Additional site and habitat data are available at the ABMI website (ABMI 2012). All ABMI collections are from organic soil layers (four 500 ml bulked cores per site) and were extracted into ethanol using Tullgren-modified Berlese funnels (Krantz & Walter 2009). The Moose Pasture Reference Site (MPRS) and some other collections are from a variety of litter, soil, and other organic substrates as noted. Slide-mounted specimens were cleared in lactic acid and mounted in a polyvinyl alcohol medium (Krantz and Walter 2009). Specimens for scanning electron microscopy were dried through absolute ethanol and acetone, mounted on Al-stubs with double sided sticky tape, and gold-coated in a Hummer sputter apparatus. SEMs of the new species are all from ABMI 910 SW (54.68661118, -115.556122) near Freeman Lake, 10 km W Swan Hills, 14.vi.2010; others are from the MPRS or as noted. Differential interference contrast images were obtained on a Leica DM 2500 microscope using a DFC 420 camera; images stacks were combined using the Combine ZP (2010) image stacking software when appropriate to achieve better depth of field. Abbreviations used ABMI Alberta Biodiversity Monitoring Institute http://www.abmi.ca/abmi/home/home.jsp. DEW D. E. Walter (author) CNC Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada. MPRS Moose Pasture Reference Site USNM National Museum of Natural History, Washington, DC, USA. PMAE.IZ Royal Alberta Museum, Invertebrate Zoology, 12845—102 Avenue, Edmonton, AB, T5N 0M6, Canada USA United States of America Systematics Genus Protoribates Berlese, 1908 Type species: Oribata dentata Berlese, 1883: 1. Diagnosis. Oripodoidea with pteromorphs subtriangular, hinged, movable, and associated with large muscle insertions on notogaster in region of Aa; discidium present as tectum, needle- to blade-like custodium usually present. Sensillus usually reclinate with sublanceolate head, rarely setiform or with erect club-like head. Lamella narrow; sublamella vestigial; prolamella absent; tutorium usually present as ridge; pedotecta I–II small, not visible 484 · Zootaxa 3620 (3) © 2013 Magnolia Press WALTER & LATONAS in dorsal view. Notogaster with octotaxic system composed of porose areas with distinct ring-like rims (in transmitted light), 10 pairs of short to vestigial notogastral setae. Epimeral setation 3-1-3-3; 5 pairs of genital setae; one pair of aggenital setae; 3 pairs of adanal setae. Chelicerae robust, chelate-dentate; palpal solenidion and eupathidium acm form double-horn on short to long apophysis. Tarsi usually monodactyl, less commonly heterotridactyl, rarely bidactyl. Remarks. The genus Protoribates has had a long and confusing history and finding derived characters supporting this genus is difficult. As Grandjean (1936, 1954) pointed out, the genera of Haplozetidae seem best separated from other Oripodoidea by the desclerotization of the base of the pteromorph (partial in some species) to form a hinge and the development of a tectum near the insertion of legs IV, the discidium, which usually has a well developed cusp or custodium. The hinged pteromorphs can be pulled against the legs by a cluster of enlarged muscles inserted on the notogaster in the region of porose area Aa. Although possibly shared with the Parakalummidae (and apparently convergent with Galumnoidea and some Ceratozetoidea), the movable pteromorphs serve to separate Haplozetidae from other Oripodoidea. The discidium, although again apparently convergent with some distantly related groups (e.g. Oribatellidae), provides another derived character to support the Haplozetidae. Both Haplozetes and Protoribates share these characters states along with several characters of less clear polarity, e.g. usually 5 pairs of genital setae and 10 pairs of notogastral setae in the adult. The genus Haplozetes