A New Genus and Three New Species of the Mite Family Arctacaridae ( Parasitiformes , Mesostigmata ) from North America

A new genus Proarctacarus and three new species, P. canadensis (Rocky Mountains, Alberta, Canada), and P. johnstoni (Rocky Mountains, Idaho, Utah, USA), and P. oregonensis (Coast Ranges, Oregon, USA), are described and the diagnosis of the family Arctacaridae is refined. The majority of records of species of the genus Proarctacarus is associated with mountain coniferous forests. The regular arrangement of setae (transverse rows) and sigillae on the large soft opisthosoma suggests the presence of 10 abdominal segments (besides telson), including pregenital segment VII. The setae of this segment (2–3 pairs) are situated dorsolaterally at the border between podosoma and opisthosoma and are distinctly marked by the last row of podosomal setae (segment VI) and first complete row of opisthosomal setae associated with sigillae sg (genital segment VIII). The setae on pregenital segment VII are described in Mesostigmata for the first time. The taxonomic value of the character “presence/absence of ambulacrum I” and the taxonomic position of the cohort Arctacarina are discussed. Until recently, the family Arctacaridae has been represented by a single genus Arctacarus Evans including three species: A. rostratus Evans, 1955, A. beringianus Bregetova, 1977, and A. dzungaricus Bregetova, 1977. Few findings of these species were limited to tundra and mountain regions of Middle, Central, and northeastern Asia, Russian Far East (Bregetova, 1977a; McLean et al., 1978; Volonikhina, 1994), and also northern and western parts of North America (Evans, 1955; Behan, 1978; Danks, 1981; Thomas and McLean, 1988; Krantz, 1978; Johnston, 1982). A study of these rare mites is of interest in many aspects. The significant morphological originality and archaism of representatives of Arctacaridae, and their mosaic similarity to Zerconina, on the one hand, and to Parasitina and Dermanyssina, on the other, puts this family in the exclusive position in all the discussions concerning the phylogeny of the suborder Mesostigmata. This phenomenon is reflected in that the family Arctacaridae is placed in different superfamilies of various cohorts (Table 1), or ranked as a separate cohort (or suborder) pari passu Zerconina, Parasitina, and Dermanyssina (Johnston, 1982; Woolley, 1988; Evans, 1992; Norton et al., 1993). A new genus and 5 new species were revealed in the collection of Arctacaridae collected by acarologists _____________ 1 The existence of this genus was first mentioned by Johnston (1982). of different countries. An analysis of the type series of A. beringianus and A. dzungaricus and topotypes of A. rostratus, also of a new material made it possible to refine the diagnoses of the family Arctacaridae and the genus Arctacarus and to establish the synonymy of A. beringianus Bregetova, 1977 and A. rostratus Evans, 1955. The type species (and the only species known before 1977) of the family A. rostratus was described in 1955 from Arctic tundras of Alaska and after that was not mentioned for more than 20 years. Subsequent recordings from the northern parts of Asia and North America were also associated with tundra and foresttundra habitats of plain and mountain regions (Bregetova, 1977a; Behan, 1978; McLean et al., 1978; Thomas and McLean, 1988; Volonikhina, 1994; new data), whereas the distribution ranges of the rest six species of the genus, including undescribed ones, are, apparently, very limited and associated mainly with mountain coniferous forests. In the present communication, a new genus and three new species from Canada and USA are described. The nomenclature of the podosomal setae (Fig. 1, 1) is given according to Lindquist and Evans (1965) with _____________ 2 Publication with a rationale of the synonymy is in preparation. A NEW GENUS AND THREE NEW SPECIES ENTOMOLOGICAL REVIEW Vol. 83 No. 7 2003 869 Table 1. Taxonomic position of the family Arctacaridae among Mesostigmata (= Gamasida), according to different authors Taxon Evans, 1955 Evans and Till, 1979 Krantz, 1970, 1978; Krantz and Ainscough, 1990 Bregetova, 1977a Bregetova, 1977b Johnston, 1982; Woolley, 1988; Evans, 1992; Norton et al., 1993 Cohort (suborder) Epicriina Gamasina Gamasina Gamasina Gamasina Arctacarina Division (group) Epicriides Laelapina Superfamily Zerconoidea Parasitoidea Arctacaroidea