A guide to Oribatid Identification for the ABMI: - Royal Alberta Museum

Almanac of Alberta Oribatida 2.3 13 January 2013Hypochthonioidea Berlese, 1910 (ITIS 733337)(Return to Key to Major Groups)Hypochthoniidae Berlese, 1910 (ITIS 733392)Comments: This is one of the three families of the Cohort Enarthronotides with species over 0.3mm in length that is known to occur in Alberta. Species of Hypochthonius are the largest ofthese mites and the only ones that are dorso-ventrally flattened and have a single transversenotogastral furrow.Back to Table of ContentsHypochthonius CL Koch, 1835 (ITIS 733583)Diagnostic characters: relatively large, dorso-ventrally flattened enarthronotes with a singledorsal notogastral scissure (Type S); setal row e reduced to alveoli; sensillus pectinate; c2-3shorter and finer than other notogastral setae; anarthric subcapitulum; pregenital organpresent, subtriangular, with bilobed terminus; monodactyl.Also Known As: none.Type species: Hypochthonius rufulus C.L. Koch, 1835World species: 4 identifiable species including the cosmopolitan H. rufulus, Holarctic H. luteusOudemans, 1917; H. elegans Hammer, 1979 from Java; and H. montanus Fujikawa,2003 from Japan.Etymology – Hypo (beneath) + chthonius (the soil)Comments: The genus is widely distributed in Alberta, but herein are the first reports of itsoccurrence. A related genus with divided genital plates, Eohypochthonius, is not knownfrom Canada.Canadian species listed on DOC (bold = AB): Hypochthonius rufulus C.L. Koch, 1835;Hypochthonius sp.3. Key to adult Hypochthonius known from North America1. Dorsal setae relatively short (Fig. 3.1A; 3.2): in much shorter than sensillus, c1 not reachinginsertion of d1, d1 just reaching scissure; ventral length 580-650 ................................................................................................................................. Hypochthonius luteus Oudemans, 1917- Most dorsal setae relatively long (Fig. 3.1B; 3.3): in approaching length of sensillus, c1 passinginsertion of d1, d1 extending well past scissure; ventral length 650-800 ........................................................................................................................ Hypochthonius rufulus CL Koch, 183528