Cohort Gamasina - Royal Alberta Museum

Almanac of Alberta Acari Part II Version 2.02 February 2012 draftT-shaped, exs branched, exi minute, not branched, bo not branched. 4 pairs T-shaped adanalsetae, 4 pairs simple anal setae; 7 pairs simple genital setae; heterotridactyl.Collections: Dinosaur Provincial Park (DEW)DOC (5/2011): [+other] Distribution: [New Mexico, Neotropics, Palearctic, Australia].Superfamily Brachychthonioidea Thor, 1934Brachychthoniidae Thor, 1934Comments: Brachychthoniid mites are among the smallest of the Oribatida and no species inAlberta reach the 0.3 mm length limit. Unlike many soil microarthropods, brachychthoniidsare able to tolerate the disturbance of cropping and maintain a high diversity and abundancein some systems (Osler et al. 2008).Brachychthonius Berlese, 1910Type species: Brachychthonius berlesei Willmann, 1928 (=Brachychthonius brevis Michaelsensu Berlese, 1910)Also Known As: Brachychochthonius Jacot, 1938Brachychthonius berlesei Willmann, 1928 (Osler et al. 2008)Brachychthonius nr. berlesei Willmann, 1928 (Lindo & Visser 2004)Also Known As: Brachychochthonius berlesei (Willmann, 1928); Brachychthonius brevisBerlese, 1910ABMI code: BRACBERDiagnostic characters: 196-212 longCollections: EMEND (56.46, -118.22), Lethbridge (49.48 N, 112.54’ W)DOC (5/2011): [+other] Distribution: AB; NU, NT; [Holarctic].Overview: Specimens have been found in the feathers of birds in Russia, a possible means oflong distance dispersal (see Krivolutsky & Lebedeva 2004).Brachychthonius bimaculatus Willmann, 1936Also Known As: Brachychochthonius bimaculatus (Willmann, 1936)ABMI code: BRACBIMDiagnostic characters: prodorsal and notogastral setae ciliated; Na with a pair of eye-like spots;sensillus strongly clavate and with two rows of cilia.Overview: a very similar mite with smooth setae on the pygidial shield occurs in Canola fieldsnear Lethbridge (49.684619°, -112.749009°).14