Pleistocene grasshoppers, fleas, thrips, and mites: rare and new records from Arctic ground squirrel middens in east Beringia in Yukon Territory, Canada

The field of Quaternary entomology has focused primarily on the study of beetles (Coleoptera) and, to a lesser degree, nonbiting midges (Diptera: Chironomidae). Beetles typically predominate because they have heavily sclerotised exoskeletons, and they are abundant in a great variety of habitats. Because of taphonomy and scarcity, other Quaternary invertebrates have been less studied.

Only a few records of fleas (Siphonaptera) and mites (Acari) are reported from Pleistocene deposits that span the Seward Peninsula in Alaska, United States of America, to the Klondike goldfields in central Yukon Territory, Canada. Grasshoppers (Orthoptera) and thrips (Thysanoptera) have not been reported previously from Quaternary deposits across the Arctic’ s Beringia region. However, recent extensive sampling of Arctic ground squirrel, Urocitellus parryii Richardson (Rodentia: Sciuridae), middens from permafrost deposits of the Klondike goldfields has yielded specimens from each of these underrepresented invertebrate groups.

Here, we present records of fleas (Oropsylla alaskensis Baker (Ceratophyllidae )), mites (including Fusacarus Michael (Astigmata: Glycyphagidae) and cf. Haemogamasus Berlese (Mesostigmata: Laelapidae )), and the first records of grasshoppers (Acrididae: Gomphocerinae) and thrips (Thysanoptera: Thripidae) from Beringia from six middens spanning approximately 80 000–13 500 years BP. We also provide brief reviews of the fossil history of each major taxon.