Siphonaptera The Canyon Creek midden (GZ-2014-CC-1) is the oldest in this study, at approximately 80 000 years BP, and the Mint Gulch midden (DF18-37) is the youngest at 13 680 cal. yr BP. All identifiable flea specimens presented in this study are Oropsylla alaskensis (Ceratophyllidae). Of the nine fleas collected, five are females and four are males. Most specimens were heavily sclerotised (Fig. 2A and C), with the exception of fleas from SC22-HC-37 (Fig. 2D), four of which (3♂, 1♀) are pharate (Fig. 2B), and around which there was particulate materials, perhaps associated with their cocoons. Two pharate males could be identified as O. alaskensis. One female from this site was well sclerotised and identified as O. alaskensis. The male from SLC21-KL-1 was badly fragmented, with only head and thoracic segments present in pieces; it could be identified only as Ceratophyllidae. Specimen DF18-37 is a pharate female Oropsylla cf. alaskensis. The hilla of the spermatheca in this specimen is partially collapsed, and measurements of the hilla could not be made. Although the abdomen of DF09-HC-29 is slightly retracted, the hilla and posterior margin of STVII are sufficiently intact to identify this specimen as O. alaskensis. Specimen GZ-2014-CC-1 is the oldest specimen in the series (∼ 80 000 years old) and is a fully sclerotised female. It is in remarkably good condition despite being separated into two pieces at the posterior abdomen (Fig. 2A). The spermatheca (cracked) and STVII are sufficiently intact and characteristic of O. alaskensis (Fig. 3B).

Published as part of Cocker, Scott L., Proctor, Heather C., Galloway, Terry D., Miskelly, James, Jensen, Britta J. L. & Froese, Duane G., 2025, Pleistocene grasshoppers, fleas, thrips, and mites: rare and new records from Arctic ground squirrel middens in east Beringia in Yukon Territory, Canada, pp. 1-25 in The Canadian Entomologist (e 21) (e 21) 157 on page 7, DOI: 10.4039/tce.2025.14, http://zenodo.org/record/15701779