Centroptilum Eaton and Pseudocentroptilum bogoescu of Manitoba (Ephemeroptera: Baetidae) : classification, species groups, and post-glacial dispersal

Abstract

The life stages of seven Manitoba species of Centroptilum Eaton sensu lato species are described or redescribed and keys are provided to identify nymphs and male and female images. The species are C. album, C. bifurcatum, C. conturbatum, C. infrequens, c. quaesitum, C. rufostrigatum, and C. victoriae. Nymphal and imaginal character states were evaluated phylogenetically using the Hennigian system with Callibaetis as the out-group. Centroptilum quaesitum and C. infrequens are closely related and together with C. rufostrigatum form a monophyletic group that should be transferred to Pseudocentroptilum sensu Keffermller and Sowa. The remaining four species form a monophyletic group that is phylogenetically more similar to Centroptilum sensu stricto than it is to Pseudocentroptilum. It is recommended that the name Centroptilum be used for these four species. Literature references and museum specimens were compiled and known geographical ranges are drawn. Centroptilum bifurcatum is a western species known from the interior of British Columbia eastward to Winnipeg, Manitoba. It ranges north to the Pembina River, Alberta and south to Yellowston National Park, Wyoming. Centroptilum victoriae is an eastern species known from Cape Breton Island, southern Ontario, and west-central Manitoba. Centroptilum album is a transcontinental species. Its northern record is in Churchill, Manitoba and its southern record is in North Carolina. It has not yet been found in the western United States. Centroptilum conturbatum is a western species that ranges east from southern British Columbia to west-central Manitoba and south to Waddell Creek, California. Pseudocentroptilum rufostrigatum is an eastern species that ranges from New Brunswick to west-central Manitoba. Its northern record is in Rivire du Castor, Quebec and its southern record is in Meade County, Kentucky. Pseudocentroptilum infrequens is a northwestern species. Its northern and western record is in the Nahanni National Park, Northwest Territories. It ranges east and south to southeastern Manitoba. It has not yet been found in British Columbia or in the Yukon Territory. Pseudocentroptilum quaesitum is a western species that ranges from the Okanagan area of British Columbia to eastern Manitoba. Its northern-most record is in Churchill, Manitoba and its southern Canadian record is in Medicine Hat, Alberta. There is one disjunct record of this species from Cairo, Illinois. It has not otherwise been found in the United States. Distribution patterns are classified according to post-glacial dispersal routes of Flannagan and Flannagan (1982). c. album has a South Transcontinental distribution. C. victoriae and P. rufostrigatum have an East Agassiz distribution. P. infrequens has a West Agassiz distribution while C. bifurcatum, C. conturbatum, and P. quaesitum all have a Saskatchewan-Montane distribution.