Posted: Mar 25, 2018 8:22 pm
According to the paper, Bombus glacialis speciated allopatrically from the Bombus lapponicus species complex about 6.4 million years ago, possibly from B. lapponicus itself, though B. sylvicola has to be factored in too. Whichever was the case, glacialis drops out as a sister clade to lapponicus and sylvicola in just about every phylogenetic tree you construct for the Pyrobombus SubGenus. The species then persisted on Novaya Zemlya through the Pleistocene ice ages, and the combination of large island size and somewhat mountainous topography, helped populations of the bee survive the island being used for Soviet nuclear tests. Though the Tsar Bomba probably didn't do the species any favours when it was detonated. 