Two new species of Xironogiton (Clitellata: Branchiobdellida) from western North America

Xironogiton, a genus of crayfish worm (order Branchiobdellida), is historically endemic to North America. To date, six species of Xironogiton have been described, including five and one from areas west and east of the Continental Divide, respectively. Recent collections of the crayfishes Pacifastacus connectens and Pacifastacus leniusculus from the endorheic Harney Basin in south-eastern Oregon, USA, revealed the presence of two previously unknown Xironogiton species, which we describe herein. Discovery and characterisation of Xironogiton bibendumi sp. nov. and Xironogiton malheurensis sp. nov. suggests that much work remains to understand branchiobdellidan diversity in western North America, and additional targeted sampling is needed to determine intra- and interspecific variation, and thus define species limits.