A pictorial key to differentiate the recently detected exotic Haemaphysalis longicornis Neumann, 1901 (Acari, Ixodidae) from native congeners in North America

Abstract

Until recently, only two haemaphysaline species, <i>Haemaphysalischordeilis</i> (Packard, 1869) and <i>Haemaphysalisleporispalustris</i> (Packard, 1869), were known to occur in the United States, and neither was considered to be of significant medical or veterinary importance. In 2017-2018 established populations of the Asian longhorned tick, <i>Haemaphysalislongicornis</i> Neumann, 1901, were detected in the eastern US for the first time. <i>Haemaphysalislongicornis</i> has the potential to be a significant threat to human and animal health, and the urgent need to determine the full extent of its distribution and host range requires availability of a straightforward and practical guide to differentiate it from native species. We created a pictorial dichotomous key to all stages of <i>Haemaphysalis</i> spp. known to occur in North America with scanning electron photomicrographs of all <i>H.longicornis</i> life stages, including rarely seen males, to aid researchers in differentiating these species. The largely Neotropical species <i>Haemaphysalisjuxtakochi</i> Cooley, 1946, with established populations in Mexico and sporadic detections in the US on migrating birds is also included.