Zoogeography and taxonomy of Dirofilaria scapiceps (Leidy, 1886) and D. uniformis Price, 1957 (Nematoda: Filarioidea) of lagomorphs in North America

Abstract

Dirofilaria scapiceps (Leidy, 1886) was found in 62% of 404 Lepus americanus, 27% of 89 Sylvilagus floridanus, 13% of 31 Orytolagus cuniculus (domestic), 4% of 26 L. capensis, and none of 15 L. timidus, 2 L. californicus, and 50 L. townsendii collected in various regions of North America. Dirofilaria scapiceps in L. capensis is a new host record. The two species of Dirofilaria, D. scapiceps and D. uniformis Price, 1957, known from lagomorphs are redescribed. Dirofilaria scapiceps occurs predominantly in connective tissue surrounding tendons in the ankle region and rarely in intermuscular fascia near the knee joint of the hind leg; D. uniformis occurs in subcutaneous tissues of the trunk. Both D. scapiceps and D. uniformis are known only from lagomorphs in North America, D. scapiceps from L. americanus, L. capensis, S. floridanus, S. palustris and O. cuniculus and D. uniformis from S. floridanus, S. palustris and O. cuniculus. Dirofilaria scapiceps is present in lagomorphs in Alaska, Canada, eastern United States and Wyoming whereas D. uniformis is known only from lagomorphs in southeastern and south central United States. Dirofilaria uniformis may have evolved, through paedomorphosis, from D. scapiceps.