Aspidodera kinsellai n. sp. (Heterakoidea: Aspidoderidae) from the 9-banded armadillo, Dasypus novemcinctus, is herein described. This nematode occurs from Costa Rica north through central Mexico where it can be found causing co-infections with Aspidodera sogandaresi. Aspidodera kinsellai n. sp. can be discriminated from this and all other species in the family based on 3 key features, including (1) conspicuous lateral grooves with no lateral alae starting immediately after the hood and terminating at the cloacal/anal region; (2) long hoods in both male (360 μm) and female (401 μm), and (3) a relatively long (152 μm) terminal spine or terminus that gradually tapers to a point from the last pair of papillae. This is the 18th recognized species of the family and the 3rd in the genus present outside of South America. A phylogenetic analysis of the species in the genus with the use of the mitochondrial partial genes cytochrome C oxidase subunit 1 (cox1), the ribosomal large subunit (rrnL), and the internal transcriber spacer (ITS) shows that 2 species of Aspidodera may have entered into North America from the south via 2 independent events.