The North American antlion genus Paranthaclisis is comprehensively revised for the first time. Four species are recognized: P. congener (Hagen), P. floridensis Stange & Miller, P. hageni (Banks) and P. nevadensis Banks. Redescriptions, distribution maps and figures of diagnostic morphological characters are provided for adults of each species. A key to adults of Paranthaclisis is also included. Paranthaclisis californica Navas (1922) is recognized as a new synonym of P. hageni Banks. The monophyly of, and interspecific relationships within, the antlion genus Paranthaclisis, and its relationships to other genera within the tribe Acanthaclisini, are investigated using multiple datasets. Fifteen datasets were produced and analyzed to explore the effects of inference method, alignment strategy and data partitioning on phylogenetic estimates using morphological, molecular and mixed data inputs. Eighteen unordered and unweighted morphological characters were coded from across adult body regions. Molecular sequence data generated for this study consisted of two ribosomal genes, 16S and 18S. Paranthaclisis was recovered as monophyletic in analyses using 14 of 15 datasets, with low to moderate support in maximum parsimony and maximum likelihood analyses and high support from Bayesian inference methods. A sister-group relationship between Paranthaclisis and Vella, the only other New World acanthaclisine genus, was also recovered in analysis of 13 of 15 datasets, with low to moderate support in all phylogenetic inference methods tested. Choice of phylogenetic inference method and partitioning of gene datasets had the most influence on resulting topologies and support values. Choice of alignment strategy resulted in few topological differences, but Clustal datasets generally had higher clade support values, compared to MAFFT-aligned sequences.