Molecular characterization of from the black-faced spider monkey () with phylogenetic inference of relationships among of Neotropical primates.

Species of the genus are parasitic nematodes of the family Onchocercidae (Nematoda; Filarioidea) which infect the peritoneal cavity of Neotropical primates. Of these, six species have been taxonomically described, two of these have been reported infecting the black-faced spider monkey (): and . Description of species have been based on morphological characteristics, and their phylogenetic relationships remain unresolved. A few molecular studies have been carried out in spp. infecting Neotropical primates. Seven filarioid nematodes (6 females and one male) recovered from one in the Peruvian Amazon rainforest were morphologically identified as and molecularly characterized. A multi-locus genetic analysis of nuclear ribosomal region (18S) and mitochondrial (, 12S, and ) gene sequences supported as a distinct lineage and yielded a highly resolved phylogenetic lineage tree for this filarioid genus of Neotropical primates. Our results highlighted that species are divided in two well-supported clades, one containing and , and the second containing , and . Due to sequence ambiguities from GenBank entries, relationships among isolates of and cannot be fully resolved, which requires further investigation. However, this suggests that these could represent a species complex. Our study confirms that is a valid species and constitutes the first molecular phylogenetic analysis of this parasite in black-faced spider monkeys.