Cryptic diversity in a gastrointestinal acanthocephalan of New World primates from Costa Rica

Abstract

Abstract Prosthenorchis elegans is a worm of the family Archiacanthocephala that infects non-human primates in the Americas, producing an intestinal pathology that may compromise the life of its hosts. Squirrel monkeys, Saimiri oerstedii citrinellus, were found with P. elegans in Costa Rica. Histopathological analysis revealed a severe pyogranulomatous response composed by macrophages, neutrophils, eosinophils, fibroblasts and lymphocytes. Morphological analyses revealed 36 hooks in the proboscis distributed in six rows and total body, hook and lemnisci length compatible to the original descriptions of P. elegans. In addition, phylogenetic, haplotype network and genetic distance analyses were done on cytochrome oxidase subunit 1, cox1, sequences obtained from the collected specimens. Sequences obtained herein clustered separately with high posterior probabilities in a Bayesian Inference tree and showed 8.43% nucleotide differences when compared to P. elegans from Colombia. This high divergence was confirmed in the TCS network that separated Colombian and Costa Rican sequences by 32 mutational steps and a genetic distance PCA which grouped sequences from both geographical locations by 89.5%, indicating the presence of cryptic divergence in P. elegans. Additional studies from specimens collected from other definitive hosts and geographical locations are required to better understand the biodiversity of this species.