Pachysentis

Pachysentis is a genus in Acanthocephala (thorny-headed or spiny-headed worms) that parasitize primates and carnivorans. The eleven species are distributed across Africa, the Middle East, and the Americas. Pachysentis species attach themselves to the inner lining of the gastrointestinal tract of their hosts using their hook-covered proboscis. Their life cycle includes an egg stage found in host feces, a cystacanth (larval) stage in an intermediate host which is usually an insect, and an adult stage where cystacanths mature in the intestines of the host. This genus appears identical to the closely related Oncicola apart from a greater number of hooks on the proboscis. There are eleven species assigned to this genus, although P. septemserialis is of uncertain taxonomic status. The female worms range from long and wide in P. lauroi to long and wide in P. dollfusi. Virtually all of the length is the trunk, with a short proboscis. There is pronounced sexual dimorphism in this species as females are around twice the size of the males. Infestation of P. canicola in the Sao Miguel island fox caused inflammation, degradation, and perforation of the intestines and death of the intestinal tissues, but no infestations in humans have been reported.

==Taxonomy== The genus Pachysentis was established with three species by Anton Meyer in 1931, with P. canicola designated as the type species. The genus underwent a significant expansion in 1972 when parasitologist Gerald D. Schmidt reclassified seven species into Pachysentis including six formerly belonging to Prosthenorchis and one from Oncicola. The status of P. septemserialis remains contentious; inconsistencies between the original 1950 description and the surviving paratype led Gomes et al. in 2019 to suggest it may be a synonym of P. lenti.