Intraproboscis

Intraproboscis is a genus of Acanthocephala (thorny-headed or spiny-headed parasitic worms) containing a single species, Intraproboscis sanghae. Found in central Africa, it infests the black-bellied pangolin and the tree pangolin, which are both threatened with extinction. The genus is described from several females and one incomplete male. Female worms reach up to 180 mm long (mostly trunk) and 2 mm wide; males seem to be smaller in all dimensions. The body consists of a long, narrow trunk and a tubular proboscis covered with hooks, which is used for feeding and attachment. The proboscis has 34 to 36 rows of 6 to 7 hooks at the front and 15 to 17 spinelike hooks on the back that are used to pierce and hold the host's intestinal wall.

This genus closely resembles the genus Mediorhynchus but differs in having mammalian hosts instead of avian hosts, a simple proboscis receptacle that is completely suspended within the proboscis, and a complete lack of neck. The first discovery of a parareceptacle structure, a distinct sac-like structure adjacent to the proboscis receptacle, in the class Archiacanthocephala was from Intraproboscis and represents an important taxonomic and evolutionary bridge between different acanthocephalan groups.

The life cycle of I. sanghae remains unknown but, in common with other acanthocephalans, it likely involves a complex life cycle with at least two hosts. The intermediate host of Intraproboscis has not been definitively identified, but it is believed to be an arthropod, such as an insect. Within this host, the larvae develop into an infectious stage called a cystacanth. When a vertebrate consumes the intermediate host, the cystacanths enter the vertebrate’s intestines where they mature into adult worms and reproduce sexually, and it becomes the definitive host. The resulting eggs are expelled and hatch into new larvae. Infestation by I. sanghae can cause intestinal perforation and death in the black-bellied pangolin.