Sangsue Des Raies

Overview

Branchellion torpedinis is a specialized marine leech that lives as an obligatory ectoparasite on various elasmobranchs, including sharks, rays, and skates. First described in 1822, this species is widely distributed across the North Atlantic Ocean, the Caribbean Sea, and the Mediterranean Sea.

Appearance

This leech typically reaches lengths of about 5 to 10 cm. Its body is divided into a narrow anterior region and a wider, cylindrical trunk. A defining characteristic is the presence of 11 pairs of lateral, leaf-like outgrowths along the abdomen, which function as gills to assist with respiration. The animal also features prominent, pedunculate suckers at both ends, which it uses to anchor itself firmly to its host.

Biology & behavior

As a permanent parasite, B. torpedinis spends its life cycle attached to the skin, gills, or claspers of its host. It is a blood-feeding organism, using its anterior proboscis to feed on the host's blood. While often found in isolation, these leeches are occasionally observed in groups. Although they are generally considered rare, they have been documented on a variety of hosts, including electric rays, angelsharks, and cownose rays. In some instances, heavy infestations have been associated with significant health impacts on the host.