Egg capsules of the dusky catshark Bythaelurus canescens (Carcharhiniformes, Scyliorhinidae) from the south-eastern Pacific Ocean.

The external morphology of the egg capsule of Bythaelurus canescens and its fixation to the substratum are described. Bythaelurus canescens egg capsules are typically vase-shaped, dorso-ventrally flattened, pale yellow in colour when fresh and covered by 12-15 longitudinal ridges. The anterior border of the capsule is straight, whereas the posterior border is semicircular. Two horns bearing long, coiled tendrils arise from the anterior and posterior ends of the capsule. The presence of longitudinal ridges and long coiled tendrils at both anterior and posterior ends of the capsule readily distinguish these egg capsules from those of other chondrichthyans occurring in the south-east Pacific Ocean.