Holocep’ – Chimaeras
Also known as rat fish or ghost sharks; unlike sharks, they have no visible gills
A fascinating group of cartilaginous fish commonly known as chimaeras or ratfish. Their lineage traces back over 400 million years, making them ancient survivors of Earth’s dynamic evolutionary processes. Fossil records suggest that these enigmatic creatures share a common ancestor with the elasmobranchs, including sharks and rays.
One of the most notable features of holocephalans is their unique chimaeric appearance. Unlike sharks, holocephalans possess a single gill opening on each side, covered by a gill plate. This is in contrast to sharks, which typically have multiple gill slits. The elongated bodies of chimaeras are covered in dermal denticles, providing a rough texture to their skin. The most distinctive feature, however, is their tooth plates, which are adapted for crushing rather than tearing prey.