Chimaeriformes – Chimaeras
Their evolutionary history, dating back over 400 million years, makes them one of the oldest living groups of jawed vertebrates
One of the most notable characteristics of chimaeras is their rough skin, covered in tooth-like scales called dermal denticles. These denticles give their bodies a unique texture, setting them apart from their shark relatives and other fish.
Unlike sharks, which typically feature multiple gill slits on each side, chimaeras possess a single gill opening on each side, covered by a protective gill plate. This single gill opening is a key anatomical distinction that differentiates them from sharks.
However, the crowning jewel of their uniqueness lies in their elongated snout, which is crucial to their survival. This snout has a specialized sensory organ called the “rostral organ.” This sensory adaptation allows them to detect and locate prey on the ocean floor, showcasing their remarkable ability to navigate and forage in their deep-sea habitats.
Chimaeras are predominantly denizens of the deep sea, inhabiting environments at varying depths, ranging from a few hundred meters to several thousand meters below the ocean’s surface. Their distribution spans across temperate and tropical oceans, with some species favoring continental slopes and abyssal plains. These remarkable creatures have evolved to withstand the extreme pressures and low temperatures of the deep sea, exemplifying their extraordinary adaptations to the challenging conditions of these profound oceanic realms.