Chimaera
A cartilaginous fish in the subclass Holocephali, distinguished by a fused upper jaw, tooth plates, and gill openings covered by a flap of skin.
Holocephali: A subclass of cartilaginous fishes that includes chimaeras and their extinct relatives. Chimaeras are the living members of this lineage.
Upper jaw: The upper part of the jaw apparatus in vertebrates. In chimaeras, it is fused to the skull, unlike the mobile upper jaw of most sharks.
Rabbitfish: A common name for chimaeras in the family Chimaeridae, noted for their rabbitlike teeth and snout. It is one of the best-known common names for chimaera species.
Shark: A cartilaginous fish in the subclass Elasmobranchii, typically with exposed gill slits and replaceable rows of teeth. Sharks are the best-known cartilaginous fishes, but belong to a different subclass.
Chondrichthyes: The class of jawed fishes with skeletons made primarily of cartilage, including sharks, rays, and chimaeras. This broader fish group provides chimaeras’ evolutionary and anatomical context.
Lateral line: A sensory system that detects water movement and pressure changes around an aquatic animal. It helps chimaeras locate prey and orient themselves in dark water.
Spotted ratfish: A North Pacific chimaera, Hydrolagus colliei, marked by pale spots and a long tapering tail. This coastal species is among the most familiar chimaeras in North America.
Ray: A flattened cartilaginous fish in the subclass Elasmobranchii, with enlarged pectoral fins and gill slits on its underside. Rays share cartilaginous ancestry with chimaeras but have a very different body plan.
Cartilage: A firm, flexible connective tissue that forms much of the skeleton in chondrichthyan fishes. It forms the supporting framework beneath a chimaera’s distinctive head and fins.
Ampullae of Lorenzini: Electroreceptive organs that detect weak electric fields in water. These sensors can reveal prey hidden in sediment.