Shark Identification

Chimaeras are grouped in the subclass Holocephali. There are only a little over 50 chimaera species worldwide. The last common ancestor of chimaeras, sharks and rays lived about 420 million years ago.

The name chimaeras fits this class of cartilaginous fish, because they also have features of bony fish. Thus, they are the only cartilaginous fish that do not have 5 to 7 gill slits but a gill plate (like bony fish) with a gill opening. Chimaeras have long bodies with a dominant head and grow up to 150 cm long. However, in many species the very long and thin tail, with the cartilaginous spine ending in the upper lobus, makes up a large part to its length. The pectoral fins are large and expansive. In front of the first dorsal fin is a large, venomous spine for defense. The upper jaws are fused to the skull. They have one tooth plate in the lower jaw and two in the upper jaw. The placoid scales or skin teeth typical of cartilaginous fish are almost completely absent, making their bodies very smooth. Skin teeth are found only on the reproductive organs (claspers) of males.
Chimaeras all have internal fertilization and the females lay eggs, which are protected by a leathery egg case.
Chimaeras are inhabitants of the temperate zones and most species live at depths up to 2,600 m.

Skates and rays, along with sharks, belong to the subclass of Elasmobranchii. Today, over 630 species of skates and rays are known, almost all of which are endangered. Skates are of the order Rajiformes, rays are composed of the orders sawfish (Pristiformes), stingrays (Myliobatiformes) and electric rays (Torpediniformes). Skates are egg-laying (oviparous) and reproduce with eggs in a species-specific, leathery egg case. Rays are ovoviviparous, with the young maturing in eggs but hatching in the female and being born alive. Externally, the simplest distinguishing feature is the tail. Skates have a long, whip-like and fleshy tail without spines, while rays all have spines on their tails. Skates are also usually smaller than rays and their dorsal fins are clearly visible.
In general, skates and rays are very flat and broad and their large pectoral fins are fused directly to the head. They have 5 gill slits on each side. Bottom-dwelling species often suck water through a spiraculum (a type of snorkel) on the top of the body through the gills. They move around by flapping or undulating their large pectoral fins. Many are bottom-dwelling and distributed worldwide as far north as the polar regions. Some species live in the deep sea, others are also found in brackish water and freshwater.
The main reason for their endangerment is national and international fishing. The meat and fins of skates and rays are even traded as delicacies in some countries.