Chimeras, "ghost sharks,"  are a part of class Chondrichthyes just like sharks, skates and rays. They share a common ancestor with modern-day sharks about 400 million years ago. There are 50 species of Chimera extant today. Because of the depth at which they reside, little is known about chimeras compared to their elasmobranch relatives. While there are a few coastal species, a majority of chimeras reside at depths at or below 500m (1,600ft). Because of the relative scarcity of food at these depths, chimeras are opportunistic feeders that consume a wide variety of invertebrates. Chimeras can be anywhere from 60 to 120cm in length. They are oviparous, which means they reproduce by laying eggs. Chimeras have very large pectoral fins, dorsal fins, and eyes. Uniquely, male chimeras possess a tentaculum on their forehead that attaches to the female to hold them in place during mating. Unlike sharks, chimeras only have one gill opening on each side. 

Unlike the replaceable rows of teeth seen in their true sharks cousins, chimaeras have permanent tooth plates, and the upper tooth plate is fused to the neurocranium (skull). These are used to consume a variety of crunchy, benthic prey, such as crustaceans. As the chimaera grows, its jaw strength (and crushing force) increases substantially, allowing the chimaera to consume a wider variety of prey as adults