Chondrichthyes Hailey & Collin

A. Kingdom - Animalia, Phylum - Chordata, Subphylum - Vertebrata, Infraphylum - Gnathostomata, Class - Chondrichthyes B. Carcharodon Carcharias (Great White) Taxonomic Classification

They're cartilaginous fish, have a skeleton of cartilage. Moveable jaws that typically have well developed teeth Mouth is almost always ventral, or under the head Paired lateral fins for efficient swimming Rough, sandpaper like skin, due to tiny placoid scales Include sharks, rays, skates, and chimaeras (also called ghost sharks) Key Characteristics

First appeared roughly 395 million years ago Sharks are can be referred to as "living fossils" Caudal fin, or tail fin, is well developed and very powerful Tail is usually heterocercal, meaning the upper lobe is longer than the lower lobe Ancestors had bone, developed into cartilage Adaptations

Require salt water or, with some species, freshwater A food source (fish, plankton, crustaceans, etc.) Most rays require warmer temperatures Most sharks require open waters Habitat needs

Fertilization is internal Development is usually live birth However, some species lay eggs (oviparous) Some rare species are viviparous, meaning that the embryo develops inside the mother, eventually leading to live birth. Some Chondrichthyes guard their eggs, but there is no care for the young after birth Reproduction

Most sharks have tongues, but not all of them can move them Sharks do not have a swim bladder; instead they have a large liver filled with oil for buoyancy, with the exception of the Sandtiger Shark who swallows air to stay buoyant. The Spiny Dogfish may incubate its young for as long as two years Interesting facts

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