246 Shark mid Covipmiy 



rays, and their relatives, which are all grouped under the classification 

 Batoidei. The Batoids appeared in more recent geological eras than the 

 sharks, but they have been around for a long time. Their oldest known 

 members can trace their lineage back to, at least, the Upper Jurassic Age 

 in geological time, about 1 30 million years ago by some estimates. 



Most Batoids are easily recognized by their disk-like shape. But this 

 characteristic is not found in all Batoids. The Batoids can be divided into 

 five major groups, each of which is further subdivided down to species. 

 The groups are: 



Electric Rays 



Unlike any other Batoids, or sharks for that matter, these unique 

 Selachians have highly developed electrical organs. (In this respect alone 

 they are similar to the much-feared electric eel of South America.) They 

 have a shark-like tail, although reduced in size. 



Rays 



Typically, rays are shaped like a boy's kite, complete with tail. In 

 many species, the tail is armed with one or more barbed points (techni- 

 cally called spines). 



Skates 



They resemble rays at first glance. But their tails are lobed, none have 

 poison stingers in the tail, and the tails are fleshier and heavier than in 

 rays. Few grow to large size. They have fleshy, movable fins, usually 

 attached to the anterior margin of each pelvic fin, on which they can 

 "walk" across the bottom. 



Sawfishes 



Their long, narrow snouts are flat and each edge has a single row of 

 large, pointed tooth-like structures, giving the snout the appearance of 

 a double-edged saw. Sawfishes are not disk-shaped; their bodies are shark- 

 like. They are classified among the Batoids because of certain anatomical 

 details, such as gill slits on the underside of the body, which differentiate 

 them from the sharks. 



Guitarfishes 



Their name discloses their shape. They are probably links between 

 sharks and rays. 



Like their close relatives, the sharks, the Batoids range the world. 

 They are found in polar and tropical seas, near shore and at great depths. 

 Some have infiltrated fresh waters. They have branched off into hun- 

 dreds of varied species and some have developed somewhat peculiar 



