Lab 4.-Hagfishes, Lampreys, Sharks, Skates, Rays, and Chimaeras
Kingdom Animalia	Phylum Chordata
Subphylum Myxini	Class Myxini
Order	Family	Genus	Species	Common name	Etymology
Myxiniformes	Myxinidae			Hagfishes	Greek. myx = slime
					myxnos = kind of viscose skin
		characteristics:	lack eyes, but have photoreceptors
Subphylum Vertebrata, Class Cephalaspidomorphi
Order	Family	Genus	Species	Common name	Etymology
Petromyzontiformes	Petromyzontidae	Ichthyomyzon	castaneus	Chestnut lamprey	ichthy = a fish, myzon=sucking	castaneus = chestnut color
		characteristics:	dorsal fin continous or separated by a shallow notch, disc teeth well developed
Petromyzontiformes	Petromyzontidae	Lampetra	aepyptera	Least brook lamprey	lampetra = sucker of stones	aepy=high, pteron  = fin
		characteristics:	dorsal fin divided by deep notch, disc teeth poorly developed
Class Chondrichthyes
Order	Family	Genus	Species	Common name	Etymology
Carcharhiniformes	Carcharhinidae			Requiem sharks	Greek, karcharos, -ou = cutting, sharp and also a kind of shark + Greek, rhinos = nose
		characteristics:	Gill openings 5, the fifth behind origin of pectoral fin. Small to large sharks with round eyes, internal nictitating eyelids, no nasoral grooves or barbels, usually no spiracles. Teeth usually bladelike with one cusp.
Squaliformes	Squalidae			Dogfish sharks	Latin, squaleo, squalidus = with rough skin
		characteristics:	Both dorsal fins with spines, not grooved; teeth on lower jaw not much larger than those on upper jaw; upper precaudal pit usually present; caudal peduncle with a pair of lateral keels.
Rajiformes	Rajidae			Skates	Latin, raja = ray
		characteristics:	Mouth transversed to arched, with numerous teeth. Five pairs of ventral gill slits. Tail very slender, with lateral folds, usually 2 reduced dorsal fins and a reduced caudal fin. Electric organs weak, developed from caudal muscles. Skin prickly in most species, the prickles often in a row along midline of dorsal.
Class Chondrichthyes
Order	Family	Genus	Species	Common name	Etymology
Pristiformes	Pristidae			Sawfishes
		characteristics:	Snout elongated into a long flat blade with teeth of uniform size deeply embedded on each side. No barbels. Head depressed. The body more or less resembling a shark. Two distinct dorsal fins.
Myliobatiformes (now grouped with Rajiformes)	Dasyatidae			Stingrays	Greek, dasys = hair
		characteristics:	Side of head continuous with the anterior margin of pectoral fin. Respire by drawing water through a small hole behind the eye and expelling it through gill slits on the underside of the disc. Dorsal fin totally absent or indistinct, when present. Disc about 1.2 times as broad as long. No caudal fin. Tail long and whip-like. Most species with at least 1 long venomous spine on tail, which can cause excruciating pain to humans.
Chimaeriformes	Chimaeridae			Ratfishes	Latin, chimaera = monster
		characteristics:	Short and rounded snout. First dorsal fin erectile, with a strong spine; second dorsal fin long and low. Diphycercal tail, i.e. vertebral colum runs straight to the tip, dividing the caudal fin symmetrically. Anal fin confluent with caudal fin in Hydrolagus; separate in Chimaera. Males with head clasper. Dorsal spine with associated poison gland, the venom of which hurts humans.