Phylum: Chordata

Superclass: Agnatha

Class: Cephalaspidomorphi (Lamprey)

Family: Petromyzontidae

Lampreys

• 22 species in North America
• Approximately half are parasitic
• Eel-like body with no scales
• 1 or 2 medial fins
• No paired appendages
• Rudimentary true vertebrae
• Fibrous & cartilaginous skeleton
• Eyes

Eating/Digestion

• Mouth – esophagus – intestine with typhlosole – cloaca
• Buccal funnel (mouth area) allows for attachment to fish

Circulatory System & Respiratory System 

• Blood is osmotically regulated with water
• Heart – atrium & ventricle
• Aortic arches in gills
• 7 pairs of gills with gill openings
• Water moves in and out gill openings (unusual)

Anadromous

• Adults spawn in winter/spring
• Leave marine to freshwater for breeding
• Some are “land-locked” & stay in freshwater (Problem in Great Lakes)

Reproduction

• Males build nest
• Females join later with male attaching to her head
• Eggs fertilized externally
• Eggs adhere to pebbles & covered by sand
• Adults die
• Eggs hatch (2 wks) –Larvae (ammocoetes)—Drift downstream to ocean (As adults)