Agnatha Hagfish & Lamprey Vertebrate Zoology Agnatha Hagfish & Lamprey

Key Features Jaws are absent. Paired fins are generally absent. Early species had heavy bony scales and plates in their skin

Key features con’t In most cases the skeleton is cartilaginous. The embryonic notochord persists in the adult. Seven or more paired gill pouches are present. Hagfish sheds slime layer

Key features con’t A light-sensitive pineal eye is present. The digestive system lacks a stomach. External fertilization; both ovaries and testes present in individual but gonads of only one sex functional in hagfishes, no larval stage; separate sexes and a long larval stage in lampreys.

Jawless, bony plated Ostracoderm fish Ordovocian Period 505 mya Paleozoic Scavengers/ filter feeders

Lamprey Classification Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Cephalaspidomorphi Order Petromyzontiformes Family Petromyzontidae

Lamprey Structure Structure Round, suckerlike jawless mouth filled with rows of horn-like teeth. Internal ring of cartilage supports rim of mouth. Single nostril on dorsal side of the head. Skeleton doesn’t exist, only cartilage.

Lamprey Digestion Digestion Pierces flesh of prey with numerous small horn-like teeth. Tongue creates suction and tongue draws back body fluids. Rasp into the flesh and feed on body fluids.

Lampreys mouth I luv you

External Fertilization

Hagfish Classification Kingdom Animalia Phylum Chordata Class Pteraspidomorphi Order Myxiniformes Family Myxinidae Genus Myxine Species glutinosa

Slime Glands

Hagfish secrete slime when disturbed

Hagfish Structure Structure Body supported by heavy cartilage. 91 cm. Long Continuous fin extending upper and lower body. No bone structure Mucous producing pores along body length.

Hagfish Hagfish can be found in chilly waters They tend to live on and in muddy sea floors in very dense groups (up to 15,000 in an area). Because females tend to produce large eggs in small numbers, their population sizes suggest a low death rate.

Hagfish Diet is made up of marine worms and other invertebrates; dead and dying sea life (eats them from the inside out). They have a ring of short sensitive tentacles around their mouths. Large slime glands line their sides along the length of their bodies. Can sneeze to clear slime from nostrils

No jaws. Instead they have two pairs of rasps on top of a tongue No jaws. Instead they have two pairs of rasps on top of a tongue. They pull meat into their mouths with the tongue, then tear it off the prey with the rasps.

Hagfish have a very low metabolism Hagfish have a very low metabolism. Once they eat, they may not have to again for up to seven months. Although hagfish have a partial skull, they have no back bone, so are not true vertebrates. What skeleton they do have is made of cartilage.

Hagfish Anatomy