Agnatha By: Bryce Carr

Agnatha Phylum Tree

Characteristics of the kingdom Eukaryotic Multicellular They are heterotrophic Generally digests food in internal chambers

Characteristics of Chordata A notochord A dorsal hollow nerve cord Pharygneal slits A post anal tail

Characteristics of the class All Agnatha are jawless Paired fins are generally absent The skeleton consists of only cartilage The embryonic notochord persists in the adult Consists of seven or more paired gill pouches There digestive system does not contain a stomach

Classification Brook lamprey hagfishSea lemprey KingdomAnimalia phylumChordatachordata Class/superclassAgnatha orderpetromyzontiformesmyxiniformespetromyzontiformes familypetromyzonitemyxinidaepetromyzotidae Genuslampetraeptatretuspetromyzon speicesL. planeristoutiiP.marinus

Lamprey 1/2 Marine Lamprey can range from 13 to 100 cm long. Lacking paired fins, adult lampreys have large eyes, one nostril on the top of the head, and seven gill pores on each side of the head. The unique morphological characteristics of lampreys, such as their cartilaginous skeleton, suggest they are the sister taxon of all living jawed vertebrates, and are usually considered the most basal group of the Vertebrata. Instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord. Parasitic lampreys feed on prey as adults by attaching their mouthparts to the target animal's body, then using their teeth to cut through surface tissues until they reach blood and body fluid.

Lamprey 2/2 The pharynx is subdivided; the ventral part forming a respiratory tube that is isolated from the mouth by a valve called the velum. This is an adaptation to how the adults are feeding, which both prevents the prey's body fluids from escaping through the gills or interfering with the gas exchange, which takes place by pumping water in and out of the gill pouches instead of taking it in through the mouth. Near the gills are the eyes, which are poorly developed and buried under skin in the larvae. The eyes' development is completed during metamorphosis, and is in adults covered by a thin and transparent layer of skin that becomes opaque in preservatives.

Lamprey Life Cycle

Fun/interesting facts Agnatha is actually the Greek word for no jaws, thus why animals under the Agnatha are jawless. The average lifespan of a sea lamprey is actually around 14 years! That’s as much as the average dog! Hagfish can absorb nutrients through there skin! Estimated around 76 different species of hagfish live throughout waters of our world.

Changes Agnatha is actually a very new super class but there is controversy of what should be put in the class such as the hag fish, which people still judge to date whether it is inverterbrae or verterbrae. The old name for Agnatha was Hyperoartia which was what scientist used to classify certain marine life that all contained vertrebrae. Other then that there has been no major change to anything in the Agnatha classifcation.

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