Zooplankton Identification Guide Prepared by Emi Yamaguchi & Caitlin Bell (2007)

adult copepod Copepods are the most common zooplank-ton worldwide. They are an integral part of the food web as both predator and prey.

copepod nauplius The nauplius is a common early larval stage of crustaceans. Some nauplii have spines while others do not.

adult Oikopleura sp. This organism is actually an adult tunicate that retains its notochord and tail. The tail beats back and forth rapidly to create a current that brings food near the mouth.

polychaete worm larvae These organisms are the marine rela-tive of earthworms. The larvae are found in the plankton. The adult form, seen in the invertebrate lab, is benthic.

cypris larva The cypris is the final larval stage of a barna-cle. It must find a suit-able attachment site to become an adult.

tunicate (sea squirt) larva This “tadpole” is an early life stage of a tunicate. Tunicates are related to humans because they have a notochord, although it disappears as the larva matures. Sea squirts, found in the inverte-brate lab, are adult tunicates.

barnacle nauplius Barnacle nauplii are distinguished from crab larvae by the “spikes” on their heads. This stage comes be-fore the cypris stage.

The University of Georgia Marine Education Center and Aquarium http://www.marex.uga.edu/aquarium

zoea The zoea is a larval stage of a crab or shrimp. Zoea have two large spines that are used for protection and flota-tion.

megalops The megalops is the final larval stage of a crab. During this stage, the abdomen is ex-tended. The abdomen is folded under the body as an adult.

Zooplankton Identification Guide Prepared by Emi Yamaguchi & Caitlin Bell (2007)

tintinnid Often referred to as a “tintinnid cup,” a tintinnid is a ciliate with a hard outer covering.

hydroid medusa This photo shows the medusa stage of a hydroid. The medusa stage has stinging cells for protection and food capture. This stage reproduces sexually to form polyps. Polyps then repro-duce asexually to produce the medusa form.

veliger larva A veliger is a free-swimming larval stage of a mollusk. Veligers have the beginnings of a foot, shell, and mantle. This photo shows a veliger of a Littorina snail.

rotifer Rotifers’ cilia are in constant motion. Only a few species are found in marine and brackish water.

The University of Georgia Marine Education Center and Aquarium http://www.marex.uga.edu/aquarium

fish larvae This juvenile fish will develop into a nektonic or benthic adult form. It is considered planktonic at this very young stage.