Crayfishes of Georgia
Crayfishes of Georgia Overview List of Georgia Species Species Lists by Drainage Crayfish Identification Keys by Drainage Ecology and Life History Links and Other Useful Information Glossary


Glossary of Terms

Abdomen- the rear half of the crayfish, posterior to the cephalothorax

Anterior- directional term indicating front end of an organism; toward the front

Aquifer- underground layer of water

Areola- the space found on the dorsal surface of the carapace between two curved grooves

Carapace- The exoskeleton of a crayfish that covers the cephalothorax portion of the body

Carina- small ridge; usually referring to raised area down the center of the rostrum

Cephalothorax- the anterior portion of the body made up of the fused cephalic and thoracic regions; anterior to the abdomen

Cervical spine- sharp point on either side of the cephalothorax

Dorsal- directional term indicating the "back" or "top" of an animal or object

Endemic- native to a particular place

Exoskeleton- the hard outer covering (skeleton) of crayfish and other arthropods; this covering is shed during molting.

Fingers- the two long appendages of a claw used for grasping or defending.

Fixed finger- non-movable finger on the claw

"in berry"- term used to describe a female crayfish carrying eggs under her abdomen

Impervious- surfaces around water bodies that do not allow percolation of rain into the soil (eg. parking lots, roads, roof tops) that cause streams to receive explosive runoff during rain events

Karst- limestone area where erosion has created sinkholes, caves, and underground streams

Lateral- directional term indicating “to the side”

Lentic- areas with non-moving water such as ponds or swamps

Macrophytes- plants large enough to be observed with the naked eye

Medial- pertaining to the middle

Mesial- directional term indicating "toward the middle or midline of the animal"

Molting- the process of shedding the exoskeleton

Obliterated- no space between the grooves that delineate the areola

Omnivore- animals that eat both plant and animal matter

Palm- the portion of the claw that is not composed of fingers

pH- measure of acidity or alkalinity of a solution

Posterior- directional term indicating rear end of an organism; toward the rear

Postorbital ridge- the ridge (raised area) directly behind the eyes

Riffle- areas of fast flow in a stream where surface of water is agitated

Riparian- area along the margin of a stream

Rostrum-the "nose" of the crayfish; the portion of the carapace that is anterior to the eyes

Setae- hair-like structures

Swimmerets- paired “feathery” appendages on the ventral side of the abdomen

Telson- center segment of the tail

Troglobitic- related to living in underground habitats

Tubercle- rounded projection or bump

Ventral- directional term indicating the "belly" or "bottom/underside" of an animal

Glossary definitions taken in part from:

Fetzner Jr. JW (1999). Key to the Astacidae website. Accessed: 2 October 2008.  Based on the original publication:  Horton H. Hobbs, Jr.  1972.  Biota of Freshwater Ecosystems:  Identification Manual No. 9.  Crayfishes (Astacidea) of North and Middle America.  For the Environmental Protection Agency, Project # 18050 ELD.

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