Decapod anatomy
The
Cephalothorax
Head
- antennules
- antennae
- mandibles
- first maxillae
- second maxillae
The head also bears the (usually stalked) compound eyes. The distal portion of a mandible or maxilla which has a sensory function is known as a palp.
Thorax / pereon
- first maxillipeds
- second maxillipeds
- third maxillipeds
- first pereiopods
- second pereiopods
- third pereiopods
- fourth pereiopods
- fifth pereiopods
Maxillipeds are appendages modified to function as mouthparts. Particularly in the less advanced decapods, these can be very similar to the pereiopods. Pereiopods are primarily walking legs and are also used for gathering food. They are also the ten legs from which decapods take their name.[2] Those pereiopods which are armed with a claw (chela) may be referred to as chelipeds. The moveable fingers of a claw are known as dactyls. The pereiopods bear the sexual organs, which are the third pereiopod in the female and the fifth pereiopod in the male. Each appendage from the second maxilla to the fifth pereiopod also bears a gill. In the Anomura (hermit crabs and related animals), the fifth pair of pereiopods is often hidden inside the branchial chamber, where they are used to clean the gills. The cephalothorax is covered by a carapace which protects the internal organs and the gills; the section of the carapace that projects in front of the eyes is called the rostrum.
Abdomen / pleon
- first pleopods
- second pleopods
- third pleopods
- fourth pleopods
- fifth pleopods
- uropods
Pleopods (also called swimmerets) are primarily swimming legs, and are also used for brooding the eggs (except in
Telson
At the end of the pleon is the tail fan, comprising a pair of
In crabs and some other carcinised decapods, the abdomen is folded under the cephalothorax.
See also
References
- ISBN 9780643069060.
- ^ a b Robert P. D. Crean (November 14, 2004). "Characters and Anatomy". Order Decapoda. University of Bristol. Archived from the original on November 10, 2013. Retrieved April 23, 2012.