|Revising the definition of the crustacean seta and setal classification systems based on examinations of the mouthpart setae of seven species of decapods|Garm, A. (2004). Revising the definition of the crustacean seta and setal classification systems based on examinations of the mouthpart setae of seven species of decapods. Zool. J. Linn. Soc. 142(2): 233-252. hdl.handle.net/10.1111/j.1096-3642.2004.00132.x
In: Zoological Journal of the Linnean Society. Academic Press: London. ISSN 0024-4082, more
Functional morphology; Marine
The crustacean cuticle has numerous projections and some of these projections, the setae, have important mechanical as well as sensory functions. The setae display a wide diversity in their external morphology, which has led to great problems separating setae from other projections in the cuticle and problems in making a consistent classification system. Here, the cuticular projections on the mouthparts of seven species of decapods are examined by scanning and transmission electron microscopy. A new definition is given: a seta is an elongate projection with a more or less circular base and a continuous lumen; the lumen has a semicircular arrangement of sheath cells basally. From the details of the external morphology the mouthpart setae are divided into seven types: pappose, plumose, serrulate, serrate, papposerrate, simple and cuspidate setae, which are suggested to reflect mechanical functions and not evolutionary history. This classification system is compared with earlier systems.