The postlarval development of gill raker
denticles is described for the engrauloid (anchovy) genera Coilia, Lycothrissa, Setipinna, Thryssa, Stolephorus, and Encrasicholina based on scanning electron microscopy. The raker structure of adult Papuengraulis is also described. In the coiliid genera Coilia, Lycothrissa, Setipinna, Thryssa, and Papuengraulis,
denticle development is not confined to particular region(s) of the raker. With few exceptions, the proliferation of
denticles with growth is greatest along the upper raker edge;
denticles are smaller and less dense on the raker faces and along the lower raker edge. Some Thryssa and Setipinna have a derived condition of
denticle clustering along the upper raker edge. In Stolephorus and Encrasicholina,
denticle development is confined to the upper raker half and includes the development of a single row of
denticles along each raker face. A phylogenetic analysis of engrauloid raker structure, incorporating data from Bornbusch ( 88: Copeia 1988:174-182) and based on outgroup comparisons, indicates that for the Engrauloidea: (1) the pattern of
denticle development shared by coiliids is plesiomorphic; and (2) the pattern of
denticle development shared by Stolephorus, Encrasicholina, and most other engraulids is synapomorphic for the Engraulidae. There is no evidence that the studied coiliids Stolephorus and Encrasicholina are
suspension feeders. The engraulid pattern of raker
denticle development which is retained in
suspension feeding engraulids of the genus Engraulis was thus derived before the derivation of
suspension feeding in Engraulis. Comparative morphological and phylogenetic studies of clupeomorph raker structures and feeding behaviors can infer the historical origins of morphology-behavior associations, help define possible directions for analyses of raker
denticle function, and thereby help elucidate the significance of structure-function couplings in the evolution of such clupeomorph trophic behaviors as
suspension feeding. © 1992 Wiley-Liss, Inc.