Key to the species of Bairdiella

1a. Dorsal-fin rays 25-29; gill rakers on first branchial arch 25-27; dark spot at base of pectoral fins............ B. icistia (eastern Pacific from Gulf of California to Guatemala)

1b. Dorsal-fin rays 19-24, gill rakers on first branchial arch 22-24; without dark spot at base of pectoral fins............ 2

2a. Six pores on chin; anal-fin rays 8-10, more commonly 9; second anal fin spine thin, shorter than first anal-fin ray.. ...................................................................... B. chrysoura (western Atlantic, from Cape Cod to western Gulf of Mexico)

2b. Five pores on chin; anal-fin rays 8-9, more commonly 8; second anal fin spine robust, as long as first anal-fin ray.... 3

3a. Body silvery without stripes or dark spot; head profile slightly convex; 55 or more scales along lateral line up to caudal fin base ................................................. B. ensifera (eastern Pacific, from Southern Mexico to Peru)

3b. Body with wavy stripes or dots; head profile straight or slightly concave; 46-53 scales along lateral line up to caudal fin base...................................................................... 4

4b. Eyes large, orbital diameter larger than 8% SL .............. ............................................................... B. goeldi sp. nov. (western Atlantic, Brazilian coast)

4a. Eye small, orbital diameter less than 8% SL................. 5

5a. 46-49 scales with pores along lateral line up to caudal fin base ........................................................... B. armata (eastern Pacific, from Gulf of California to Colombia)

5b. 50-53 (rarely 49) scales with pores along lateral line up to caudal fin base ............................................................ 6

6a. Dorsal fin relatively high and head relatively small, hei- ght of dorsal fin 1.2-1.5 times the height of the head; hei- ght of dorsal fin 1.2-1.5 times the width of the head........ ................................................................... B. veraecrucis (western Atlantic, Gulf of Mexico)

6b. Dorsal fin relatively low and head relatively large, height of dorsal fin 1.7-2.7 times height of the head; height of dor- sal fin 1.6-2.5 times the width of the head ......... B. ronchus (western Atlantic, Caribbean Sea)