Akko rossi Van Tassell & Baldwin 2004

photo by Julie Mounts
El Salvador Pacific

IDENTIFICATION

Head Pores - Cephalic head pores B', G' - pores small

Scales - About 115 scales, overlapping only on caudal peduncle

 

Fins - The first dorsal fin has 7 spines; the second dorsal and anal fins both have 16 elements, the first element a spine in both. The caudal fin is lanceolate with 17 segmented rays, 4 upper and 5 lower procurrent rays. The first and second dorsal, anal, and caudal fins are connected. Median fin rays are serially branched with 4 to 5 branches. The pectoral fin is short, ending well before the anus, with 19 dichotomously branched rays. Pelvic fins are united forming a disk with a well-developed anterior frenum. The pelvic base is formed into a muscular pedicel with strong muscle bundles extending from the vicinity of the pelvic process to the vicinity of the pelvic spine, with some of the fibers inserting on the spines. Rays 1, 2, and 3 are serially branched; rays 4 and 5 dichotomously branched.

Head - The mouth is large, the opening at an angle of 50° to the horizontal. No rostral frenum is present, and the upper jaw is only slightly protrusible. The oral velum has dorsal and ventral projections at the midline. The anterior nostril is a short thickened tube. The posterior nostril is a slit. There is no pseudobranch. The eye is tiny with a large lens occupying most of the eye. The gill opening extends from opposite the base of the sixth pectoral fin ray and extends ventrally to the pelvic-fin base where it forms a flap supported by the second branchiostegal ray.

Papillae - The pattern is the same as that of Akko brevis. Horizontal row b has an elongate anterior extension ending under the eye; row d is complete, not divided into two sections, and row ot extends ventrally onto the branchiostegals, ending just past the second branchiostegal ray. The first vertical papillae row is complete, extending from the eye to near row d. Additional vertical rows are divided by row b, with two rows above and four rows below. Only the last vertical row below row b extends below the level of row d. Dorsal rows X1 and X2 are continuous or nearly so as is row n.

Color - The head and dorsal portion of the trunk are brown in the preserved specimen. The ventral section, below the midline, is a pale tan anteriorly, becoming tan to light brown posteriorly. The fins are dark brown, becoming light brown or speckled brown at the base only. The pigment is restricted to the membranes in all fins except the first dorsal, in which the membrane covering the spines is also brown. The genital papilla is brown, the tip and remainder of the surrounding ventral area white.

Distribution - Known only from the holotype collected in the Gulf of Fonseca, El Salvador.

Habitat - Mud

Notes -