Apogon aurolineatus (Mowbray)

Baldwin, Carole C., Brito, Balam J., Smith, David G., Weigt, Lee A. & Escobar-Briones, Elva, 2011, Identification of early life-history stages of Caribbean Apogon (Perciformes: Apogonidae) through DNA Barcoding, Zootaxa 3133, pp. 1-36 : 21-23

Apogon aurolineatus (Mowbray)

Identification. Four adult specimens of A. aurolineatus provided the basis for genetic identification of seven larvae and one juvenile (Appendix 1, one adult is shown in Fig. 24 ). Adult A. aurolineatus can be distinguished from other Apogon by the combination of eight segmented anal-fin rays, 10–11 gill rakers on the lower limb of the first gill arch, 16–18 circum-caudal-peduncle scales, no dark markings or saddles on the posterior portion of the body, and two to four short dark lines radiating from the eye ( Böhlke & Chaplin 1993; Gon 2002).

Juveniles ( Fig. 25 ). The single juvenile, a reared specimen of 12 mm SL, has a pale salmon body color, and the opercular and abdominal regions are silvery. In preservative, there are no distinctive markings except a few melanophores on top of the head. There are 11 gill rakers on the lower limb of the first gill arch.

Comparisons Among Juveniles. Of the Apogon species for which juveniles are known, A. aurolineatus most closely resembles A. quadrisquamatus in lacking dark blotches or markings on the body. The reared juvenile of A. aurolineatus can be separated from juvenile A. quadrisquamatus in having a pale body color (vs. orange in A. quadrisquamatus ), in lacking yellow on the dorsal and caudal fins, and in lacking an orange spot on the center of the caudal peduncle. Preserved juveniles of the two species are very similar, but eye diameter may be useful in separating the species (diameter of bony orbit approximately 13% SL in the 12.0-mm SL juvenile of A. aurolineatus vs. 15% SL in 14.0–16.0-mm SL juveniles of A. quadrisquamatus ). Preserved juveniles of A. aurolineatus also are similar to those of A. robbyi and A. mosavi in having a pale body, but A. aurolineatus lacks the blotch of melanophores on the caudal peduncle present in those species.

Larvae ( Fig. 26 ). Apogon aurolineatus larvae genetically analyzed in this study are all approximately 8 mm SL. They are bright orange in life and have orange pelvic, anal, and second dorsal fins. The first dorsal fin is orange at the base, but most of the fin is bright yellow. The pectoral and caudal fins are clear. There are some pale areas on the head—below the anterior portion of the eye and above the tip of the snout. The top of the head has yellow pigment in some specimens. There are no dark markings on the body except sometimes a few melanophores on the top of the head. There are barely observable melanophores scattered on the jaws. The caudal-peduncle length ranges from 27 to 29% SL.

Comparisons Among Larvae. Fresh specimens of A. aurolineatus larvae are easily distinguished from other known Apogon larvae by the combination of bright orange body coloration and yellow pigment on the first dorsal fin. Preserved specimens usually have fewer melanophores on top of the head than larvae of other Apogon (zero to several vs. many) and a shorter caudal peduncle (27–29 % SL vs. 30–40 % SL in other species).

Apogon robinsi Böhlke and Randall

Identification. One adult specimen of A. robinsi was collected and analyzed genetically (Appendix 1). Because the photograph of that specimen is not of good quality, we selected a photograph of a specimen not included in the genetic analysis to represent the species ( Fig. 27 ). Adult A. robinsi can be distinguished from other Apogo n species by the combination of eight segmented anal-fin rays, body and lateral-line scales of similar size, body with two distinct dark markings (one bar below and just behind second-dorsal fin and a bar on the posterior part of caudal peduncle—the distance between the two bars larger than the width of the posterior bar), and premaxillary dentition extending outside the mouth laterally on the bone ( Böhlke & Chaplin 1993, Gon 2002). No larvae or juveniles analyzed in this study genetically match A. robinsi .

Figures

FIGURE 24. Apogon aurolineatus, adult, 30.0 mm SL, DNA # BLZ 6176, photograph by J. Mounts and C. Baldwin.

FIGURE 25. Apogon aurolineatus, juvenile, 12.0 mm SL, DNA # BLZ 5497, reared, photograph by L. Weigt.

FIGURE 26. Apogon aurolineatus, larva, 8.0 mm SL, DNA # BLZ 5221, photograph by J. Mounts.

FIGURE 27. Apogon robinsi, adult, 35.5 mm SL, USNM 395831, not a DNA voucher, photograph by J. T. Williams.