Apogon quadrisquamatus Longley

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 : 23

Apogon quadrisquamatus Longley

Lineage A

Identification. A single adult specimen from Belize ( Fig. 28 ) constitutes the genetic lineage herein referred to as Apogon quadrisquamatus Lineage A. Adult A. quadrisquamatus can be distinguished from other Apogon by the combination of eight segmented anal-fin rays; lateral-line and body scales of similar size; no dark marking or bar beneath the second dorsal fin; caudal-peduncle spot small, circular, of varying intensity, and usually restricted to middle of caudal peduncle; and 12–14, modally 13, gill rakers on the lower limb of the first arch, ( Böhlke & Chaplin 1993, Dale 1977, Gon 2002). The adult specimen in this lineage keys to Apogon quadrisquamatus and is distinct from A. mosavi and Apogon sp. 2 in having a circular blotch of melanophores in the center of the peduncle vs. a rectangular bar ( A. mosavi ) or very diffuse oval ( Apogon sp. 2) of melanophores. Apogon robbyi has a similar circular, basicaudal blotch, but that species is distinctive in having dusky stripes on the trunk. Apogon quadrisquamatus Lineage A is further distinguished from A. mosavi in having 12 gill rakers on the lower limb of the first arch (possibly a rudiment is forming), vs. 14–15 in A. mosavi . The body is mostly orange, and the median fins are yellow. Additional material and further study are needed to determine if this lineage and A. quadrisquamatus Lineage B (see next section) are morphologically distinct, and, if so, which one represents A. quadrisquamatus Longley 1934 . No larvae or juveniles match the single adult specimen of this lineage in our genetic analysis.

Figures

FIGURE 28. Apogon quadrisquamatus Lineage A, adult, 21.0 mm SL, DNA # BLZ 8291, photograph by C. Baldwin