Molecular identification and morphological description of totoaba Totoaba macdonaldi and curvina Cynoscion reticulatus preflexion larvae (Perciformes: Sciaenidae)

Preflexion larvae of Sciaenidae taxa collected in the upper Gulf of California on 29 March 2011, were identified as Totoaba macdonaldi (n = 4; notochord length 2.83 mm ± 0.22), an endemic species, and Cynoscion reticulatus (n = 11; notochord length 4.51 mm ± 0.47) on the basis of genetic divergence of partial sequences of 16S rRNA gene (448 base pairs) of mitochondrial DNA. Molecular identification was supported by clustering of preflexion larvae with adult specimens in the phylogenetic analysis, intraspecific (<1 %), and interspecific (>1 %) genetic divergences. Detailed observations allowed morphological descriptions and suggested diagnostic pigmentation in ventral midline of gut, one in T. macdonaldi, but three to four pairs in C. reticulatus; no spots were present on the dorsal tail in T. macdonaldi, but one or two were present in C. reticulatus. Totoaba macdonaldi had more than 20 pigment spots on the ventral tail, but there were only six in C. reticulatus. These larvae descriptions would be useful to identify areas and period of spawning of both species in ichthyoplankton studies.