Description of larvae and juveniles of Bairdiella ronchus (Sciaenidae: Teleostei) in southeastern Brazil

• Main Authors: Michael Kengo Itagaki, Márcio Hidekazu Ohikawara, June Ferraz Dias, Mario Katsuragawa
• Format: Article
• Language: English
• Published: Consejo Superior de Investigaciones Científicas 2007-06-01
• Series: Scientia Marina
• Subjects: larval description; bairdiella ronchus; southeastern brazil
• Online Access: http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/4

Developmental stages from flexion larvae to early juvenile of Bairdiella ronchus were described and illustrated from specimens collected along the margins of tidal creeks in the southern zone of the Cananéia-Iguape System on the southeastern coast of Brazil. The B. ronchus larvae were identified working backwards from the juvenile using characteristics common to successively earlier ontogenetic stages. The number of myomeres was 25 (11+14). The flexion of notochord was completed by 5.5 mm SL. The fin formation began in the following sequence: caudal, second dorsal and anal, pelvic fins, first dorsal and pectoral. It was fully completed in this sequence: principal caudal, second dorsal, anal, first dorsal, pelvic and pectoral fins. Squamation began between 10.0 mm SL and 11.1 mm SL, and was entirely completed by 35.0 mm SL. The major head spines included the posterior preocular, supraocular and post-temporal. The larval morphology and pigmentation, mainly the swath pigmentation pattern, were very similar to those described for B. chrysoura in the South Atlantic Bight of the United States. Among sciaenid larvae co-occurring in the study area, Stellifer rastrifer shows larval characteristics more similar to those of B. ronchus, mainly in the preflexion and flexion stages, and in the contraction of the swath pigmentation. They can be differentiated by the fact that in S. rastrifer there is a post-anal lateral pigmentation or caudal pigment on the ventral midline radiating dorsally, which is absent in B. ronchus.