Megaleporinus macrocephalus, (Garavello & Britski, 1988) (Garavello & Britski, 1988)

Almeida, M. S., Moraes, P. S. S., Nascimento, M. H. S., Birindelli, J. L. O., Assega, F. M., Barros, M. C. & Fraga, E. C., 2022, New records of the occurrence of Megaleporinus macrocephalus (Garavello & Britski, 1988) (Characiformes, Anostomidae) from the basins of the Itapecuru and Mearim rivers in Maranhão, Northeastern Brazil, Brazilian Journal of Biology (e 232868) 82, pp. 1-6 : 3-4

3. Results

On the Mearim River , one M. macrocephalus specimen was collected on the lower course of the river at Laje dos Currais , in the municipality of São Mateus, during the flood season, while two specimen was obtained on the middle course of the river in the town of Pedreiras during the dry (low water) season. The M. macrocephalus specimen was collected at the locality of Pé da Serra in the municipality of Caxias during the dry season.

The four M. macrocephalus specimens ( Table 1 ) present a characteristic coloration pattern, with a darker superior half of the body, three large black spots on each flank, and dark lines between the rows of scales ( Ramirez et al., 2017). The body is robust, and the mouth terminal, with three teeth in the pre-maxillary bone and three teeth in the dentary bone ( Figure 2 ). The specimens have 42–43 scales in the lateral line, seven rows of scales between the lateral line and the origin of the dorsal fin, six rows of scales between the lateral line and the origin of the pelvic fin, and 16 rows of scales around the caudal peduncle. These characteristics, together with the morphometry of the specimens, are fully consistent with the descriptions of M. macrocephalus published Garavello and Britski (1988) and Britski et al. (1999), and leave no doubt with regard to the identity of the taxon.

Four COI sequences were obtained, one from the specimen collected from the Itapecuru River, and three from the specimens obtained from the basin of the Mearim River. Comparisons with the sequences available in the BOLDSystems database confirmed the morphological identification of the specimens.The COI sequences obtained from the specimens collected in the present study were more than 99% similar to that of M. macrocephalus from the basin of the Paraná River ( Table 2 ). This value is well within the 2% threshold for the identification of fish species by DNA barcoding ( Ward et al., 2009; April et al., 2011; Carvalho et al., 2011; Mabragaña et al., 2011; Castro Paz et al., 2014).

Figures

Figure 2. Megaleporinus macrocephalus, MZUEL 20221, 387.10 mm SL.