MOLECULAR DIVERSITY OF Pimelodus blochii (Valenciennes, 1840) (SILURIFORMES, PIMELODIDAE) OF THE TAPAJÓS RIVER AND LOW AMAZONES
Barcoding DNA, Pimelodidae, Genetic variation.
The Pimelodidae family (Siluriformes) encompasses at least 112 recognized species classified
in 32 genera. The genus Pimelodus has a wide distribution by the rivers of South America.
The following species occur in the Amazon basin: P. blochii, P. albofasciatus, P.
microstoma, P. jivaro, P. ornatus, P. tetramerus, P. altissimus and P. pictus that present a
great morphological variation, making it difficult to taxonomic revision of the genus. The
species P. blochii occurs in a wide territory of the Amazon basin, where it has relative
importance in the subsistence fishery and riverside population feeding. Morphometric and
cytogenetic data suggest that P. blochii may represent a species complex. In the present work
will be investigated the molecular genetic diversity of P. blochii from the Tapajós and Lower
Amazonas rivers. Will be utilized mitochondrial genetic markers Cytochrome Oxidase
Subunit I (COI) and the control region D-loop. Were obtained 66 COI sequences from the
Amazonas, Tapajós and Trombetas rivers were compared with other sequences deposited in
GenBank belonging to 12 congeners, including P. blochii from different locations. The
average intra and interspecific genetic divergence was 1,26 and 18,32%, respectively. The
cluster analysis of neighbors revealed clusters and the existence of a single population of P.
blochii with wide distribution between the basin of the Amazon and Itapecuru rivers.
However, the P. blochii population of the Magdalena River in Colombia diverged in 6% of
the other samples indicated for this species.