Hoplias malabaricus, popularly known as trahira is classified inErythrinidae, Order
Characiformes. Cytogenetic studies showed highchromosomal variation among
populations,have been classified into seven cytotypes (A-G). Molecular data
evidencedhigh levels of genetic diversity and support the hypothesis of
H.malabaricusasa species complex, including independent biological units. Genetic
studies in populations of trahiras in the Amazon Basin are scarce and the studies
developed so farrarely resolved this species complex.This work describes the
molecular and chromosomal diversity in the complex H. malabaricusfrom Amazon
basin.Were collected 59 specimens fromeight localities in the lower Amazon River,
state of Pará, Brazil.For chromosomal analysis, it was processed conventional
staining, C-banding, Ag-NOR staining, CMA3 staining and FISH with 18S rDNA
probes. For molecular analysis the genetic distances were accessed from DNA
barcodes sequences (gene cox I) using Neighbor-joining with K2P model, and
median joining for haplotype network.Thestudy showed the presence of distinct
karyotypes with diploid numbers of 40, 41 and 42, that were classified in four
cytotypes: A, C, E and G; NORsshowed different number and locations between
cytotypes andcollection points. The C-banding pattern was homogeneouswithin each
cytotype.DNA Barcode analysis clearly revealed two groups, which canindicate the
presence of an undescribed Hoplias in the lower Amazon region.This is the firstwork
in the lower amazon that aim to discriminate species of the Hoplias
malabaricuscomplex, correlating data with cytogenetic markers andcontributing to the
molecular validation of the efficacy of DNA Barcode.
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