Revisão taxonômica e sistemática filogenética de Phrynops geoffroanus (Schweigger, 1812) (Testudines: chelidae)

Abstract

Turtles are freshwater turtles belonging to the Pleurodira suborder, are included in the family Chelidae that at present is represented by 56 species. The genus Phrynops endemic to South America has four nominal species: Phrynops geoffroanus, P. hilarii, P. tuberosus and P. williamsi, the first species has the largest geographical distribution among all representatives of the family Chelidae. It is distributed from the south of Venezuela to the north of Argentina. Considering its wide geographical distribution, several authors have indicated the possible existence of a complex of species that will be divided into distinct entities. The only reappraisal of the genus Phrynops occurred in the early 2000s. Between 2010 and 2015, 223 specimens from all regions of Brazil, north, north-east, central-west, southeast and south were collected covering much of their geographic distribution currently known. The samples were collected using a variety of collecting methods such as "hoop traps" traps, trammel nets, hooks, and sanders. Morphometric and molecular data (mitochondrial genes, nuclear - genomic data) have been important tools to help delineate distinct evolutionary lineages and their respective geographical distribution boundaries. Using mtDNA sequencing of the 16S, Cytochrome b and Cytochrome oxidase I genes with the aim of studying and revealing the genetic diversity patterns of P. geoffroanus to test the existence of cryptic diversity. Through genetic analysis using concatenated data of the mitochondrial genes it was possible to observe the distinction of four lineages. Morphological data also helped to distinguish clusters formed by the morphometric forms of the specimens studied. We suggest the existence of cryptic diversity in P. geoffroanus that may possibly be fractionated in other taxonomic entities.