Systematic and phylogenetic revision of the stingrays of the family Potamotrygonidae Garman, 1877 (Chondrichthyes: Batoidea: Myliobatiformes), with inferences about the origin and evolution of the group

• Grant number: 22/12849-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): May 01, 2023
• Effective date (End): April 30, 2025
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Aléssio Datovo da Silva
• Grantee: Thiago Silva Loboda
• Host Institution: Museu de Zoologia (MZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The family Potamotrygonidae currently comprises two subfamilies, five genera, and 40 species, being the second family with the greatest diversity in the order Myliobatiformes. In the last 10 years, the family is no longer a clade that embraces only the South American freshwater stingrays (subfamily Potamotrygoninae). Two species of the genus Styracura (subfamily Styracuninae) that occurs in Atlantic and Pacific marine waters of the northern part of South America and coastal regions of Central America, were incorporated into the Potamotrygonidae. During this period, there were also descriptions of 12 new species plus a new genus (Heliotrygon), making a systematic reconfiguration in the family, and also a major taxonomic reformulation, with the incorporation of a few characters defining its supraspecific intrataxons, and of course the family itself. The phylogenetic relationship currently accepted between the family genera is: Styracura + (Heliotrygon + Paratrygon) + (Plesiotrygon + Potamotrygon). However, some questions remain about this current resolution: 1) what are the family synapomorphies with the inclusion of Styracura? 2) Is Plesiotrygon the sister group of Potamotrygon or its species are included in the latter genus? 3) What are the relationships between Potamotrygon species? The most important point about these issues however is that a phylogenetic analysis among all species has never been performed before. Here we propose a comprehensive phylogenetic and systematic review of the Potamotrygonidae family based mainly on unpublished morphological characters covering all its taxa, as well as performing additional analyzes with molecular characters and with characters from fossils of the family. From the results of these analyses, we will elaborate a hypothesis about the origin, evolution, and diversification of potamotrygonids across the American continent. (AU)