New report and range extension of smallmouth flounder, Etropus microstomus (Actinopterygii: Carangiformes: Cyclopsettidae), in the Gulf of Mexico

The smallmouth flounder, Etropus microstomus (Gill, 1864), is a species of benthic habits, associated with soft sandy bottoms, and distributed from Canada to the New Orleans coasts, and with specific reports in Corpus Christi, TX, USA. No records have been available from the Mexican coast, however. In the presently reported study, the first finding of this species, in three proximate localities, is described from the Mexican coast. This record constitutes a considerable expansion range in the Gulf of Mexico. Ten specimens were identified through traditional taxonomic characters, together with a CO1 genetic sequence. The presence of this species in the Mexican coastal zone may be due to the dissemination of ichthyoplankton in the ballast water of commercial ships or to the ocean currents along the coasts of the Gulf of Mexico.