Fishes of the Persis region of Iran: an updated checklist and ichthyogeography

This study provides a new and updated checklist of the freshwater fishes of the Persis region which drains to the Persian Gulf. The list is based on historical literature records and taxon occurrence data obtained from natural history collections and new fish collections. The confirmed freshwater fishes of the Persis region (sub-basin) comprise 44 species in 34 genera, 14 families, 11 orders and one class. The most diverse order is the Cypriniformes with 23 confirmed species (52.25%) followed by Cyprinodontiformes (6 species, 13.65%), Mugiliformes (4 species, 9.1%), Gobiiformes (3 species, 6.8%) and Perciformes with 2 species (4.55%). Acipenseriformes, Clupeiformes, Gonorynchiformes, Siluriformes, Salmoniformes and Synbranchiformescomprise only one species (2.25%). New species have been discovered, some subspecies have been elevated to species, some are being resurrected from synonymy and some taxonomic problems remain and are commented on briefly. Eleven endemic species (25%) in seven genera and four families and 10 exotic species (22.7%) in 8 genera and 3 families are listed here. The fish taxa were classified into different major groups based on the fish ichthyogeographical origin, ecoregion and ecological factors (tolerance to salt water and mode of life). The long history of connection and isolation from fresh and marine waters, multiple sources of species, uneven distribution of inflows and nutrient inputs, and the low to moderate ranges of salinity, different types of habitat (both fresh and brackish water habitats including rivers, lakes, lagoons, marshes, and marine environments), have all contributed to the high ichthyodiversity of the Persis region. It is proposed that the current isolated river systems of the Persis, Zohreh, Tigris and Kor River basins were interconnected during the Last Glacial Maximum of the Late Pleistocene (21,000–18,000 y. BP) and remained so until the sea-level rise of the Early Holocene (11,000 y. BP.). The predicted geographic distributions for the eight species of this region based on current bioclimatic variables revealed that a relatively large area of suitable climate for these native species in the Persis basin extend to western parts of Iran.