Continental fishes of Nicaragua: diversity, distribution and conservation status; with an annotated and illustrated checklist of species and an identification guide to families.

Based on a combination of intensive literature review, electronic database searches, re-identification of museum specimens, and fieldwork, we provide an updated checklist of the continental fishes of Nicaragua. This checklist, systematically arranged at the ordinal and familial level, includes nomenclatural revisions, distributional information, conservation status, and when appropriate, cross-references to previous lists and revisionary works on the fish fauna of the country and region (Central America); illustrations and descriptions to the family level and color photographs of some representative species are also included. According to our results, the native Nicaraguan continental fish fauna is composed of 244 species, divided into 111 genera, 45 families, 24 orders, and two classes; increasing by 60 (i.e., 32.6%) the number of species originally reported by Villa (1982; i.e., the most comprehensive work published to date). The majority of the Nicaraguan native continental fish species, according to their supposed tolerance to salinity, are peripheral (68.9%), followed by secondary freshwater fishes (23.8%), and primary freshwater fishes (only 7.4%). Fish diversity in the 19 major river basins ranged between 21 and 90 species (mean = 58 species, median = 60); the Escondido (Es; 87 species), in the Atlantic, and the Pacfico de Nicaragua (PN; 90), in the Pacific, presented the highest species richness. Most species (188) are restricted to elevations between 0 and 100 meters above sea level (masl); only a few species (18), in contrast, were found at elevations greater than 500 masl (up to 780 masl). Fourteen species in this revision are listed as endemic to Nicaragua. Regarding their conservation status, 22 species (9.0%) are categorized, according to the International Union for Conservation of Nature (IUCN), as Data Deficient, 186 (76.2%) as Least Concern, and seven (2.9%) as Near Threatened; while 24 species (9.8%) are listed as Threatened, thirteen (5.3%) as Vulnerable, two (0.8%) as Endangered, and nine (3.7%) as Critically Endangered. Five species (2.0%) have not yet been evaluated. Six exotic species are also reported. Our results provide a framework for future taxonomic and biogeographic works on fishes from this country and region (Central America), particularly by providing up-to-date knowledge on nomenclature and distributions. In addition, the data provided in this revision will help to monitor fish distributional changes in the future due to human introductions and global change and will aid in conservation decisions concerning Nicaraguan continental fishes.