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The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large‐scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

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<p><strong>Background: </strong>Mexico has a high diversity of aquatic and subaquatic plants that occur between 1,000 and 2,500 m of elevation, although a larger proportion of aquatic plants is concentrated at lower altitudes. Temporary wetlands harbor close to 73 % of the aquatic species in Mexico. These systems are under a strong anthropogenic pressure and suffer constant degradation.</p><p><strong>Questions:</strong> i) How many species grow in highland temporary wetlands? ii) Are they floristically similar? iii) Is there a latitudinal pattern of species richness?</p><p><strong>Studied groups: </strong>Charophyta, Pteridophyta, Angiosperms.</p><p><strong>Study site and years of study:</strong> Central Mexico (39 wetlands) from 2015 to 2016.<strong></strong></p><p><strong>Methods: </strong>We collected in 39 temporary wetlands for two years. We made a presence/absence list of species per locality, and calculated floristic similarities and correlations between wetlands. We include data characterizing life form, plant use, and conservation status.</p><p><strong>Results:</strong> We found 126 species belonging to 80 genera and 38 families. The richest families were Cyperaceae, Asteraceae, and Poaceae. As to genera, <em>Eleocharis</em>, <em>Cyperus</em>, and <em>Juncus </em>had more species. Species with the widest distributions were <em>Persicaria mexicana</em>, <em>Marsilea mollis</em>, <em>Luziola fluitans</em>, <em>Heteranthera peduncularis</em>, and <em>Nymphoides fallax</em>.  We found five different life forms – all herbaceous, including 27 threatened species, 24 species with economic use, 48 endemic species, and 19 cosmopolitan species. In addition, we found 20 species recorded for the first time in some states included in our study, and two species of <em>Eleocharis</em> that might represent undescribed species. The richest wetland harbors 40 species, the poorest has only five. Wetlands were comparable to each other in species composition, and species richness increases towards the south.</p><p><strong>Conclusions:</strong> Temporary wetlands harbor a high floristic diversity and are similar to each other. Lower latitudes host higher numbers of species.</p>

To determine potential drivers of the global distribution of ploidy in aquatic macrophyte species we allocated ploidy state to 1572 species occurring in 238 10 × 10° gridcells worldwide. Analysis of the relationship of 16 global-scale spatial, landscape, environmental, and biotic variables with ploidy state using Boosted Regression Trees revealed temperature variables and evapotranspiration as the strongest predictors. There were contrasting latitudinal patterns between haploid/diploid and polyploid species, while species richness measures also influenced ploidy state. Polyploid species occupied larger geographical ranges than haploid/diploid species. Mixed ploidy species showed the highest latitudinal range size and maximum latitude of species occurrence. Our findings suggest that increased chromosome number is associated with tolerance of a wider range of environmental conditions in macrophyte species. Mixed ploidy could reflect adaptability to expand geographical occurrence via chromosome number change, with such species predominantly occupying a latitude range intermediate between haploid/diploid and polyploid macrophyte dominance.