Data from: The role of ecology in allopatric speciation of darters in the Central Highlands, USA

Allopatric speciation is the predominant mode of speciation in riverine
fishes. However, the relative importance of genetic drift versus natural
selection in the allopatric speciation of these fishes remains uncertain.
Here, we present a case study that demonstrates the role of ecology in the
diversification of a group of imperiled freshwater fishes from the central
United States. We integrate a phylogenomic dataset with analyses of
streamwise distance, environmental variables, meristic and morphological
traits, and diet to investigate the ecological context and outcomes of
allopatric speciation within a species complex comprising the Slenderhead
Darter Percina phoxocephala (Nelson), Ouachita Darter Percina
brucethompsoni (Robison, Cashner, and Near), and Longnose Darter Percina
nasuta (Bailey). We find that two of the species traditionally delimited
based on disparity in snout length, P. phoxocephala and P. nasuta, are
polyphyletic, revealing three instances of the parallel evolution of snout
length disparity. We propose a revised taxonomy including the delimitation
of six new species based on disparity in phenotypic traits and
phylogenomic analyses. We find that morphological differences are not
correlated with genetic divergence but are congruent with with variations
in diet and environmental niches, suggesting a role for ecological factors
in allopatric speciation of riverine fishes. The resources associated with
this manuscript include genomic data, phylogenetic analyses, genomic
analyses, morphological measurements of museum specimens, gut contents
from museum specimens, and geospatial analyses of publically available
environmental variables.