Data from: Molecular evidence for the monophyly of flatfishes (Carangimorpharia: Pleuronectiformes)

Proliferation of phylogenetic studies based on poor taxonomic sampling or
insufficient molecular evidence usually leads to conflicting results. As a
consequence, advancement of systematic knowledge yields to confusion. The
problem is exacerbated for taxonomic groups with historically difficult
resolution of evolutionary relationships such as the flatfishes. Molecular
evidence to support monophyly for this emblematic group of fishes and
their interrelationships has been elusive, and a recent paper published in
this journal went as far as to claim that flatfish monophyly can be
rejected with molecular data, implying that the asymmetric body plan
unique to these fishes had two independent origins. A reanalysis of this
evidence suggests the contrary and combination of the new data with
existing datasets unequivocally supports the monophyly of this group based
on analyses of concatenated data as well as species tree approaches.
Resolution of difficult phylogenetic problems requires analysis of larger
datasets with adequate taxonomic coverage and sound hypothesis-testing
procedures. Proliferation of partial studies claiming extraordinary
results should be avoided in order to advance the field of molecular
phylogenetics.