The medaka is a fish that has served as a model organism for over a century, yet there is still
much to learn about its life in the wild. Here we summarize the current knowledge, highlight …

An increasing volume of empirical studies demonstrated that hybridization between distant
lineages may have promoted speciation in various taxa. However, the timing, extent and …

Closely related species have been used as representative systems to investigate the genetic
mechanisms involved in the early stages of species differentiation. Previous studies have …

In medaka fishes, the family Adrianichthyidae, tropical species are known to be sexually
more dimorphic than temperate species. If this reflects that tropical species are exposed to …

Geographic isolation is the primary driver of speciation in many vertebrate lineages. This
trend is exemplified by North American darters, a clade of freshwater fishes where nearly all …

A key question in ecological speciation is to understand the causes and consequences of
phenotypic divergence among populations. In this work, we analyzed the body shape and …

Sexual dimorphism, the phenotypic differences between males and females within a
species, is widespread in the animal kingdom. This study investigates the extent of sexual …

Sympatric speciation is considered to be difficult without the coupling between ecological
traits that allow resource partitioning and reproductive traits that allow assortative mating …

Tandem gene duplication has led to an expansion of cone-opsin repertoires in many fish,
but the resulting functional advantages have only been conjectured without empirical …

Although there are many examples of color evolution potentially driven by sensory drive,
only few studies have examined whether distinct species inhabiting the same environments …