About this Research Topic
In vertebrates, viviparity (livebearing) has evolved independently several times. With the exception of birds, viviparity is found in all vertebrate groups. In bony fishes alone, viviparity has arisen independently at least 13 times, and in cartilaginous fishes at least 9 times. The repeated evolution of viviparity in widely divergent animal lineages has brought a staggering array of morphological, physiological, and behavioral adaptations that facilitate the internal development of embryos. Viviparous fishes have been particularly important model systems for understanding these adaptations, including their function, genetic bases, specialized anatomical features, and the ecological factors that served, and may still serve, as selective agents for the evolution of viviparity.
Beyond their role as models to study the proximate and ultimate functions of viviparity in itself, some groups of viviparous fishes, such as the Neotropical families Poeciliidae and Goodeidae, have served as study systems to explore other major genetic, physiological, behavioral, ecological, and evolutionary processes. Through the study of viviparous fishes, a wealth of knowledge has emerged on pre- and post-copulatory sexual selection, complex social behavior, learning and cognition of vertebrates, the origin of unisexual species, genetic variation in natural populations, assembly of freshwater communities, and even the genetic factors involved in the formation of tumors, to name only a few.
In this Research Topic, we search for recent, cutting-edge advances in the knowledge of viviparous fishes. In particular, we aim to expand our understanding of the interplay between physiological, reproductive, and behavioral mechanisms, the ecological factors that directly affect the expression of such mechanisms, and the evolutionary forces that have shaped the genetic and phenotypic diversity of all these traits in viviparous fishes. We seek contributions from scientists working across levels of biological organization (genotypes, individuals, populations, and communities) in any group of fishes that include viviparous species. Studies focused on the conservation of threatened taxa, or on the management and control of invasive species, are also welcome.
Keywords: adaptations, internal development, livebearing, phenotypic diversity, viviparity
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