The complete genome sequence of the protogynous hermaphrodite North American annual killifish Millerichthys robustus (Rivulidae, Cyprinodontiformes).

Abstract

The Mexican Rivulus, Millerichthys robustus, is an enigmatic species of seasonal killifish endemic of the Southeast Mexico that has changed paradigms on the evolution of annualism in killifishes. This species survives in ephemeral environments that experience a period of seasonal drought that causes the death of all adult fish. However, populations persist due to their drought-resistant embryos capable of arresting their development in diapause until the next the rainy season. Millerichthys evolved unique characteristics within annual killifishes as a functional sequential hermaphroditism, in which females change to males (protogynous) under perceived conditions of mate competition. Also, M. robustus express different color phenotypes in both sexes: five-color phenotypes continuously distributed in various perceptual units between yellow and red in males, and different number of ocelli disposed in caudal peduncle in females. The phylogenetic relationships of M. robustus revealed that it is a sister clade to two non-annual species found exclusively in Cuba (Rivulus cylindraceus and Rivulus berovidesi), indicating that the annual life cycle, through the acquisition of embryonic diapause, has evolved independently in this species. Here, we present the complete genome sequences for the North American annual killifish Millerichthys robustus. The raw data and assembled genome are available in GeneBank.