Developmental ecology in embryos of an estuarine pupfish endemic of the Yucatan peninsula: Survival out of water, metabolic depression, and asynchronous hatching.

Background: Theory predicts that drought-resistant embryos with extended incubations are evolutionarily favored in environments with high mortality of larvae but safe for eggs. Here, we experimentally test, under common garden conditions, the effect of three incubation temperatures and media on embryonic developmental length, extended incubation out of the water, survival, metabolic rate, and hatching dynamics in the estuarine pupfish Garmanella pulchra. We also described the morphological changes of embryonic cortical structures related to air exposure.

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

The Mexican Rivulus, , 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.

Morphofunctional analysis of the gastrointestinal tract of an annual killifish: In search of structural traits related to the annual life history.

Annual killifishes have active and voracious rates in acquisition of food resources with display of behaviors that allow them to maintain high metabolic rates to deal with the harsh and unpredictable conditions prevalent in temporary pools where they inhabit. The objective of this research was to describe histologically and ultrastructurally, the digestive system of the annual killifish Millerichthys robustus to identify morphological traits related to its annual life history and digestive physiology. Also, we quantify food items along the intestine as a proxy for rates of digestion.

How maternal age and environmental cues influence embryonic developmental pathways and diapause dynamics in a North American annual killifish.

Background: Temporary pools are variable environments with seasonal drought/flood phases. Annual killifish have adapted to life in temporary pools by producing embryos that undergo diapause to traverse the dry phase. To fill existing knowledge gaps about embryo diapause regulation and evolution in annual killifishes, we test the effect of maternal age, incubation temperature, and incubation medium on diapause induction and length in Millerichthys robustus, the only North American fish species that has evolved an annual life history.

Protogynous functional hermaphroditism in the North American annual killifish, Millerichthys robustus.

Sex change (sequential hermaphroditism) has evolved repeatedly in teleost fishes when demographic conditions mediate fundamentally different sex-specific returns for individuals of particular age and size. We investigated the conditions for potential sex change in an annual killifish (Millerichthys robustus) from temporary pools in Mexico. In natural populations, we detected adults with intersex colouration and gonads.