| Abstrakt: |
Background: Annual or seasonal killifishes (Cyprinodontiformes: Nothobranchiidae) are unique among fish in their ability to enter into developmental arrests (diapauses: DI, DII, and DIII). They have a short lifespan and their embryos are exceptionally tolerant to a variety of environmental stresses. These traits make them a popular model for studying vertebrate diapause, aging, stress tolerance, genome adaptation, and evolution. In such issues, in a comparative evolutionary framework, Fundulopanchax gardneri, a popular aquarium fish from Africa, is commonly used as a representative non‐annual model though its development is not studied in detail and whether it includes diapauses remains uncertain. Results: We described in detail for the first time embryonic development of F. gardneri and revealed it to resemble that in the undoubtedly annual Austrofundulus limnaeus killifish in displaying two developmental depressions. However, if compared with A. limnaeus, these developmental states look like "less intense" versions of DII and DIII rather than true diapauses. Conclusions: To determine whether developmental depressions in F. gardneri represent "true" diapauses or only their functional equivalents, detailed studies of embryonic development of different killifish both annual and non‐annual are needed. Before that, acceptance of F. gardneri as a representative non‐annual fish seems premature. Key Findings: Aplocheloid annual killifish (Cyprinodontiformes) are unique among fish in the ability to arrest development at different embryonic stages and prolong it for months and years. These and other traits make them a popular model in studying of aging, stress tolerance etc. In these studies, in a comparative framework, aplocheloid Fundulopanchax gardneri is usually used as a representative non‐annual fish though its developmental life‐history remains obscure.This study provides detailed description of F. gardneri development from early embryonic stages till sexual maturation with focus on developmental arrests, divergent developmental trajectories, duration of embryonic period, etc.The data provided in this study indicate F. gardneri to display developmental traits characteristic for annual killifish but in the "less expressed" form. Acceptance of F. gardneri as annual vs non‐annual is premature until the detailed study of embryonic development in other killifish both annual and non‐annual. [ABSTRACT FROM AUTHOR] |
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