Cynops cyanurus Embryonic Development
A photo series by Ferenc Bády
In 2013 I decided to document the embryonic development of this species in as much detail as I can. I wanted to take photos at least once a day until the larva started eating. On the morning of April 6 I collected some freshly laid eggs from the tank where one of the females was housed temporarily. The egg shown on the first photo seemed infertile, so I chose another one. The rest of the images show the same individual. It was stored in a separate dish, and I changed the water about twice a week. For taking photos I placed it into a black film box cap. On the day 18, due to a little disturbance while setting it up for taking the photo, the weakened egg shell was torn and the larva hatched. After this it was put in a transparent plastic box for each photograph.
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Day 1, shortly after laying. |
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A few hours later, after the first cell division. The embryo consists of two cells. |
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In the evening. The third cell division has just started along the horizontal plain. |
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Two hours later the embryo has reached the morula stage. |
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Day 2, in the morning. Early blastula stage. |
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Day 2, in the evening. A more advanced blastula. |
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Day 3, in the morning (dorsolateral view). The mass of small, quickly-dividing, yolk-free cells in the animal pole started to expand over the larger, yolk-rich cells of the vegetal pole (margin shown by arrows). The layer created by the former cells will form the ectoderm and mesoderm, while the latter ones will create the endoderm. |
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Day 3, in the evening (ventral view). The above mentioned process in a more advanced stage. |
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Day 4, in the morning (ventral view). Gastrulation is in process: ectodermal cells are migrating into the blastocoel through the blastopore (arrow) to create the mesoderm. |
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Day 4, in the afternoon. The neural plate appears and starts to separate from the ectoderm (anterior end is upper left). |
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Day 4, in the evening. Neural plate is folding into a tube. |
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Day 5, in the morning. The anterior end of the neural tube is transforming into the brain, and the head is starting to develop (on the left). |
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Day 6, in the morning. Primordium of the inner ear (arrow) and tail bud are visible. |
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Day 7, in the morning. Body is becoming elongated, and the tail bud is longer too. |
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Day 8, in the morning. The first pigment cells and gill buds appear. |
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Day 9, in the evening. Tail fin appears. All of the subsequent photos were taken in the evening. |
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Day 10. Fins are higher, tail is longer. |
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Day 11. |
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Day 12. |
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Day 13. |
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Day 14. |
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Day 15. Eye and balancer are visible. |
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Day 16. |
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Day 17. |
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Day 18. Larva hatched. |
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Day 19. Developing forelimb is visible (arrow). |
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Day 20. |
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Day 21. |
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Day 22. Hind limb buds are visible (arrow). |
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Day 23. Most of the yolk has absorbed, and the next day the larva started eating. |