About Obelia geniculata (Linnaeus, 1758)
Obelia geniculata is a cnidarian species in the Campanulariidae family, commonly called the Knotted Thread Hydroid, and it has a cosmopolitan distribution. O. geniculata reproduces asexually via budding from blastostyles. When medusa buds are ready to be released from the blastostyle, the lateral wall bursts at the distal end. Once the buds become free-floating, they are classified as gonangia. These gonangia reproduce sexually through broadcast spawning: male and female gonangia release sperm and eggs directly into the water. Fertilized zygotes go through complete cleavage to develop into planular larvae. These planula larvae swim through the water until they attach to a suitable substrate, where they eventually grow into hydranths.
