Back to the roots, Part 1—early life cycle data of Rhopaliophora (Scyphozoa, Cubozoa and Staurozoa)

Abstract

The phylogeny of the Rhopaliophora (Scyphozoa, Cubozoa and Staurozoa) has been discussed and modified extensively up to the present day. Attempting to finally solve this question, the morphology and development of the different early life history stages stages of 17 scyphozoan, 2 staurozoan and 8 cubozoan species were investigated. Due to the magnitude of the study, the findings will be published in two parts. This first part will focus on the comparison of early life cycle stages, the second part (to be published in the following issue of Plankton & Benthos Research) will focus on the evolutionary connection and systematics. The present part of the study focused on the morphology of different types of sessile stages (polyps), the processes of strobilation and metamorphosis, and the resulting products (residues and ephyrae/young medusa) and their further development. The different morphological characters in the polyps helped to categorize them into types. By using the strobilation rates and information on the way morphological characters changed during the process of strobilation/metamorphosis, the strobilae were able to be separately categorized.

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