A stable phylogenetic hypothesis for families within jellyfish class Scyphozoa has been elusive. Reasons for the lack of resolution of scyphozoan familial relationships include a dearth of morphological characters that reliably distinguish taxa and incomplete taxonomic sampling in molecular studies. Here, we address the latter issue by using maximum likelihood and Bayesian methods to reconstruc...

In Cnidaria, the medusae of Scyphozoa and its sister-group Cubozoa uniquely possess rhopalia at their bell margin. These sensory centers coordinate behavior and development. We used fluorescent in situ hybridization and confocal microscopy to examine mRNA expression patterns in Aurelia sp.1 (Cnidaria, Scyphozoa) during early medusa formation, while simultaneously visualizing the developing nerv...

The frequency of jellyfish blooms is generating a world-wide discussion about medusae population explosions, mainly those associated with stings. We report over 20,000 envenomations caused by Chrysaora lactea (Scyphozoa) in the State of Paraná (southern Brazil) during the austral summer of 2011-2012. Envenomations were considered mild, but almost 600 cases were treated in emergency services, wi...

Polyps of Aurelia aurita can transform into several medusae (jellyfish) in a process of sequential subdivision. During this transformation, two processes take place which are well known to play a key role in the formation of various higher metazoa: segmentation and metamorphosis. In order to compare these processes in bilaterians and cnidarians we studied the control and the kinetics of these p...

Aquatic invertebrates are excellent models for the study of animal feeding behavior and at the same time are very important fisheries resources that are frequently harvested using baited fishing gears. Studies on their chemical senses can bring a better understanding to the factors affecting feeding processes in simple organisms, as well as contribute to the development of better baiting techni...

Aim Phylogeography provides a framework to explain and integrate patterns of marine biodiversity at infraand supra-specific levels. As originally expounded, the phylogeographic hypotheses are generalities that have limited discriminatory power; the goal of this study is to generate and test specific instances of the hypotheses, thereby better elucidating both local patterns of evolution and the...

The phylogeny of the Rhopaliophora (Scyphozoa, Cubozoa and Staurozoa) has been discussed modified extensively up to present day. Attempting finally solve this question, morphology development different early life history stages 17 scyphozoan, 2 staurozoan 8 cubozoan species were investigated. Due magnitude study, findings will be published in two parts. This first part focus on comparison cycle...