Overview of morphology and neuromuscular system of coronate polyps on the example of Linuche sp. (Scyphozoa, Coronatae)

Abstract

Jellyfish from the class Scyphozoa have been the subject of numerous studies due to their blooms and impacts on the economy. The polypoid stage plays a main role in the occurrence of blooms, as it forms young medusae during strobilation. Ecological aspects that affect the strobilation has been well studied over the years, while morphological data on polypoid stage is available mainly for model species, such as members of genera Aurelia and Cassiopea. One of the less studied polyps are from the order Coronatae – the basal group of Scyphozoa. In this work, we focused on the morphology of the Linuche sp. coronate polyp.

For the first time, we describe the histological features and general topology of the neuromuscular system of Linuche sp. polyps using confocal laser scanning microscopy and semi-thin sections, also we provide information on the structure of its periderm tube and cusps – important taxonomic characters of coronate polyps – with usage of scanning electron microscopy. Its nervous system is presented as a nerve net in the body column with longitudinal neuron groups accompanying the muscle bands, and two nerve rings in the capitulum, acting as integrative centers. The muscular system in Linuche sp. has a complex organization with numerous groups of muscular processes in the capitulum that are intertwined with the musculature of the body column and tentacles. Comparison of the organization of polyps from Coronatae and Discomedusae revealed significant differences in their anatomy, due to the presence of the periderm tube in coronates.