Coronatae

Article By:

Morandini, André C. Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.

Last reviewed:December 2019

DOI:https://doi.org/10.1036/1097-8542.163200

One of the three orders of the cnidarian class Scyphozoa; often referred to as crown jellyfishes. The Coronatae are mainly known as free-swimming marine jellyfishes (medusae) with conspicuous bell shapes and colored abyssal (deep-water) forms, but several species of polyps (attached sessile forms) and shallow-water medusae are now also known. The main distinguishing morphological feature in the medusoid stage is the exumbrella (the outer convex surface of the umbrella of jellyfishes), which is divided into two parts by a circular or coronal furrow: an upper central disk and a lower marginal coronal part (see illustration). The central disk is usually flat or domelike; however, in medusae of the genus Periphylla, it narrows toward the top, forming a helmetlike bell. The pedalia are marginal gelatinous thickenings, situated on the radii running from the center of the umbrella to the tentacles and the sensory organs. The pedalia are separated from one another by clefts (or radial grooves), running down the radii, that are halfway between each tentacle and rhopalium (a sensory organ). The mouth has four simple lips. The central stomach is lined by four groups of gastric filaments.

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