# Regeneration and Musculature in Halved Cassiopea xamachana Ephyrae

## TL;DR

This study explores how young jellyfish called ephyrae from Cassiopea xamachana regenerate after being cut in half, showing they can regrow into smaller, functional jellyfish.

## Contribution

The study provides the first detailed documentation of regeneration in C. xamachana ephyrae under controlled lab conditions.

## Key findings

- Cut ephyrae regenerate into two smaller, functional ephyrae with normal behavior in about two weeks.
- Regeneration includes re-symmetrization and fewer rhopalia in the new individuals.
- Older ephyrae regenerate more slowly than younger ones.

## Abstract

Adult Cassiopea medusae and their polyps have been known to regenerate tissue in uncontrolled and controlled conditions; however, the regeneration capabilities of Cassiopea xamachana ephyrae are largely unexplored. Here, we detail the development and regeneration of ephyrae under known laboratory conditions. Ephyrae were cut in two and then followed as they regenerated back to complete individuals. We visually document all the developmental stages of the medusa leading up to the trauma and the complete regeneration process of the two halves. We show how ephyrae of C. xamachana, when cut in halves, undergo both regeneration and re-symmetrization, generating, in about 2 weeks, two functional smaller ephyrae with fewer rhopalia and normal behavior. We also show that regeneration is slower in older ephyra.