First record of Cassiopea xamachana ephyrae from the wild in India, with insights into its life history and development

Ranjith, L and Saravanan, Raju and Sobhana, K S and Jagadis, I and Ramkumar, S and Kalidas, C and Linga Prabu, D and Kavitha, M and Nevathitha, P and Mathan Babu, A and Sarathapriya, D and Edward, Loveson and George, Grinson (2026) First record of Cassiopea xamachana ephyrae from the wild in India, with insights into its life history and development. Regional Studies in Marine Science, 95. pp. 1-13. ISSN 2352-4855

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Abstract

The upside-down jellyfish Cassiopea spp. (Scyphozoa: Rhizostomeae) displays a metagenetic life cycle comprising medusoid and polyp stages, with the ephyrae as an intermediate stage. This study reports, for the first time, the occurrence of wild Cassiopea ephyrae from Indian waters with different developmental morphologies under a controlled rearing system. Ephyrae was collected from the primary settlement unit of a slow sand filter facility supplied source seawater from Tuticorin Bay on the southeastern coast of India. The molecular results showed a close identity to Cassiopea xamachana (Bigelow, 1892), with 99.54 % similarity in the COI gene sequence analysis. The distinct characteristics of the newly liberated ephyrae (1.4–2.5 mm) included a long manubrium (more than half of the central disc diameter), 16 spatula-shaped velar lappets, and 32 outwardbent rhopalial lappets with zooxanthellae distributed in the mesoglea. The development of ephyrae into young medusae occurred within 3–4 days under controlled laboratory conditions. This study revealed that ephyrae readily accepted live feed and exhibited substantial growth and morphogenesis in young medusae. This study provides insights into the critical early-life parameters of C. xamachana, which are essential for understanding its swarming behavior in the wild.

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