Morphologic and molecular redescription of Catostylus mosaicus conservativus (Scyphozoa: Rhizostomeae: Catostylidae) from south-east Australia

Catostylus mosaicus (Quoy & Gaimard, 1824) is a rhizostome jellyfish endemic to eastern Australia. Originally described from Port Jackson (Sydney) in New South Wales (Quoy & Gaimard, 1824), the species is thought to range from Port Phillip (Melbourne) in Victoria to the Torres Strait (Kramp, 1965; Southcott, 1982), i.e. across three biogeographic boundaries. Given recent reports of multiple cryptic species in widely distributed scyphozoans (Dawson & Jacobs, 2001; Dawson, 2004; Holland et al., 2004) the taxonomic singularity of C. mosaicus might best be viewed with caution. von Lendenfeld (1884) reported C. mosaicus of two distinct colour types: a blue morph in Port Phillip and a brown morph in Port Jackson. He considered the geographic, environmental, and morphological differences sufficient to recognize two varieties, possibly species: a blue ‘conservativa’ and brown ‘symbiotica’. The names were attributed on the basis that the blue form ‘[conserved] the habits of its ancestors’ while the brown colour was due to ‘yellow cells ... known as Zooxanthella[e].’ The validity of these varieties is questionable on several grounds. First, colour is geographically inconsistent. Although brown morphs were never found in Port Phillip, von Lendenfeld (1884) reported blue morphs in the vicinity of Sydney, albeit occasionally and in low frequency. Blue medusae are also common, along with a ‘milky-white’ morph, in Queensland’s waters (Southcott, 1982). Second, colour may have been temporally inconsistent. Quoy & Gaimard (1824) originally described C. mosaicus in Port Jackson as ‘toute blanche ou plutôt glauque’ i.e. all white or rather dull blue-green. von Lendenfeld (1884) himself noted, when proposing the two varieties, that all prior descriptions from Sydney were of blue to grey medusae, not the bright brown medusae despite their colour being ‘so very striking’. Third, C. mosaicus in Port Jackson may be variegated, from bread-white through blue to coffee coloured (von Lendenfeld, 1884; Mayer, 1910). Finally, the difference in colour may not be attributable to the establishment of symbioses with zooxanthellae (Kingsford et al., 2000; Pitt, 2000). Neither Mayer (1910) nor Kramp (1961, 1965) recognized the varieties proposed by von Lendenfeld (1884) in their monographs on the medusae. However, recent ecological data have indicated distinct stocks of C. mosaicus in New South Wales (Pitt & Kingsford, 2000a), a result supported by phylogeographic analyses using mitochondrial cytochrome c oxidase subunit I (COI; Dawson, 2005). The COI sequence data also reveal reciprocally monophyletic ‘Southern’ (Victoria and Tasmania) and ‘Central’ (New South Wales and Brisbane) clades of medusae that apparently diverged during the early Pleistocene Morphologic and molecular redescription of Catostylus mosaicus conservativus (Scyphozoa: Rhizostomeae: Catostylidae) from south-east Australia