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Family: Oceaniidae
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Polyp: Colony of variable height, from sparingly branched with shoots only a few mm high to much branched and polysiphonic colonies up to 35 mm high. Hydranths with 12-20 tentacles. Periderm two-layered. Hydranths colorless or pinkish. Reproduction: Gonophores released as free medusae. Newly released medusa with 8 tentacles, manubrium with yellow-fluorescent interradial pads, vacuolated cells visible. Adult medusa up to 2.7 mm in height, diameter 3.2 mm; mature specimens with 8-20 tentacles (observed by S. Piraino in laboratory, may differ in nature), sometimes with terminal swellings; manubrium reaching to bell margin; ocelli rust-colored; gonads brownish, with 4 interradial rust-colored dots; proximal ends of radial canals swollen through vacuolated gastrodermal cells, the four swellings not fused into a single mass; sexes separate, females oviparous. Ecology and Distribution: First described from Naples (Italy), commonly found on rocky substrates in the Western Mediterranean and Adriatic Sea; introduced populations known from Indian River Lagoon (Florida), both Caribbean and Pacific coasts of Panama, and Japan. Such populations are thought to have been introduced through ballast water, “silently invading” oceans world-wide. In Bocas del Toro found in all sampling locations except for Punta Hospital and Bocas del Drago. Remarks: Medusa buds on polyps and liberated medusa can metamorphose back into polyp stage. Often confused with and identified as Turritopsis nutricula McCrady, 1857. Similar taxa: Congeneric Turritopsis spp. also recorded in Bocas del Toro. |