engleski

New Proschkinia species associated with sea turtles

The marine diatom genus Proschkinia Karayeva (Karayeva 1978) currently comprises seven valid species occurring worldwide in benthic and planktonic habitats. The taxa are characterized by having delicate frustules, a cingulum composed of numerous copulae and lanceolate valves whose outer surface is often ornamented with longitudinal ridges. A distinctive feature of the genus is the isolated pore called a fistula positioned near the central raphe endings. We have recently observed several distinct populations of Proschkinia species growing on skin and carapaces of various sea turtles from different habitats in the Mediterranean Sea, Indian, Pacific and Atlantic Oceans. Based on detailed SEM observations of wild populations as well as the one cultivated strain, we distinguished at least 5 new Proschkinia species whose morphology is presented and compared based on scanning electron microscope observations (SEM). All species presented a different morphology of the fistula along with several other discriminating features. Two species have been observed from loggerhead turtles in the Adriatic Sea (Croatia), of which Proschkinia sp. 1., previously found in samples taken from olive ridleys from Ostional (Pacific coast of Costa Rica), has fistulae internally occluded by one domed hymen and Proschkinia sp. 2. has fistulae internally segmented in a series (3-4) of small rounded openings occluded by raised convex hymenes. Proschkinia sp. 3 also has fistulae internally occluded by one domed hymen and was observed growing on Kemp’s ridleys, loggerheads, and green turtles from Long Island (New York, USA) and on loggerheads from Florida and South Carolina (USA). Proschkinia sp. 4 was found on Kemp’s ridleys and green turtles from Long Island (New York, USA) and on loggerheads from Kosi Bay (South Africa). Proschkinia sp. 5 has been observed from loggerheads and green turtles from Florida, and isolated into culture, and it is the smallest species without external longitudinal ribs and fistula internally occluded by one domed hymen. We will also present DNA sequence data for several strains of Proschkinia sp. 5 isolated from different sea turtle hosts, which suggest an evolutionary relationship to Fistulifera Lange- Bert., Stauroneis Ehrenb.and Craticula Grunow.

diatoms ; taxonomy ; seaturtles ; epibionts

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