engleski

A new epizoic Olifantiella species found on loggerhead sea turtles

The marine genus Olifantiella Riaux-Gob. & Compère was only recently described from the coral sands of Réunion Island (Riaux-Gobin & Compère 2009), characterized by a so-called buciniportula, a raised internal tubular process, opening externally by a small funnel- shaped slit or pore. Other discriminating features include a naviculoid valve outline, rather small valve dimensions, parallel striae composed of one transapically elongated areola, a rather simple raphe structure with short distal fissures and only weakly deflected proximal endings and a typically raised siliceous nodule between the two internal proximal raphe endings. So far, only nine taxa were described in the genus Olifantiella, most of them only found in the tropical regions of the Indo-Pacific basin (Riaux-Gob. & Compère 2009, Riaux-Gobin & Al-Handal 2012, Riaux-Gobin 2015). Recently, a new Olifantiella was described from a temperate environment, the Port of Antwerp in Belgium (Van de Vijver & al. 2016). During a survey of the epizoic diatom flora on carapaces of loggerhead sea turtles (Caretta caretta) from the Adriatic Sea, a relatively large population of an unknown Olifantiella species was observed. Comparison with all other Olifantiella species, based on detailed LM and SEM observations, indicated that it should be separated as a new species. The new species is characterized in having a slender, elongated valve outline with parallel margins and clearly protracted, rostrate apices. Internally, a clear buciniportula can be observed. Several smaller, more sturdy valves were likewise observed showing a more lanceolate outline with shorter, rostrate apices ; however it is unclear at the present whether they represent yet another separate species. The poster illustrates the morphology of a new species and discusses its similarities and differences with all other Olifantiella species worldwide.

diatoms ; taxonomy ; morphology ; sea turtles

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