New insights to the ultrastructure of some marine Mastogloia species section Sulcatae (Bacillariophyceae), including M. neoborneensis sp. nov.

Abstract

Pennesi C., Poulin M., De Stefano M., Romagnoli T. and Totti C. 2011. New insights to the ultrastructure of some marine Mastogloia species section Sulcatae (Bacillariophyceae), including M. neoborneensis sp. nov. Phycologia 50: 548–562. DOI: 10.2216/10-39.1

This paper describes the morphology of six Mastogloia species of the section Sulcatae, including one new species, M. neoborneensis. Specimens were collected from seagrass and macroalgae in tropical (Siladen Island, Celebes Sea, Indonesia), subtropical (Sharm el-Sheikh, Red Sea, Egypt) and temperate (Patmos Island, Aegean Sea, Greece) regions. Scanning electron microscopy observations showed that all six species, M. baldjikiana, M. borneensis, M. hustedtii, M. mediterranea, M. neoborneensis and M. umbra, have different-shaped median depressions on the external surface of the valve face between the raphe-sternum and the margin, and variably developed siliceous outgrowths (conopeum and pseudoconopeum) covering the depressions to various degrees. This study provides new information on the frustule ultrastructure and geographical distribution of these Mastogloia species.

Key Words::

• Mastogloia
• Microphytobenthos
• Subtropical region
• Sulcatae
• Taxonomy
• Temperate region
• Tropical region
• Ultrastructure

ACKNOWLEDGEMENTS

This project was funded by grants from the Polytechnical University of the Marche and by financial support from the Canadian Museum of Nature to MP. We thank Drs F. Azzini and L. Bongiorni for collecting the samples in Indonesia and Egypt, respectively, Dr L. Gobbi for technical assistance and Prof. N. Totti for the Latin translation.