Licmophora colosalis sp. nov. (Licmophoraceae, Bacillariophyta), a large epiphytic diatom from coastal waters

Abstract:

The characteristic wedge-shape and large size of some diatom species in the genus Licmophora can make them seem relatively easy to identify. However, this is not always the case, as many specific diagnoses are based solely on light microscopy, type material is not available and species may be difficult to distinguish from each other. This study provides the description and phylogenetic position of Licmophora colosalis sp. nov., which has large cells and extremely long dichotomously branched stalks that form macroscopic arborescent colonies. Material for this study was collected from a hypersaline Mediterranean lagoon but this species has also been reported from Florida and the Red Sea. It was studied using scanning electron microscopy and sequencing of the nuclear small subunit rDNA (SSU) and the chloroplast marker rbcL. Its colonies and cell morphometry are compared with three morphologically similar taxa: Licmophora remulus, Licmophora gigantea and Licmophora grandis.

Key Words::

• Benthic diatoms
• Epiphytes
• Giant cells
• Marine diatoms
• Mediterranean coast

ACKNOWLEDGEMENTS

We are grateful to Matt P. Ashworth and T.A. Franckovich for providing supporting materials to assist with the identification of specimens from Florida Bay. We thank Jamal S. M. Sabir, Nabih A. Baeshen, Mohamed N. Baeshen, Njud S. Alharbi, Meshaal J. Sabir and Matt P. Ashworth for identifying the location in the Red Sea. We would also like to thank Christopher S. Lobban for providing contacts to help find the Florida strain.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/15-108.1.s1