Frankophila wayqechae sp. nov., a new aerophilic diatom species from the Peruvian Andes, South America

Abstract

The genus Frankophila Lange-Bertalot is characterized as a small chain-forming diatom with frustules held together by interdigitating marginal spines. Both valves of the species in this genus possess a short raphe at the distal ends. Five species of Frankophila have been recognized to date with most being described from subaerial habitats. Exploration of moist, vertical, rock walls in the Peruvian Andes led to the discovery of a new Frankophila species, F. wayqechae Furey, Mayama, Lowe & Catenazzi, sp. nov., which is described from a high altitude (3506 m above sea level), moist, vertical wet wall located in the transition zone between the grasslands and cloud forests growing on the eastern slope of the Andes in Manu National Park. Light and scanning electron micrographs of internal and external morphology and ultrastructure are presented along with basic ecological information. This new taxon is compared with species in the genus Hygropetra Krammer & Lange-Bertalot, primarily H. gelasina Mayama & Idei, and phylogenetic relationships inferred from valve and chloroplast features are discussed. The triseriate striae and depressions in the valve axial area of F. wayqechae differentiate it from other currently described Frankophila species. The velum at the inner opening of the areolae and triseriate striae of F. wayqechae are similar to the genus Hygropetra which suggests a close relationship between these taxa. Frankophila wayqechae has a single chloroplast per cell that expands in the large area beneath one valve without lobes along a sternum. The nature of the chloroplast, combined with the pattern of areolation in the striae and internal areola occlusion by a hymen also suggests F. wayqechae may be a close relative of Planothidium Round & Bukhtiyarova. Frankophila wayqechae appears to be restricted to high elevation areas in the Peruvian Andes, and is likely an endemic taxon, emphasizing the importance of biodiversity hotspot studies for future species conservation.

Keywords:

• Frankophila
• Hygropetra
• Andes
• Peru
• wet walls
• subaerial habitats

Acknowledgements

A special thank you to Sandra Almeyda and Juan Carlos Jahuanchi for assistance with collecting samples from Peru. We acknowledge the Manu National Park, Peru for granting research permits and the Wayqecha Biological Station for logistic support. Fieldwork was supported with grants from the Amazon Conservation Association and the Rufford Small Grants Foundation. AC was supported by a Postdoctoral Fellowship from the Swiss National Science Foundation (#116305). PCF received postdoctoral fellowship support in part by the National Center for Earth-surface Dynamics (NCED) and a National Science Foundation grant awarded to Jill Welter [NSF-DEB 0950016] of St. Catherine University. Thank you to Bowling Green State University, Department of Biological Sciences for access to and use of their scanning electron microscope. Thank you to Bart Van de Vijver of the National Botanic Garden of Belgium for the Latin translation.