Three new species of Delicata (Bacillariophyceae – Cymbellales) from New Caledonia and further observations on Delicata nepouiana Krammer and D. neocaledonica Krammer

Abstract

A recent survey of epilithic diatoms in the running waters of the main island of New Caledonia led to the discovery of three new species of Delicata, Delicata pouemboutensis sp. nov., Delicata gobiniana sp. nov. and Delicata karembeui sp. nov. Delicata pouemboutensis is characterized by a strongly convex dorsal side and a low length/breath ratio (3.2–5.0). Delicata gobiniana has an acicular, almost naviculoid outline, with a high length/breath ratio (7.1–8.7). Delicata karembeui has an unusual stria structure for the genus and a valve face with shallow depressions along the dorsal and ventral sides of the valve. Delicata karembeui can be distinguished from other cymbelloid genera by a combination of features including outline, size, raphe course and stria structure. Delicata neocaledonica Krammer and Delicata nepouiana Krammer, so far only described with light microscopy, were also examined and additional scanning electron microscope observations are included.

Keywords:

• Delicata
• New Caledonia
• pseudostigmoids
• taxonomy
• ultrastructure

Acknowledgments

The authors are grateful to the CMEAB staff (Centre de Microscopie Électronique Appliquée à la Biologie) for their technical assistance and advice during SEM sessions. The authors also thank Dr Michel Poulin for valuable English corrections. The authors thank anonymous referees for their valuable and constructive comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has benefitted from Association Nationale de la Recherche et de la Technologie (ANRT), the Observatoire de l'environnement Nouvelle–Calédonie (OEIL) and Direction des Affaires Vétérinaires, Alimentaires et Rurales (DAVAR) grants.