Heydrichia cerasina sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta) from the southernmost tip of Africa

Abstract

Maneveldt G.W. and van der Merwe E. 2012. Heydrichia cerasina sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta) from the southernmost tip of Africa. Phycologia 51: 11–21. DOI: 10.2216/11-05.1

A new species of Heydrichia (Sporolithales), Heydrichia cerasina sp. nov., is described, found only on pebbles in the low intertidal zone along a 10 km stretch of the South African south coast from Cape Agulhas to Struisbaai. The species is characterized by the following suite of features that distinguish it from the other two species of Heydrichia found in South Africa: (1) unusual cherry-red colour when freshly collected; (2) uniformly warty growth form; (3) relatively thin crust (up to 1400 µm thick); (4) tetra/bisporangial sori comprised of mostly single sporangial chambers; and (5) unbranched spermatangial structures distributed on the floor, walls, and roof of the mature male conceptacle. The species appears to be most closely related to Heydrichia homalopasta from Australia. This study has affirmed that the distribution of spermatangial structures within male chambers is a feature that cannot be used to separate Heydrichia from Sporolithon, the only other genus in Sporolithales, although features of thallus construction and tetra/bisporangia continue to distinguish the genera. A key to the southern African species from the order Sporolithales is provided.

Key Words::

• Heydrichia
• Heydrichia cerasina
• Non-geniculate coralline algae
• South Africa
• Sporolithales
• Taxonomy

ACKNOWLEDGEMENTS

We thank the Department of Biodiversity and Conservation Biology at the University of the Western Cape for providing funding and research equipment, and the South African National Research Foundation (NRF) for a research grant to GWM. Adrian Josephs and Dawn Faroe provided assistance with the operation of the SEM and digital imagery microscope respectively. We are most grateful to Alex George (Murdoch University, Australia) for rendering the Latin translation of the description. John Bolton (University of Cape Town, South Africa) and Paul Gabrielson (University of North Carolina, Chapel Hill, USA) are thanked for invaluable comments. The reviewers are gratefully thanked for their contributions in strengthening the manuscript.