Shallow-water scleractinian corals of Ascension Island, Central South Atlantic

Helmut Zibrowius,Francesca Benzoni,Flavia L.D Nunes,Peter Wirtz,Bert W Hoeksema

doi:10.1017/s0025315414001465

Abstract

The presence of five shallow-water scleractinian species at Ascension Island is confirmed, i.e. Favia gravida, Madracis sp., Siderastrea radians, Polycyathus atlanticus and Rhizosmilia gerdae. The three former are zooxanthellate, the two latter azooxanthellate. A sixth species, Cladocora debilis (azooxanthellate), dredged from moderately deep water is also expected to occur in shallow water. Madracis sp. and P. atlanticus are new records for the island. A previous record of Astrangia solitaria at Ascension is now referred to as P. atlanticus. Favia gravida, S. radians and C. debilis are amphi-Atlantic. Rhizosmilia gerdae is currently known only from Ascension Island and the Western Atlantic. None of the species are endemic to Ascension Island. No member of the family Dendrophylliidae has as yet been found at Ascension, whereas that family is represented at its nearest neighbour, St Helena Island.

Highlights

Ascension Island (7857′S 14822′W) is one of the most remote islands in the Atlantic, being located ~1300 km from St Helena, ~2300 km from Recife (Brazil) and ~1500 km from Cape Palmas (Liberia)
Sequences for cytochrome oxidase I (COI) were obtained for S. radians specimens Coel. 40164 and 40165, but because they were identical to specimen RMNH Coel. 40163, only one sequence was submitted to GenBank
None of its coral species are endemic whereas the fauna of much older St Helena Island, the other very isolated island of the tropical South Atlantic, includes two endemic species, Balanophyllia helenae Duncan, 1876, and Sclerhelia hirtella (Pallas, 1766), both of which can be found in shallow water by snorkelling (Den Hartog, 1989b)

Summary

Introduction

Ascension Island (7857′S 14822′W) is one of the most remote islands in the Atlantic, being located ~1300 km from St Helena (the nearest island), ~2300 km from Recife (Brazil) and ~1500 km from Cape Palmas (Liberia). The island has been less visited by expeditions or individual naturalists than most other Atlantic islands or archipelagos and for a long time the description of the island’s biological diversity remained relatively incomplete. A representative list of the older visiting expeditions and corresponding literature can be found in Manning & Chace (1990). The onset of main collecting efforts is quite recent, made possible when Ascension became more accessible as an important military and space communication base. This resulted in some monographic work on major zoological groups such as molluscs (Rosewater, 1975), echinoderms (Pawson, 1978), fishes (Lubbock, 1980) and decapod crustaceans (Manning & Chace, 1990). The newly obtained data are combined with information collected from the literature and from investigating museum

Methods

Results

Conclusion