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The Extant Scleractinian Corals of New Zealand

Introduction

Introduction

The Scleractinian corals of New Zealand have received so little attention that they have remained one of the larger unknown quantities of modern coral faunas. Knowledge of the diversity and content of the fauna has in the past been based upon an assortment of miscellaneous notes and records, many erroneous, which account for the known faunal records of about 18 species. On the basis of these records, Vaughan and Wells (1943, p. 88) more or less correctly assessed the zoogeographical relationships as being with the Indo-Pacific faunas while noting that most of the species were endemic and traceable in antecedents to the Tertiary faunas. The New Zealand fauna warrants more recognition as it is the most southerly outpost of the western Indo-Pacific, also being in reach of the faunas of the great Southern Ocean. In contrast, the scleractinian faunas of southern Australia are of a highly local flavour coloured by many autochthonous endemic taxa.

Distributional and quantitative studies of the living Scleractinia of New Zealand are impossible at the present time because of the inadequate sampling of the shelf faunas. It may be seen from the distribution chart (Text–figure 1) that collecting has been highly centralised in the Cook Strait and Bay of Plenty–Hauraki Gulf regions, with only scattered records from other areas. If the sampling of the shelf fauna has been inadequate, knowledge of the slope and deep water faunas is almost non-existent. Most of the specimens recorded here have been obtained either as the result of accidental bottom trawling, or by isolated, highly localised collecting efforts. Many of the specimens obtained by such earlier naturalists as Captains Suter and Bollons have been carefully preserved in museums although locality and depth data, if ever present, have been misplaced. Perhaps the largest single effort in the collecting of Scleractinia was that of the late William Foster, Engineer in the Post and Telegraph Department, whose gleanings from cables during their lifting for repairs may be found in every museum in New Zealand. Collections such as these, in so far as they are representative, are enough to develop only the rudiments of the distribution of the modern fauna. The known propensity of the scleractinians for "plastic" response to environmental factors (cf. Gardiner, 1939) must lead to conservatism when examining collections of small size in which variability cannot be assessed.

The coral faunas of New Zealand as would be expected, are entirely of the ahermatypic facies. Not since the mid-Tertiary have there been reef building corals present in the fauna, although the northern tip of the North Island is barely within the limits tolerable by some of the more hardy hermatypic forms. The absence of the rich and diversified reef corals does not mean that the coral fauna is limited or restricted, for the erroneously termed "simple" ahermatypic corals may be present in considerable array. Certainly when the geographic net of collecting stations page 2 has been expanded and the great diversity of substrate conditions sampled, it may be expected that the numbers of species will be greatly increased. It would appear that the bulk of collections at hand represent the hard substrate environment, the mud or sand bottoms having been dredged only in the northern regions. It need not be thought that the coral fauna is accessible only through dredging operations for at least two species, Flabellum rubrum and Culicia rubeola, are known to occur just below the intertidal zone. It is to be hoped that these corals, if not those occurring in deeper waters, may be the subject of ecological and physiological studies in the future.

The present study was commenced several years ago by one of us (P.M.R.) when available specimens at the several museums in New Zealand were assembled at Victoria University. These were preliminarily described and photographed. Renewed interest has been taken in investigation of the deeper water marine bottom faunas, resulting in increased numbers of corals represented in collections and in 1959, under the auspices of the Fulbright Program, the other (D.F.S.) was able to visit universities and museums throughout New Zealand to observe more recently acquired material.