Azooxanthellate Scleractinia of Western Australia 
regions. These tropical species are subdivided into 
categories 1 A-E in Table 2, in order to show the 
extent of the distributions of these species in 
tropical areas beyond Western Australia. Nine 
species (9/87 = 10%), category IE of Table 2, are 
endemic to this province, which is consistent with 
the degree of endemicity of other benthic 
invertebrates groups (i.e., molluscs, brachyuran 
decapods, echinoderms), summarized by Morgan 
and Wells (1991), as 10—17%. There is a general 
correlation between depth of occurrence and 
endemicity among the nine endemic species (Table 
3: pattern IE), 7 of the 9 endemic species (78%) 
being found at shallow depths (0-200 m), whereas 
only 48% (38/79 species of categories 1A-D, 2A of 
Table 3) of the more widespread tropical species 
are found at depths shallower than 200 m. 
Another category of "tropical" species (patterns 
2 A and B of Table 2) are those azooxanthellate 
species that occur both in tropical and temperate 
Western Australian regions, most of which occur 
not only in the tropical realm but also off warm 
temperate South Australia, Victoria, Tasmania, 
New South Wales, and/or Japan. Nineteen species 
have such distributions (Tables 1-2, pattern 2A), 
even though in some cases these species may not 
yet have be recorded from the tropical region of 
Western Australia (e.g., Desmophyllum dianthus and 
Solenosmilia variabilis ) or the warm temperate 
region of Western Australia (e.g., Paracontrochus 
zeidleri, Guynia annulata, and Flabellum hoffmeisteri). 
In general, these species occur deeper than the 
exclusively tropical species (Table 3), 68% of the 19 
species occurring exclusively deeper than 200 m. 
One species, Rhizosmilia mult ipalifera, categorized 
as having pattern 2B, occurs from Cape Jaubert to 
31°30'S latitude, and is thus far endemic to the 
western coast of Western Australia. Not 
surprisingly, it has a relatively shallow depth 
range. 
As previously suggested, the number of tropical 
azooxanthellate species gradually attenuates with 
increasing southern latitude. Comprehensive 
numbers of species for various regions along the 
coast, such as those provided by Morgan and Wells 
(1991) for Crustacea, Veron and Marsh (1988) for 
corals, and Wells (1980) for molluscs, are not 
available for deep-water corals. To a certain degree 
our knowledge of the deep-water coral 
distributional ranges is a reflection of the regions 
and depths at which dredging vessels happened to 
make stations. Nonetheless, a preliminary 
tabulation can be given of the southern limit of the 
tropical species (Tables 2-3, categories 1 and 2) for 
which adequate data are available. For instance, of 
the species known from Western Australia, eight 
extend no farther south than the region defined by 
Browse, Scott, and Cartier Islands, 5 extend to 
Dampier Land, 5 to Rowley Shoals and Cape 
367 
Jaubert, 37 to the continental slope between Rowley 
Shoals and Port Hedland, 13 to Dampier 
Archipelago, 4 to the Cape Range/North West 
Cape region, 4 to Shark Bay, 5 to the Houtman 
Abrolhos Islands, 6 to Rottnest Island, one 
(Conocyathus zelandiae) to King George Sound, one 
(Cyathelia axillaris) to Esperance, and 3 (Culicia 
australiensis, Conotrochus funicolumna, and 
Cyathotrochus pileus) to the Great Australian Bight 
near Eucla. Thus the highest attrition rate of 
tropical species (50 species) appears to be the 
region between Cape Jaubert (coastal)-Rowley 
Shoals (oceanic) to Dampier Archipelago (coastal)- 
Glomar Shoal (oceanic). 
Temperate West Australian Fauna.- Of the 26 
azooxanthellate species that occur in the Southern 
Australian Warm Temperate Province (Table 1, 
column 5), 11 (11/26 = 42%) are endemic to this 
region. According to Morgan and Wells (1991), 
endemicity of shallow water benthic invertebrates 
and fish for this region is usually much higher (e.g., 
63-95%); however, this discrepancy can be partially 
explained by the fact that whereas 10 of the 11 
warm temperate endemics are shallow in 
distribution (Table 3), only 8 of the 15 non-endemic 
species occur in shallow water, the other 7 species 
being found deeper than 200 m and thus having 
the potential for a broader geographic range. Of 
these 11 endemic temperate species: 4 can be 
categorized as having a "Southeastern Australian" 
pattern (sensu Wilson and Allen 1987), being found 
only marginally off southeastern Western Australia 
in the Great Australian Bight; 5 extend to Albany/ 
King George Sound region ("endemic south coast" 
pattern of Wilson and Allen 1987); and 2 species 
(i.e., Trematotrochus verconis, and Rhizotrochus 
Table 3 General Bathymetric Ranges of Western 
Australian Azooxanthellate Species in 
relation to Distribution Pattern (see Table 1). 
0-200 m 
(shelf) 
Intermediate 
(shelf+slope) 
> 200 m 
(slope) 
TROPICAL 
1A (Widespread) 
3 
0 
3 
IB (IWP) 
14 
1 
8 
1C (W. Pacific) 
9 
4 
16 
ID (Amphi-lndian) 
1 
0 
1 
IE (Endemic) 
7 
0 
2 
TROPICAL and TEMPERATE 
2A (Widespread) 
5 
1 
13 
2B (Endemic) 
1 
0 
0 
ENDEMIC TEMPERATE 
3A (southern Australia) 
10 
0 
1 
3B (s. Australia and S. Africa) 0 
0 
1 
Unclassified 
3 
0 
1 
TOTAL: 
53 
6 
46 
