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12 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
the 18 scleractinian genera known from the temperate
northeastern Pacific, 12 (67%) are also represented in the
northwestern Pacific.
TEMPERATE NORTHWESTERN PACIFIC.—The warm temperate
northwestern Pacific Japan Province is dominated by the
northerly flowing tropical Kuroshio Current. Its boundaries are
quite complicated because of the complex geography of the
region and the variations in the path of the Kuroshio (Veron,
1992). According to Briggs (1974), the southern limit of the
warm temperate province is Hong Kong, China and includes
the Chinese mainland to Wenling, the west coast of Taiwan,
Formosa Strait, and most of the East China Sea, but not the
southern Ryukyu Islands. The northern boundaries of the Japan
Province include the southern tip of South Korea (Haenam to
P'ohang), Korea Strait (including Tsushima and Mishima), the
southwestern tip of Honshu to about the latitude of Hamada, the
northern Ryukyu Islands from Tokara Retto northward, and the
east coast of Honshu to Cape Inubo. Unlike the warm temperate
northeastern Pacific in which zooxanthellate corals are absent,
zooxanthellate corals are present in the Japan Province to its
northern limits (Eguchi, 1968; Tribble and Randall, 1986;
Veron, 1992). The 92 azooxanthellate species known from this
province (Table 5) consist of six cosmopolitan species, 21
(23%) endemic species, 58 (63%) eurythermic tropical species,
six species characteristic of the boreal temperate region, and
one species that remains unclassified {Stenocyathus vermiformis).
Of the 21 endemic species, 13 are poor indicators of
endemism as they are known from only one or two records, but
the remaining eight species appear to be characteristic of this
province: Deltocyathus vaughani, Rhizosmilia sagamiensis,
Dasmosmilia pacifica, Phyllangia hayamaensis, Flabellum
apertum borealis, Truncatoguynia irregularis, Balanophyllia
teres, Eguchipsammia wellsi, and Dendrophyllia boschmai.
Among the eurythermic tropical species, many conform to the
previously stated northern border of the warm temperate
province (i.e., southern South Korea, Mishima, Cape Inubo),
including: Letepsammia formosissima, Culicia japonica,
Cyathelia axillaris, Caryophyllia quadragenaria, Javania
insignis, and Endopachys grayi; however, the range of at least
six species extend slightly farther north into the cold temperate
Sea of Japan coast of Honshu as far as Oki Channel (e.g.,
Stephanophyllia fungulus, Fungiacyathus paliferus, Anthemiphyllia
dentata, Flabellum deludens, Truncatoflabellum
formosum, and T. gardineri), and two more species penetrate to
Wakasa Bay {Rhizotrochus typus and Balanophyllia cumingii).
Several other species reported from this province are primarily
tropical with only marginal occurrences in the southern warm
temperate province, such as: Tropidocyathus lessoni, Stenocyathus
vermiformis, Truncatoflabellum sp. A, T. sp. B, and
Enallopsammia rostrata. The six cold temperate species found
in the Japan Province are: Oulangia stokesiana miltoni,
Caryophyllia compressa, C. japonica, Aulocyathus matricidus,
Balanophyllia sp. A, and Rhizopsammia minuta mutsuensis.
According to Briggs (1974:267), the lower boreal cold
temperate Oriental Province includes the Yellow Sea and much
of the Sea of Japan, from P'chang, South Korea to Oh'ongjin,
North Korea to the west, Hamada to Tsugaru Strait on the west
coast of Honshu, and from Cape Inubo to Tsugaru Strait on the
east coast of Honshu. Of the 24 scleractinian species known to
occur in this province (Table 5), the largest component (11
species, 46%) is that of eurythermic tropical species, most of
which are found only a short distance into the province along
the west coast of Honshu (e.g., Oki Channel, Wakasa Bay, see
above). Of the remaining 13 species, five are cosmopolitan,
none are endemic, six are characteristic of the northwestern
temperate region, and two are unclassified {Caryophyllia
alaskensis and Dendrophyllia japonica). Although no endemics
are known, Rhizopsammia minuta mutsuensis typifies this
province, being found only slightly north and south of the
stated borders of the province. Of the six temperate species,
four are found in the Japan and Oriental Provinces {Oulangia
stokesiana miltoni, Carophyllia compressa, Balanophyllia sp.
A, and Aulocyathus matricidus), the other two being characteristic
of all three provinces of the northwestern Pacific region:
Caryophyllia japonica and Rhizopsammia minuta mutsuensis.
Only eight species of Scleractinia are known from the upper
boreal cold temperate Kurile Province (Table 5), defined as the
northern Sea of Japan, off Hokkaido, and the eastern coasts of
the Kurile Islands and Kamchatka Peninsula. The affinities of
this fauna are quite similar to the upper boreal of the
northeastern Pacific Aleutian Province, consisting of: two
cosmopolitan species, one endemic {Fungiacyathus sp. A), one
bitemperate species {Leptopenus discus), two northwestern
temperate species {Caryophyllia japonica and Rhizopsammia
minuta mutsuensis), one upper boreal endemic (Javania
borealis), and one species having a disjunct distribution in the
tropical and boreal regions {Leptopenus solidus).
A second, upper boreal cold temperate province is recognized
by Briggs, the Okhotsk Province, which includes the Sea
of Okhotsk, but no Scleractinia have been reported from this
province.
COMPARISONS.—According to the zoogeographic synthesis
of Briggs (1974:196), warm temperate marine faunas are
usually strongly influenced by the adjacent eurythermic
tropical species or simply by dispersal of tropical species that
happen to be carried to higher latitudes by strong currents. This
would be especially true of northwestern boundary currents,
wherein a warm northerly flowing current (e.g., Gulf Stream,
Kuroshio) brings tropical species into northern latitudes. This
phenomenon is clearly seen in the northwestern Pacific warm
temperate Japan Province wherein 58 (63%) of the 92 species
are eurythermic tropical species, but less evident in the
California warm temperate province wherein only 5 (29%) of
the 17 species are considered as eurythermic tropical. The
much higher number of azooxanthellate species in the Japan
Province (92) compared to that of the California Province (17)
is undoubtedly also due to their proximity to tropical faunas of
vastly different sizes, i.e., the estimated number of tropical
eastern Pacific azooxanthellates (Durham and Barnard, 1952;
Squires, 1959; Cairns, 1991a) is about 55; that of the Indo-West