Barnacle Symbionts of Gorgonian Sea Fans 
Description of Seven New Species (Archaeobalanidae: 
Cirripedia) from the Philippines, Including a Key to Western 
Pacific Species of Conopea 
Robert J. Van Syoc Dana Carrison-Stone, Liezl Madrona, and Gary C. Williams 
Department of Invertebrate Zoology and Geology, California Academy of Sciences, 
San Francisco, California 94118. 
1 Corresponding author: bvansyoc@calacademyorg 
Seven new species of barnacle symbionts of gorgonian sea fans are described, six 
species in the genus Conopea and one in the gtnmAcasta (Archaeobalanidae: Cirri¬ 
pedia). Host gorgonians of the new species are generally identified to genus level and 
to species where possible. Conopea sabangensis sp. nov. and C. willhearsti sp. nov. are 
found only on gorgonians in the family Melithaeidae. Gorgonians in the family 
Ellisellidae are hosts for C basicuneata sp. nov., C. margaretae sp. nov., C. miny- 
rostrum sp. nov. and C. exothobasis sp. nov. The description of these new species 
increases the known western Pacific Ocean species of gorgonian symbiotic Conopea 
from 12 to 18. Acasta vipensis sp. nov. is found only on hosts in the family Plexauri- 
dae. Sequence data for a portion of the cytochrome C oxidase subunit I (COl) gene 
correlates with the morpho-species and host data. Conopea species clades in the COI 
tree suggest the invasion and expansion into diflerent host family taxa, with the 
greatest barnacle species richness appearing within the host gorgonian family 
Ellisellidae. A key to the octocoral symbiotic species of western Pacific Conopea is 
presented. 
The Philippines Archipelago, comprised of over 7000 islands, is arguably the most species 
diverse ocean environment on Earth. In 2011, the California Academy of Sciences (CAS) partnered 
with colleagues at institutions in the Philippines to study a few small portions of this rich environ¬ 
ment. Two of us (RVS, GW) were among those collecting specimens of marine species in the Verde 
Island Passage area, southwest of Luzon, for further study and inclusion in the scientific collections 
at CAS and the National Musemu of the Philippines in Manila. Although it will take more time to 
complete our studies of the several thousand specimens of marine invertebrates resulting from the 
expedition, we have already discovered a large number of new species. In fact, a majority of the 
barnacle species collected appear to be new to science. 
Among our early discoveries are several new species of barnacle symbionts of gorgonian octo- 
corals. Most of these are in the barnacle genus Conopea. Species in the genus Conopea are obli¬ 
gate symbionts of gorgonian octocorals (sea fans and sea whips) or antipatharians (black corals). 
There are currently 23 described species of Conopea. Although the genus has a global distribution 
in tropical and warm temperate seas, only 15 species are known from the western Pacific Ocean. 
These 15 species range from Japan in the north to Indonesia and northwestern Australia in the 
south. Three of the 15 western Pacific species are symbionts of antipatharians, the remaining 12 
live in association with gorgonians. The cuixent paper considers only those Conopea symbionts of 
gorgonian hosts. 
The 12 known western Pacific gorgonian symbionts in the genus Conopea are: C. acuta (Nils- 
son-Cantell, 1921), C. canaliculatus Ren and Liu, 1978, C. cornuta (Hoek, 1913), C. dentifer 
(Broch, 1922), C. fragilis (Broch, 1931), C. investita (Hoek, 1913), C. longibasis (Hiro, 1937), 
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