Emeritus Curator of Invertebrate Zoology and Geology
Research interests include the systematics and evolutionary biology of octocorals (soft corals, gorgonians, and pennatulaceans), which comprise 65% of all coral species diversity. Fieldwork is currently focused on two bathymetrically opposite regions of the world's oceans: coral reefs of the tropical western Pacific (the Philippines, Melanesia, and Micronesia), and the deep-sea benthos (particularly the west coast of North America and various deep ocean basins worldwide). Scuba diving is essential to my coral reef research since the highest diversity of octocorals is found between about 3 and 35 meters in depth, while ROV's (Remote Operational Vehicles) are of primary importance in deep-sea research.
A broad interest in natural history developed during childhood, in a relatively uncrowded San Francisco Bay Area - before much of the enormous influx of human population that extinguished much of the open space and altered the regional biodiversity forever. An early fascination in the plants and animals of the undeveloped open spaces near my childhood home in the North Bay soon led to collecting and identifying the local insects, trees, and wildflowers. An interest in marine life was influenced by two enthusiastic marine biologists - Dr. Gordon Chan (College of Marin, Biology Instructor) and Dusty Chivers (Senior Curatorial Assistant in the Academy's Department of Invertebrate Zoology).
Octocorallian coelenterates include some of the most beautiful and morphologically diverse animals in the world's oceans - these are the soft corals, sea fans, and sea pens. They are a group of corals characterized by having eight feathery tentacles surrounding the mouth of each polyp. Due to a paucity of good characters and the great phenotypic variability of species, octocoral systematics has traditionally been difficult and disputatious - partly explaining why there is a corresponding paucity of octocoral systematists! Other factors that make the field challenging include the extreme difference in appearance between live and preserved material, and the poor attention to detail in much of the older descriptive literature.
Soft corals are most abundant on shallow reef flats, while gorgonians are more abundant on slopes, walls, and rocky outcrops in a wide depth range. In addition, sea pens are encountered at all depths and are often important constituents of the ocean floor. For further information, check out the Octocoral Research Center website.
Students - Graduate students in Biology at San Francisco State University and undergraduate interns during the Academy's Summer Systematics Institute.
Selected Scientific Publications
Perez, C.D., R.T. Cordeiro, G.C. Williams, and S.D. Cairns. 2016. Diversity and Distribution of Octocorallia. In: S. Goffredo and Z. Dubinsky: The Cnidaria, Past, Present, and Future - The World of Medusa and her Sisters. Springer Book Publishers.
Williams, G.C. 2015. A new genus and species of pennatulacean octocoral from equatorial West Africa (Cnidaria, Anthozoa, Virgulariidae). ZooKeys 546: 39-50.
Chen, J-Y and G.C. Williams. 2015. X-ray microanalysis and the chemical elemental composition of gorgonian and pennatulacean axial structures (Anthozoa, Octocorallia.Proceedings of the California Academy of Sciences 62(16): 399-415.
Williams, G.C. and A.K. Matsumoto. 2015. A Review of the Pennatulacean Genus Stylatula, with a Description of a New Species from Japan (Cnidaria: Octocorallia). Proceedings of the California Academy of Sciences 62(8): 257-266.
L. A. Rocha et al. 2014. Specimen collection: An essential tool. Science 344: 814-815.
Williams, G.C. and T.M. Gosliner (editors). 2014. The Coral Triangle: The 2011 Hearst Philippine Biodiversity Expedition. California Academy of Sciences. 592 pp.
Williams, G.C. 2014. The three components of the 2011 Hearst biodiversity expedition to the Philippines, pages 53-66. In: GC Williams and TM Gosliner (editors), The Coral Triangle: The 2011 Hearst Philippine Biodiversity Expedition. California Academy of Sciences. 592 pp.
Williams, G.C. and J.-Y. Chen. 2014. Illustrated key to the shallow-water gorgonians and pennatulaceans of the Verde Island Passage, northern Philippines, including synopses of the the Taxa and a glossary of terms (Cnidaria: Anthozoa: Octocorallia), pages 67-128. In: GC Williams and TM Gosliner (editors), The Coral Triangle: The 2011 Hearst Philippine Biodiversity Expedition.California Academy of Sciences. 592 pp.
Williams, G.C. 2014. Epilogue, the 2011 Hearst Philippine Biodiversity Expedition, pages 565-567. In: GC Williams and TM Gosliner (editors), The Coral Triangle: The 2011 Hearst Philippine Biodiversity Expedition. California Academy of Sciences. 592 pp.
Van Syoc, R.J., D. Carrison-Stone, L. Madrona, G.C. Williams. 2014. 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, pages 171-211. In: GC Williams and TM Gosliner (editors), The Coral Triangle: The 2011 Hearst Philippine Biodiversity Expedition. California Academy of Sciences. 592 pp.
Williams, G. C., et al. 2013. A fifth morphological polyp in pennatulacean octocorals, with a review of polyp polymorphism in the genera Penatula and Pteroeides (Anthozoa: Pennatulacea). Zoological Studies 51(7): 1006-1017.
Williams, G.C. 2013. New taxa and revisionary systematics of alcyonacean octocorals from the Pacific coast of North America (Cnidaria: Anthoza). ZooKeys 283: 15-42.
Breedy, O., G.C. Williams, H. Guzman. 2013. Two new species of gorgonian octocorals from the Tropical Eastern Pacific Biogeographic Region (Cnidaria, Anthozoa, Gorgoniidae). ZooKeys 350: 75-90.
Williams, G.C. 2012. Pennatulacea. In: The magnitude of global marine biodiversity (W. Appeltans, editor). Current Biology 22(23): 2189-2202.
Williams, G.C. and C. Chen. 2012. Resurrection of the octocorallian genus Antillogorgia for Caribbean species previously assigned to Pseudopterogorgia, and a taxonomic assessment of the relationship of these genera with Leptogorgia (Cnidaria, Anthozoa, Gorgoniidae). Zootaxa 3505: 39-52.
Carrison, D., R. Van Syoc, G. Williams, B. Simison. 2012. Two new species of the gorgonian inhabiting barnacle, Conopea (Crustacea, Cirripedia, Thoracica), from the Gulf of Guinea. ZooKeys 270: 1-20 .
Williams, G.C. 2011. The global diversity of sea pens (Cnidaria, Octocorallia, Pennatulacea). WoRMS collection: The magnitude of global marine species diversity (WoRMS, World Register of Marine Species). PLoS ONE 6(7): 1-11.
Williams, G.C. and P. Alderslade. 2011. Three new species of pennatulacean octocorals with the ability to attach to rocky substrata (Cnidaria: Anthozoa: Pennatulacea). Zootaxa 3001: 33-48.
Williams, G.C. and P.J. Lopez-Gonzalez. 2011. A new deep-sea pennatulacean (Anthozoa: Octocorallia: Chunellidae) from the Porcupine Abyssal Plain (NE Atlantic). Helgoland Marine Research 65: 309-318.
Leviton, A.E., M.L. Aldrich, G.C. Williams, P.U. Rodda. 2010. Geology at the California Academy of Sciences, 1853-1907. Proceedings of the California Academy of Sciences 61(11): 547-573.
Williams, G.C., J.C. Delbeek, B. Shepherd, S. Wolters. 2010. Zooxanthellae in ellisellid gorgonians of the Philippines. Proceedings of the California Academy of Sciences 61(18): 647-648.
Williams, G.C. 2007. New species of the pennatulacean genera Acanthoptilum and Stylatula (Octocorallia: Virgulariidae) from New Zealand and the Campbell Plateau: both genera previously considered endemic to the west coast of the Americas and Atlantic Ocean. Proceedings of the California Academy of Sciences 58(15): 339-348.
Williams, G.C. 2007. History of Invertebrate Zoology at the California Academy of Sciences. Proceedings of the California Academy of Sciences 58(12): 197-239.
Williams, G.C. 2006. Replacement Name Proposed for the Genus Simpsonella Stiasny, 1940 (Octocorallia: Chrysogorgiddae), Precoccupied by Simpsonella Cockeraell, 1903 (Bivalvia: Unionidae). Proceedings of the California Academy of Sciences 57: 733-735.
Williams, G.C. and P.J. López-González. 2005. A New Genus and Species of Gorgonian Octocoral (Anthozoa: Plexauridae) from Antarctic Waters. Proceedings of the California Academy of Sciences 56 (26): 379-390.
Williams, G.C. 2005. New Taxa of Octocorals (Anthozoa: Octocorallia) from the Northeastern Pacific Ocean. Proceedings of the California Academy of Sciences 56 (5): 53-65.
Williams, G.C. and O. Breedy. 2004. The Panamic Gorgonian Genus Pacifigorgia (Octocorallia: Gorgoniidae) in the Galapagos Archipelago, with Descriptions of Three New Species. Proceedings of the California Academy of Sciences 55 (3): 55-88.
Williams, G.C. 2004. William Dampier: Pre-Linnean Explorer, Naturalist, Buccaneer. Proceedings of the California Academy of Sciences 55 (Suppl. 2): 146-166.
Williams, G.C. 2001. First Record of a Bioluminescent Soft Coral: Description of a Disjunct Population of Eleutherobia grayi (Thomson and Dean, 1931) from the Solomon Islands, with a Review of Bioluminescence in the Octocorallia. Proceedings of the California Academy of Sciences 52 (17): 209-225.
Williams, G.C. and S. A. Little. 2001. A New Species of the Soft Coral Genus Eleutherobia Pütter, 1900 (Coelenterata: Alcyoniidae) from South Africa. Proceedings of the California Academy of Sciences 52 (16): 195-208.
Williams, G.C. 2000. "Stinging Seas - Tread Softly in Tropical Waters," California Wild 53 (4): 12-17.
Williams, G.C. 2000. A New Species of the Soft Coral Genus Eleutherobia Pütter, 1900 (Coelenterata: Alcyoniidae) from the Tonga Islands. Proceedings of the California Academy of Sciences 52 (13): 159-169.
Williams, G.C. and J. Starmer. 2000. A New Genus and Species of Soft Coral (Octocorallia: Alcyoniidae) from South Africa. Proceedings of the California Academy of Sciences 52 (8): 87-96.
Williams, G.C. 2000. Two New Genera of Soft Corals (Anthozoa: Alcyoniidae) from South Africa, with a Discussion of Diversity and Endemism in the Southern African Octocorallian Fauna. Proceedings of the California Academy of Sciences 52 (6): 65-75.
Williams, G.C. and P. Alderslade. 1999. Revisionary Systematics of the Western Pacific Soft Coral Genus Minabea (Octocorallia: Alcyoniidae), with Descriptions of a Related New Genus and Species from the Indo-Pacific. Proceedings of the California Academy of Sciences 51 (7): 337-364.
Williams, G.C. 1999. Index Pennatulacea: Annotated Bibliography and Indexes of the Sea Pens (Coelenterata: Octocorallia) of the World 1469 - 1999. Proceedings of the California Academy of Sciences 51 (2): 19-103.
Williams, G.C. and K.G. Lindo. 1997. A Review of the Octocorallian Genus Leptogorgia (Anthozoa: Gorgoniidae) in the Indian Ocean and Subantarctic, with Description of a New Species and Comparisons with Related Taxa. Proceedings of the California Academy of Sciences 49 (15): 499-521.
Williams, G.C. 1997. A New Genus and Species of Nephtheid Soft Coral (Octocorallia: Alcyonacea) from the Western Pacific Ocean, and a Discussion of Convergence with Several Deep-Sea Benthic Organisms. Proceedings of the California Academy of Sciences 49 (12): 423-437.
Williams, G.C. 1996. "Nature's Plankton Net: Sea Fans of the Pacific," Pacific Discovery 49 (3): 42-43.
Williams, G.C. 1995. Living genera of sea pens (Coelenterata: Octocorallia: Pennatulacea): illustrated key and synopses. Zoological Journal of the Linnean Society 113: 93-140.
Williams, G.C. 1992. Revision of the Soft Coral Genus Minabea (Octocorallia: Alcyoniidae) With New Taxa From the Indo-West Pacific. Proceedings of the California Academy of Sciences 48 (1): 1-26.