The USC Marine Research Station has collaborated with Dr. Sarah Lemer, postdoctoral fellow from the Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University in Cambridge, Massachusetts, and graduate student David Combosch, from 8 to 17 May 2013, in collecting bivalve species commonly known as pen or fan shells (Family Pinnidae), locally known as “tab” in Cebu and Bohol to investigate its taxonomy, radiation and diversity, and to supply in DNA a phylogenetic revision of this family.
The project conducted a nationwide collection in partnership with researchers from Southeast Asian Fisheries Development Center (SEAFDEC), University of the Philippines Visayas, University of San Carlos, Bicol University and National Museum of the Philippines, which are more knowledgeable about the collecting areas and the environment and are able to pursue the collecting activities on a long-term basis.
Fan or pen shells are widely distributed in shallow waters of temperate to tropical seas and exhibit an extraordinary variety of shell morphological traits along with variable habitat and life history trait. They are important members of various marine ecosystems like sand flats, seagrass beds and coral reefs where they can sometimes be found in large densities, providing food for several predators and shelter for many associate species such as crustaceans, fish and mollusks (Poppe, 2010).
Altogether, 57 species are commonly recognized with more than 100 ambiguous species. Hence the number of valid species requires further scrutiny. So far, there is no proposed phylogeny of the family and species delimitations are based on morphological characters only. This lack of precise information on the phylogeny of this family leaves a gap that has to be filled in order to improve our understanding of the diversity and the conservation of this group.
Although the Philippines is considered the epicenter of marine biodiversity, the full extent of marine mollusk biodiversity in general, and of Pinnidae in particular, remains unknown in this region. By collecting Pinnidae species in the Philippines the researchers aimed to resolve the phylogeny of the family by the identification of cryptic phylogenetic separations masked by conserved morphologies. Accurate species identifications are crucial for conservation and natural resource management and protection (Bickford, 2007).
Due to the particular life history traits of many pen shell species, their ecological and economic importance in the Philippines, over-exploitation and declining populations often due to habitat destruction, it has become urgent to improve our knowledge of their diversity in this region, known to host the richest concentration of marine life on the planet.
Of the 57 species of pen shells recorded worldwide, 15 species have been reported in the Philippines. The present expedition focused its collecting efforts on the areas where these species have been previously observed, mainly in the Central Visayas, Bicol and Mindoro Island. A maximum of 10 tissue samples per putative species per site were collected, using a non-lethal method based on the sampling of mantle tissue in situ. In parallel, 1 to 3 whole specimens per putative species per site were collected for subsequent taxonomical identification and vouchering. In Cebu out of the 9 species reported the team was able to collect 5 within the waters off Caubian Island, Olango Island, Punta Engano and in front of the USC Marine Research Station, while in Bohol only 1 from Panglao IslandSource: Dr. Sarah Lemer and Dr. Filipina Sotto
May 31, 2013