Meeting Abstract

P2.150  Wednesday, Jan. 5  Barnacle and Sponge Symbiosis: Host Specificity and Systematics of Acastinae from the Philippines JACKSON, Amberlea*; VANSYOC, Robert; California Academy of Sciences, San Francisco and University of California, Berkeley; California Academy of Sciences, San Francisco amberpeach66@berkeley.edu

Although barnacles can be found riding whales or clustered around the base of a pier, the sessile barnacle family Acastinae from the Philippines have settled mainly in Porifera. This symbiotic relationship provides the barnacles with a habitat relatively free of spatial competitors as well as protection from various predators. In the course of our phylogenetic analysis, we hoped to determine species level host specificity by analyzing a combination of morphological and molecular data taken from 20 samples. Utilizing auto montage images of the whole shell and scanning electron micrograph images of the shell walls and opercular plates, we discovered several potential new species. Molecular data, taken from sequenced fragments of CO1 and H3 genes, supported the morphological findings. Next, we constructed a phylogeny of the molecular data and mapped morphological characteristics on it, including species from the Acastinae family found in other areas of the world. Further examination of this phylogeny revealed an Acasta sp. from Madagascar which clustered with three new species from the Philippines, all living in the same host species. This implies that host specificity has a global reach and evolved early on in the development of the sponge to barnacle symbiotic relationship.