A grant has been awarded to the University of Alabama at Birmingham under the direction of Dr. Robert W. Thacker for assembling the phylogenetic tree of sponges. Sponges are an ancient animal group with simple body construction. They are extremely efficient at filtering bacteria and other small food particles from the water in which they live, with thousands of different sponge species found in the world's oceans and freshwater habitats. Along with their important ecological roles, sponges can yield potential new medicines and host an extraordinary diversity of microbial life. Despite their widespread presence in aquatic habitats, the study of sponges has lagged behind that of other more charismatic marine fauna. Sponges pose special difficulties for those interested in deciphering their taxonomy, classification, and evolutionary relationships because sponge bodies are quite plastic, varying from one individual to the next. These difficulties hamper progress in basic studies of sponge biology and biodiversity, including comparative studies aimed at understanding the evolution of animals and efforts to conserve or economically exploit aquatic ecosystems. Using molecular genetic data from 8,000 sponge specimens, this project will provide a phylogenetic context that will improve the understanding of all aspects of sponge biology.

Proper Incorporation of sponges in the Tree of Life is imperative, because there is wide consensus that sponges comprise the primary trunk leading to more complex animals. Data from this project will test this hypothesis and resolve many "branches" within the sponge tree of life. This project will assist communication and collaboration within the international sponge research community by creating an internet-accessible database. This project will provide numerous outreach and educational opportunities, including undergraduate and graduate student training, intensive field courses, professional workshops, and conference symposia. This project benefits society as a whole by helping to track the origin and distribution of crucial genes (and chemical markers) that are useful in medicine and industry and by establishing new model systems for the study of early animal evolution.

Project Report

The major goal of the Porifera Tree of Life (PorToL) project was to support collaborative research to evaluate the taxonomy, systematics, and evolutionary history of sponges (phylum Porifera). Sponges are currently classified into 4 classes, 25 orders, 128 families, and 680 genera, with over 8,500 described species. We sought to construct a definitive phylogeny for Porifera using a variety of molecular and morphological approaches to systematics. We also sought to support graduate student research on Porifera and to develop an international team of collaborators. This project sponsored multiple field expeditions to collect sponge specimens from diverse marine environments, including the Bocas del Toro Archipelago (Panama? hosted by the Smithsonian Tropical Research Institute) and the San Juan Islands (Washington, USA? hosted by the University of Washington Friday Harbor Laboratories). In addition, we obtained specimens from permanent collections at the Smithsonian Institution (National Museum of Natural History, Washington, D.C.) and the California Academy of Sciences (San Francisco, California). From these specimens, we extracted DNA and sequenced multiple genes, including the 18S and 28S nuclear ribosomal subunits and mitochondrial cytochrome oxidase subunit I. These annotated DNA sequences are publicly available in the GenBank database. We sponsored 3 taxonomic workshops for sponge experts from multiple universities and museums around the world. These workshops allowed us to document the morphological features of each specimen and to correctly identify (or revise the identifications of) each specimen. The workshops facilitated collaboration and cooperation among a diverse group of taxonomists at multiple stages of career development, including students, postdoctoral researchers, junior and senior professors, and even retired taxonomists eager to share their knowledge with a new generation. We also sponsored 2 courses on the "Taxonomy, Systematics, and Ecology of Caribbean Sponges" at the Smithsonian Tropical Research Institute's Bocas del Toro Research Station. These courses trained 36 graduate students in sponge systematics. In January 2013, PorToL sponsored a symposium at the annual meeting of the Society for Integrative and Comparative Biology (SICB). The symposium presented many new conclusions derived from analyses of both molecular and morphological datasets, yielding 12 papers in a special issue of the journal Integrative and Comparative Biology. A total of 19 publications have been supported by this project, with at least 4 additional publications in preparation. This research revealed that our current view of sponge systematics is in dire need of revision. We focused our efforts on resolving taxonomic placements of families and orders. In doing so, we found support for: Four classes of sponges within the phylum Porifera. Before this project began, only 3 classes were recognized. The fourth class, Homoscleromorpha, was accepted by the taxonomic community based on the data generated by this project. Four subclasses of the class Demospongiae. Before this project began, there were no recognized groupings of orders within this class. Our research has proposed the establishment of four subclasses: Myxospongiae, Keratosa, Haploscleromorpha, and Heteroscleromorpha. Polyphyly of the majority of families within Demospongiae. Before this project began, there were few concerns that the accepted classification of sponges could reflect polyphyletic groupings, i.e., groupings that include mixtures of species with multiple ancestors (as opposed with monophyly, a grouping that includes species of a single common ancestor). Our datasets reveal that the vast majority of families within Demospongiae are polyphyletic, and thus do not reflect the evolutionary history of sponges. For example, within order Haplosclerida, we found that the 2 suborders, 5 of 6 families, and the majority of genera are polyphyletic. In addition, this project described 5 sponge species that are new to science, as well as a new genus. We discovered at least 20 more new species that we have yet to describe. This project sponsored the development of several Internet-based resources for sponge taxonomy, including the main project website PorToL.org. We created a digital thesaurus of sponge morphology (portol.org/thesaurus), expanded an interactive guide to the sponges of south Florida (portol.org/guide), and established a platform for contributions to the Encyclopedia of Life (porifera.lifedesks.org). Finally, PorToL contributed to several new initiatives that we did not anticipate when our project began in 2008: We partnered with the NSF-sponsored Phenotype Research Coordination Network to create an ontology of sponge morphology. This ontology is now being used by the NSF-sponsored Next-Generation Phenomics research team to test the ability of natural language processing software to read and interpret written species descriptions of sponges. We partnered with the Earth Microbiome Project and a team of microbiologists to create the "Sponge Microbiome Project", submitting over 400 PorToL specimens for microbiome analyses. We partnered with the France/Brazil project "MARRIO" to survey the sponge communities of Martinique, assisting with a course on sponge taxonomy that included graduate students from the United States, France, and Brazil. The datasets generated by this project provide a framework for testing new hypotheses of sponge evolution and for revising the taxonomy of sponges.

National Science Foundation (NSF)
Division of Environmental Biology (DEB)
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Simon Malcomber
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University of Alabama Birmingham
United States
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