Unionoid cladomics: a novel biodiversity informatics approach to the new freshwater mussel taxonomy
by Daniel L. Graf
Presented at the virtual annual meeting of the American Malacological Society, 1-4 August 2023.
Abstract.The MUSSEL Project Database (MUSSELpdb; www.mussel-project.net/) was developed to document the accumulated taxonomic and specimen-based data on freshwater mussel species, genera, and families (Bivalvia: Unionoida). Over the past two decades, there has been a community-wide shift in the philosophy, methods, and pace of revisionary work, as evidenced by the proliferation of publications, cladograms, and applicable nucleotide sequences. Before 2001, there were 20 publications with 33 freshwater mussel cladograms, and these were based on fewer than 150 phylogenetically useful DNA sequences (i.e., mtGenomes, COI, ND1, 16S, 18S, 28S, ITS, H3) or morphology. Today, there are more than 470 such cladograms (14x increase) and Genbank has more than 30,000 such DNA sequences (up 200x). As expected, there has been a major impact on freshwater mussel systematics. In 2007, the MUSSELpdb reported the Recent richness of freshwater mussels as 840 species in 161 genera. Today, there are 990 species in 201 genera.
Phylogenetic data in the form of trees depicting evolutionary relationships among DNA sequences representing taxa based on cladistic methodology have superseded traditional revisionary work (e.g., synonymies, cresonymies). Freshwater mussel taxonomy today follows post hoc from phylogenetic analyses and fluctuates with analyses and results. The MUSSELpdb has adapted to accommodate these new types of data that form the basis of freshwater mussel taxonomy.
The MUSSELpdb includes resources to document and analyze freshwater mussel cladomics — that is, the sets of phylogenetic topologies (i.e., clades) relevant to supra-specific taxa (https://mussel-project.uwsp.edu/db/cladomics_farq.html). The MUSSELpdb cladomic summary for each genus, tribe, family, etc. ranks cladograms according to their usefulness for testing monophyly and sister-relationships, describes statistics of cladogram quality, and depicts relevant species-tree topologies for comparison. My talk will describe some recent innovations to an already innovative dataset and summarize some of the lessons learned to-date. |
