Phylogenetics of a small caddisfly genus (Thremmatidae: Oligophlebodes ): comparison among multiple hypotheses from DNA barcode data

Barcoding datasets can serve as a resource for species associations and delineations, but single-gene trees estimated by distance methods do not provide strong estimates of phylogeny. Using DNA data from the Barcode of Life Database (BOLD), we calculate a phylogenetic tree for Oligophlebodes (Trichoptera: Thremmatidae), a small genus of caddisfly endemic to the Western United States. Here we estimate a preliminary phylogeny for Oligophlebodes using Bayesian likelihood, and compare it to trees produced by distance and standard likelihood methods. Using the barcode region of the cytochrome oxidase 1 (COI) gene, we analyzed 44 individuals representing five species (and 2 unknowns) and a sister-genus outgroup ( Neophylax ) from locations ranging from Southern New Mexico northwest into British Columbia. Partitioned Bayesian likelihood analysis under the F81 (1 st codon positions) and HKY80 + I + Γ (for both the 2 nd and 3 rd codon positions) model gave the consensus topology ( Neophylax toshi , ( O. sierra , ( O. ruthae inc. spc. 1 & 2, O. sigma, (spc. 3 & 4, ( O. ardis, O. minutus )))). Species identifications were supported by monophyly of most species-level taxa. However, confirmation of species identifications of unknowns was complicated by incomplete taxon sampling for spc. 1 & 2. Placement of spc. 3 & 4 may serve as support for taxonomic review of O. minutus . Compared with an existing published phylogeny of Oligophlebodes BOLD sequences constructed under RAxML, the Bayesian hypothesis had higher resolution at the basal node of Oligophlebodes . Because of their support values, both likelihood trees are recommended over the BOLD TaxonID tree (an unrooted neighbor joining tree using the Kimura 2-parameter model). The novel topology produced in the Bayesian tree supports further explorations by likelihood-based methods, including partitioned analyses, of our preliminary Oligophlebodes dataset that can be used as additional lines of evidence to support morphological work.