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Detection of aquatic species is imperfect, especially if the species is rare and exhibits spatial and temporal variability. Many fish species require a number of sampling trips before detection is positive. And yet, information on species persistence is critical for effective conservation efforts. New forensic genetic techniques, such as environmental DNA (eDNA), have been developed and successfully used to validate the presence of exotic aquatic species in new areas. We compared detection of a federally listed, threatened, migratory fish species the Slackwater darter (Etheostoma boschungi); using eDNA to concomitantly collected field collections. Detection probabilities for this species are variable, but consistently low in recent collections. Our results indicated that detection using eDNA was vastly more effective than traditional sampling at confirming the presence of the Slackwater darter. Positive detection at non-breeding sites was half of the detection rate at breeding sites, most likely to the greater area available in non-breeding streams. These data suggest that eDNA is an effective tool for quickly evaluating a relatively large number of sites for the presence of rare aquatic species.

Annelida, one of the most successful animal phyla, exhibits an amazing variety of morphological forms. Disparity between some of the forms is so great that until molecular tools were used, some annelid lineages (for example, echiurids and pogonophorans) were not commonly recognized as belonging to the group. Although it is easy to assign annelids to a given family, understanding the deeper relationships within the group has been difficult. The main working hypothesis for annelid phylogeny is based on morphological cladistic analysis. However, the recent work using molecular tools has caused a revision of our view of annelid evolutionary history. For example, Scolecida and Palpata appear not to be natural groups, and the phylogenetic positions of some aberrant taxa (for example, Siboglinidae, Poeobius, Pisione) have been determined. Herein, we discuss some of the main molecular markers that have been used to elucidate annelid phylogeny and the contribution that such work is making to our understanding. A table highlighting the molecular literature and the genes used is included.