Meeting Abstract
Unbeknownst to most people, the majority of species on Earth, especially in the marine environment, remain undescribed. In the context of the current biodiversity crisis, it is clear that characterizing existing diversity should be a priority, in order to establish a baseline for monitoring change. Biodiversity researchers must deal with the challenge of cataloguing the vast number of undescribed species while operating under deficit of time, funding, and taxonomic expertise. Characterizing undescribed diversity is further complicated by cryptic speciation, outdated and inefficient standards of species descriptions, and the need for revisionary systematics. Understudied taxa, like ribbon worms (phylum Nemertea), are in particular need of attention. In the Caribbean Sea there are ~38 described species of nemerteans, but DNA-barcoding of specimens collected over the past 20 years suggests there are several times that number of operational taxonomic units (OTUs), i.e. putative species, most of which are undescribed, cryptic, and a large fraction only known in the larval form. Preliminary species accumulation curves based on 108 OTUs (361 adult individuals as of early 2018) suggested a further ~50 species would be discovered by barcoding an additional ~1000 individuals. We now sequenced a few hundred additional adult individuals, and already surpassed the predicted number of species. How can we describe all of this diversity in our lifetimes? How does one deal with describing cryptic species (morphologically indistinguishable, yet distinct) or those only known as larvae? And how many species of nemerteans are there in the Caribbean Sea? Here we offer an update on the diversity of Caribbean nemerteans, and discuss some of the challenges associated with identifying and describing this diversity.
