Meeting Abstract
Phylum Hemichordata has about 130 described species; however, recent studies of hemichordate phylogeny and taxonomy suggest the species number has been largely underestimated. One issue is that species are described by experts, and historically few taxonomists have studied this group of marine invertebrates. Despite this previous lack of coverage, hemichordates have been rediscovered and researched for the past 20 years, and are critical to understanding the evolution of the chordates. We provide an overview of our current knowledge of hemichordates, focusing on their global biodiversity, geographic distribution, and taxonomy. Using information available in the World Register of Marine Species and the published literature, we assembled a list of described, extant species. The majority (83%) of these species are enteropneusts, and more taxonomic descriptions are forthcoming. Family Ptychoderidae currently contains the most species, closely followed by the Harrimaniidae. Hemichordates are found throughout the world’s oceans, with the highest reported numbers in the Northern Pacific and Atlantic provinces. Pterobranchs, the colonial Class of Hemichordata, are abundant in Antarctica, but have also been found at lower latitudes. We consider this a baseline report and expect, as new marine habitats are characterized and explored, new species of Hemichordata will continue to be discovered and characterized. Molecular phylogenetics, combined with taxonomy, has allowed documentation of new species, as both tornaria larvae and adults can be studied morphologically and sequenced.
