A taxonomic revision of the family Harrimaniidae (Hemichordata: Enteropneusta) with descriptions of seven species from the Eastern Pacific

The family Harrimaniidae (Hemichordata: Enteropneusta) is revised on the basis of morphological characters. The number of harrimaniid genera is increased to nine by the addition of Horstia n. gen., Mesoglossus n. gen., Ritteria n. gen. and Saxipendium, a genus previously assigned to the monospecific family Saxipendiidae. The number of species is increased to 34, resulting from the description of five new species from the eastern Pacific — Horstia kincaidi, Mesoglossus intermedius, M. macginitiei, Protoglossus mackiei and Ritteria ambigua. A description is supplied for a sixth harrimaniid species, Stereobalanus willeyi Ritter & Davis, 1904, which previously had the status of a nomen nudum. Four harrimaniids previously assigned to the genus Saccoglossus are transfered to the genus Mesoglossus — M. bournei, M. caraibicus, M. gurneyi and M. pygmaeus, while Saccoglossus borealis is reassigned to the genus Harrimania. Notes on habitat and zoogeography are included for the seven foregoing species and a table of diagnostic characters for existing and new species and a dichotomous key to the enteropneust families and harrimaniid genera are provided. Finally, a phylogenetic hypothesis concerning the Harrimaniidae is postulated, with discussion on the evolution of the group.