Description of the Southern swamp leech Philobdella floridana (Verrill, 1874) (Annelida: Hirudinea) from the Outer Banks, North Carolina, USA, with a revision of the species

Abstract

The jawed leech Philobdella floridana (Verrill, 1874) occurs widely in swamps of the southeastern United States. The discovery of a population of P. floridana in Lake Phelps, an isolated lake in the Albemarle Peninsula in the Outer Banks region of North Carolina, is by far the northernmost record for this species. Description of the Lake Phelps leech in this paper is the first comprehensive account of the internal anatomy of P. floridana. Comparable internal descriptions of P. floridana from other geographic regions are also presented for the first time. This new understanding of the internal features of this species is the basis of a taxonomic revision of P. floridana.        All specimens examined in this study possessed remarkably similar jaws and teeth within the range of 22–26 per jaw, regardless of the size or origin of the leech. All mature specimens possessed external copulatory slits and pores which uniquely characterise the genus Philobdella. This study shows for the first time that these external features are attributable to a complex internal network of gastropores emanating from the crop caeca of the genital segments. Nonetheless, the reproductive anatomy of this species is by far the most rudimentary of any Hirudinidae in North America.        A major finding of this study is that the Lake Phelps population differs significantly from other known P. floridana in one significant respect. Specifically, the gut has an intimate anatomical association with the nephridia, an enteronephric feature previously unknown within the Hirudinea. At least in this study, enteronephry may be confined to Lake Phelps, leaving open the possibility that this population of P. floridana may be endemic to this relict lake which has a history of endemicity.