Redescription and Molecular Characterization of Placobdella nuchalis Sawyer and Shelley, 1976 (Hirudinida: Glossiphoniidae)

Abstract Placobdella nuchalis Sawyer and Shelley, 1976 was originally described based on specimens from Four Hole Swamp (type locality) and a stream near Ashepoo River in South Carolina, USA, and Merchant's Millpond and Nine Mile Creek in North Carolina, USA. Leeches collected during August 2014 and August 2015 from Four Hole Swamp (type locality) and Merchant's Millpond (paratype locality) facilitated a redescription and molecular characterization of Placobdella nuchalis. Two additional specimens of Placobdella nuchaliswere collected on 10 August 2014 from Nassawango Creek, Maryland, USA, representing a state distribution record. Placobdella nuchalis has a brownish green dorsum with a dark medial line interrupted three times by yellow-cream spots, a pair of paralateral rows of unpigmented papillae with adjacent dark green papillae, and a distinct discoid head. Molecular comparison of cytochrome c oxidase subunit I (CO-I) sequence data from a specimen of Placobdella nuchalis from Four Hole Swamp (type locality) revealed a 94.5% similarity to a specimen collected from Merchant's Millpond (paratype locality) and 14.2% to 17.5% differences among other species of Placobdella.