Kroyeria caseyi sp.nov. (Kroyeriidae: Siphonostomatoida), a parasitic copepod infesting gills of night sharks (Carcharhinus signatus (Poey, 1868)) in the western North Atlantic

Abstract

Kroyeria caseyi sp.nov. (Kroyeriidae: Siphonostomatoida) is described from male and female specimens collected from gills of night sharks (Carcharhinus signatus (Poey, 1868)) captured in the western North Atlantic. Kroyeria caseyi is the only known member of the Kroyeriidae that is a mesoparasite, females being found partially embedded in the interbranchial septa of their hosts. Kroyeria caseyi is easily distinguished from other Kroyeria species by the armature of its swimming legs. Additionally, the genital complex of female K. caseyi is extremely long, composing up to 96% of the total body length. With some females reaching over 6 cm long, K. caseyi dwarfs all known congeners. First-stage nauplii collected from ruptured egg sacs are also described.