Taxonomy and Biology of Some Newfoundland Marine Leeches (Rhynchobdellae: Piscicolidae)

Abstract

Taxonomy and biology of 4 species of marine Piscicolidae belonging to the Malmiana–Oceanobdella complex were studied on the coast of Newfoundland from 1970 through 1974. Species include Malmiana brunnea, M. scorpii, and Oceanobdella microstoma, which infest shorthorn (Myoxocephalus scorpius) and longhorn sculpin (M. octodecemspinosus) and O. sexoculata, which occurs in the buccal cavity of ocean pout (Macrozoarces americanus). Laboratory studies included host proclivity, mating, deposition and hatching of cocoons, and growth of the progeny. Malmiana brunnea and M. scorpii have the potential of producing 2 generations each year, but the life cycle in nature is probably annual: the young emerge in July through September, mature and breed in the spring of the next year, and die by midsummer following cocoon deposition. Life cycles of O. microstoma and O. sexoculata are also annual. Although cocoons of O. sexoculata hatch in August, young of O. microstoma do not emerge until late November. Young of both species mature the following spring, deposit cocoons, and die. Cocoons of M. brunnea and M. scorpii each contain an average of 3 and 5 eggs, respectively, but those of O. microstoma and O. sexoculata contain only 1 egg.Malmiana nuda Richardson, 1970 and Platybdella buccalis Nigrelli, 1946 are considered junior synonyms of M. brunnea (Johansson, 1896) and Oceanobdella sexoculata (Malm, 1863), respectively.