Morphology and host specificity of Cryptobia catostomi n.sp. (Protozoa: Kinetoplastida) from white sucker (Catostomus commersoni) in southern Ontario

Abstract

During the summer of 1975, 285 white sucker from 10 localities in southern Ontario were examined for haemoflagellates. Cryptobia catostomi n.sp., found in the blood of 43.4% of the fish examined, occurred in all populations of adult fish and in one of three populations of juvenile fish.The morphology of C. catostomi n.sp. based on over 500 specimens stained with Giemsa's stain, varied considerably. Cloning showed that this species is pleomorphic and has morphological features and body measurements which encompass most other Cryptobia spp. previously described from the blood of fishes. Cryptobia catostomi n.sp. was distinguished by its host specificity. Infections could not be transmitted to 16 other species of fishes by inoculation of blood from infected sucker. Fishes refractive to infection included Cyprinus carpio, Carassius auratus, Rhinichthys atratulus, Semotilus atromaculatus, Salmo gairdneri, Oncorhynchus kisutch, and Esox lucius from which other species of Cryptobia (C. borreli, C. cataractae, C. salmositica, and C. gurneyorum) have been reported in North America.