The Flagellate Cryptobia in Two Species of Deepsea Fishes from the Eastern Pacific

Abstract

Since 1888, eight species of Cryptobia (= Trypanoplasma) have been described or mentioned from marine fishes. The present paper describes two new species: C. stilbia, from the stomach of Bathylagus stilbius, a mesopelagic fish from the coast of California, and C. coryphaenoideana from the stomach of Coryphaenoides acrolepis, a bathypelagic fish from the coasts of Mexico and California. Transmission of the parasites is probably accomplished by direct transfer from the stomach of the host through the mouth and into water swallowed by another fish. The biology of the host fish is briefly discussed. During a study of parasitism in deepsea fishes from the coasts of California and Mexico, I found protozoan flagellates belonging to the family Cryptobiidae in the stomachs of the deepsea smelt, Bathylagus stilbius, a mesopelagic species collected from depths to about 750 m, and the macrourid, Coryphaenoides acrolepis, a bathypelagic species taken at 900 to about 2,500 m. These flagellates have not previously been reported from deepsea fishes. Approximately 45 species of cryptobiids have been described or mentioned in the literature, including eight from marine fishes, 24 from freshwater fishes, two free living, and one each from salamanders, a frog, heteropod, planarian, siphonophore, chaetognaths, leech, mole cricket (Gryllotalpa), lizard and two or three from snails. Most of the above species of flagellates are poorly described, and the validity of some of them is questionable. The eight species from marine fishes are as follows: (1) Cryptobia dahli (Mibius, 1888) Alexeieff, 1912, from the esophagus and stomach of Cyclopterus lumpus collected near Bergen, Norway. (2) Trypanoplasma intestinalis Leger, 1905, from the esophagus and stomach of Box boops in the Mediterranean. Martin (1914) observed three anterior flagella in this species, and consequently he changed the name to Trypanoplasmoides intestinalis. (3) Trypanoplasma congeri Elmhirst and Martin, 1910, from the stomach of Conger niger at Millport, Scotland. (4) Cryptobia trematomi Woodcock and Lodge, 1921, from the stomach and ascending intestine of Received for publication 8 December 1967. * Supported by NSF G.B. 6356 and NSF G.B. 4669. Trematomus bernacchii from waters off Cape Evans and Cape Adare, in the Antarctic region. (5) Trypanoplasma parmae Mackerras and Mackerras, 1925, from the blood of Parma microlepis collected near Sydney, New South Wales. These authors stated in 1961 that in their original preparations the blood may have been contaminated with fluid from the esophagus of the host. The site of infection is therefore in doubt. (6) Trypanoplasma flesi Nowicki, 1940, from the blood of Pleuronectes flessus, was mentioned as often occurring in the host, but it was never described. It therefore should be considered a nomen nudum. (7) Trypanoplasma makeevi Achmerov, 1959, from the blood and spleen of salmon, Onchorhynchus gorbuscha and 0. keta, collected at the mouth of the Amur River, Russia. The parasites were presumably of marine origin. (8) Cryptobia bullocki Strout, 1965, from the blood of Pseudopleuronectes americanus, Liopsetta putnami, Fundulus heteroclitus, and F. maialis collected from the coast of northern New England, USA. The most recent discussion of the problem of generic designation of these flagellates is that of Strout (1965). Like others before him, Strout concluded that until more information about the parasites is known a single genus should be retained. I agree with this conclusion. Cryptobia Leidy, 1846, described from the seminal vesicles of a snail, has priority over Trypanoplasma Laveran and Mesnil, 1909, described from the blood of a freshwater fish. MATERIALS AND METHODS Specimens of Bathylagus stilbius (Gilbert) (Family Bathylagidae) were collected with an Isaacs-Kidd midwater trawl and examinations made of living material on board ship. The area