External Anatomy of the Female Haemobaphes cyclopterina, a Copepod Parasite of Marine Fishes

Abstract

A single complete specimen from a new host, the snake blenny (Lumpenus lumpretaeformis), caught in the Bay of Fundy, is described, with particular attention to the anterior end. The appendages and oral area are similar to those of other lernaeocerids, notably Lernaeocera branchialis, but comparison with the only published description of the first copepodid stage suggests that changes during development may be more extensive than usual. Synonymy, hosts, and distributional records are tabulated. H. cyclopterina appears to be a circumboreal host-tolerant plastic species, possibly comprising diceraus Wilson, 1917, and theragrae Yamaguti, 1939. The genus is placed in the Lernaeoceridae Milne Edwards, 1840, and the name Lernaeoceriformes suggested to replace Lernaeiformes Gurney, 1933, within the Caligoida. Haemobaphes cyclopterina (Fabricius, 1780) is a lernaeocerid copepod. Probably, as in other members of this family, the entire life history takes place in the sea and involves initially free-swimming larvae, then a series of chalimus (copepodid) stages attached to the first host (possibly a fish) and a temporarily motile adult phase (if the first host is not the final one), before the female becomes fixed to the final fish host. Evidently she attacks through the gills, penetrating until her anterior end lies in the ventral aorta, the posterior part of her body remaining external. Insemination may take place while the adults are still on the first host or when they are free but it is not likely that the male survives for long or becomes parasitic again. In any event, only the nauplius and first copepodid stage have been described (Heegaard, 1947) in addition to the terminal female. It is with this last that the following account deals. According to the literature, the adult parasite has an arctic circumpolar distribution, being recorded up to 79?35' N (Sars, 1886), but it is also found in the North Temperate Zone as far south as 36?21' N (Wilson, 1917, supplemented by Anonymous, 1907). Although depth has seldom been mentioned, it seems probable that no collection was made from more than 250 fathoms (that of Wilson, 1917, Received for publication 15 March 1963. suppl.) and most from much shallower water, usually close to land. The roster of hosts is varied and extends over several teleost groups (Table I). However, many of the records for this copepod lack description. Most were based on the exposed part of the body only, and some state the main diagnostic feature to be the coiled egg sacs-a generic or group rather than a specific character. It is not impossible, then, that more than one species has been included in the literature under the ame H. cyclopterina. The present study began in April 1962, when we received the trunk of a copepod, identifiable as an ovigerous Haemobaphes, from Dr. Roland F. Wigley (U. S. Bureau of Commercial Fisheries Laboratory, Woods Hole, Mass.). Morphologically this part of the animal appeared to be somewhat intermediate between H. cyclopterina and H. diceraus Wilson, 1917, according to the descriptions of both given in that paper. Through the further kindness of Dr. Wigley, R. U. G. was able to dissect the anterior end of the copepod from the host fish. In addition to the taxonomic problem, a detailed description of the anterior end seems important both per se and for comparison of its appendages with the results of recent excellent studies on Lernaeocera branchialis (L.) (Kabata, 1961, 1962), a copepod belonging to the same family. We hope that our work may