A Note concerning Certain Microphallid Trematodes Infecting Shore Birds (Limosa fedoa and Catoptrophorus semipalmatus inornatus) with Description of a New Species (Levinseniella charadriformis)

Abstract

Young (1938) described the life history of a trematode, tentatively identified as Levinseniella cruzi, from certain shore birds of the California coast but was unable at that time to experimentally transfer the worm from the intermediate (Emerita analoga), to the final hosts (Limosa fedoa and Catoptrophorus semipalmatus inornatus). Cable and Hunninen (1940, p. 153) have stated that the species might belong to either Levinseniella or Spelotrema as these genera are distinguished at present. Tentative identification was based on the classification of Travassos (1921) in which Spelotrema is given as a synonym of Levinseniella, but subsequent studies have shown that this was an error, which is corrected in the following account. There are at least four microphallid species in these shore birds, a Maritrenma, two species of Spelotrema, and a Levinseniella. The first of these has not been studied in detail, but its intermediate host is probably the sand flea (Orchestoides). One of the spelotremas is apparently S. papillorobusta of Rankin (1940), but material is too scanty to permit a final determination, while the other, which was tentatively identified as Levinseniella cruzi in the earlier paper (Young, 1938), closely resembles S. nicolli Cable and Hunninen, 1940, although differing from the latter in certain minor details. These concern chiefly egg size, form of vitellaria and proportions of oral and ventral suckers. The eggs of S. nicolli measure from 18-22 x 8-13 ~, while in the present specimens they average 25 x 12 ~, with a range between 21-28 x 8-13 ~. Cable and Hunninen described the vitellaria as so diffuse that a count of their lobes could not be made with certainty. As shown in Figure 3, there are 6-8 distinct lobes in the specimens at hand. However the lobes are fused at the center in a manner that suggests that their definition probably is largely a matter of technique. In S. nicolli, the acetabulum exceeds the oral sucker by 2 p (58 vs. 56), while in the present specimens the reverse is true; again a difference of 2 p (43 vs. 45). This criterion is not a satisfactory one, since in different specimens of the same species the relative proportions may be reversed. Nor is the extent of the intestinal ceca satisfactory. In some individuals these organs reach to or beyond the middle of the acetabulum, while in one at least they terminate much anterior thereto, the difference depending largely on the amount of contraction of the specimen. These differences do not warrant the separation of the present form from S. nicolli, since in all other respects the two are in agreement. The presence of all four of the foregoing species in shore birds which have recently fed on Emerita and of metacercariae excysting in the stomachs of the birds is suggestive of the source of infection, but does not show which of the parasites is derived from this source, or whether more than one is so derived. Furthermore, as noted in the previous paper (Young, 1938), it is possible to obtain a temporary infection of fish by feeding them infected Emerita.