Meeting Abstract
Two different larval cestodes were found at similar abundances in two penaeid shrimp (Sicyonia ingentis and S. pencillata) collected in trawls at a depth between 20 and 150m off the Palos Verdes coast in Southern California. The presence of two bothria and four retractable tentacles identified them as trypanorhynchs; one of 17 orders of the subclass Eucestoda within the class Cestoda. Trypanorhynchs are commonly found in marine organisms. One larval trypanorhycnh was further identified as part of either genus Dolfusiella or Eutetrarhynchus based on the morphology of the microthrix patterning and tentacular armature. Adults of the tapeworm, identified as such by the similarity in tentacular armature, were found in the skate Raja inornata. The stomach of one of the skates contained a shrimp containing a larval tapeworm, partially completing the life cycle for at least one of the species with the passage from the final skate host back to the shrimp still to be discovered. It is predicted to involve a small crustacean such as a copepod. Genetic sequencing is being used to further confirm that the larvae found in the shrimp and the adult worms found in skates are the same species. The possible route of nutrient absorption was addressed by following permeability of the larvae to tracers such as ferritin and lanthanum. The composition of the film surrounding the larvae within the digestive gland of the shrimp and of possible shrimp hemocyte origin is also being examined.
