Balaenophilus umigamecolus: A New Ectoparasite Found on Sea Turtles

                Ogawa et al. (1997) identified a new parasite found on the skin of a young loggerhead sea turtle (Caretta caretta) in the Kushimoto Marine Park Center in Japan. The parasite was first identified because the turtle was weak, and had a discoloration on its neck which drew its caretaker’s attention. The discoloration was actually the parasite feeding on its skin (this is known as an ectoparasite). The parasite was washed off of the sea turtle, and filtered through paper to collect over 440 specimens.

                The collected samples of the unidentified ectoparasite were initially thought to be Balaenophilus unisetus, a parasite that is found on whales with a very similar appearance. However, when the newly gathered samples were compared to B. unisetus they were too different to be the same species. Ogawa et al. (1997) continued by describing the measurement and body shapes that were observed in the new ectoparasite, Balaenophilus umigamecolus. There are distinct differences between the sexes that were noted, and the measurement for copepod characteristics were recorded including the body length, the caudal rami, antenna, mandible, and comparison of features on the legs.

                In order to be absolutely sure that Balaenophilus umigamecolus was not the already identified Balaenophilus unisetus Ogawa et al. (1997)spent a portion of their investigation comparing the physical characteristics between the two species. B. umigamecolus is different because it has a smaller size, it has three apical claws on the 3^rd segment of the first leg when B. unisetus only has two, B. umigamecolus has a lack of seta of the 2^nd expod segment of a leg and has a short length of caudal rami (Ogawa et al., 1997). The mentioned characteristics made it clear that they were indeed two separate species.

                There also was a very limited and brief description of the lifecycle in terms of the young, which was particularly interesting. There were limited young found in the numerous specimens collected from the infected C. caretta. There were 10 specimens found clinging to the egg sacks right after hatching that were in the naupilis stage, and only 5 specimens were found in the other copepodid stages and only in the 3^rd, 4^th, and 5^th stages (Ogawa et al., 1997). Even as someone who knows very little about crustacean anatomy, I found this to be interesting because of the implications it has on the life cycle. If there were so many different stages of B. umigamecolus found on the host species, then that means that it is possible that the species spends its entire life on its host species. This fact was supported by the evidence that the nauplius larva has clasping appendages rather than the normal ones of a planktonic nauplius (Ogawa et al., 1997). Many parasites have a more complex lifecycle that involve definitive hosts, intermediate hosts, and reservoir hosts. If B. umigamecolus only needs to be in a single location for its entire lifecycle then it will have continuous access to its host and what it needs to survive.

Work Cited:

Ogawa, K., Matsuzaki K., Misaki H. 1997. A New Species of Balaenophilus (Copepoda: Harpacticoida), an Ectoparasite of a Sea Turtle in Japan. Zoological Science 14: 691-700.