Moving on from the Intestine: New Species of Trematode Take up Residence in the Gall Bladder

            Tkach et al. (2012) add Opisthioglyphe sharmai to the growing list of parasitic species that have turtles as their hosts with their species description. The turtles were bought from professional trappers in Malaysia and were killed about a week later in order to necropsy them and search for internal parasites. A new species of trematode was identified in the gall bladder, which is a highly unusual location in the definitive host (Tkach et al., 2012). The specimens were then collected for close observation and identification.

            Many characteristics were noted such as the body length, width, various ratios of body parts, the size/shape/location of male and female reproductive organs and the differences between juvenile and adult specimens (Tkach et al., 2012). There were many features that indicated that O. sharmai was indeed a new species of trematode. Their cirrus sac extends farther posterior to the ventral sucker, when all other species of Opisthioglyphe have a cirrus sac that is anterior to the ventral sucker or partially overlaps it. Tkach et al. (2012) proceeded to mention specific details that differentiate O. sharmai from other species in the same genus. The definitive hosts of O. sharmai are Malayan box turtles, Cuora amboinensis, and black marsh turtles, Siebenrockiella crassicollis.

            Tkach et al. (2012) conclude their species identification by mentioning the differentiation that they believe exists between the new species (O. sharmai) and another species (Opisthioglyphe koisarensis) that supposedly also has a posteriorly extending cirrus sac. Tkach et al. (2012) consider the drawings and article that introduce O. koisarensis to be brief and incomplete, which questions the validity of truth of the article. The authors actually consider O. koisarensis to belong in Dolichosalcus because of the shown distribution of vitelline follicles are characteristic of Dolichosalcus and not of Opisthioglyphe  (Tkach et al., 2012). Future studies should be done to try to find O. koisarensis and compare it directly to O. sharmai in order to know for certain that they are separate species.

            The information that is introduced by Tkach et al. (2012) continues to expand on the already known parasites of turtles introduced by previous articles. Ogawa et al. (1997) introduced Balaenophilus as an ectoparasite of sea turtles, and Rigby et al. (2008) introduced two species of nematodes from Camallanus. All of these articles emphasize the importance of details and an analytical mind when comparing species to discover if there really is a new species discovered. In this case, Tkach et al. (2012) introduce the importance of continuously critiquing scientific knowledge. There was already a species with a posteriorly extending cirrus sac (O. koisarensis), but the authors looked at it and came to the conclusion that what was written wasn’t accurate. 

Works 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.

Rigby, M. C., R. S. K. Sharma, R. F. Hechinger, T. R. Platt and J. C. Weaver. 2008. Two New Species of Camallanus (Nematoda: Camallanidae) from Freshwater Turtles in Queensland, Australia. The Journal of Parasitology 96 (4): 752-757.

Tkach, V.V., T.R., Platt and S.E. Greiman. 2012. A New Species of Opisthioglyphe (Trematoda: Telorchiidae) from Gall Bladder of Turtles in Malaysia. The Journal of Parasitology 98 (4): 863 – 868.