New Species of Camallanus in Freshwater Turtles

            Rigby et al. (2008) discovered two new species of nematodes within Camallanus and did an in depth examination to ensure that their discoveries were truly new species. The researchers examined the newly found species by looking at known characteristics, and measuring those specific features with a light microscope. They also utilized SEM as a technique to examine the buccal capsules in detail (Rigby et al., 2008).

            The first species that Rigby et al. (2008) discovered was Camallanus nithoggi, which infects the small intestines of their host Elseya latisternum (a freshwater turtle). C. nithoggi was determined to fall into Camallanus because of the characteristic smooth longitudinal ridges located on the two lateral buccal capsules. Named after a Norse god, C. nithoggi was described in great detail in order to differentiate it from other species of the same genus (Rigby et al., 2008). Rigby et al. (2008) mentioned the differences between sexes, the shape of buccal capsule, the excretory pore location, papillae arrangement, esophagus shape, and many other things that separate it from known species.  They focus primarily on buccal characteristics including the compososition of three parts, the number of ridges for each sex (four for males, five for females), the three peribuccal shields that exist and the species specific characteristic of buttressing on the buccal capsule.

            The second species discovered by Rigby et al. (2008) was Camallanus waelhreow, which was identified as a separate species of Camallanus using the same methodology for C. nithoggi. C. waelhreow is found in the small intestine of river turtles:  Emydura krefftii, Emydura macquarrii and Emydura macquarrii dharra (Rigby et al., 2008). I personally found it intriguing that this species name came from the Old English word for bloodthirsty, which is appropriate considering its diet of blood.

            Rigby et al (2008) focused the end of their species summation on the features of the buccal capsule that are visible because the use of SEM. The observed buccal capsule features had never been seen on another species before, which is interesting in itself. More interesting is that the buttressing on both of the new species is unique but has no function. Rigby et al. (2008) hypothesizes that these observed characteristics represent an intermediate step in the evolution of the posterior buccal capsule in species of Paracamallanus and Oncophora.

Rigby et al. (2008) focused a lot on the technical jargon of specific species identifiers that are very scientifically relevant but do not interest me very much. Despite that, Rigby et al. (2008) managed to emphasize the importance of the details in identifying a new species concisely. The mention of these species’ as an evolutionary stepping stone is also very interesting because discussion of evolution on a large scale is very common but rarely happens on the smaller level of parasitic organisms.

            Rigby et al. (2008) expanded upon my accumulated knowledge about parasites that infect turtles. Ogawa et al. (1997) introduced a new species Balaenophilus in their species description, but it was an ectoparasite and a copepod which is very different from a nematode species description. However, the similarities between the two articles as species descriptions were evident in terms of the great detail that was given.

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.