|Photo composed from Fig. 5 & 6 of the paper|
With T. rex being one of the most badass dinosaur of all time, it is appropriate that the species of Trichomonas that we are featuring today - T. gypaetinii - is found in some pretty badass living dinosaurs as well. This parasite was first isolated from a bearded vulture (Gypaetus barbatus) - which I am sure most would agree is a very handsome and intimidating bird. When T. gypaetini was initially isolated, it was not fully described as a species, as there was insufficient material to do so. However, this study reports on newer samples obtained from a wide epidemiological study of avian trichomonosis in Spain. The research team managed to obtain isolates of T. gypaetini from another two species of vultures - the Egyptian Vulture (Neophron percnopterus) and the Black Vulture (Aegypius monachus) - and now we have a formal description.
So what differentiates T. gypaetinii from canker-causing T. gallinae? There was nothing about their appearance which separates the two species, but when the research team did some genetic analysis on the parasite, they found that all the Trichomonas samples from vultures were perching on their own branch, far away from T. gallinae. When they search for previously published sequences of Trichomonas from vultures, they hit upon the previously undescribed isolate from the bearded vulture mentioned earlier.
So where does T. gypaetinii sit on the Trichomonas family tree? Genetically, T. gypaetinii is actually more similar to T. vaginalis - a sexually transmitted parasite that infects over 160 million people worldwide each year - most of the time without them being aware of it as most cases show no symptoms. Much like those cases of T. vaginalis infection, T. gypaetinii does not appear to cause any problems to their bird host either.
Furthermore, it seems that T. gypaetini is only found in carrion-feeding birds. Other birds of prey can get infected by T. galinae - the canker-causing species - through eating other birds, especially pigeons. But the vultures' comparatively specialised diet and digestion physiology (especially that of the bone-munching bearded vulture) means that T. gypaetinii is the only Trichomonas that can successfully make vultures their hosts.
Martínez-Díaz, R. A., Ponce-Gordo, F., Rodríguez-Arce, I., del Martínez-Herrero, M. C., González, F. G., Molina-López, R. Á., & Gómez-Muñoz, M. T. (2015). Trichomonas gypaetinii n. sp., a new trichomonad from the upper gastrointestinal tract of scavenging birds of prey. Parasitology Research 114: 101-112.