Previous studies had associated nematodes with manatee skin. One in 2011 described an “extraordinary” long-tailed diplogastrid nematode, Cutidiplogaster manati, found in skin lesions on West Indian manatees in an aquarium in Okinawa, Japan. This sparked the interest of these authors, who hoped to learn more about C. manati. In 2013, they began collecting samples from Florida manatees at the Crystal River National Wildlife Refuge, and the project became Mr. Gonzalez’s master’s thesis.
The team found what was likely C. manati – and two other nematodes.
Gonzalez, who worked with researchers conducting an annual manatee health assessment, collected dead skin from the tails of seven of the mammals in 2018 and another seven in 2019. The collection process is similar to a human backbone, and the animals are quickly returned to the water, Mr. Gonzalez said, to minimize stress.
The samples were examined under a microscope and their DNA was extracted. The new nematodes had large teeth – perhaps for eating other nematodes, or for “ something tricky, ” like splitting diatom algae and eating their insides, said Robin Giblin-Davis, a recently retired nematologist at the University of Florida and a co-author of the study. The team speculates that C. manati and one of the others, a previously unidentified species they called “Long Tail,” could use their long tails to anchor themselves in the waves.
While more work is needed for formal species descriptions of the two new nematodes, “I think you could safely say that these are new species,” said Adler Dillman, associate professor at the University of California, Riverside, who is not on the study. was involved. .
The nematodes, the study suggests, were specially adapted to thrive in this dilapidated micro-landscape, where structures on the skin would be as big to them as trees to humans. All three manatee eels were found on all manatees sampled in 2018 and 2019, but no skin lesions were found; the authors concluded that the nematodes were unlikely to hurt their hosts. Perhaps, they suggested, they are passed between manatees as human skin mites.
For now, the researchers hope to generate more enthusiasm for both nematodes and their friendly manatee hosts.