Previous studies have associated nematodes with hippo skin. One in 2011 described an ‘extraordinary’ long-tailed diplogastridal worm, Cutidiplogaster manati, found in skin lesions of West Indian hippos in an aquarium in Okinawa, Japan. This aroused the interest of these authors, who hoped to learn more about C. manati. In 2013, they began collecting samples of Florida hippos in the Crystal River National Wildlife Refuge, and the project has Mr. Gonzalez’s master’s thesis.
The team found what was probably C. manati – and two other nematodes.
Mr. Gonzalez, who works with researchers who conduct annual health assessments of hippos, has collected dead skin from its tails of seven of the mammals in 2018 and another seven in 2019. The collection process is comparable to a human backbone, and the animals are quickly taken back to the water, said Mr. Gonzalez said to reduce tension.
The samples were examined under a microscope and then their DNA was extracted. The new nematodes had large teeth – perhaps for eating other nematodes, or for ‘something troublesome’, such as tearing open diatomaceous earth algae and digesting their insides, said Robin Giblin-Davis, a recently retired nematologist at the University of Florida and an author of the study. The team speculates that C. manati and one of the others, a previously unidentified species they called ‘Long Tail’, can use their long tails to anchor themselves in the waves.
Although more work is needed for formal species descriptions of the two new nematodes, ‘I think you could comfortably say they are new species,’ said Adler Dillman, an associate professor at the University of California, Riverside, who did not study was not involved. .
The nematodes, according to the study, have been specially adapted to thrive in this dilapidated micro-landscape, where structures on the skin will be as high for them as trees are for humans. All three hippopotamus worms were found on all the hippos tested in 2018 and 2019, but no skin lesions were found; the authors concluded that the nematodes were unlikely to harm their hosts. Perhaps, as suggested, they are passed on between hippos like human skin mites.
For now, the researchers hope to create more enthusiasm for nematodes as well as their gentle hippo hosts.