"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

April 16, 2010

April 16 - Tyrranobdella rex

A new genus and species of leech, Tyrranobdella rex Phillips et al. 2010 with enormous teeth was described in the journal PLoS ONE on Wednesday of this week. Found feeding from the nose of a 9 yr old child in the upper Amazon by Renzo Arouco-Brown of the School of Medicine at the Universidad Peruana Cayetano Heredia, this new T. rex is known from 3 nasopharyngeal cases, and may well be the first leech species for which Homo sapiens is the type-host.

Phylogenetic work in the publication demonstrates that T. rex is part of a larger evolutionary group of mammal-specific endoparasites, the Praobdellidae, which includes the terrible ferocious leech (Dinobdella ferox) from Asia as well as African and Mexican pests. Mucosal leech infestations by members of this family typically involve the naries, pharynx and hypopharynx, though more alarming mucosal infestation sites are noted by Anna Phillips of the American Museum of Natural History and her co-authors. While leeches are not typically thought to be significant parasites of humans, praobdellid leeches like T. rex have been known to cause life-threatening conditions that range from choking to severe anemia and even death.

In addition to Phillips and Arauco-Brown, authors of this new and formidable T. rex include Mark Siddall and Alejandro Oceguera-Figueroa, also of the American Museum of Natural History, Gloria P.Gomez of the Department of Microbiology at the Universidad Peruana Cayetano Heredia in Lima, María Beltrán of the Enteroparasitology Laboratory at the Peruvian Public Health Center, and Lai Y-Te of the National Taiwan University in Taipei.

Contributed by Mark Siddall.


  1. So the official name of this species will be Tyrranobdella rex Phillips, Arauco-Brown, Oceguera-Figueroa, Gomez, Beltrán, Lai,and Siddall, 2010. Not to be an old curmudgeon (which I am), but this seems a little absurd. There is an alternative to this in the rules of nomenclature which allows all the author's names to be on the paper, but only 1 or 2 of the names to be on the species. I hope future authors will take advantage of this rule.

  2. a leech up the nose? Amazing! I would be hard pressed to think of a scarier scenario.

  3. My, What Big Teeth You Have. That's one scary leech.

    (BTW does the email plasmodium@mac.com for the theme ideas working? I keep getting a delivery failure notice from my email program)

  4. Try "plasmodium@me.com" - those apple accounts are finicky.

  5. reply to Mike Kinsella:
    Zoological Code
    Recommendation 51C. Citation of multiple authors. When three or more joint authors have been responsible for a name, then the citation of the name of the authors may be expressed by use of the term "et al." following the name of the first author, provided that all authors of the name are cited in full elsewhere in the same work, either in the text or in a bibliographic reference.