ScienceDaily (Apr. 15, 2010) — The new T. rex has ferociously large teeth lining a single jaw. But its length is less than 2 inches. Tyrannobdella rex, which means tyrant leech king, is a new species of blood sucker that lives in the remote parts of the Upper Amazon. Although its regular host remains unknown, it was discovered three years ago in Perú when a 44.5 millimeter leech was plucked from the nose of a girl who had recently been bathing in a river.
This single jaw of Tyrannobdella rex was taken with a stereomicrograph and showing large teeth. Scale bar is 100 micrometers. (Credit: Phillips, et al. PLoS ONE 2010)
"Because of our analysis of morphology and DNA, we think thatTyrannobdella rex is most closely related to another leech that gets into the mouths of livestock in Mexico," says Anna Phillips, a graduate student affiliated with the American Museum of Natural History and the first author of the paper. "We think the leech could feed on aquatic mammals, from their noses and mouths for example, where they could stay for weeks at a time."
Discoveries of new leech species are not uncommon occurrences. Although there are 600 to 700 species of described leeches, it is thought that there could be as many as10,000 species throughout the world in marine, terrestrial and fresh water environments. Tyrannobdella rex was first brought to the attention of Mark Siddall, curator in the Division of Invertebrate Zoology at the Museum, when he received a specimen collected by Dr. Renzo Arauco-Brown, a Peruvian medical doctor from the School of Medicine at the Universidad Peruana Cayetano Heredia in Lima who was working at a clinic in Chanchamayo province. Siddall immediately recognized it as a new species. His student Alejandro Oceguera-Figueroa described its weird morphology -- a single jaw with eight very large teeth, and extremely small genitalia. Two earlier cases from 1997 were re-discovered from different clinics in the western Amazon, one from Lamas province and the other from Yochegua province.
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1 Department of Biology, The Graduate Center, The City University of New York, New York, New York, United States of America, 2 Sackler Institute of Comparative Genomics, American Museum of Natural History, New York, New York, United States of America, 3 School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Perú, 4 Department of Microbiology, Universidad Peruana Cayetano Heredia, Lima, Perú, 5 Enteroparasitology Laboratory, Peruvian Public Health Center, Peruvian Health Institute, Lima, Perú, 6Institute of Zoology, National Taiwan University, Taipei, Taiwan
Abstract
Background
Leeches have gained a fearsome reputation by feeding externally on blood, often from human hosts. Orificial hirudiniasis is a condition in which a leech enters a body orifice, most often the nasopharyngeal region, but there are many cases of leeches infesting the eyes, urethra, vagina, or rectum. Several leech species particularly in Africa and Asia are well-known for their propensity to afflict humans. Because there has not previously been any data suggesting a close relationship for such geographically disparate species, this unnerving tendency to be invasive has been regarded only as a loathsome oddity and not a unifying character for a group of related organisms.
Principal Findings
A new genus and species of leech from Perú was found feeding from the nasopharynx of humans. Unlike any other leech previously described, this new taxon has but a single jaw with very large teeth. Phylogenetic analyses of nuclear and mitochondrial genes using parsimony and Bayesian inference demonstrate that the new species belongs among a larger, global clade of leeches, all of which feed from the mucosal surfaces of mammals.
Conclusions
This new species, found feeding from the upper respiratory tract of humans in Perú, clarifies an expansion of the family Praobdellidae to include the new species Tyrannobdella rex n. gen. n.sp., along with others in the genera Dinobdella, Myxobdella, Praobdella and Pintobdella. Moreover, the results clarify a single evolutionary origin of a group of leeches that specializes on mucous membranes, thus, posing a distinct threat to human health.
Citation: Phillips AJ, Arauco-Brown R, Oceguera-Figueroa A, Gomez GP, Beltrán M, et al. (2010)Tyrannobdella rex N. Gen. N. Sp. and the Evolutionary Origins of Mucosal Leech Infestations. PLoS ONE 5(4): e10057. doi:10.1371/journal.pone.0010057
Editor: Robert DeSalle, American Museum of Natural History, United States of America
Received: December 4, 2009; Accepted: February 24, 2010; Published: April 14, 2010
Copyright: © 2010 Phillips et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was financially supported by the National Science Foundation (DEB-0640463), the Stavros Niarchos fund for Expeditionary Research, a Theodore Roosevelt Memorial Grant, and a CUNY Science Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: siddall@amnh.org
Received: December 4, 2009; Accepted: February 24, 2010; Published: April 14, 2010
Copyright: © 2010 Phillips et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was financially supported by the National Science Foundation (DEB-0640463), the Stavros Niarchos fund for Expeditionary Research, a Theodore Roosevelt Memorial Grant, and a CUNY Science Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: siddall@amnh.org
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