Newly-identified blood-sucking leech has been quietly living in American swamps for decades
It may not be a Bigfoot or a Loch Ness Monster, but a somewhat creepy new animal species has recently been discovered. Named Macrobdella mimicus, it's the first medicinal (human-blood-sucking) leech to be described in North America in over 40 years.
The fun started in 2015, when Anna Phillips – who is the Curator of Parasitic Worms at the Smithsonian's National Museum of Natural History – returned from a field expedition with several orange-spotted, olive-green leeches she'd collected from a Maryland swamp.
Initially, she thought they were all members of the Macrobdella decora species, which is commonly found throughout the northern US. When their DNA was analyzed by National Autonomous University of Mexico grad student Ricardo Salas-Montiel, however, it turned out that some of them were different. Upon closer examination of those individuals, it was noted that their multiple reproductive pores – known as gonopores and accessory pores – were located differently relative to one another.
In a subsequent field trip to South Carolina, Phillips (pictured above) and her team found more leeches with that same pore placement, that had the same DNA as the oddballs from Maryland. When she then went through the Smithsonian's collections, she found other examples of the species, which had been identified as M. decora when filed away. They had been gathered at locations ranging from Long Island south to Georgia, as far back as 1937.
Anna later found other preserved specimens in collections at the North Carolina Museum of Natural Sciences and the Virginia Museum of Natural History, plus she captured new live specimens in Georgia and North Carolina. It is now thought that M. mimicus has been occupying "a sliver of the eastern United States" between the ranges of two other medicinal leeches, for at least the past several decades.
"We found a new species of medicinal leech less than 50 miles [80 km] from the National Museum of Natural History – one of the world's largest libraries of biodiversity," says Phillips. "A discovery like this makes clear just how much diversity is out there remaining to be discovered and documented, even right under scientists' noses."
A paper on the research, which also involved scientists from Canada's Royal Ontario Museum, was recently published in the Journal of Parasitology.