Tulodens. I ran across them while skimming the Wikipedia article on Protozoa, and the name didn’t ring a bell. However, the free encyclopedia assured me that there are “an estimated 30,000 protozoan species,” so it wasn’t too surprising that I’d missed these guys.
Apparently, there are at least two of them, or two kinds, and they move slowly, with the help of flagella. Or cilia, or possibly pseudopods.
A suspicious Wikipedian had already pinned a “citation needed” tag to that first sentence, so I thought I’d better corroborate the claim. A Google search turned up hundreds of references to these Tulodens. The organism was mentioned in a 24-page brochure on the most common causes of calf diarrhea. It was listed among the germs on All About Germs. On a Q&A site, somebody asked for the name of a protozoan that moves “by lashing one or more of its whiplike parts,” to which a user named 1Jazz helpfully responded: “Tulodens are a form of protozoa that move using a whip-like tail.” That’s the internet for you, always ready to help a guy with his homework.
So, are Tulodens parasitic? We already suspect that they cause calf diarrhea, but what else is known? All sources agree that they are very slow. Evidently they are also common, and possibly heterotrophic. If you like, you can read about them in a book called Fundamentals of Plant Pathology, by N. G. Ravichandra. The paperback isn’t cheap, but the Kindle edition is a very affordable CDN $7.32. Ravichandra discusses Tulodens briefly on page 254, but unfortunately does not add to what we already know. They are “slow moving.” Well, sure.
But it would be nice to know what they look like. A search in Google Images called up all kinds of sciencey pictures: stained mounts, petri dishes, an Asian-looking guy peering into a microscope. Google Images also threw up a pretty cool papier-mâché model of a Vorticella made by a schoolboy in Spain as a science fair project. The boy’s blog post includes another passing reference to the famously slow-moving Tulodens, and he is careful to cite Wikipedia as his source (which makes him a more conscientious scholar than “world renowned parasitologist” Dr. Amin).
Tulodens are also known to the Germans, the Portuguese and the Russians, so presumably their distribution is cosmopolitan. Curiously, all these sources seem to have pulled their information from the same place: the English Wikipedia article on Protozoa.I wasn’t learning anything new, so I turned to the biodiversity databases. I checked the Catalogue of Life, the Encyclopedia of Life, Algaebase and WoRMS. I’m happy to say that Tulodens did not appear in any of them. Perhaps some Wikipedia editor had simply misspelled the name of some legitimate protist? I ran my eye down a few alphabetized species lists, but didn’t see any likely candidates.
At this point, I decided to see what I could learn about the Wikipedian who had introduced this organism to the world. Luckily, Wikipedia discards almost nothing: every version of every page is saved, so it is easy to retrace the entire history of an article back to the very moment it was created. The protozoa article has been edited thousands of times since it was created on May 3, 2001, but it did not take me long to find the original appearance of Tulodens, on Feb 21, 2010. It read:
Tulodens are one of the slow moving form of protozoans. They are mainly found in Leyte, Philippines. Treatment would be axing, retrenching and other form of lay away operations. Exposure usually takes two years to get rid of and are usually costly to the host.
The rascal who inserted that did not leave his name, but Wikipedia records the IP address of everyone who alters a page. In this case, the editor’s IP was 184.108.40.206, which (according to WHOIS) belongs to a company called Apac Customer Services, in Bannockburn, Illinois. Apparently, somebody at that IP used to edit Wikipedia from time to time, in a desultory and occasionally mischievous way, between 2008 and 2010. Whoever it was, he seems to have had a recurring interest in both parasites and the Phillipines, and was once blocked for editing the Wikipedia article (since deleted) on Apac Customer Services.
A couple of weeks later, another editor came along and removed the scary bit about the “axing and retrenching” treatment needed to cure a Tulodens infection. Within the month, somebody else edited out the observation that Tulodens were “mainly found in Leyte, Phillipines.” Now, nothing stood between Tulodens and the claim that these little fellows “move around with whip-like tails called flagella.” There was still a certain awkwardness in the passage, though, which described the “Tulodens” (plural, presumably) as “one of the slow moving form of protozoans.” It was two years before another editor solved that problem by ingeniously changing the phrase to read “Tulodens are 2 of the slow-moving form of protozoa.” Recently, that was changed again, to read “two of the slow-moving form of protozoa.” Wikipedia’s Manual of Style stipulates that integers below nine should be spelled out as words, and Wikipedians are very careful about things like that. Somewhere along the way, somebody added a hyphen between “slow” and “moving.”
Having satisfied myself that Tulodens don’t exist outside the internet, I removed them from the original article. There’s no way to delete them from all those other sites, though, and it will be interesting to see how long they last, now that the source is gone. During their five year run on Wikipedia Tulodens managed to wriggle into hundreds of other hosts. They’re informational parasites, you could say. They may be slow, but they get around.
Sometimes, it happens automatically. Web bots and data scrapers find these tasty scraps of knowledge as they’re scuttling around the net, and simply scoop up the content and repackage it. It’s nothing remarkable, just the machinery of the internet babbling to itself. More troubling, I think, is the way this fanciful critter–dreamed up, apparently, by a bored employee at a mid-western customer services company–has found its way into so many credible-looking commercial and educational sites. Some of these sources appear, at a glance, more professional and authoritative than Wikipedia, with better web design and nicer pictures, and none of them can be edited by their readers. That last point is the important one, I think. Some might think the moral of this little story is something along the lines of “don’t trust Wikipedia,” but that isn’t it at all. Anyone can change Wikipedia for the better, if they feel like it, but there’s not much we can do about diploma mills and fake textbooks and quack doctors who are quite happy to resell the information they picked up for free, but can’t be bothered to check its veracity. I think that tells us who the real parasites are.