Naturespeak A naturalist's view of the world

July 26, 2009

O.M.G. What is That?

Filed under: Uncategorized — wykes @ 8:04 pm

 Most people squirm at the sight, or even the thought of, leeches. I’d like you to think about leeches for just a moment . Go ahead and grab a salt shaker if you must, but this is for your own good. Frankly, I find the little blood suckers fascinating but I admit that they are a little unimaginative. As a group they don’t appear to vary too much in form and all are basically flattened segmented worms with sucker discs at both ends. Some species explore a variety of patterns and color shades, but that’s about it. When sucking blood, one doesn’t want to appear too flashy – that is a vampire’s rule.

A recent call from an old friend put me in contact with a pair of very unique leeches that bend the leech persona just a bit.  These creatures came from the gill arches of a fish called a freshwater drum or sheepshead. A local fisherman noticed two globular “growths” firmly attached to the gills of his catch. They were very difficult to pull off but, pull them off he did and he then transported the pair within a water-filled butter tub (see below). Although my first verbal impression was “O.M.G., what in the heck are these?” , I eventually learned that they were examples of a rarely encountered parasitic leech called Actinobdella pediculata.  Wow, eh? well hold on now, there’s more.

These creatures are only found on sheepshead fish (see here) and pose absolutely no threat to humans. They have no common name and only barely express their leechness (or is it leechennocity?).  Of the pair, the larger one was willing to show his two sucker ends for the camera  (see above) before contracting into a smooth gray ball (see first picture). The body segments were just barely visible. The other one tightened up into a hard heart shaped lump decorated with a fancy frill at the edge like some demented Valentine gift (see below). There was something creepy about the second one.  Neither one fully opened up during their captivity, but this one only gave name, rank, and serial number even after it’s partner uncurled.

OMG Leeches, as I will call them for lack of a better name, spend their lives as permanent blood-sucking parasites within the gill chambers of their exclusive host. I’m sure these fish are honored. The parasites anchor their large posterior sucker deep (up to 1/2″) into the flesh of the fish and wedge the disc firmly into place. The long slender sucker at the other end is the business sucker. 

Few people see these things. Even among seasoned fishermen, they go un-noticed. The fellow who initially described them  in 1903, Ernest Hemingway (Ernest A.  of the Univ. of Minnesota and not Ernest M. of “For Whom the Bell Tolls” fame) had to examine “hundreds” of sheepshead and succeeded in obtaining only 3 small specimens.  There are virtually no images of this creature other than those appearing in Hemingway’s original article and a few highly specific leech works.

So, there you have it. An obscure ugly leech is revealed in the full light of day on a blog that reaches 10’s of people. O.M.G. that’s exciting, eh?  Eh? Where did you go?


  1. Something to put on your naturalist’s resume! 🙂

    Comment by Kathy — July 29, 2009 @ 8:19 pm

  2. At first, they elicit an “Ewww!”, but that is soon to be followed by an “Oh, how cool is that!” Thanks for sharing!!!!

    Comment by Ellen — September 2, 2009 @ 10:58 am

  3. Thank you for this very interesting information. A pair of Small Striped Swallows are nesting on the ceiling by our front door and this morning they must have thrown a dead youngster from their nest and 3 of these Actinobdella pediculata leeches were crawling around the dead bird. I can only assume that these parasitic leeches were brought in with the mud in an “egg form” and must have hatched the same time as the swallows. I am hopeful that there will be some surviving swallows.

    Comment by Joyce Botha — March 8, 2016 @ 2:55 am

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