At 7am on 11/04/2023 I was walking home with my dog. There were occasional wet spots in the sidewalk from the sprinklers, and I watched for
earthworms  so I could prevent myself, or the dog, from stepping on them.  I noticed something that resembled an earthworm, but then realized it wasn't moving like one.
When I realized what I'd found, I had to stop and take some pictures. I'd found a Land Planarian!  They are also known as "hammerhead worms". Way back in 2001, a
friend of mine had found some of these in his garden. He didn't know what it was, and I didn't either, until I'd looked found information about them. He let me use his
pictures back then on my webpage here:  https://www.rickubis.com/rick/hammworm.html 
I'd never seen one myself until now, November 2023. I took some pictures and video clips of it on the sidewalk--which wasn't that easy with my dog pulling on the leash
because she wanted to get home. I remembered a few things about these animals: 1) they are an introduced, invasive species; 2) they are predators of earthworms,
and are a potential threat to their survival; 3) they can regenerate if their bodies are cut into pieces. For those reasons, I tried to dispose of it by shredding it.
A few days later, 11/06/2023 I found another one, about 10 yards from where I'd found the first one and at about the same time.  I took more pictures and video clips
on the sidewalk along with my my Geologist's Scale (I usually have one in my pocket).Then I decided to carry it back with me, by letting it crawl onto the scale .

    
The dog and I usually end our walk with a 15-minute pause at the top step to enjoy the morning. While sitting there, I was able to take more photographs of the Planarian
 as it crawled and climbed on the scale. The closer pictures show dark lines on a brown background, with a black "collar" open at the top that goes around the neck.
 So, this one was probably a Bipalium kewense. After taking lots of pictures and video clips, we went inside, and this time I placed the worm into a plastic sample bag
 and placed that into my freezer.  Most of these images are frames from the video clips. I've edited some of those together into the video linked here.

    
Flatworms move on a layer of slime they produce, propelled by actions of very tiny hairs (cilia). Their head has "eyes numerous, minute, around the dorsal head within
margin, crowded in lateral neck region, sparsely in staggered submarginal row along body." (A revision of the cosmopolitan land planarian Bipalium kewense Moseley,
 1878 (Turbellaria: Tricladida: Terricola) by L. Winsor).
Inspired by this encounter, I updated my limited knowledge about this species. Along with the 3 items mentioned above, this species (Bipalium kewense) and another
 flatworm (Bipalium adventitium) also carry Tetrodotoxin--which is a potent neurotoxin. This was described in this study:  Confirmation and Distribution of Tetrodotoxin
 for the First Time in Terrestrial Invertebrates: Two Terrestrial Flatworm Species (Bipalium adventitium and Bipalium kewense) by Stokes, Ducey et. al.  From the abstract:
 " Tetrodotoxin (TTX) is a low molecular weight compound that acts  by blocking voltage-gated sodium channels, inducing paralysis. However, the origins and ecological
 functions of TTX in most taxa remain mysterious. " 
While the  study proves that the worms have TTX, it does not confirm what the neurotoxin is used for. Observations of these Land Planarians feeding on worms show what
appears to be paralysis of the prey after it is attacked. It's also probable that the TTX also works as a deterrent to predation upon these flatworms. Here's a partial list
 of other organisms that carry TTX-some of which may be familiar to you:  Blue-ringed octopus, various pufferfish, several starfish and... Eastern Newts
 (Notophthalmus viridescens)--yes, the species of newt that we find at BBSP.  Most sources I've found suggest that the various species of invasive terrestrial flatworms
 that have appeared in the U.S. were carried inside the soil of various potted plants. They have been found in the U.S. since the early 1900s.

Apparently my adventures with invasive flatworms were not over. On 11/29/2023 (about 3 weeks after I found the hammerhead worm), I was taking a very short walk with
 my dog at 9:20pm.  On my way back, about 5 steps away from the stairway to my apartment, I noticed something dark and shiny at the edge of the sidewalk. And, it
 was moving. I put the dog inside and hurried back out to examine the creature.  This was another worm, almost black in the artificial light, and very shiny. It was not an
 earthworm and it was crawling back into the shadows.  I captured it and brought it inside to photograph.
   

I had a difficult time with the various lights I had available, but I was able to bring out better color. I could see a faint light line along the center of the back.  A search online
 revealed that I'd found a different species of flatworm; a New Guinea Flatworm  (Platydemus manokwari).
This species is known as a predator of molluscs, posing a special threat to terrestrial snails where this worm has been introduced. Apparently P. manokwari has wiped
 out some species of snails in island environments where it has appeared. However, it isn't as successful eating slugs, or snails that produced large amounts of slime. 
I briefly wondered if they'd be effective against Apple Snails...but those aren't a terrestrial species. I know that introducing a foreign species to control an invasive
foreign species usually does NOT work well, but since the worms are apparently already here....
   

I'd never heard of this species before, and its movement was fascinating. Unlike the gliding movement shown by the hammerhead worm, this one appeared to "pour"
itself along a surface. It would anchor with a blob of itself, then push off from that blob. It would put down multiple blobs, and bridge itself between them, raising its
underside a few millimeters as those sections poured forward.
P. manokwari hunts by following a fresh slime trail left by snail. If it finds a trail, it has a 50/50 chance of picking the right direction (i.e. following the snail instead of going
along backtrail). If the worm reaches the end of the trail and there's no snail, it will turn and go the other way. It seems likely that it could overtake most snails.
(Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari by Noriko Iwai & Shinji Sugiura & Satoshi Chiba (2010))
Since this is also a land planarian, and invasive, I made sure it was taken out of the environment by placing it into a small specimen bag and placing it in the freezer.
Some of these images are frames from video, which I've edited into a video file which is at this link.
     

09/19/2021 -- I was in Brazos Bend State Park, on the t-shaped fishing pier in 40 Acre lake. I was watching an alligator that I noticed under the pier, to see how it was
behaving while people were fishing from the pier.  I also like to see what kinds of fish people catch, if they catch anything.  As some more walked up, one of them looked
at the alligator below me, and asked if it had a leech on it.  I've seen leeches on Alligators at Brazos Bend State Park often, so when I examined the alligator I expected
to see leeches like the ones in these pictures from about 6 years ago--11/01/2015.

    
      Alligator at Spillway 11/01/2015       Leeches are probably on a wound 11/01/2015      Pile of leeches on the gator 11/01/2015             

It took me longer than it should have to find the leech, since I was looking for something dark grey or black.  When I finally found the leech, I was very surprised.  I can't recall ever
seeing anything like this at BBSP.  The alligator was in the water, so I tried my best to get zoomed-in photos.  The pictures below show the leech. Multiple view show that the leech
was moving, and alive. By the ay, there are two alligators in the picture. There was a brief, low-key confrontation between them when one tried to "share" the pier with the one that
was already there. It was eventually chased away by the gator that had been there when I'd arrived.

    
  Turtle leech on a gator 09/19/2021
        
  
                     
I looked around online, and I am still surprised by the apparent lack of published literature describing leeches. From what i could find, it seems that this is called a "Smooth Turtle Leech",
(Placobdella parasitica),.  I found a few mentions indicating that these leeches normally prey on turtles.  The one I saw was obviously not riding on a turtle, but didn't appear to be
feeding, either. If it was, I think the smaller end (where the mouth is) would have been attached to the alligator.  It's not unlikely that the leech was just riding.  This was an uncommon
sight for me. Of course, the leech was attached to an alligator  and alligators are always amazing.  UPDATE-- I posted this little story and a few pictures on Twitter, and the "fancy
leech" was apparently pretty popular for a while.   Biologist Danielle dDecarle (@danielledecarle) supplied verified  I.D. as Placobdella parasitica.  Herpetologist Arik Hartmann (@AmphibiArik)
linked me to this paper: "Observations on the Leech Placobdella ornata Feeding From Bony Tissues of Turtles" by Mark E. Siddall, Eugene S. Gaffney (link to abstract  is here) The paper
describes a different species than "fancy leech", but it feeds on turtles. However, P. ornata attaches to a turtle's shell (since P. parasitica "fancy" attaches to legs, tail, etc.--taking the preferred
feeding areas.  Then, it probes between the sheets of horny external covering until it hits the bones underneath. Somehow (possible by dissolving with its saliva) the leeches erode the bone until 
they reach the blood vessels inside bone...and then drink the blood that comes out.  

Horsehair Worm

12/24/2006---It's cold and nasty this morning--well at least for the Houston area. After spending 3 hours outside in the misty dampness, I was walking up the sidewalk to the Visitor/Nature 
center at Brazos Bend State Park. As I passed over a puddle of water, I noticed movement just at the lower edge of my vision. When I stopped to look, I saw long, thick hairs moving in the
water. I got excited when I saw these, because I'd read about them some time ago. They were Horsehair Worms.  Horsehair Worms (or Gordian Worms, named after the Gordian Knot of 
legend because mating worms become a huge tangle) are classed as "nematomorphs". All of the information I can find about them comes from the internet, so of course needs to be 
verified. However, some of the internet sources are uploaded scientific papers, so much of the information available is probably valid. They are parasites, usually of various invertebrates; 
often arthropods like insects. How they get into their hosts is still under discussion. Some feel that they are injested while the insect eats infested plant material. Perhaps a carnivorous insect
eating an infected herbivore can also become infected. In any case, the larva grow into an adult from inside the host, until the parasite is many times the length of the host.  Pretty nasty, isn't it.
  As if that wasn't creepy enough--when the worm matures, it then alters the behavior of the host so that it will end up in water. This releases the worm, and the host usually drowns afterwards.
The mechanism of this control has been under study. The worm chemically alters the function of the host somehow, and it ends up in water. How the host is drawn to water, or even if it is drawn
to water, or some other mechanism is at work, is unknown.  Sometimes these worms are found when an insect is crushed. If the insect is eaten by a larger vertebrate, such as a frog, the worm
will sometimes crawl out of the predator! Horsehair worms are harmless to humans, and according to some sources are somewhat beneficial because they kill certain insects.  Of course, I 
already knew that before I picked one up. In keeping with the alternate title for this page (Rick, don't touch THAT!), there is the image below left.. Here some more images as well.   There's 
also a short video clip (4,887 kb, wmv) showing what one looks like moving in the palm of my hand, and on the ground.
-------
--------     ------DON'T TOUCH THAT!-------                          -----------GIVE ME SOME SKIN---------                        -----------WELL, IT'S SKINNY-------                      -----------------CLOSER LOOK -------------------
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------if--
     
                  PICKING UP THE WORM
                    VIDEO CLIP (4,887 KB WMV)

I don't often link to external pages for a number of reasons, but this is such a unique creature that I'm including some external links on this page. You can also find your own by searching for 
"horsehair worm", "gordian worm", or "nematomorph".  I've also seen video clips on youtube and google video.  Here are some links: (the links I had all died, but I first wrote this in 2006 (15 
years ago--today is 9/24/2021. So, no links--but the internet has sure grown since then.)

Hammer-Headed Worm (Land Planarian)
First appeared on my page July 3, 2001    Updated 06/23/2015
It started with a comment by my friend Don about something he'd found and killed in his garden. He described it as some kind of "hammer-headed worm".  Well, of course, that aroused my 
curiosity. People that know me always tell me things like this, probably because they know it drives me crazy if I don't know what it is. Anyway, this was sometime last year (2000), and as soon
as I got time, I started looking around. I searched the internet. The creature in question was described as slimy, maybe about a foot long, with an odd, hammerlike head.  Don didn't really have
many other details, and he'd disposed of the thing over the weekend. I might have driven him crazy asking if he'd seen any other ones for some months after. I looked through anything I could think
of, starting at reptiles (legless lizards and skinks) and working towards simpler animals, like amphibians, and various segmented worms. (I was thinking perhaps some kind of sandworm-type 
creature) But, I couldn't find anything that matched the description. But, I didn't forget. Then Don mentioned that he'd found another one, and he'd tried to catch it, and keep it with some dirt. It dried
out very quickly, though, and once again was thrown away.  Then, during a search for something else (I can't remember what), I found this web page.  The page describes a creature called a "land
planarian". This is a "flatworm", a LARGE flatworm. Flatworms are considered "less complex" animals than segmented worms (and that's as where I'd stopped).  I showed the image to Don, and
he thought that that was the creature. This all happened last year.  Today-- July 3, 2001-- Don found more of the critters in his garden. This time though, he took some pictures, and sent them to me.
And he gave me permission to use them on a website. (Remember, all the pictures he took are used on this page BY PERMISSION.)  So here are the pictures of the extremely weird beast in his
garden.  Click on the images to see them larger.

-----    
              Full view of the land planarian.                           Closeup of the head.                         Another view of the flatworm.  View with a tape measure. Look at the length of this thing!
                                                                                                                                                                                                                                                                     Click here for an even larger view.

  Here are some more links with information about flatworms.

     University of Florida  (same link as above.)

     Texas A & M

       One thing I've seen that seems to be important about these worms, is that they pose a grave danger to earthworm
       populations within their range. I've also seen that there seems to be no way to kill these, either. Their occurrence in
       Houston could be cause for concern.  Since I've only been able to verify this today, more research is pending. This
       page will be updated as I get more information. According to the TAMU website, this planarian is Bipalium kewense. It is easily identified by the long striping along the body.

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