Prince Marvin Of Nemertinea

29 May, 2013


A brightly-colored ribbon worm, Tubulanus polymorphus, possibly bearing aposematic coloration

Landmark or Tankmark Events

I am sure I am no different from other aquarists in having certain specific events, or notable animals that I have kept, in my various systems through the years, seared into my memory. Sometimes, most of the time, these are good memories, such as having beautiful animals thrive. Some other times, not so much, as attested to by the term, “Lake Shimek”, describing the transitory, but surprisingly large, body of water found on my office floor upon my arrival to work one Monday morning. Not surprisingly, I suppose, one particular organism that became etched indelibly in my memory was the largest organism I ever kept. It probably comes as no surprise to any reader of these posts that it was not a fish, nor even a coral, but a worm. Not just any worm, though. Well over 12m (40 feet) long (!), this worm, Prince Marvin of Nemertinea, graced a display/research/laboratory aquarium system I maintained in a teaching laboratory for a few months in 1978.

For anyone who has regularly read my posts over the long years that I have been writing them, it probably is somewhat of a surprise that it was not a polychaete or “bristle” worm, even though some polychaetes are amongst my favorite animals. It is probably also not a surprise that this animal was not a coral reef animal.  Indeed, I collected this critter in Alaska in the spring of 1978, and I released it back to the wild a couple of months later.

Long before the first dreams of coral reef aquaria as we now know and love them had breached the consciousness of any aquarist, self-contained, marine aquaria that were relatively good copies of some reef tanks to come were being sold to universities as teaching tools.  The updated systems, which look very much like the ones I used 30 years ago are still offered for sale.

The System

Anticipating that such a system would have some good use as a teaching tool, I had the University of Alaska, Anchorage, purchase a couple of those self-contained aquarium systems and set them up in one of the teaching labs to provide demonstrations for the students. I filled them with local animals which were kept at the local ambient water temperatures, generally between 40° F and 50° F.

Compared to today’s aquarium systems, these systems were crude and clunky.  And ABSOLUTELY WONDERFUL to have in a classroom!!  I could show my students what some of the animals I talked about looked like and moved and…and…  Remember, this is before digital anything.  Good movies were rare.  But, here was a way to show how the animals actually lived.  Off the soap box, Ron.

Only a true aquarium addict such as myself and, I suppose, many readers of CORAL, would want to have one of these in their house. But, if so, it would be in a dedicated room. A Do-It-Yourselfer’s dream, these systems invited – NAY – THEY REQUIRED – a lot of innovative “tweaking” to set up properly.  But, once fine-tuned, they had one notable attribute, they worked marvelously well.

If memory serves, the basic system was a square tank on a sturdy wheeled cart. The tank had a slate bottom and, I believe, a stainless steel frame. Approximately, the back about one fourth of the tank’s volume was set off behind a partition. This volume contained mesh sacks of “chicken oyster shell”. This material was roughly crushed oyster shells, more-or-less finger-nail-sized fragments used for supplying calcium to chickens. Here it acted, ostensibly, as a filter medium and probably supplied calcium and alkalinity to the system. I should note that nobody at this time tested for calcium or alkalinity. There were, as far as I knew at the time, no test kits for these substances.  And nobody paid them any mind anyway. But, these tanks were not meant to be used to keep corals or other calcium consuming animals, so the calcium levels were probably immaterial. The bags of shell fragments were topped with a layer of glass wool to act as mechanical filtration collecting particulate material in the water. There was also a rack of heat exchanger coils connected to a refrigeration unit which set below the tank, and which was controlled with a thermostat.

My recollection is that water was flowed from the display through openings in the partition, where it flowed through the glass wool and then through the filter medium. It was then pumped through the heat-exchanger tubes in the refrigeration unit and back to the display.

Temperature and salinity were the only factors that were checked. Temperature was the most critical. The animals that were being maintained were found in cold water, and if the temperature rose much over 10°C (50° F), the animals would perish. And, it was better that they were maintained at about 4.5°C (40.1°F). So, these systems had the additional attribute of cooling the room; even a large laboratory could feel their effects. This was nice in summer, no so much in the Alaskan winter; it was opportune that the University was paying the heating bills.

The sea water was an early version of some artificial sea water; this was not today’s salt!  But it was all we could get at the time.   Evaporation water was topped off with distilled from our chemistry department still. A thin sand layer in the bottom of the display compartment was provided for the animals’ well-being. The system was stocked with animals and algae collected by some of my students and me from our scuba dives. These animals included many of the common animals obtained from some of the dive sites around south central Alaska. These included several small anemones, a couple of sea urchins, some cukes, and other assorted animals. Over the year, we would trade animals in and out of the tank so that most residents were there for no more than a month or two. This allowed us, the instructors, to continually have short new lab exercises, generally of the “Oh Wow, Gee Whiz! Will You Look At That!” type for our classes. However, by doing this regularly, we stealthily taught the students something new about their local fauna all semester long. And because it didn’t seem too important, most students did a good job of learning it, without griping.

THE Critter

On the afternoon of March 11, 1978, I was surveying a subtidal sandy and sandy mud area near Lowell Point, close to Seward Alaska. There were three of us in the water, myself, and two of my students as “pseudo” dive partners. Because of the nature of the substrate, we arranged that they were to be each other’s diving partners and to leave me alone and let me do my searching untroubled by the silt clouds that diving partners kick up in these sorts of areas. This dive was in quite shallow habitat, only to a maximum depth of about 9m (30 feet), and most of it shallower than that. We were in about two meters (seven feet) of water, when I came across a large Cerebratulid Nemertean. Nemerteans have the common name of “ribbon worm”, which is actually fairly apt. They are unsegmented and generally flattened, so they sort of look like thick ribbons. They are often brightly color, as well.

Cerebratulus ? Head

Prince Marvin’s Head. Photographed off shore near Lowell Point, Alaska. 18 March, 1978. The animal is about 1 cm in diameter.

Cerebratulid anal region

Prince Marvin’s other end.

This animal was about the diameter of my little finger and it appeared to be a striking color, somewhere between “1940s-lipstick-red” and hot pink! To say that it was visible against the gray brown mud/sand was an understatement. At that shallow depth, I think it probably would have been visible from a boat passing over it on the surface. While the color was notable, the other factor that got my attention was that this worm was HUGE! And I do mean seriously big. Long. Really long. Truly lengthy. Even longer than that. I photographed the head and then swam along the length of the animal, and estimated the length to be at least about 13 m (42 feet). Now, a worm that long is one large worm! I photographed the hind end as well.

Missing an opportunity of a life time, I didn’t photograph anywhere else along the worm. I should have taken images of the entire worm, which could have allowed me to unambiguously document the entire unstretched length of the worm. But, nope, I realized that that sort of imaging would use all of the film in my camera, and I was hoping to get some images of other critters. Of course, that meant I didn’t see anything else worth photographing during the dive, AND I didn’t get images of the entire worm, either. Truly I was batting a negative 1.000 for that dive!

Tubulanus albocinctus head

Another large nemertean; this one, Tubulanus albocinctus, was photographed near Friday Harbor, Washington in 1983. This is the head end.

A long Tubulanus albocinctus

This mosaic of three images shows much of the entire worm whose head is imaged in the previous photograph.

Anyway, then I collected the worm; I had a 1000ml (about 1 quart) wide-mouth plastic jar as a collection vessel, and I was able to “roll up” the worm and put it in the jar. After the dive, in very shallow water on the beach, I took the animal out of the collection jar and we measured it with a 25m measuring tape I had packed in my extra diving gear (we were biologists, remember; not just regular scubie divers; I packed this sort of thing routinely back in the day). The animal’s length, when we extended it in shallow (about 6 inches deep) water was 17.3 m (about 56.8 ft) long, maybe… Nemerteans are notoriously flexible and fragile. Small nemertine worms often break into a lot of small fragments if handled, at all. Consequently, the worm was handled very carefully, and we definitely tried to ensure the worm was not being stretched, but that was very hard to do. We definitely did not want to pull it apart! Being conservative is a good idea with these sorts of measurements, so we figured that the “unstretched/manipulated” length was somewhere between 16 and 18 m (52.5 and 59 feet). We had done a couple of dives in the area (the preceding week) and had seen several other large worms, apparently the same species, in this area, but they were a lot smaller, only about 3 or 4.5 meters (10 to 15 feet) long. The following year I found two or three other specimens with lengths comparable to this one in the intertidal zone at my Homer, Alaska study site as well.  Additionally, about three years later, upon my return to the University of Washington’s Friday Harbor Laboratories, one of my colleagues reported seeing a worm of similar size and color in the intertidal on a small island near there.

A Canadian Tubulaus albocinctus

Another long Tubulanus albocinctus. This one was photographed in Barkley Sound on Vancover Island.


A large nemertean, a 5+ meter long Tubulanus albocinctus

This the “rest of the Tubulanus albocinctus photographed above. While not as long as Prince Marvin, these Tubulanus are still “respectably” large

We (mostly, I) had collected a few other critters during our dives; we had been diving in an area near Seward, Alaska, while we stayed for a couple of days at the marine station run by the University of Alaska, Fairbanks. Mostly, the animals I collected were a few individuals of some of the snail species I had worked with whilst doing my doctoral research. I thought I would look at these animals and compare their gut contents with those from the southern populations I was more familiar with. Additionally, we also collected a smattering of neat-looking critters and algae that would look good in our display tank, and I thought this big worm would definitely fit the bill in that regard.

The Display

Once the display was set up, the big worm was truly a hit. It was somewhat hard to “worm-proof” all the small holes crevices, and to seal the tank a bit, but we had to do this, as the worm was perfectly capable of crawling around in our local “dry intertidal zone”, otherwise known as our classroom lab benches. Word of mouth advertising was great and with all of the visitors to the lab to see our critters, it soon became evident that we needed to name the worm, as well as provide some informational poster displays about him. The latter were good extra credit work in the introductory biology class labs, and, in addition to discussing Nemerteans, we managed to pull in a lot of information about the intertidal environment in the South Central Alaskan region.

A swimming Cerebratulus.

An individual of a smaller Cerebratus species. These flattened animals are highly muscular and quite good swimmers. They are nocturnally active and often swim by undulating their bodies in response to divers shining their lights on them.

As for a name… Most of our students had no real idea of what this worm was, nor any real idea of its rarity. For most students, normally any worm is a worm is a worm is ugly. But this fellow, obviously a supreme example of worminess, was also quite obviously unlike any worm that most of the students had ever seen. Most students admitted, without any hesitation, this was a beautiful animal. And its size!!! Wow!! That made it truly top-rate. Truly a worm’s worm, it needed a name befitting its exalted position amongst vermiform creatures.

A contest, held to choose a name, resulted in one name, Marvin, rising rapidly to the top of the foaming sludge mass of votes. Why Marvin? As with all academic institutions, this small school suffered from a plethora of overly vocal, overly tedious, and fundamentally inept administrators, one of whom, a Dr. Marvin “X” had become legendary amongst both the students and faculty for his copious production of academic mucus. Immense and frothing masses of meaningless words; the best example I remember , was an administrative memo to “faculty, staff, and students” that was typed, single spaced and about one and a half pages long. It didn’t seem to make much sense – not that this was exceptional for his missives – so several of the faculty set down to analyze the statement and as near as we could determine, it was: about 350 words long, had many declarative phrases, but lacked altogether a verb… Basically, it was meaningless babble. Such sterling efforts could not go unrewarded.  Henceforth, the worm was known by the exalted title of “Prince Marvin of Nemertinea”.

Our Prince lived in luxury, except for the lack of food (gulp!!), for a month or two, and then it became time to return him to his native land lest he perish from the lack of appropriate vittles and sustenance. It should be pointed out that such dietary information for these animals was at that time, and has remained since, unknown. On a dive near the end of the spring term, my diving partners and I released Marvin back in his home sand habitat.

Maintaining this animal was a great experience, but it was also amazingly frustrating. Free-living nemerteans are considered to be predatory. However, we were never able to see him eat anything, and given the amount of class time spent with someone watching the worm, if he ate something it would likely have been noticed. Probably, the appropriate food was not present in our system.

Additionally, Marvin was very mobile and we got to perform some simple and, I think, illustrative, experiments. Large cerebratulid nemerteans, such as this worm, had been shown to have a very slow nervous conduction rate, around 1 meter/second. My students were able to confirm this by allowing the animal to become extended, as well as we could. He was looped several times around the bottom of the tank.

The students were able to show some reflex responses to simple stimuli. For example, they poked the most posterior part of the worm with a pin. This resulted in the relatively rapid contraction of longitudinal muscles causing the posterior end to be pulled forward a few inches. A different stimulus was applied with the intent of trying to mimic the effects of a predator. Here, the most posterior part of the worm was pinched and pulled a few times to mimic the stimulus of a predator taking Marvin’s rear end in its mouth where it was being pulled on. Not surprisingly, the worm responded with a much more vigorous response of coiling and retraction of its posterior end, but the most vigorous reaction to the stimulus was noticeably delayed. It took almost a minute for the response to occur from the time the worm was stimulated. This made good sense, the worm was about 20 m long. With a nervous conduction rate of about 1m/sec, it took a couple of seconds for the stimulus to reach an appropriate threshold, and then the stimulus went from the most posterior part of the worm via its sensory nerves to the brain, near the front end. Maybe a second or two elapsed whilst Marvin cogitated on the situation, and then the motor neurons causing the appropriate muscle contractions were triggered, and the message was sent from the front to the back end. Total elapsed time: 2-3 seconds to reach the threshold, about 20 seconds for the message to go to the brain, nervous reactions maybe 1-2 seconds, and about 20 seconds for the message to from the brain to the muscles in the appropriate area, for a total of about 45 seconds. Such a slow nervous response to potential predation seems very maladaptive.

A Tubulanus polymorphus about 30 cm long.

Another brightly-colored ribbon worm, Tubulanus polymorphus, possibly bearing aposematic coloration.  The head is to the left.  This animal was about 30 cm (1 foot) long.

Or maybe not!  The students made the hypothesis that the worm’s bright coloration was a warning coloration to possibly some bad tasting compounds in the worm’s tissues. Such a situation would definitely be beneficial to such a worm. Many nemertineans are brightly colored, and having aposematic or warning coloration would make logical sense. Unfortunately, as far as I know the possibility of warning coloration in large nemertean worms has never been tested. Ah well, I left Alaska a couple of years after these events transpired and much to my regret, I never again saw one of these large pink worms.

More Later…

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About the author

Ronald L. Shimek, PhD
Ronald L. Shimek, PhD

I am a marine biologist/invertebrate zoologist who got captivated by - or sucked into - the reef aquarium hobby late in the last millennium, I have written widely in the hobby press and elsewhere, mostly about invertebrates (in the context of the hobby, anything but fishes) and how to keep them alive. I reside in Wilsall, Montana, about as far from the ocean as one can get and still live in the contiguous 48 states, go figure... What can I say, it is home. :-)


  1. June 19, 2013

    Hi Ron,

    A couple weeks ago we noticed a similar worm in one of our water tables at the Feiro Marine Life Center in Port Angeles WA. The color was very similar to that of a Blood Star (Henricia sp.) and we originally thought that we were seeing one arm of an otherwise hidden star – then it started moving in a way that simply wasn’t starfishlike. I was only able to watch it for a few minutes before it withdrew under a rock but after comparing to field guide photos I think it looked more like a cerebratulid than anything else. Only about two or three inches were visible but the diameter seemed to be about 1/4 to 1/3 of Prince Marvin’s. I’ve been tempted to dig it out for a closer examination, a photo op, and maybe an I.D. but the group’s reputation for fragility has me worried.
    The fun thing is that we didn’t knowingly bring this animal into our facility; it may have hitchhiked or it may have recruited to the tank via the plumbing. Whatever the case may be, it seems to be making a life for itself on the food available in the tank.
    Longingly yours,

  2. June 21, 2013

    Hi Alex,

    As always, good to see a comment from you.

    There are several species of smaller Cerebratulids reported from your region, you might check Kozloff’s Keys to the Inverts to get a feel for the diversity. Unfortunately, almost no work has been done on them since the invention of wheel. Names were applied to individuals rather haphazardly and, then entered the record as having been found in the region. So, we really don’t have any sort of real idea of what is present. Nonetheless, some of them appear to be quite abundant. Most of them appear to be nocturnal, and so I generally saw cerebratulids during night dives. These are generally smaller worms, being only about a meter in length.

    They were flattened but thick and muscular, generally up to about 2 to 3 cm wide. They were wider in the middle and tapered smoothly to their edges. Unlike Prince Marvin these worms are quite actively mobile and can swim quite well by throwing their body into undulations, superficially like an epitoke. To have one of them approach oneself out of the dim, dark, murk, at night can be unsettling to say the least. They are rumored to eat small crustaceans and, perhaps, polychaetes. As there are several species in the regioin, they probably differ somewhat in prey eaten.

    Cerebratulids have the proboscis that nemerteans are justifiably famous for, but lack a piercing stylet.

    Individuals in the species of Prince Marvin ARE likely to be found in the Straits of Juan de Fuca, and the San Juan Islands, and perhaps upper Puget Sound. I have not seen such anmals there, but certain professors of my acquaintance collected a few in ages past in the intertidal zone of Turn Island, just outside the harbor entrance of Friday Harbor, Washington.



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