Cristatella mucedo
Cristatella mucedo
In first impression Cristatella mucedo resembles a caterpillar. In reality a colony has 2 to 3 rows of polyps that align a shared open space. The colony starts round and then elongates as it grows.
This picture shows young still round colonies. The picture was made later in the year and, if observed closely, shows statoblasts.
The next picture gives a close view of individual polyps.
The next picture shows a large old colony filled with statoblasts.
It also illustrates the way the polyps extend significantly from the common jellylike colony base.
The following picture shows a colony that is filled to capacity with statoblasts. All zooids have died, the colony is waiting to rupture and spill the statoblasts into the open water.
I even managed a photo that shows a free floating statoblast.
A new year an new beginning (and taken with a new camera)
I always thought that bryozoans, including C. mucedo, needed a firm substrate to attach to. This picture shows this is not true. Here C. mucedo colonies grow on a very loose silt and peat fibre substrate. The smalles movement creates a cloud of silt and peat fibres, so there is no 'grip' on this substrate.
I assume these colonies could grow here due to a low rain period so there was no current to whash them away.
I have hunted for a colony that was in the process of splitting up. This colony seems to do that in two places at the same time.
In this colony the process has made more progression.
I have also wondered how a C. mucedo colony got grip on the substrate as it clearly is not cemented to it, like several Plumatella species. This picture shows a bottom view. It is interesting to note a few strands of algae are sufficient to get a grip.
The following picture shows the colony bottom in even more detail. Note how the colony bottom actively grips the substrate, as little as there is to grip. Apparently there is some form of muscles in the colony bottom.
These colonies make hanging to an art form. The upper colony hangs from one tip (not well shown in the image) and the other colonies hang from eachother. In full resolution (not shown) it can be seen that the colonies have an active hold on each other rather than are glued together.
I also found a died off colony, full of statoblasts, that had just burst open releasing the statoblasts.
This colony is shown in (almost) see through.
This is what i mean with densly packed colonies. This is only part of a sawn off submerged tree of about three meters long and 50 cm wide that was almost covered in Cristatella colonies.
