Plumatella fungosa

Proposal for common name: Fungoid bryozoan or moss animal

Classification

Class	Family	Genus	Species	First described by
Phylactolaemata	Plumatellidae	Plumatella	P. fungosa	Pallas 1768

Synonyms

The following synonyms have been used to indicate P. fungosa

Tubularia fungosa (Pallas 1768)
Alcyonella fluviatile (Bruguière 1789)
Alcyonella fungosa (Van Beneden 1848)
Alcyonella flabellum (Van Beneden 1848)
Alcyonella fungosa (Allman 1856)
Plumatella polymorpha var. fungosa (Kraepelin 1887)
Plumatella repens var. fungosa (Vangel 1894)
Plumatella repens va. fungosa (Annandale 1910)
Plumatella fungosa (Abrikosov 1925)

Description

Also see the generic class and genus description in the classification page.
A combination of literature has been used to create this description.

General	Zooids grow tightly together, closely packed as a crust, or a mantle / knoll on/around the substrate Cystids are mostly at right angles to the substrate and are tightly packed. On cross section this gives a honeycomb like structure Zooids are fully aligned; cystid openings are closely aligned Forms large tight spongy colonies of up to several meters diameter and a honeycomb like appearance colony partly standing up
Color	Red-brown to deep brown, in some parts of a colony translucent and clear.
Tentacle crown	Tentacle crown horseshoe shaped with 70 tentacles maximum.
Size	One zooid is 1 to 4 mm long A colony 20 cm in diameter maximum and to 1 kg in weight
Statoblasts	Floating statoblasts (floatoblasts). Capsule (and sometimes the annulus) covered in ridges in a reticulated pattern Looks like P. repens. Floatoblasts a bit larger (420 x 320 µm) There are multiple statoblasts per zooid
Conditions	Tranquil food rich waters. Common. On firm substrate such as rocks and tree trunks Has a preference for submerged branches and reeds
Distribution	< TO BE DONE >
Additional	None

Relevant literature

To be completed

[Mundy] - A key to the British and European Freshwater Bryozoans
[Wood II] - A new key to the freshwater bryozoans of Britain, Ireland and Continental Europe

My observations

I have found P. fungosa only in locations with higher current levels as compared to P. repens. Mainly on the concrete basis of bridges
P. fungosa is often described as forming compact (ball shaped) colonies. I found also P. fungosa on flat surfaces in a 'lawn' growthform AND as fairly loose creeping colonies (see pictures).
I have the impression that the P. fungosa colony form is dependent on local circumstances and a reaction on the danger of suffocation (no more food) by settling silt:
- On a branch as substrate and a fair amount of settling silt => bulbous colony
- On a flat surface and a fair amount of settling silt => 'lawn' colony
- On a flat surface and limited settling silt (vertical substrate, current) => loose crawling colony
P. fungosa is described as red-brown to dark brown. In my experience grey is a better description of the color, as this is the first impresson of the field of tentacles. It may be that the literature describes the colony above water, while my observations are in natural habitat and therefore describe the appearance of the tentacle crowns.
Small colonies observed from some distance are easily confused with sponge colonies
Discerning P. fungosa in fungoid form from P. repens is not really easy when finding them in their habitat.
Some pointers are:
- P. repens looks like a lawn that has not had any care for some time, P. fungosa is much more smooth
- P. repens has a shoddy colony border, forming lobes or extending creeping tubes while P. fungosa colonies have smooth edges
- P. repens looks yellowish, P. fungosa more grey
- P. repens has bigger tentacle crowns than P. fungosa
Also see pictures below.

Below to help compare both species they are shown side by side: P. fungosa (left) and P. repens (right).

Plumatella fungosa

Plumatella repens