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Bryozoa - the Sea Mats - and Phoronids


Bryozoa, the Sea Mats

Adults of Sea Mats are so called as they create flat, dense colonies on seaweeds and rocks. Each individual secrets a tough "cell" in which the tiny creature lives, glued to its surrounding neighbours. They produce huge numbers of larvae (called cyphonautes) which are liberated into the plankton. 

A selection of cyphonautes is below. They can be seen at most times of the year but some months, e.g. November and March, they can be especially abundant.

Bryozoa cyphonautes larva
Cyphonautes advanced stage

Mature cyphonautes 

Cyphonates larva early stage

A young cyphonautes

Bryozoan Cyphonautes larva x200


Phoronids are often linked with bryozoa but are not often found, living in sediment. They have a very strange larva that spents a short time in the plankton. When first released from the adult it immediately starts to produce appendages. The photo below has around 6- 8 which indicates that it is less than 12 hours old. The numbers continue upwards of 40-50. Soon after it matures into an adult.

Phoronid larva
Phoronid early stage larva
Phoronid larva

This could be a phoronid as it is 0.5mm across otherwise it looks like a Muller larva. Unknown!

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