I don't see any polychaetes but 2-3 ophiuroids hiding underneath the rock.

Found any bryozoans?

I agree with Björn. I see no polychaetes, but I certainly see multiple ophiuroids (brittle stars).

I'm with Björn and Jeff.

So, its a brittle star! I've cross-checked pics of brittle stars and convinced. thanks for comments!

It is a brittle stars,..no doubts

Based on what I am seeing you are looking at 4 arms of an ophiuroid

To me it looks like a bristle star (Ophiuroidea) hiding under the rock with its arms sticking out. Compare with this picture of Ophiura sp.

Definitely an ophiuroid

Yes, it's 5 arms of an ophiuroid (center), 2 arms under the stone (left) and 2 right : 3 ind.

Dear Felix Bast,

I agree with Bjorn and Jeff, I could not find any segmented worm (Annelida).

These are arms of Brittle stars. Check our website (www.biorede.pt) following this path Diversidade Animal > Invertebrados > Equinodermes > Ofiurídeos > Algumas espécies > Ophiocomina

The site is Portuguese but we have photos from Ophiocomina nigra (France, Roscoff) that seems your species.

Good luck!

Ana Rodrigues

It is certainly an echinoderm of the class Ophiuroidea. It is very similar to Ophiocomina nigra from the European coasts but the arms are of greater length. On the coast of Australia there is another species: Ophiocomina australis but I do not know if this is the species of photography. In this paper you can find literature on these animals

James & Lal Mohan-1969-Bibliography of the Echinoderms of the Indian Ocean. Bull. cent. mar. Fish. Res. Inst. 15: 1-43

http://eprints.cmfri.org.in/589/1/Bulletin_15.pdf

Brittle star for sure. Echinoderm / Ophiuroidea

I can certainly see arms of a bristle star (Ophiuroidea). The main body looks covered under soil.

Tunde Imoobe

I suspect it is a Brittle Star as well, however, I am not 100% positive. However, in my opinion, it is very unlikely to be a Polychaete.

This is the representant of Ophiuroidea

Dear felix

i think it is a Annelids (phylum Annelida) are bilaterally symmetrical worms which may or may not be segmented. The name “Annelida” comes from the Latin word "annellus", which means "little rings", as traditionally this phylum only includes segmented worms which mostly have a body made up of a series of identical segments, separate by ring-like constrictions (annuli). Recent phylogenetic studies, however, have shown that many unsegmented worms are genetically very similar to the annelids, and are in fact more closely related to annedids like earthworms than many marine annelids. These unsegmented worms are hence now placed under this phylum as well. As a result, there is no single external feature that can be used to differentiate annelids from other phyla.Generally, the segmented annelids will have a body comprising identical segments (excluding the head and tail) containing the same set of organs, and in some cases, external structures used for locomotion. They should not be confused with arthropods like millipedes and centipedes, which will have segment legs that annelids lack. The above picture features an unidentified annelid worm.

The unsegmented annelids are believed to have lost the segments through evolution to better adapt to survive in their habitats.

Many annelids, except leeches, are known to be able to regenerate lost body parts, even their heads. A number of species can also reproduce asexually by splitting into two or several parts and regrow the lost parts. Some annelids can even regrow from severe damages, such as from a single segment! Most also reproduce sexually, and are mostly hermaphrodites with both male and female reproductive organs.

it is a brittle star, for identify to taxonomic level of family, genera or specie could you follow a taxonomic guide, here there are a key of Brazilian researchers.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3689063/pdf/ZooKeys-307-045.pdf