Dear sir 

you read this papers which contain some information related to your image

Plz check..Luida senegalensis

I have to admit I am not a sea star taxonomic expert, but I did my thesis on the feeding habits of Astropectin verrilli and looked at a lot of Luidia foliolata stomach contents.  Looking at the relationship between the disk diameter and arm width it looks more like an ophiuroid. 

This looks like Ludia senegalensis. Might you please say where this specimen was collected?

This was collected from the sediment of outer channel area of Chilika lagoon. The salinity of outer channel area  was fluctuated between 24 psu to 35 psu in extreme summer. It is the connecting region between the Bay of Bengal and Chilika lake proper.

Dr. Tom Trott, many many thanks to provide cue for the  identification, but still I am very much interested to hear from you in detail. Thanks.

Dear Debasish, As does your specimen, Ludia senegalensis has the unusual characteristic of having 9 arms. I have never seen one as small the one in these photos. However, your specimen was collected outside the known range of this species but within temperatures similar to its known range. I suggest consulting the attached files that may be more  helpful in confirming your species. Kindest regards, Tom

Thanking you very much for these valuable information.

But,  I want to know that what forced the coral reef dwelling organisms to invade  the shallow coastal ecosystems like estuaries and lagoons.

Your species may be Ludia maculata Müller & Troschel, 1842 but you will need to confirm my speculation. Please consult http://www.marinespecies.org/asteroidea/aphia.php?p=taxdetails&id=213112 and the key Clark, A. M.; Rowe, F. W. E. (1971). Monograph of shallow-water indo-west Pacific Echinoderms. Trustees of the British Museum (Natural History). London. x + 238 p. + 30 pls., available online at http://www.abctaxa.be/downloads/additional-information-volume-1/works-famous-holothuroid-workers/fwe-rowe/MonographIndoWestPacific.pdf (see pages 30 & 43).

Storms and salinity changes are suggested to influence the movements of starfish, but there is no experimental evidence supporting these ideas for Ludia.

Thanks a lot

I can't find any description of Luidia or any asteroidean having attached larvae. Are you sure it's not a hydroid?

Yes Tim I am sure that it is not a hydroid

Tim, I believe the word "attached" refers to the images that were attached to Debasish's original message.

I would contact Chris Mah at the Smithsonian (his web page: http://invertebrates.si.edu/mah.htm) , he is always looking at interesting echinoderms. You should also check out his blog: The Echionoblog (http://echinoblog.blogspot.com/) which includes all sorts of wonderful and unique echinoderms.

Thanks Rooney for the kind suggestions.