Hi, I have some problem with the identification of these Ophiura from the Ionian sea (Mediterranean Sea). Could someone help me? Could someone suggest me any paper or books useful for the identification of Mediterranean species of Ophiuroidea?
The barbed spines suggest the genus Ophiothrix. There are two Mediterranean species; count the number of spines on each half of the arm segment as the two usually differ in the number of spines.
I agree with PJ SChembri (although I am not a specialist of morphology). A good way to decide is to amplify the barcoding COI fragment and obtain its DNA sequence. Several Ophiothrix fragilis (including cryptic species are available in Genbank, as well as Amphipholis squamata (it looks alike also, but I do not think this is this species). If you want to be sure...
This is a juvenile Ophiothrix, probably fragilis but there have been recent data on the presence of at least one unidentified, undescribed species of Ophiothrix in the Mediterranean. See http://doi.wiley.com/10.1111/j.1463-6409.2012.00573.x and http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.2005.00155.x/abstract;jsessionid=92905F8BF0CBCB597DD6F094AE87AEEB.f03t01 (for the really interested http://www.nature.com/articles/srep32425)
Dear Valerio, there is of course still the controversial O. quinquemaculata.
Did you mean to ask if your other photos also show Ophiothrix? The answer is yes. But they are all juveniles and cannot be identified, definitely not from these images.