I need some Marine biologist, Oceanographer, Hydrobiologist or Marine ecologist to help me with some identification manuals for Echinoderms, marine molluscs and polychaetes that could be used for afrotropcal marine studies.
Yes, there are two approaches. Either specialised global reviews of particular families; or regional guides. Regional guides may not be available for all groups and will still be divided by major taxa (unless very basic). You would need to be more specific about the area: east and west Africa are different; but the east is mostly similar to the wider Indo-Pacific.