By means of the shell structure glossary mentioned in the page Shell Structure – and by means of macro picture documents – I will successively overlook the manifold of Angaria variants.
It will prove that some of the species are unambiguously determinable.
Such sphaerula, tyria, vicdani, melanacantha, lilianae, javanica, rugosa, nodosa, neglecta, nhatrangensis will prove as unambiguous. And formosa is clearly differentiable against delphinus and is not at all a form of it. But delphinus, aculeata and poppei have an enormous manifold of variations.
But a detailed study of the shell details: general shell conture, structuring of the surface, the order of cords, the colouration, and last but not least the macro view on the spine structure as the most important detail will lead to further differentiations.
As a result of these studies there a found a series of unambiguous new species.