There are around 800 extant species and the group has a long and detailed fossil record stretching back about 450 million years ago to the Late Ordovician Period. They belong to the Echinoidea, one of ...
WE DEPEND ON RIVER DOLPHINS Where freshwater dolphin populations are thriving, it is likely that the overall river systems will be flourishing too – as well as all of the communities, companies and ...
Pliocene, New Zealand; Recent, Indo-Pacific and Atlantic. Differs from Asthenosoma in having large membranous gaps at the outer end of genital plates through which the gonopores open, and with sparser ...