Platelet's Problem in Echinodermata: Transmission Electron Microscopy Observations

We observed a new structure similar to a blood platelet using transmission electron microscopy methods. This structure was about 5 µ in length. It included many mitochondria and "azurophile granulations" (osmiophile granulations) which are typical of human blood platelet. The similarity of this structure to a platelet reveals the high degree of sophistication of Asterids from an evolutionary point of view. As a result, the blood platelets and sea star platelet may have the same embryonic origin. It is obvious that this observation must be completed by genomic studies.