These included raised blood levels of VEGF, thrombocytes, and/or erythrocyte parameters. CD61 is a cluster of differentiation found on thrombocytes. A single megakaryocyte can give rise to thousands of thrombocytes. Instead of having platelets, non-mammalian vertebrates have nucleated thrombocytes, which resemble B lymphocytes in morphology. Platelets, or thrombocytes, are disk-shaped blood elements which aid in blood clotting.