Key to mediterranean Echinocardium species just by top view of the test
1a - Anterior central petal shaped like a plateau, pores only at center: -> 2
2a - Bulky heart shape: Echinocardium mediterraneum (-4cm)
2b - Round "inflated" shape: Echinocardium mortenseni (-5cm)
2c - Similar to b, but with tubercules between anterior and posterior petals: Echinocardium flavescens (-3cm)
1b - Anterior central petal shaped like a channel with rows of pores all along the length: -> 3
3a - Pores of anterior petal in one row to each side; number of pore pairs on posterior petal (11)-12+: Echinocardium fenauxi (-8cm)
3b - Pores of anterior petal in more than one row to each side; number of pore pairs on posterior petal 8-10: Echinocardium cordatum (-9cm)
... I'll happily stand corrected if some of my infos are outdated or wrong.
