Heads of the Epicurean school

From Epicurus Wiki

The known heads of the Epicurean school in Athens, according Diogenes Laertius, are, in order of succession:

• Epicurus
• Hermarchus
• Polystratus
• Dionysius
• Basilides
• Apollodorus
• The two Ptolemys of Alexandria, Ptolemy the Black and Ptolemy the Fair
• Zeno of Sidon
• Demetrius Laco
• Diogenes of Tarsus
• Orion

Needed: approximate dates of ascendency.