Αἴαντε
As discussed above on 10.53, at one time this dual referred to the fighting team of Ajax and Teucer, which would be a most appropriate meaning here. The dual, then, could mean not that Ajax son of Telamon and Ajax son of Oileus each individually volunteered (no other two warriors are listed as volunteering this way), but rather that Ajax and Teucer volunteered as a team. This interpretation is strengthened by the fact that two-horse chariot teams are described in the dual (as at 10.530–531), as are Diomedes and Odysseus when they are working as a unit, as we will see. (See below on 10.243.) Likewise, when Diomedes makes his case for taking a partner on the expedition (10.222–226), he uses the dual to describe the advantages of such a pair. The Aktorione-Molione, the possibly conjoined twins who fought Nestor in his youth (Iliad 11.709–752 and 23.638–642), are, of course, yet another pair of warriors who are described in the dual. The dual thus seems to be a traditional way of referring to a closely linked fighting team.
If the dual in this line is referring to Ajax and Teucer, then there is no mention of Ajax the son Oileus volunteering. We can speculate that in some performances of Iliad 10, especially those composed at a time when the dual was understood to refer to Ajax and Teucer, this dual meant that fighting team, although in our version Ajax son of Oileus is specifically named as someone to gather for the meeting at 10.110. It is worth noting that in Iliad 7.164, when the two Ajaxes are included among the heroes who volunteer to fight Hektor one-on-one, the form attested there is the plural, not the dual.