An ancient Greek hero might expect a bit of help from a female, whether goddess, witch, or princess/queen, but he wouldn't ordinarily expect to have to share the glory with a woman. Although goddesses and Amazons might be powerful, ancient Greek women typically weren't, so it takes a truly exceptional woman to earn a main stage place in the performance of the main heroic events. The other heroes treat her as an equal, although her beauty prevents them from forgetting her gender.
Atalanta and the Argonauts:
Atalanta, daughter of a king of Arcadia or Boeotia and possibly another exposed baby* (hallmark of "the hero"), was the only woman in the crew of the Argo, which puts her among the Greek heroes from one generation before the Trojan War.
The Argo was the ship in which the Argonauts sailed with Jason to fetch the Golden Fleece from Colchis. The witch princess of Colchis, Medea, provides the information Jason needs to take the fleece, but she is never treated as one of Jason's merry, competitive band. Atalanta is not included in all lists of Argonauts, but when she is listed, it's because of her hero-appropriate skill -- as a runner, like Achilles in the Trojan War.
*Other Legendary Figures Exposed at Birth
Atalanta and the Golden Apples of the Hesperides:
Slow and steady wins the race. So much may be said of the race between a fabled tortoise and hare or Atalanta and her suitor.
Atalanta is best known for losing a footrace because her competitor, who was hardly in her league, kept dropping the Golden Apples of the Hesperides to distract her -- at strategic moments. This competitor and suitor (for his prize would be Atalanta as bride) was either Melanion or Hippomenes. Had he lost the race, he would have forfeited his life.
The suitor had been given the apples by Aphrodite. When later he failed to honor the goddess, both he and Atalanta were turned into lions.
Atalanta as an Argonaut:
Atalanta is listed as an Argonaut in some lists - Apollodorus 1.9.16 and Diodorus Siculus 4.41.2.
Atalanta and the Calydonian Boar:
Atalanta shot the Calydonian Boar. In one version of the myth, Meleager, who actually killed the boar, awarded it to Atalanta as prize because she had drawn first blood.
The stories about Atalanta are varied and contradictory. It is possible there were two Atalantas.
Read a Story About Atalanta:
In his Golden Fleece, Padraic Colum tells the story of Atalanta, whose beauty captured the heart of her fellow Argonaut, Meleager, and whose arrow first hit the Calydonian boar.
Atalanta and Artemis:
Atalanta is associated with the goddess Artemis, as you can see in this hymn:
Callimachus: Hymn to Artemis
"[The comrades of the goddess Artemis :] Yea and Kyrene thou madest thy comrade . . . And [Prokris] the fair-haired wife of Kephalos . . . and fair Antikleia . . . These were the first who wore the gallant bow and arrow-holding quivers on their shoulders; their right shoulders bore the quiver strap, and always the right breast showed bare. Further thou didst greatly commend swift-footed Atalanta, the slayer of boars, daughter of Arkadian Iasios, and taught her hunting with dogs and good archery. They that were called to hunt the boar of Kalydon find no fault with her; for the tokens of victory came into Arkadia which still holds the tusks of the beast. Nor do I deem that Hylaios and foolish Rhoikos, for all their hate, in Haides slight her archery. For the loins, with whose blood the height of Mainalos flowed, will not abet the falsehood."
~ Callimachus, Hymns and Epigrams. Lycophron. Aratus. Translated by Mair, A. W. & G. R. Loeb Classical Library Volume 129. London: William Heinemann, 1921.
Apollodorus, Apollonius, Callimachus, Diodorus Siculus, Hesiod, Hyginus, Propertius, Sophocles, Statius, and Pausanias.