Medusa (Ancient Greek: Μέδουσα) in this atlas entry is a Mycenaean princess, daughter of King Sthenelus and Nicippe (Antibia / Archippe) daughter of Pelops, and sister of Eurystheus and Alcyone. She is not the Gorgon slain by Perseus.
Adapted from Wikipedia, "Medusa (mythology)" · CC BY-SA 4.0
I.Perseid princess
Apollodorus (Bibliotheca 2.4.5) names Medusa among Sthenelus' children by Nicippe beside Alcyone and Eurystheus. Some later notices call her Astymedusa and make her a second wife of Oedipus after Jocasta — a Theban marriage tradition, not Homeric.
In the atlas she is typed to the Mycenaean Perseid genealogy; no independent deed is recorded beyond kinship to the taskmaster king Eurystheus.
II.Homonym care
Never merge with the Gorgon Medusa (atlas medusa), nor with Medusa daughter of Priam, Medusa daughter of Pelias, or Medusa wife of Polybus of Corinth. The atlas id medusa-sthenelid is Sthenelus' daughter alone.