Nubes (Latin for "cloud") is the cloud-mate Hyginus names with Ixion as parent of wild centaurs such as Nessus and Eurytion. She corresponds to the unnamed cloud Zeus shaped in Hera's likeness in Apollodorus — the mother of Centaurus — and must be distinguished from Nephele, the cloud-wife of Athamas who bore Phrixus and Helle.
Adapted from Wikipedia, "Nephele" · CC BY-SA 4.0
I.Ixion and the false Hera
When Ixion lusts after Hera, Zeus forms a cloud in the goddess's image. Ixion couples with the cloud; punishment (binding to a fiery wheel) follows the outrage against hospitality and the queen of heaven.
Apollodorus says the cloud bears Centaurus, who then fathers the horse-men on Magnesian mares. The cloud herself is usually left unnamed in that account.
II.Hyginus' Nubes
Hyginus Fabulae names Nubes explicitly as mother, with Ixion, of centaurs including Nessus and others of the wild brood. In that Latin handbook the cloud is a genealogical parent rather than a silent prop.
The atlas keeps this Hyginus naming under nubes-ixion so that centaur parent edges can point at a stable node without collapsing her into the Boeotian Nephele.
III.Homonym: Nephele of Athamas
Nephele, first wife of Athamas and mother of Phrixus and Helle, is a different cloud-nymph with a separate myth (the golden ram, the Hellespont). Sharing the language of clouds does not make the two figures one person; sources and children diverge cleanly.
Reception sometimes speaks loosely of "Nephele" for Ixion's cloud; in this dataset the Athamantid remains nephele and the Ixion mate remains nubes-ixion.