Definition of palaeogean in US English:

palaeogean

(also palaeogaean, paleogean)

adjective

  • Biology. Of or relating to the Old World or Eastern hemisphere considered as a biogeographical region.

Origin

Mid 19th century; earliest use found in Philip Lutley Sclater (1829–1913), zoologist. From palaeo- + ancient Greek γαῖα, γῆ the earth + -an.