ABSTRACT
Examination of the fossil record of two decapod crustacean groups, the Aeglidae and the raninid genus Lyreidus, shows that they originated in the southern circum-Pacific region in Late Cretaceous and Eocene time, respectively, and that dispersal into lower latitudes probably occurred in the early Oligocene. Fragmentation of the southern Pacific landmass, dominated by Antarctica and Australia, and concomitant development of the circum-Antarctic current system severely reduced the probability of further dispersals along this route. These interpretations, based on extremely limited fossil data, parallel conclusions drawn regarding the paleobiogeographic distribution of mollusks in the early Tertiary Wedellian Province.
