[3] Based on molecular evidence as of 2009, it is now widely believed that these two infraorders represent two distinct lineages separate from one another.

[4] Axiidea are noted for the burrows with complex architecture that they make in the ocean floor sediment.

[5] These burrows can be classified based on their external characteristics in the sediment as well as the trophic group that the species falls into.

[6] The population density of most species of Axiidea tends to be high, so these organisms play an important role in the biogeochemical processes of the ocean floor sediments, and in the creation of habitats that favor various marine benthic communities.

[6] The infraorder Axiidea belongs to the group Reptantia, which consists of the walking/crawling decapods (lobsters and crabs).

The cladogram below shows Axiidea as more basal than Gebiidea within the larger order Decapoda, from analysis by Wolfe et al., 2019.

[3][disputed – discuss] Similarly, molecular studies do not support the subfamily Eiconaxiidae being separate from family Axiidae.

[6] Duration of egg incubation periods, and therefore also larval development, is dependent on the environmental factors surrounding the habitat of each individual species.

Environmental factors tend to include developmental constraints, salinity of the marine environment, and temperature of the water.

The megalopa stage represents the transition from plankton to their benthic habitats, and morphological development is marked by the growth of functional mouthparts resembling those of juveniles or adults.