Elastia

Elastia is a genus of small, benthic crustaceans that belong to the family Communalidae within the order Decapoda. First described in 1907 by marine biologist L. M. Smith, the genus was initially established from a single species collected off the coast of New Zealand. Subsequent explorations in the Pacific and the Atlantic found three additional species, making a total of four recognized members of the genus. Elastia species are distinguished by their translucent carapace, elongated thoracic appendages, and a unique pattern of fine spines along the postabdomen, which set them apart from other genera in Communalidae.

The morphology of Elastia species is typical of small decapods that inhabit soft‑sediment environments. They possess a set of broad, uniramous appendages used for locomotion and feeding. Their carapace is flattened, allowing them to dwell in narrow interstitial spaces between grains of sand. Many species exhibit sexual dimorphism; males typically have longer first antennae and a pronounced cheliped, while females bear large, swept‑back abdomens that accommodate multiple eggs. Elastia typically construct communal burrows that are shared by several individuals of the same species.

Elastia populations are predominantly found in temperate coastal zones, with most species restricted to the Southern Hemisphere. Recent molecular studies suggest a close evolutionary relationship with the genus Paracommuna, indicating that both lineages may have diverged during the late Cretaceous. While they are not of commercial significance, Elastia species have become useful indicators of sediment quality and marine ecosystem health. Environmental monitoring programs in New Zealand and Chile include regular sampling of Elastia populations to track changes in benthic community composition.

Research on Elastia remains limited, and taxonomic revisions are anticipated as more detailed morphological and genetic data become available.