Halocyprida

Halocyprida is an order of seed shrimp (ostracods), small crustaceans in the class Ostracoda and the subclass Myodocopa. Members are typically marine and occur worldwide in a variety of habitats, from coastal waters to the open ocean and the deep sea. Many species are planktonic, freely drifting or swimming in the water column, while others are epibenthic or otherwise associated with the seafloor. They are distinguished by features of their calcareous, two-valved carapace, which is often used for species identification in both living and fossil forms.

The morphology of halocyprids includes a simple body plan with a head and trunk hidden inside the carapace; limbs and internal organs support feeding and reproduction. Like other ostracods, they pass through nauplius and cypris larval stages, and most species reproduce sexually. Their calcified shells preserve well in the fossil record, making Halocyprida an important group for biostratigraphy and paleoceanographic studies.

Taxonomically, Halocyprida encompasses several families and higher taxa, reflecting a diversity of ecological roles and life histories. Ongoing research, including morphological and molecular analyses, continues to refine its classification. Halocyprida thus represents a major and ecologically varied component of ostracod diversity, contributing to our understanding of marine ecosystems and their histories.