Gromiida

Gromiida are a class of single-celled eukaryotes belonging to the phylum Cercozoa. They are characterized by their testate (shelled) structure, composed of organic material and sometimes incorporating foreign particles, and their reticulopodia, which are branching and anastomosing networks of pseudopodia used for locomotion and feeding.

Gromiids are primarily found in marine environments, including deep-sea sediments and shallow coastal waters, as well as in brackish and freshwater habitats. Some species are free-living, while others are known to be epibionts, attaching to other organisms.

The test of a gromiid can vary in shape and size, and often has a single aperture through which the reticulopodia extend. The cytoplasm within the test contains various organelles, including the nucleus and food vacuoles.

Gromiida are heterotrophic organisms, feeding on bacteria, algae, and other small particles that they capture with their reticulopodia. The captured prey is then transported into the cell for digestion.

Reproduction in Gromiida is primarily asexual, through binary fission or multiple fission. Sexual reproduction has not been definitively observed in all species, but evidence suggests it may occur in some.

Gromiida play a role in marine and freshwater ecosystems as consumers of bacteria and other microorganisms, contributing to nutrient cycling and the food web. Their fossil record is relatively sparse, but they are believed to have a long evolutionary history.

The classification of Gromiida within the Cercozoa has been subject to revision based on molecular phylogenetic data. They are closely related to other testate cercozoans and contribute to the diversity of protists in various aquatic environments.