Discosea

Discosea is a class of amoeboid protists within the phylum Amoebozoa. Members are characterized by a flattened, disc-like body and a ventral feeding groove. Unlike true amoebae of the class Tubulinea, Discosea lack a tubular pseudopod and instead form broad lamellipodia that spread over surfaces. The cell membrane is highly dynamic, allowing rapid changes in shape without cytokinesis between phases. Most species exhibit a uniform surface, often with microtubule‑based ridges or patches that aid in locomotion and substrate attachment.

Ecologically, Discosea are predominantly heterotrophic, grazing on bacterial colonies and organic detritus in both freshwater and marine environments. They play a role in nutrient cycling by breaking down organic matter and controlling bacterial populations. Some species are found in extreme habitats, such as hypersaline lakes or geothermal springs, indicating a broad physiological tolerance.

Phylogenetically, Discosea cluster with the group Excavata in the genus Amoebozoa based on molecular data. The discovery of novel genetic markers within the alveolates has refined the classification, proposing that Discosea form a monophyletic lineage distinct from other amoeboid classes. Recent genomic analyses have revealed unusual collections of lateral gene transfers, especially from bacterial sources, which may contribute to their adaptability.

Research on Discosea contributes to understanding protist evolution, cell motility, and the ecological roles of microscopic eukaryotes. Studies employing electron microscopy, single‑cell transcriptomics, and environmental DNA sequencing have expanded knowledge of their diversity and distribution and continue to reveal new species in understudied habitats.