Silicispina

Silicispina is a genus of extinct radiolarians, single-celled marine protists within the Rhizaria that are primarily known from their delicate siliceous skeletons. The name combines silicis (silica) and spina (spine), reflecting the characteristic spine-bearing tests that distinguish many species in this genus.

Morphology and anatomy commonly described in Silicispina species include a robust, interlocking silica test with a central capsule and multiple slender spines projecting outward. The skeletons show diverse arrangements of spines and pore patterns, with features that are diagnostic at the species level. The spines likely served in buoyancy control and stabilization in the water column, while the central capsule housed the cell body.

Stratigraphic range and distribution are based on fossil records recovered from marine sedimentary rocks of various paleolatitudes. Silicispina fossils are found in rocks dating from parts of the late Paleozoic through portions of the Mesozoic, indicating a long-lived and widespread lineage in ancient oceans. The widespread preservation of their silica skeletons makes them useful for microfossil studies and biostratigraphy.

Ecology and paleoenvironmental significance point to a planktonic lifestyle, with individuals dispersed through ancient oceans as part of the zooplankton community. In paleontological research, Silicispina contributes to reconstructions of past ocean chemistry, silica cycles, and marine circulation patterns, and provides taxonomic markers for correlating marine sediment sequences across regions.

Note on taxonomy: as a radiolarian genus, Silicispina is classified within the broader framework of Radiolaria and is distinguished from related groups by the specific morphology of its tests and spines.