Microspina

Microspina is a genus of fossil marine invertebrates belonging to the phylum Mollusca, specifically within the class Rostroconchia. These extinct organisms are known from the Paleozoic Era, with their fossilized shells being the primary evidence of their existence. Rostroconchians, in general, are characterized by their unique bivalved shells that did not fully enclose the animal's soft body and possessed a gape. The genus Microspina is distinguished by the morphology of its shell, often featuring fine, radiating ribs or micro-sculptures. These shells are typically small, hence the genus name "microspina" which translates to "small spine" or "small prickle," likely referring to these delicate surface features. Microspina fossils are found in marine sedimentary rocks, indicating their habitat was in ancient seas. Their phylogenetic position within Rostroconchia places them among a group of mollusks that had no modern-day descendants, making them important for understanding the evolutionary history of mollusks. Study of Microspina and other rostroconchians contributes to our knowledge of ancient marine ecosystems and the diversity of life during the Paleozoic.