gastroporites

Gastroporites are a hypothetical group of fossil organisms proposed in the early 20th century, primarily by paleontologist Alfred Romer. The name "gastroporites" was intended to describe a type of fossil that exhibited characteristics of both gastropods (snails) and poriferans (sponges). The concept arose from observations of certain fossilized structures that appeared to have a spiral or coiled form, reminiscent of gastropod shells, but also contained pores or canal-like features, suggesting a porous, sponge-like body.

Romer and others interpreted these fossils as potential early mollusks or organisms with a unique evolutionary lineage that combined features of different phyla. However, the concept of gastroporites has largely fallen out of favor within the scientific community. Modern paleontological research and advancements in microscopy have led to re-interpretations of these enigmatic fossils. Many specimens previously attributed to gastroporites are now understood to be either misidentified or represent non-biological structures, such as mineral formations, or are reclassified as different types of organisms, including some types of early invertebrates or even colonial organisms. The term gastroporites itself is rarely used in current paleontological literature.