Pachys

Pachys is a genus of small, extinct marine invertebrates that lived during the Silurian period, approximately 443.8 to 419.2 million years ago. These organisms are known from fossil evidence, primarily found in marine sedimentary rocks. Pachys are characterized by a somewhat flattened, circular body with a series of radiating grooves or striae on their upper surface. Their exact classification has been a subject of debate among paleontologists, with various interpretations suggesting affinities to different phyla, including echinoderms or cnidarians.

The fossils of Pachys are typically preserved as impressions or casts in fine-grained sediments. They are often found in association with other marine life from the Silurian seas. The limited number of well-preserved specimens and the unusual morphology of Pachys make it challenging to definitively determine their lifestyle, feeding habits, or reproductive strategies. However, their marine environment suggests they were likely benthic, living on or near the seafloor. The radiating structures on their body may have played a role in respiration, nutrient absorption, or anchoring. Ongoing research continues to analyze the available fossil data to better understand the evolutionary position and biology of Pachys.