Tessellidae

Tessellidae is a hypothetical genus of marine invertebrates proposed in early paleontological studies, though its validity as a distinct taxonomic group is now largely considered dubious. The name was coined to describe fossils exhibiting a mosaic-like or tessellated pattern on their surface, often found in Paleozoic rock formations. Early researchers interpreted these patterns as evidence of a unique skeletal structure or a specialized mode of life.

The fossils attributed to Tessellidae are typically small and exhibit a variety of shapes, including flattened discs, irregular masses, and sometimes more complex, segmented forms. The defining characteristic, the tessellation, refers to the arrangement of small, interlocking plates or granules that create a textured appearance. The exact nature of these structures has been a subject of debate, with interpretations ranging from mineralized epidermal cells to secreted skeletal elements.

Modern paleontological analysis, utilizing advanced imaging techniques and comparative anatomy, has often reclassified these specimens. Many have been identified as internal molds of other organisms, poorly preserved fragments of known taxa, or even inorganic structures that mimic biological patterns. The term "tessellated" is now more commonly used as a descriptive adjective for surface texture rather than a defining feature of a specific genus. Consequently, Tessellidae is rarely used in contemporary scientific literature, having been superseded by more precise classifications based on detailed morphological and phylogenetic evidence.