Hermoilla

Hermoilla is a fictional genus of freshwater invertebrates created for illustrative purposes in speculative biology and science fiction contexts. The name appears in several imagined taxonomies and serves as a case study in how new lineages might be described.

Taxonomy and naming: In the imagined scheme, Hermoilla is placed within the Domain Eukaryota and Kingdom Animalia. Some authors assign it to the phylum Mollusca with a class Gastropoda, while others propose a dedicated lineage, Hermoiidae, to reflect its distinctive morphology. The name is sometimes cited with uncertain status (incertae sedis) within its hypothetical family.

Description: Hermoilla species are small, encrusting invertebrates measuring 2–5 mm across. They have a tessellated calcareous shell and a translucent mantle. The colonies form flat mats on submerged rocks in freshwater environments. They lack prominent mobility.

Distribution and habitat: In fictional accounts, Hermoilla is reported from temperate freshwater streams in the Mistwood region and later from other analogous ecosystems in the same world. It favors clean, well-oxygenated water with moderate flow.

Ecology and life history: Hermoilla are sessile filter feeders, feeding on microalgae and organic detritus. Reproduction is described as sexual with external fertilization, and some models include asexual budding to form clonal patches. Predators are imagined to include small crustaceans and waterfowl. The genus is often discussed in pedagogy as an example of how new taxa might be circumscribed and tested in hypothetical biology.