Monoplacophorans [Tryblidia]
Description
Monoplacophorans, known scientifically as Tryblidia, represent a primitive class of small, deep-sea mollusks. These creatures were once thought to be extinct and only known from fossils until living specimens were discovered in the 1950s. Monoplacophorans are characterized by their single, cap-like shell, which covers a body that is bilaterally symmetrical. They possess multiple pairs of gills, kidneys, and reproductive organs, a feature that sets them apart from other mollusks and suggests a segmental organization similar to that of annelid worms. Their simple nervous system and radula (a tongue-like organ with teeth) further highlight their primitive status within the Mollusca phylum. Monoplacophorans inhabit deep-sea environments, often found embedded in soft substrates where they feed on detritus and microorganisms. This order includes a very limited number of species, all of which are of significant interest to scientists studying the evolution and phylogeny of mollusks.