Monoplacophora is a polyphyletic class of molluscs that lives at sea bottoms. They are univalved and untorted molluscs that are not related to gastropods. Here, let us learn about Monoplacophora with examples.
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What Are Monoplacophora?
Monoplacophora, which means “bearing one plate,” is a polyphyletic superclass of molluscs that formerly lived at the bottom of the deep sea. Its shell resembles a cap.
Members of the Monoplacophora class have an undivided arching shell, a broad flat foot, serially repeated pairs of gills and foot-retractor muscles. Despite being dioecious, nothing more is known about their embryology. Until 1952, this group of molluscs was only known through fossils.
Fossil Records
The first undeniable molluscs were monoplacophorans, which were discovered in rocks from the earliest Cambrian period. The group was very diversified during the Paleozoic, according to the fossil record. Later Paleozoic forms are more frequently discovered in deeper waters with soft, muddy sea floors than Cambrian forms, which primarily lived in shallow seas.
The recent monoplacophorans comprise a unique clade and it is simple to distinguish between their characteristics and those of the other extant molluscan groups. Monoplacophorans are untorted, univalved (but not gastropodal) and limpet-shaped. The characteristics that set some Paleozoic monoplacophorans apart from torted gastropods and vice versa are amenable to different interpretations.
See more: Pila globosa (Apple Snail) – Diagram and Description
Monoplacophora Examples
The majority of monoplacophorans are aquatic and all reside at considerable depths. There are several extant species under the class Monoplacophora. Some examples of Monoplacophora are given below:
- Laevipilina antarctica
- Micropilina minuta
- Monoplacophorus zenkevitchi
- Adenopilina adenensis
- Neopilina bruuni
All these extant monoplacophoran species belong to the order Tryblidiida. It is the only representative of living monoplacophorans with 37 known species. The extinct examples of monoplacophorans are:
- Knightoconus antarcticus
- Crytolites spp
- Kirengella spp
Keep exploring BYJU’S Biology to learn more such exciting topics.
Also Check:
- What Are Fossils?
- Difference between Cephalopods and Gastropods
- Difference between Crustaceans and Molluscs
