Difference Between Mollusks and Arthropods | Mollusks vs Arthropods

Mollusks vs Arthropods

Identifying the difference between mollusks and arthropods is not so difficult if you pay careful attention to the anatomy of each. Phylum Mollusca and Phylum Arthropoda are two major vertebrate phyla that include the highest number of species’ diversity than any phyla in Animal Kingdom. Due to this huge diversity, people find difficult to classify them under the correct phyla. This article analyses the anatomy of each and identify the structural features that help to differentiate between mollusks and arthropods.

What are Mollusks?

Phylum Mollusca is considered as one of the largest phylum and is second only to Phylum Arthropoda. The phylum consists of more than 110,000 identified species and they inhabit both terrestrial and aquatic environments on earth. Mollusks are soft-bodied invertebrates with one or two shells and bilateral symmetry. The most common examples for mollusks include snails, clams and squids. All mollusks have a thin outer layer called the mantle, which surrounds the body organs located insides the visceral mass. Mantle secretes the protective shell of the body. Gas exchange is taken place in gills. Mollusks have an open circulatory system in which the heart pumps blood into the open space around the body organs. They have a prominent head with a mouth and sensory organs. Mollusks like snails have a well-developed muscular foot for movement and adhesion. Squids have tentacles that are used to catch prey and for movement. Three major classes of Phylum Mollusca includes Gastropoda (Snails and conchs), Bivalvia (clams, oysters, and scallops), and Cephalopoda (squids, octopuses, cuttlefish, and chambered).