Feb 4, 2026 · crustacean, any member of the subphylum Crustacea (phylum Arthropoda), a group of invertebrate animals consisting of some 45,000 species distributed worldwide. Crabs, …

Feb 4, 2026 · These two processes at the tail end of the body vary greatly in form; in many crustaceans they are short, but in some they may be as long as the rest of the body. The …

Feb 4, 2026 · The earliest of the definite fossil crustaceans are ostracods; a decapod occurs in the Devonian. In classifying the Crustacea, a variety of structural features are important.

Feb 4, 2026 · Molecular data may help resolve this and other uncertainties in the coming years. The fossil record, although fairly rich, has not solved any of the questions about the early …

Feb 4, 2026 · There is no universal agreement on the classification of the Crustacea and even less agreement on the interrelationships between the various groups. Alternative …

crustacean , Any member of the 45,000 arthropod species in the subphylum Crustacea. Distributed worldwide, crustaceans are distinguished by having two pairs of antenna-like …

Crustaceans are a group of invertebrate animals consisting of some 45,000 species worldwide. Crabs, lobsters, and shrimps are all counted among the subphylum Crustacea. Crustaceans …

Malacostracan, any member of the more than 29,000 species of the class Malacostraca (subphylum Crustacea, phylum Arthropoda), a widely distributed group of marine, freshwater, …

Crustaceans are a group of invertebrate animals consisting of some 45,000 species worldwide. Crabs, lobsters, and shrimps are all counted among the subphylum Crustacea. Crustaceans …

Feb 5, 2026 · Their relationships both within the phylum and with other animal phyla are uncertain. Phylum Arthropoda consists of the subphyla Chelicerata, Crustacea, Myriapoda, …