Malacostraca n. pl. : A subclass of Crustacea, including Arthrostraca and Thoracostraca, or all those higher than the Entomostraca.

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Taxonomy
segments, Class Malacostraca, Latreille, Subclass, crustaceans, Calman, free encyclopedia, thoracic segments, Superorder, subphylum, Crustacea, shrimp, mantis shrimp, malacostracans, monophyly, pairs, appendages, maxillipeds.

Defination from the web:
Malacostraca (Greek: "soft shell") are the largest class of crustaceans and include most of the animals that non-experts recognize as ... Malacostraca image key - Guide to the marine zooplankton of south eastern Australia, Tasmanian Aquaculture and Fisheries Institute. v • d • e ...