Crustaceans (Crustacea)

Subphylum of arthropods (arthropoda)

Food, Animal source foods, Arthropods (Arthropoda)

Consumption area(s): Earth

Introduction

Crustaceans (Crustacea) represent a subphylum within the arthropods, predominantly consisting of marine species, though a significant number thrive in freshwater habitats, and a few have successfully colonized terrestrial environments.

Notably, some crustaceans are land-dwelling, including species commonly mistaken for insects, such as woodlice. In everyday language, the term crustacean generally refers to small or medium shrimps, large or jumbo shrimps, crabs, isopods, amphipods, and related animals, all of which are exclusively members of the class Malacostraca.

Description of crustaceans (crustacea)

Crustaceans represent a highly diverse group, yet they share a few fundamental morphological traits. One key feature is the presence of two pairs of preoral appendages—the antennules and antennae—on the cephalon (head), which otherwise resembles that of myriapods and hexapods in segment number and arrangement. Another characteristic is the presence of biramous appendages.

In the most primitive crustaceans, traces of homonomous metamerism remain in the trunk, the only body region following the cephalon. Here, each trunk segment carries locomotor appendages, which typically decrease in size toward the last segment, often ending with a rigid furca.

In more advanced crustaceans, the trunk is divided into a thorax and abdomen, known as the pereion and pleon. This division is accompanied by a functional specialization of the appendages: pereiopods on the pereion mainly support locomotion, with the anterior ones sometimes adapted for grasping and processing food, in which case they are called maxillipeds. The pleopods on the pleon perform diverse roles, such as forming swimming paddles, bearing gills, or holding eggs.

Occasionally, the last pair of pleopods is flattened and lies alongside the telson, also flattened, forming a caudal fan, as seen in lobsters. In some well-known crustaceans, the thorax and cephalon fuse into a cephalothorax, protected by a carapace often reinforced with calcium carbonate.

The eyes can be pedunculated or borne on modified appendages, enhancing vision. A prime example of extreme segment specialization occurs in crabs, where the abdomen is highly reduced, lacks appendages, and is folded beneath the cephalothorax.

Classification of crustaceans (crustacea)

Crustaceans are classified into orders. Among these, the edible ones include:

• Cirripedes (barnacles)
• Decapods (clawed lobsters, crabs, lobsters, shrimps/prawns)
• Isopods (woodlice/sea slaters)
• Stomatopods (mantis shrimps/peacock mantis shrimps)