Page 3 - Lecturer_1

What Are Crustaceans?

Almost all crustaceans are aquatic, and different species can be found in
both freshwater and saltwater environments. The more commonly
consumed species can be both wild caught as well as fishery raised.
Crustaceans are a diverse group of organisms. They are invertebrates,

meaning they do not have a backbone, and they are protected by an
outer shell called a carapace. The carapace acts as an exoskeleton,
providing the rigidity and structure that bones of an internal skeleton
would normally provide. All crustaceans have segmented bodies with
radial symmetry, meaning if you drew an imaginary line down the middle
of their back, the two sides would be approximate mirror images.
The general crustacean body type includes segments grouped within
three sections: a head, a thorax, and an abdomen. The head contains the

sensory structures, like eyes and antennae. The thorax usually contains
the legs primarily used for locomotion, and the abdomen usually
contains appendages that can be used for swimming, like a tail
or swimmerets. Swimmerets are structures similar to truncated legs
that help the organism swim.

Malacostraca: contains 5 subgroups, includes the crayfish, prawns,
crabs, krill, mantis shrimp, and sand hoppers
Almost all crustaceans are aquatic, and different species can be found in
both freshwater and saltwater environments. The more commonly
consumed species can be both wild caught as well as fishery raised. So
you probably know what happens when you eat a crustacean, but have

you ever stopped to wonder what they eat?

The different kinds of organisms we call lobsters are further subdivided
into the suborder Macrura Reptantia (from the Greek, makros meaning
long, oura meaning tail, and the Latin, reptans meaning crawling habit -
- or a long-tailed, crawling animal) which consists of three infraorders:
the Astacidea (marine lobsters and freshwater crayfishes), Palinuridea
(spiny and slipper lobsters), and Thalassinidea (mud lobsters). The

infraorder Astacidea contains three superfamilies: the Nephropoidea
(the commercially important marine lobsters) and the Astacoidea and
Parastacoidea (freshwater crayfishes of the northern and southern
hemispheres, respectively). Similarly, the infraorder Palinuridea contains
three superfamilies: the Eryonoidea (deepwater species), the
Glypheoidea (a fossil group with only one living representative), and the
Palinuroidea (the commercially important spiny and slipper lobsters).