Decapods (Decapoda)
Order of crustaceans (crustacea)
Food, Animal source foods, Arthropods (Arthropoda), Crustaceans (Crustacea)
Consumption area(s): Earth

Introduction
The decapods (decapoda), whose name derives from the Ancient Greek words for “ten” and “foot”, form one of the largest orders within the class crustaceans. This group brings together a wide range of animals, such as crabs, lobsters, crayfish, small or medium shrimps, and large or jumbo shrimps.
A great number of these animals act primarily as scavengers, playing an essential role in recycling organic matter in aquatic ecosystems. The order currently includes close to 15,000 living species spread across more than 2,700 genera, along with an additional 3,300 species known only from the fossil record.
Description of decapods
The body of decapods is divided into three major regions: the cephalon, the thorax, and the abdomen, which in some cases may be partially or completely fused.
In the cephalon are found five pairs of appendages: a pair of antennules, a pair of antennae, two pairs of maxillae, and a pair of mandibles. These structures are typical not only of crustaceans but also, in part, of other arthropods. The head also carries the eyes, sometimes pedunculated.
The thorax (or pereon) bears five pairs of walking limbs, the pereiopods, which give the order its name, literally meaning “ten feet”. Alongside them are three pairs of modified appendages, called maxillipeds, which assist in feeding.
The abdomen (or pleon) holds six pairs of pleopods, which do not serve as walking limbs. Instead, they move water forward toward the gills, allowing both respiration and locomotion. In some species, pleopods are also used to hold eggs or to assist in capturing prey. At the end of the abdomen lies another pair of appendages, the uropods, which, together with the tail fan, play a crucial role in swimming.
In simplified terms, the general body plan of decapods can be summarized as 5 + 8 + 7, meaning five pairs of cephalic appendages, eight pairs of thoracic appendages, and seven pairs of abdominal and caudal appendages.
Classification of decapods
Decapods are divided into two suborders:
- Dendrobranchiata (prawns/large or jumbo shrimps)
- Pleocyemata (crabs, crayfish, lobsters, shrimps/small or medium shrimps)
Source(s):
https://it.wikipedia.org/wiki/Decapoda
Photo(s):
1. Bart Braun, Public domain, via Wikimedia Commons