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Achelata

Achelata
Temporal range: Upper Jurassic – Recent
Haeckel Phyllosoma.jpg
The phyllosoma larva is characteristic of the Achelata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Achelata
Scholtz & Richter, 1995
Families 

The Achelata is an infra-order of the decapod crustaceans, holding the spiny lobsters, slipper lobsters and their fossil relatives.

The name "Achelata" derives from the fact that all the members of this group lack the chelae (claws) that are found on almost all other decapods (from the Greek , a- = "not", , = "claw"). They are further united by the great enlargement of the first antennae, by the special "phyllosoma" form of the larva, and by a number of other characters.

Achelata contains the spiny lobsters (Palinuridae), the slipper lobsters (Scyllaridae) and the furry lobsters (Synaxidae, now usually included in Palinuridae), as well as two extinct families, Cancrinidae and Tricarinidae.

Both Palinuridae and Scyllaridae have a fossil record extending back to the Cretaceous. The two fossil families contain a single genus each;Tricarina is known from a single Cretaceous fossil, while Cancrinos is known from the Jurassic and Cretaceous. One estimate of the divergence between Achelata and its closest relatives places it at about 341 million years ago.


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Wikipedia

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