The Achelata is an infra-order of the decapod crustaceans, holding the spiny lobsters, slipper lobsters and their fossil relatives.
Achelata Temporal range:
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The phyllosoma larva is characteristic of the Achelata (drawing by Haeckel) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
(unranked): | Reptantia |
Infraorder: | AchelataScholtz & Richter, 1995 |
Families [1] | |
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 Ancient Greek ἀ-, a- = "not", χηλή, chela = "claw"). They are further united by the great enlargement of the second antennae, by the special "phyllosoma" form of the larva, and by a number of other characters.[2]
The infraorder Achelata belongs to the group Reptantia, which consists of the walking/crawling decapods (lobsters and crabs). The cladogram below shows Achelata's placement within the larger order Decapoda, from analysis by Wolfe et al., 2019.[3]
Decapoda |
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Achelata contains the spiny lobsters (Palinuridae), the slipper lobsters (Scyllaridae) and the furry lobsters (Synaxidae, now usually included in Palinuridae),[4] as well as two extinct families, Cancrinidae and Tricarinidae.[1]
Both Palinuridae and Scyllaridae have a fossil record extending back to the Cretaceous.[5][6] The two fossil families contain a single genus each;[1] Tricarina is known from a single Cretaceous fossil,[7] while Cancrinos is known from the Jurassic and Cretaceous.[6] One estimate of the divergence between Achelata and its closest relatives places it at about 341 million years ago.[8]