Achelata

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

Achelata Temporal range: Upper Jurassic – Recent PreꞒ Ꞓ O S D C P T J K Pg N
The phyllosoma larva is characteristic of the Achelata (drawing by Haeckel)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Achelata Scholtz & Richter, 1995
Families [1]
Palinuridae (inc. Synaxidae) Scyllaridae †Cancrinidae †Tricarinidae

Description

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 α-, a- = "not", χηλή, chela = "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.[2]

Classification and fossil record

Achelata contains the spiny lobsters (Palinuridae), the slipper lobsters (Scyllaridae) and the furry lobsters (Synaxidae, now usually included in Palinuridae),[3] as well as two extinct families, Cancrinidae and Tricarinidae.[1]

Extant families of Achelata

Palinurus elephas
Palinuridae

Palinurellus gundlachi
Palinuridae, formerly Synaxidae

Scyllarides latus
Scyllaridae

Phyllosoma larva (micrograph)

Both Palinuridae and Scyllaridae have a fossil record extending back to the Cretaceous.[4][5] The two fossil families contain a single genus each;[1] Tricarina is known from a single Cretaceous fossil,[6] while Cancrinos is known from the Jurassic and Cretaceous.[5] One estimate of the divergence between Achelata and its closest relatives places it at about 341 million years ago.[7]

References

1. Sammy De Grave; N. Dean Pentcheff; Shane T. Ahyong; et al. (2009). "A classification of living and fossil genera of decapod crustaceans" (PDF). Raffles Bulletin of Zoology. Suppl. 21: 1–109. Archived from the original (PDF) on 2011-06-06.
2. Gerhard Scholtz; Stefan Richter (1995). "Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca)" (PDF). Zoological Journal of the Linnean Society. 113 (3): 289–328. doi:10.1006/zjls.1995.0011.
3. Ferran Palero; Keith A. Crandall; Pere Abelló; Enrique Macpherson; Marta Pascual (2009). "Phylogenetic relationships between spiny, slipper and coral lobsters (Crustacea, Decapoda, Achelata)". Molecular Phylogenetics and Evolution. 50 (1): 152–162. doi:10.1016/j.ympev.2008.10.003. PMID 18957325.
4. Francisco J. Vega; Pedro García-Barrera; María del Carmen Perrilliat; Marco A. Coutiño; Ricardo Mariño-Pérez (2006). "El Espinal, a new plattenkalk facies locality from the Lower Cretaceous Sierra Madre Formation, Chiapas, southeastern Mexico" (PDF). Revista Mexicana de Ciencias Geológicas. 23 (3): 323–333.
5. Joachim T. Haug; Carolin Haug; Dieter Waloszek; Andreas Maas; Matthias Wulf; Günter Schweigert (2009). "Development in Mesozoic scyllarids and implications for the evolution of Achelata (Reptantia, Decapoda, Crustacea)" (PDF). Palaeodiversity. 2: 97–110.
6. Rodney M. Feldmann; Ali Kolahdouz; Bijan Biranvand; Guenter Schweigert (2007). "A new family, genus, and species of lobster (Decapoda: Achelata) from the Gadvan Formation (Early Cretaceous) of Iran" (PDF). Journal of Paleontology. 81 (2): 405–407. doi:10.1666/0022-3360(2007)81[405:ANFGAS]2.0.CO;2. Archived from the original (PDF) on 2016-03-04. Retrieved 2012-02-05.
7. Keith A. Crandall; Megan L. Porter; Marcos Pérez-Losada (2009). "Crabs, shrimps and lobsters (Decapoda)". In S. Blair Hedges; Sudhir Kumar (eds.). The Timetree of Life. Oxford University Press. pp. 293–297. ISBN 978-0-19-160898-8.

External links

• Media related to Achelata at Wikimedia Commons