Polychelidae

Polychelidae
	Polycheles sculptus
Systematics
Trunk :	Arthropod (arthropoda)
Class :	Higher crabs (Malacostraca)
Order :	Decapods (decapoda)
Subordination :	Pleocyemata
Partial order :	Polychelida
Family :	Polychelidae
Scientific name
	Polychelidae
	Wood-Mason , 1874

The Polychelidae are a family of the decapods (Decapoda). Their species occur worldwide in all oceans and are characterized by the presence of claws on the first four pairs of legs. Fossil finds reach as far as the Upper Jurassic .

features

The carapace of the Polychelidae is flattened on the back and abdomen and has an egg-shaped to almost angular shape. Its side and front edges are protruding and pointed. The rostrum consists of one or two inconspicuous thorns. The stalked eyes are reduced, laterally aligned and connected to the edge of the carapace. The Polychelidae are blind.

The tergites and pleurae of the abdomen can be flat or highly structured and have a median ridge. The pleuron of the second abdominal segment is noticeably larger and overlaps the pleurae of the first and second segment. The telson is triangular to lanceolate. The exopodite of the uropods has no diaeresis. The endopodit can show small teeth or tips on its inner edge.

The basal segments of the first pair of antennas are relatively large, flattened and granulated or pointed towards the middle of the body (mesial). The two flagella of the first pair of antennas are of different lengths, the outer one is very short, the inner one is about as long as the flagellum of the second pair of antennas. The exopodite of the second antennae, the scaphocerite, is short and elongated or lanceolate in shape.

There are scissors on the first four pairs of striding legs . The fifth pair of striding legs is either single or chelated in both sexes, or only provided with scissors in females. The scissors of the first pair of legs are larger and more robust, the scissor fingers cross each other when the scissors are closed. The first pair of swimming legs is spatula-shaped in males, the second pair has appendices masculina. The pairs of swimming legs two to six are two-part, each with an appendix interna.

distribution and habitat

The species of the Polychelidae are distributed worldwide, although they do not occur in the polar seas. They are mainly found at sea depths of 500 m to 1500 m. Species of the genus Willemoesia live at depths between 2000 m and 5000 m.

Polychelidae are predators and part of benthos . They usually hide in caves they have dug themselves and attack their prey from this ambush.

Systematics

Phylogeny of the Polychelidae according to Ahyong 2009

Coleiidae

Coleia

Polychelidae

Willemoesia

Homeryon

Pentacheles

Cardus

	Polycheles

	Stereomastis

The Polychelidae belonged to the lobster-like (Palinura). With the splitting them to the Today Gerhard Scholtz and Stefan Richter established polychelida counted. In those Polychelida, the Polychelidae are the only recently known family and the sister taxon of the extinct Coleiidae .

The Polychelidae family consists of seven genera, one of which is known only from fossil records. There are a total of 38 species in the six recent genera. The genus Willemoesia seems to be a basal taxon (see cladogram) and is also described as the most original or primitive taxon of the Polychelidae.

Genera of the Polychelidae:

† Antarcticheles Aguirre-Urreta, Buatois, Chernoglasov & Medina, 1990
Cardus Galil, 2000
Homeryon Galil, 2000
Pentacheles Bate, 1878
Polycheles Heller, 1862
Stereomastis Bate, 1888
Willemoesia Grote, 1873

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Bella Galil: Crustacea Decapoda: Review of the genera and species of the family Polychelidae Wood-Mason, 1874 . In: A. Crosnier (Ed.): Résultats des Campagnes MUSORSTOM . tape 20 . Paris 2000, p. 285–387 ( PDF 13.3MB [accessed August 16, 2012]).
↑ ^a ^b ^c ^d ^e ^f ^g Shane T. Ahyong: The Polychelidan lobsters: Phylogeny and systematics (Polychelida: Polychelidae) . In: Joel W. Martin, Keith A. Crandall, Darryl L. Felder (Eds.): Decapod Crustacean Phylogenetics . CRC Press, Boca Raton, London, New York 2009, ISBN 1-4200-9258-8 , pp. 369–396 ( PDF 2.4MB [accessed August 16, 2012]).
^ Gerhard Scholtz and Stefan Richter: Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca) . In: Zoological Journal of the Linnean Society . tape 113 , 1995, pp. 289–328 ( pdf 2.7Mb [accessed on August 16, 2012]).
↑ Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al .: A classification of living and fossil genera of decapod crustaceans . In: Raffles Bulletin of Zoology . Suppl. 21. 2009, p. 1–109 ( PDF 7.73MB [accessed August 16, 2012]).

Web links

Commons : Polychelidae - Collection of images, videos, and audio files

[Galil-1] ↑ ^a ^b ^c ^d ^e ^f ^g Bella Galil: Crustacea Decapoda: Review of the genera and species of the family Polychelidae Wood-Mason, 1874 . In: A. Crosnier (Ed.): Résultats des Campagnes MUSORSTOM . tape 20 . Paris 2000, p. 285–387 ( PDF 13.3MB [accessed August 16, 2012]).

[Ahyong-2] ↑ ^a ^b ^c ^d ^e ^f ^g Shane T. Ahyong: The Polychelidan lobsters: Phylogeny and systematics (Polychelida: Polychelidae) . In: Joel W. Martin, Keith A. Crandall, Darryl L. Felder (Eds.): Decapod Crustacean Phylogenetics . CRC Press, Boca Raton, London, New York 2009, ISBN 1-4200-9258-8 , pp. 369–396 ( PDF 2.4MB [accessed August 16, 2012]).

[Scholz-3] Gerhard Scholtz and Stefan Richter: Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca) . In: Zoological Journal of the Linnean Society . tape 113 , 1995, pp. 289–328 ( pdf 2.7Mb [accessed on August 16, 2012]).

[Grave-4] Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al .: A classification of living and fossil genera of decapod crustaceans . In: Raffles Bulletin of Zoology . Suppl. 21. 2009, p. 1–109 ( PDF 7.73MB [accessed August 16, 2012]).