Metanephrops

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Metanephrops
Metanephrops challangeri

Metanephrops challangeri

Systematics
Class : Higher crabs (Malacostraca)
Order : Decapods (decapoda)
Subordination : Pleocyemata
Partial order : Large crayfish (Astacidea)
Family : Lobster-like (Nephropidae)
Genre : Metanephrops
Scientific name
Metanephrops
Jenkins , 1972

Metanephrops is a marine genus of the decapods (Decapoda) from the family of the lobster-like (Nephropidae). Today it comprises 18 species that are distributed in the Atlantic, Pacific and Indian Oceans. Some species are fished and are therefore of commercial interest.

description

The types of Metanephrops have a body structure typical of decapods , subdivided into the tagmata cephalothorax and abdomen . Their body sizes are different depending on the species, but are relatively large compared to other genera of the lobster family.

To distinguish reliably between Metanephrops and the genera of the lobster-like species, one characteristic cannot be used, but the combination of the following:

  • two distinct, pointed ridges that run on the back of the carapace from the eyes (supraorbital) to the transverse furrow of the carapace (postcervical groove);
  • a distinct, narrow ridge on the anterior sides of the carapace (antennal carina);
  • usually three pairs of ridges on the chest area of ​​the carapace (thoracic carinae);
  • about symmetrical, elongated-slender scissors, which can be provided with strong ridges in some species.

The exopodites of the second maxillipedas are reduced and have no flagellum. On the third maxilliped there are some spines on the posterior edge of the merus . On all pairs of striding legs there are both isolated and rows of hair. In males, the first pair of swimming legs is stiff and consists of two immobile, fused segments. The exo- and endopodite of the uropods have the same shape as those of the Nephrops species.

distribution and habitat

The species of Metanephrops are common in the shelf on the west coast of the Pacific , in the Indian Ocean and on the west coast of the Atlantic . Metanephrops does not occur in the eastern and central Pacific and in the eastern Atlantic . The distribution extends north to about 35 ° N near Japan and south to about 50 ° S near New Zealand.

Crabs of this genus are found at depths of 50 to 1,000 meters, with the vast majority of observations coming from depths greater than 150 meters. There they live more on soft mud than on sand.

Systematics

Richard Jenkins divided up the genus Nephrops in 1972 and placed all species except for the Norway lobster in the genus Metanephrops , as many details differ. So has metanephrops the rostrum only one side instead of three mandrels dorsolateral burrs from the rostrum extend up to the carapace and the antennal mandrel (antennal spine) is greater. Nephrops, on the other hand, has only five longitudinal ridges on the carapace, the exopod of the antennae (antennal scale) is narrow-lanceolate and the first pair of striding legs is noticeably unequal. Although all species of Metanephrops were initially assigned to the genus Nephrops and there are many morphological similarities, the genera Metanephrops and Nephrops are probably not sister taxa . There is thus a convergence .

Phylogenetic systematics of Metanephrops according to Thsudy et al. 2007

M. challengeri


   

M. rossensis  †


   

M. jenkinsi  †


  Binghami  

M. binghami


   

M. rubellus





   

M. thomsoni


  Japonicus  

M. formosanus


   

M. mozambicus


   

M. velutinus


   

M. sagamiensis


   

M. andamanicus


   

M. japonicus


   

M. armatus



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M. sinensis


   

M. boschmai


   

M. sibogae


  Arafuensis  

M. australiensis


   

M. arafuensis


   

M. motunauensis  †


   

M. neptunus








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The genus Metanephrops comprises a total of 18 recently and 3 fossil known species. Due to the geographical and morphological variety within the genus, Jenkins divided it into four groups as follows:

The groups cannot be distinguished from one another with sufficient certainty to define them as a subgenus . Nevertheless, the Arafuensis , Binghami and Japonicus groups are monophyletic according to a phylogenetic study based on their morphology (see cladogram).

Individual evidence

  1. ^ A b Lipke B. Holthuis: Marine Lobsters of the World . An Annotated and Illustrated Catalog of Species of Interest to Fisheries Known to Date. Ed .: Food and Agriculture Organization (=  FAO Fisheries Synopsis . Volume 125 ). Rome 1991, ISBN 92-5103027-8 ( fao.org ).
  2. ↑ a b c d e f g h i Dale Tshudy, Tin-Yam Chan, Ulf Sorhannus: Morphology based clasdistic analysis of Metanephrops: the most diverse extant genus of clawed lobster (Nephropidae) . In: Journal of Crustacean Biology . tape 27 , no. 3 , 2007, p. 463-476 , doi : 10.1651 / S-2777.1 .
  3. ^ A b Lipke B. Holthuis : The Lobsters of the Superfamily Nephropidea of ​​the Atlantic Ocean (Crustacea: Decapoda) . In: Bulletin of Marine Science . tape  24 , no. 4 , 1974, p. 723–884 ( nhm.org [PDF; 16.0 MB ; accessed on June 14, 2012]).
  4. ↑ a b c Richard Jenkins: Metanephrops, a new genus of late Pliocene to recent lobsters (Decapoda, Nephropidae) . In: Crustaceana . tape 22 , no. 2 , 1972, p. 161–177 ( nhm.org [PDF; 13.0 MB ; accessed on June 14, 2012]).
  5. ↑ YK Tam, Irv Kornfield: Phylogenetic Relationships of Clawed Lobster Genera (Decapoda: Nephropidae) Based on Mitochondrial 16S rRNA Gene Sequences . In: Journal of Crustacean Biology . tape 18 , 1998, pp. 138-149 , doi : 10.2307 / 1549528 .
  6. ↑ Dale Tshudy, Rafael Robles, Tin-Yam Chan, Ka Chai Ho, Ka Hou Chu, Shane T. Ahyong, Darryl L. Felder: Phylogeny of marine clawed lobster families Nephropidae Dana, 1852, and Thaumastochelidae Bate, 1888, based on mitochondrial genes . In: Joel W. Martin, Keith A. Crandall, Darryl L. Felder (Eds.): Decapod Crustacean Phylogenetics . CRC Press, 2009, ISBN 978-1-4200-9258-5 , pp. 357–368 ( nhm.org [PDF; 1,2 MB ; accessed on July 1, 2012]).
  7. ↑ Tin-Yam Chan: Metanephrops. In: World Register of Marine Species . 2012, accessed June 14, 2012 .

Web links

Commons : Metanephrops  - Collection of Images