Metacarcinus

Metacarcinus is a genus of crabs formerly included in the genus Cancer.[1] It includes nine exclusively fossil species and five extant species, of which four are also known from the fossil record.[2] The monophyly of this genus was not supported by a molecular study using the cytochrome oxidase I gene.[3]

Metacarcinus
Temporal range: Oligocene–Recent
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Brachyura
Family: Cancridae
Genus: Metacarcinus
A. Milne-Edwards, 1862
Type species
Metacarcinus magister
Dana, 1852

Description

Metacarcinus crabs have an oval carapace of about ⅔ of its largest width, with a surface with poorly marked division of smooth or gently colored regions. The front edge usually does not protrude before orbital, and the total length of these edges is 26-34% of the largest width of the carapace, with 5 spikes, including inner orbits, of which the middle springs lower than the others. 9-10 spikes are located on both anteroposterior lateral sides of the carapace; they can be of different shapes. The lateral edges are edged and can have one spike. The claws propodite is characterized by an upper edge at an angle of about 120° to the distal edge, equipped with sharp spines or grained or smooth keel. On the external surface of the propodite there are usually 4 balls. The cutting edges of the pliers' fingers of the claw have sharp teeth. The fixed finger has two points: middle and on the bottom edge

Extant species

Included species:[4]

ImageScientific nameCommon NameDistribution
Metacarcinus anthonyiyellow rock crab or yellow crabPacific coast of North America
Metacarcinus edwardsiimola rock crab, southern rock crab, or Chilean rock crabPacific coast between Guayaquil in Ecuador and the Beagle Channel in the southernmost Chile
Metacarcinus gracilisgraceful rock crab or slender crabfrom Alaska to Bahía Magdelena, Baja California
Metacarcinus magisterDungeness crabwest coast of North America
Metacarcinus novaezelandiaePie crust crabNew Zealand and south-eastern Australia.

Fossils
  • † Metacarcinus danai (Miocene, California)
  • † Metacarcinus davidi (Miocene to Pliocene, California)
  • † Metacarcinus goederti (Oligocene, Alaska)
  • † Metacarcinus izumoensis (Miocene, Japan)
  • † Metacarcinus jenniferae (Middle Pliocene, California)
  • † Metacarcinus minutoserratus (Pliocene, Japan)
  • † Metacarcinus starri (Early Oligocene, Washington)

References
  1. P. K. L. Ng, D. Guinot & P. J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world" (PDF). Raffles Bulletin of Zoology. 17: 1–286. Archived from the original (PDF) on 2011-06-06.
  2. 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.
  3. Michelle K. Harrison & Bernard J. Crespi (1999). "Phylogenetics of Cancer Crabs (Crustacea: Decapoda: Brachyura)" (PDF). Molecular Phylogenetics and Evolution. 12: 186–199. doi:10.1006/mpev.1998.0608. PMID 10381321.
  4. Carrie E. Schweitzer & Rodney M. Feldmann (2000). "Re-evaluation of the Cancridae Latreille, 1802 (Decapoda: Brachyura) including three new genera and three new species". Contributions to Zoology. 69 (4): 223–250. Archived from the original on 2012-12-09. Retrieved 2010-10-17. Also available as PDF.


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