{{Taksonomia/eläimet
| nimi = Taskuravut
| status = 
| status_ref = 
| kuva = Liocarcinus vernalis.jpg
| kuvateksti = ''Liocarcinus vernalis'', eräs taskurapu
| domeeni = 
| kunta = Eläinkunta ''Animalia''
| pääjakso = Niveljalkaiset ''Arthropoda''
| alajakso = Äyriäiset ''Crustacea''
| luokka = Kuoriäyriäiset ''Malacostraca''
| lahko = Kymmenjalkaiset ''Decapoda''
| alalahko = ''Pleocyemata''
| osalahko = '''Taskuravut''' ''Brachyura''
| osalahko_auktori = Latreille, 1802
| wikispecies = Brachyura
| commons = 
| commonscat = Brachyura
}}

'''Taskuravut''' (''Brachyura'') ovat äyriäisiä, joilla on kymmenen kävelyjalkaa ja yleensä litteä kuori. Useimmat taskuravut kävelevät sivuttain. Taskuravun takaruumis on taipuneena kuoren peittämän eturuumiin alle; takaruumiin leveydestä voi päätellä taskuravun sukupuolen.  
Useimmat taskuravut elävät suolaisessa vedessä, mutta on myös muutamia makean veden lajeja. Ravut luokitellaan sukuaukkojen sijainnin mukaan. Taskurapuja on 26 heimoa, joihin kuuluu n. 4000 lajia. Suomessa tavataan vuosittain villasaksirapua.

Taskurapuja kalastetaan vuosittain noin 1 500 000 tonnia. Viidesosa tästä määrästä on yhtä lajia, ''Portunus trituberculatus''. 

{{Taxobox
| name = Crabs
| image = Blue crab on market in Piraeus - Callinectes sapidus Rathbun 20020819-317.jpg
| image_width = 250px
| image_caption = ''Callinectes sapidus''
| regnum = Animalia
| phylum = Arthropoda
| subphylum = Crustacea
| classis = Malacostraca
| ordo = Decapoda
| subordo = Pleocyemata
| infraordo = '''Brachyura'''
| infraordo_authority = Linnaeus, 1758
| subdivision_ranks = Superfamilies
| subdivision = 
* '''Section Podotremata'''
**Cyclodorippoidea
**Homolodromioidea
**Dromioidea
**Homoloidea
**Raninoidea
* '''Section Eubrachyura'''
**'''Subsection Heterotremata'''
***Dorippoidea
***Calappoidea
***Leucosioidea
***Majoidea
***Hymenosomatoidea
***Parthenopoidea
***Retroplumoidea
***Cancroidea
***Portunoidea
***Bythograeoidea
***Xanthoidea
***Bellioidea
***Potamoidea
***Pseudothelphusoidea
***Gecarcinucoidea
***Cryptochiroidea
**'''Subsection Thoracotremata'''
***Pinnotheroidea 
***Ocypodoidea 
***Grapsoidea 
}}

'''Crabs''' are decapod Greek: ''brachy'' = short, ''ura'' = tail), or where the reduced abdomen is entirely hidden under the thorax. They are generally covered with a thick chelae (claws). 6793 species are known.<ref>Walters, Martin & Johnson, Jinny. ''The World of Animals''. freshwater and terrestrial crabs, particularly in tropical regions. Crabs vary in size from the m.<ref></ref>

==Diet==
Crabs are decapods - 10 legged omnivores, but the front pair of legs are specialised with enlarged claws, so they are commonly described as 8 legged. Some feed primarily on algae, others taking any type of food, including mollusks, worms, other crustaceans, fungi, bacteria and detritus, depending on their availability and the crab species. For many crabs, a mixed diet of plant and animal matter results in the fastest growth and greatest fitness.

==Crab fishery==

350px|thumb|left|[[Edible crabs being sorted by fishermen at Fionnphort, Scotland]]
Crabs make up 20% of all marine taxa include ''Charybdis spp.'', ''Cancer pagurus'', the Dungeness crab (''Cancer magister)'' and ''Scylla serrata'', each of which provides more than 20,000&nbsp;tonnes annually&nbsp;<ref></ref>.
<br clear="left">

==Evolution and classification==
thumb|left|The face of a [[dungeness crab. The two rostrum (center, above the mouth).]]
The infraorder Brachyura contains about 93 families<ref>[http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf Systema Brachyurorum: Part 1. An Annotated checklist of extant Brachyuran crabs of the world] ''Raffles Bulletin of Zoology'', 2008, 286pp.</ref>, as many as the remainder of the Decapoda.<ref name="Martin & Davis"></ref> The evolution of crabs is characterised by an increasing robustness of the body, and a reduction in the abdomen. Although other groups have also undergone similar processes of carcinisation, it is most advanced in crabs. The telson is no longer functional in crabs, and the uropods are absent, having probably evolved into small devices for holding the reduced abdomen tight against the sternum.<ref></ref>

In most decapodists, the sternum.<ref></ref> A similar change occurred, independently, with the female gonopores. The movement of the female gonopore to the sternum defines the monophyletic group.<ref name="Martin & Davis"/>  

The earliest unambiguous crab radiation of crabs in the bony fish, the main predators of crabs.<ref></ref>

About 850 species<ref></ref> of crab are freshwater or (semi-)terrestrial species; they are found throughout the world's semi-tropical regions. They were previously thought to be a closely related group, but are now believed to represent at least two distinct lineages, one in the Old World and one in the New World.<ref></ref>

==Cultural influences of the crab== 
thumb|120px|right|Moche vessel representing a crab.

The Museo Arqueológico Rafael Larco Herrera.'' New York: Thames and Hudson, 1997.</ref>

==Gallery==
<gallery>
Image:Corystes cassivelaunus.jpg|Masked crab, ''Corystes cassivelaunus''
Image:Liocarcinus vernalis.jpg|''Liocarcinus vernalis''
Image:Atelecyclus rotundatus.jpg|Circular crab, ''Atelecyclus rotundatus''
Image:Gecarcinus ruricola.jpg|The terrestrial halloween crab, ''Geocarcinus ruricola''
Image:Stenorhynchus seticornis 2.jpg|Arrow crab ''Stenorhynchus seticornis'' 
Image:Grapsus grapsus.JPG|"Sally Light Foot", ''Grapsus grapsus''
Image:Thia scutellata.jpg|Thumbnail crab, ''Thia scutellata''
Image:Spider crabs at the Kaiyukan Aquarium in Osaka close.jpg|Japanese spider crab, ''Macrocheira kaempferi''
Image:Ocypode quadrata (2).jpg|Ghost crab, ''Ocypode quadrata''
Image:Fiddler crab.jpg|Fiddler crab, ''Uca pugnax''
Image:Lyreidus tridentatus.jpg|''Lyreidus tridentatus'', a raninid
Image:Hepatus epheliticus.jpg|''Hepatus epheliticus'', a calico crab
Image:Crab larva.jpg|Crab larva (megalopa)
</gallery>

==References==<!-- Zootaxa 1558: 39 -->