编辑“︁螃蟹”︁（章节）

== 演化 ==
[[File:Fossil-crab.jpg|thumb|發現於[[阿根廷]]的侏羅紀時代的蟹化石]]
蟹原本被科學家認為是[[單源群]]，但現在認為蟹至少有兩個進化枝，分別位於[[舊世界]]和[[新大陸|新世界]]<ref>{{cite journal |author=R. von Sternberg, N. Cumberlidge & G. Rodriguez |year=1999 |title=On the marine sister groups of the freshwater crabs (Crustacea: Decapoda: Brachyura) |journal=Journal of Zoological Systematics and Evolutionary Research |volume=37 |pages=19–38 |doi=10.1046/j.1439-0469.1999.95092.x}}</ref>。最古老的蟹[[化石]]發現於[[侏羅紀]]<ref>{{cite journal |author=Carrie E. Schweitzer & Rodney M. Feldmann |year=2010 |title=The oldest Brachyura (Decapoda: Homolodromioidea: Glaessneropsoidea) known to date (Jurassic) |journal=Journal of Crustacean Biology |volume=30 |issue=2 |pages=251–256 |doi=10.1651/09-3231.1}}</ref>，而[[石炭紀]]的生物''Imocaris''也可能是一種原始蟹類，但由於只發現了其甲殼而不能確定<ref>{{cite journal |author=Frederick Schram & Royal Mapes |year=1984 |title=''Imocaris tuberculata'', n. gen., n. sp. (Crustacea: Decapoda) from the upper Mississippian Imo Formation, Arkansas |journal=Transactions of the San Diego Society of Natural History |volume=20 |issue=11 |pages=165–168 |url=http://www.biodiversitylibrary.org/item/25402#183 |access-date=2014-11-26 |archive-date=2017-05-20 |archive-url=https://web.archive.org/web/20170520145431/http://www.biodiversitylibrary.org/item/25402#183 |dead-url=no }}</ref>。蟹在[[白堊紀]]開始向世界各地[[適應輻射|輻射]]，這可能和大陸漂移或其捕食者[[硬骨魚]]的輻射有關<ref>{{cite journal |author=J. W. Wägele |year=1989 |title=On the influence of fishes on the evolution of benthic crustaceans |journal=Zeitschrift für Zoologische Systematik und Evolutionsforschung |volume=27 |issue=4 |pages=297–309 |url=http://www.zfmk.de/web/ZFMK_Mitarbeiter/WgeleJW/Publikationen/Publikationen/1989OntheinfluenceoffishesevolutionofBenthic.pdf |format=[[Portable Document Format|PDF]] |doi=10.1111/j.1439-0469.1989.tb00352.x |deadurl=yes |archiveurl=https://web.archive.org/web/20110719045829/http://www.zfmk.de/web/ZFMK_Mitarbeiter/WgeleJW/Publikationen/Publikationen/1989OntheinfluenceoffishesevolutionofBenthic.pdf |archivedate=2011-07-19 |access-date=2014-11-26 }}</ref>。