Kepiting: Perbedaan antara revisi
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Pope or lodan (specifically the non-toothed and small size) are a group of mammals that live in the ocean. References to "whale" is given to members of the Cetacea sized nation. Pope not belong to the fish family. Pope has the following characteristics: |
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Kepiting beraneka ragam ukurannya, dari [[ketam kacang]], yang lebarnya hanya beberapa [[milimeter]], hingga [[kepiting laba-laba Jepang]], dengan rentangan kaki hingga 4 [[meter|m]] <ref>{{cite web |url=http://oceanlink.island.net/records.html |title=Biggest, Smallest, Fastest, Deepest: Marine Animal Records |publisher=OceanLink |accessdaymonth=22 September |accessyear=2006}}</ref>.
== Anatomi ==
Kepiting sejati mempunyai lima pasang [[kaki artropoda|kaki]]; sepasang kaki yang pertama dimodifikasi menjadi sepasang capit dan tidak digunakan untuk bergerak. Di hampir semua jenis kepiting, kecuali beberapa saja (misalnya, [[Raninoida]]), perutnya terlipat di bawah [[cephalothorax]]. Bagian [[mulut]] kepiting ditutupi oleh [[maxilliped]] yang rata, dan bagian depan dari [[carapace]] tidak membentuk sebuah [[Rostrum (anatomi)|rostrum]] yang panjang <ref>{{cite journal | quotes=no|author = Dixon, C. J., [[Frederick Schram|F. R. Schram]] & S. T. Ahyong|year=2004|title=A new hypothesis of decapod phylogeny|journal=[[Crustaceana]]|volume=76|issue=8|pages=935–975}}</ref>. [[Insang]] kepiting terbentuk dari pelat-pelat yang pipih ("phyllobranchiate"), mirip dengan insang [[udang]], namun dengan struktur yang berbeda <ref>{{cite journal | quotes=no |author=Taylor, H. H. & E. W. Taylor |year=1992 |title=Gills and Lungs: The Exchange of Gases and Ions |journal=Microscopic Anatomy of Invertebrates |volume=10 |pages=203–293}}</ref>.
<!--Most crabs show clear [[sexual dimorphism]] and so can be easily sexed. The abdomen, which is held recurved under the thorax, is narrow in males. In females, however, the abdomen retains a greater number of [[pleopod]]s and is considerably wider <ref>{{cite web |url=http://www.dnr.sc.gov/marine/sertc/Glossary.pdf |publisher=Southeastern Regional Taxonomic Center |title=Glossary of terms for decapods |format=[[Portable Document Format|PDF]]}}</ref>. This relates to the carrying of the [[fertilisation|fertilised]] eggs by the female crabs (as seen in all [[Pleocyemata|pleocyemates]]). In those species in which no such dimorphism is found, the position of the gonopores must be used instead. In females, these are on the third [[pereiopod]], or nearby on the sternum in higher crabs; in males, the gonopores are at the base of the fifth pereiopods or, in higher crabs, on the sternum nearby.
==Diet==
Crabs are [[omnivore]]s, feeding primarily on [[alga]]e <ref>{{cite journal |quotes=no |title=Natural diet of the crab ''Notomithrax ursus'' (Brachyura, Majidae) at Oaro, South Island, New Zealand |author=Woods, C. M. C. |journal=[[New Zealand Journal of Marine and Freshwater Research]] |year=1993 |Volume=27 |pages=309=315 |url=http://www.rsnz.org/publish/nzjmfr/1993/29.php}}</ref>, and taking any other food, including [[mollusc]]s, [[worm]]s, other [[crustacean]]s, [[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 (biology)|fitness]] <ref>{{cite journal |quotes=no |title=Diet composition influeces the fitness of the herbivorous crab ''Grapsus albolineatus'' |journal=[[Oecologia]] |author=Kennish, R. |volum=105 |issue=1 |year=1996 |pages=22-29 |url=http://www.springerlink.com/content/l7m3368427059312/}}</ref><ref>{{cite journal |quotes=no |title=Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat complexity |author=Buck, T. L., G. A. Breed, S. C. Pennings, M. E. Chase, M. Zimmer & T. H. Carefoot |journal=[[Journal of Experimental Marine Biology and Ecology]] |year=2003 |volume=292 |issue=1 |pages=103-116 |url=http://cat.inist.fr/?aModele=afficheN&cpsidt=14847986}}</ref>.
==Crab fishery==
[[Berkas:Sorting Crabs Ffionphort.jpg|350px|thumb|left|[[Edible crab]]s being sorted by fishermen at [[Fionnphort]], [[Scotland]]]]
Crabs make up 20% of all marine crustaceans caught and farmed worldwide, with over 1½ million [[tonne]]s being consumed annually. Of that total, one species accounts for one fifth: ''[[Portunus trituberculatus]]''. Other important [[taxon|taxa]] include ''[[Portunus pelagicus]]'', several species in the genus ''[[Chionoecetes]]'', the [[blue crab]] (''Callinectes sapidus''), ''[[Charybdis (genus)|Charybdis spp.]]'', ''[[Edible crab|Cancer pagurus]]'', the [[Dungeness crab]] (''Cancer magister)'' and ''[[Scylla serrata]]'', each of which provides more than 20,000 tonnes annually <ref>{{cite web |url=http://www.fao.org/figis/servlet/TabLandArea?tb_ds=Capture&tb_mode=TABLE&tb_act=SELECT&tb_grp=COUNTRY |title=Global Capture Production 1950-2004 |publisher=[[Food and Agriculture Organization|FAO]] |accessdaymonth=August 26 |accessyear=2006}}</ref>.
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==Evolution and classification==
The infraorder Brachyura contains about 70 [[family (biology)|families]], as many as the remainder of the [[Decapoda]] <ref name="Martin & Davis">{{cite book |url=http://www.nhm.org/research/publications/CrustaceaClassification.pdf |title=An Updated Classification of the Recent Crustacea |author=Martin, J. W. & G. E. Davis |year=2001 |pages=132 pp. |publisher=Natural History Museum of Los Angeles County |format=[[Portable Document Format|PDF]]}}</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 [[uropod]]s are absent, having probably evolved into small devices for holding the reduced abdomen tight against the sternum <ref>{{cite journal | quotes=no |author=Guinot, D & J.–M. Bouchard |year=1998 |title=Evolution of the abdominal holding systems of brachyuran crabs (Crustacea, Decapoda, Brachyura) |journal=[[Zoosystema]] |volume=20 |issue=4 |pages=613–694 |url=http://www.mnhn.fr/publication/zoosyst/z98n4a4.html |format=[[Portable Document Format|PDF]]}}</ref>.
In most decapods, the [[gonopore]]s (sexual openings) are found on the legs. However, since crabs use the first two pairs of [[pleopod]]s (abdominal appendages) for [[sperm transfer]], this arrangement has changed. As the male abdomen evolved into a narrower shape, the gonopores have moved towards the midline, away from the legs, and onto the [[Sternum (arthropod)|sternum]] <ref>{{cite journal | quotes=no |author=De Saint Laurent, M. |year=1980 |title=Sur la classification et la phylogénie des Crustacés Décapodes Brachyoures. II. Heterotremata et Thoracotremata Guinto, 1977 |journal=[[C. R. Acad. Sc. Paris]] |volume=t. 290 |pages=1317–1320}}</ref>. A similar change occurred, independently, with the female gonopores. The movement of the female gonopore to the sternum defines the [[clade]] [[Eubrachyura]], and the later change in the position of the male gonopore defines the [[Thoracotremata]]. It is still a subject of debate whether those crabs where the female, but not male, gonopores are situated on the sternum form a [[Monophyly|monophyletic group]] <ref name="Martin & Davis"/>.
The earliest unambiguous crab [[fossil]]s date from the [[Jurassic]], although the [[Carboniferous]] ''Imocaris'', known only from its [[carapace]] is thought to be a primitive crab <ref>{{cite journal | quotes=no |author=[[Frederick Schram|Schram, F. R.]] & R. Mapes |year=1984 |title=''Imocaris tuberculata'', n. gen., n. sp. (Crustacea: Decapoda) fro the upper Mississippian Imo Formation, Arkansas |journal=[[Transactions of the San Diego Society of Natural History]] |volume=20 |issue=11 |pages=165–168}}</ref>. The [[Adaptive radiation|radiation]] of crabs in the [[Cretaceous]] and afterwards may be linked either to the break-up of [[Gondwana]] or to the concurrent radiation of [[Osteichthyes|bony fish]], the main [[predator]]s of crabs <ref>{{cite journal | quotes=no |author=Wägele, J. W. |year=1989 |title=On the influence of fishes on the evolution of benthic crustaceans |journal=J. zool. Syst. Evolut.-forsch. |volume=27 |pages=297–309}}</ref>.
About 850 species <ref>{{cite journal | quotes=no |author=Sternberg, R. von & N. Cumberlidge |year=2001 |title=On the heterotreme-thoracotreme distinction in the Eubrachyura De Saint Laurent, 1980 (Decapoda: Brachyura) |journal=[[Crustaceana]] |volume=74 |pages=321–338}}</ref> of crab are freshwater or (semi-)terrestrial species; they are found throughout the world's [[tropic]]al and [[Subtropics|semi-tropical]] regions. They were previously thought to be a closely related group, but are now believed to represent at least two distinct [[Lineage (evolution)|lineages]], one in the [[Old World]] and one in the [[New World]] <ref>{{cite journal | quotes=no |author=Sternberg, R. von, N. Cumberlidge & G. Rodriguez |year=1999 |title=On the marine sister groups of the freshwater crabs (Crustacea: Decapoda: Brachyura) |journal=[[J. Zool. Syst. Evol. Research]] |volume=37 |pages=19–38}}</ref>.
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== Galeri ==
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