Agkistrodon
657905
194276751
2008-02-26T22:39:24Z
Eubot
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Removed taxobox colour. See [[User:Eubot/Removing colours from taxoboxen]].
{{Taxobox
| name = ''Agkistrodon''
| image = Agkistrodon contortrix contortrix CDC-a.png
| image_caption = Copperhead, ''[[Agkistrodon contortrix|A. contortrix]]''
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| subphylum = [[Vertebrate|Vertebrata]]
| classis = [[Reptile|Reptilia]]
| ordo = [[Squamata]]
| subordo = [[Serpentes]]
| familia = [[Viperidae]]
| subfamilia = [[Crotalinae]]
| genus = '''''Agkistrodon'''''
| genus_authority = [[Palisot de Beauvois]], 1799
| synonyms = * ''Agkistrodon'' - Palisot de Beauvois, 1799
* ''Agkishodon'' - Palisot de Beauvois, 1799
* ''Scytale'' - Latreille ''In'' Sonnini & Latreille, 1801
* ''Cenchris'' - Daudin, 1803
* ''Cenchurs'' - Link, 1807
* ''Scytalus'' - Fischer, 1803
* ''Tisiphone'' - Fitzinger, 1826
* ''Ancistrodon'' - Wagler, 1830
* ''Acontias'' - Troost, 1836
* ''Toxicophis'' - Troost, 1836<ref name="McD99">McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).</ref>
}}
:'''''Common names''': moccasins, copperheads, cantils.<ref name="C&L04">Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.</ref>''
'''''Agkistrodon''''' is a [[genus]] of [[Venomous snake|venomous]] [[Crotalinae|pitvipers]] found in [[North America]] from the [[United States]] south to northern [[Costa Rica]].<ref name="McD99"/> The name is derived from the [[Greek language|Greek]] words ''ancistro'', meaning "hook" and ''odon'', which means "tooth", and is likely a reference to the fangs.<ref name="C&L04"/> Three species are currently recognized,<ref name="ITIS">{{ITIS|ID=174295|taxon=Agkistrodon|year=2006|date=2 November}}</ref> all of them [[polytypic]] and closely related.<ref name="G&C90">Gloyd HK, Conant R. 1990. Snakes of the Agkistrodon Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. ISBN 0-916984-20-6.</ref>
==Description==
Members of this genus have a number of features in common. All species have a relatively broad head with short fangs. A [[loreal scale]] is present, except in ''[[Agkistrodon piscivorus|A. piscivorus]]''. There are usually nine large symmetrical platelike scales on the crown of the head, but in all species these are often irregularly fragmented or have sutures, especially in ''[[Agkistrodon bilineatus|A. bilineatus]]''. All have a sharply defined [[Canthus (snake)|canthus rostralis]] and a vertically elliptical pupil. There are 6-10 (usually 8) [[supralabial scales]] and 8-13 (usually 10-11) [[sublabials]]. The [[dorsal scales]] are mostly keeled and at midbody number 21-25 (usually 23), while ''A. piscivorus'' has 23-27 (usually 25). There are 127-157 [[ventral scales]] and 36-71 [[subcaudals]]. Of the latter, some may be divided. The [[anal scale]] is single. All have a color pattern of 10-20 dark crossbands on a lighter ground color, although sometimes the crossbands are staggered as half bands on either side of the body.<ref name="C&L04"/>
The [[Phylogenetics|phylogeny]] of the three species has long been controversial. Studies based on [[Morphology (biology)|morphological]] (Gloyd & Conant, 1990) and venom characteristics (Jones, 1976) support the idea that ''A. bilineatus'' and ''A. contortrix'' are more closely related. However, an analysis of [[mitochondrial DNA]] was conducted by Knight ''et al.'' (1992), as well as more recent molecular studies (Parkinson et al., 1997, 1999) have concluded that ''A. bilineatus'' and ''A. piscivorus'' are sister taxa, with ''A. contortrix'' being a sister species to them both.<ref name="C&L04"/>
==Geographic range==
Found in [[North America]] from the northeastern and central [[USA]] southward through peninsular [[Florida]] and southwestern [[Texas]]. In [[Central America]] on the Atlantic versant from [[Tamaulipas]] and [[Nuevo León]] southward to the [[Yucatan Peninsula]], [[Belize]] and [[Guatemala]]. Along the Pacific coastal plane and lower foothills from [[Sonora]] south through Guatemala, [[El Salvador]], [[Honduras]] and [[Nicaragua]] to northwestern [[Costa Rica]].<ref name="McD99"/>
==Behavior==
All are semiaquatic to terrestrial and are often found near sources of water. However, ''[[Agkistrodon contortrix|A. contortrix]]'' and ''[[Agkistrodon bilineatus|A. bilineatus]]'' are also found in dry habitats, often far from permanent streams or ponds.<ref name="C&L04"/>
==Reproduction==
The members of this genus are all [[Ovoviviparity|viviparous]].<ref name="C&L04"/>
==Venom==
It is assumed that the venom of all three species is not unlike that of ''[[Agkistrodon contortrix|A. contortrix]]'', which contains thrombinlike enzymes that act upon the coagulant activity of the blood. A study of [[Electrophoresis|electrophoretic]] patterns of proteins in venoms among and within populations of ''A. contortrix'' and ''[[Agkistrodon piscivorus|A. piscivorus]]'' showed that substantial variation exists (Jones, 1976), and there is no reason to believe that these differences do not correspond with variations in toxicity.<ref name="C&L04"/>
==Species==
{|cellspacing=0 cellpadding=2 border=1 style="border-collapse: collapse;"
!bgcolor="#f0f0f0"|Species<ref name="ITIS"/>
!bgcolor="#f0f0f0"|Authority<ref name="ITIS"/>
!bgcolor="#f0f0f0"|Subsp.*<ref name="ITIS"/>
!bgcolor="#f0f0f0"|Common name
!bgcolor="#f0f0f0"|Geographic range<ref name="McD99"/>
|-
|''[[Agkistrodon bilineatus|A. bilineatus]]''
|[[Albert C. L. G. Günther|Günther]], 1863
|align="center"|3
|Cantil
|style="width:40%"|[[Mexico]] and [[Central America]]. On the Atlantic side it is found in Mexico in [[Tamaulipas]], [[Nuevo León]], possibly northern [[Veracruz]] and [[Chiapas]] (in the [[Grijalva River|Middle Grijalva Valley]]). On the [[Yucatan Peninsula]] it occurs in [[Campeche]], [[Yucatán]], [[Quintana Roo]] and northern [[Belize]]. On the Pacific side it is found from southern [[Sonora]] in Mexico south through [[Guatemala]], [[El Salvador]], [[Honduras]] and [[Nicaragua]] to southwestern [[Costa Rica]]. On the Pacific side the distribution is almost continuous, while on the Atlantic side it is disjunct.
|-
|''[[Agkistrodon contortrix|A. contortrix]]''<font size="-1"><sup>T</sup></font>
|[[Carolus Linnaeus|Linnaeus]], 1766
|align="center"|4
|Copperhead
|The [[United States]] ([[Texas]], [[Oklahoma]], [[Kansas]], [[Missouri]], [[Arkansas]], [[Louisiana]], [[Mississippi]], [[Alabama]], [[Georgia (U.S. state)|Georgia]], [[Florida]], [[South Carolina]], [[North Carolina]], [[Tennessee]], [[Kentucky]], [[Virginia]], [[West Virginia]], [[Illinois]], [[Indiana]], [[Ohio]], [[Iowa]], [[Pennsylvania]], [[Maryland]], [[New Jersey]], [[Delaware]], [[New York]], [[Connecticut]], [[Massachusetts]]), Mexico ([[Chihuahua]], [[Coahuila]]).
|-
|''[[Agkistrodon piscivorus|A. piscivorus]]''
|[[Bernard Germain Étienne comte de La Ville-sur-Illon La Cépède|Lacépède]], 1789
|align="center"|2
|Cottonmouth
|The eastern United States from extreme southeastern Virginia, south through peninsular Florida and west to Arkansas, southeastern Kansas, eastern and southern Oklahoma and eastern and central Texas. A few records exist from along the [[Rio Grande River]] in Texas, but these are thought to represent isolated populations that possibly no longer exist.
|-
|}
''*) Not including the nominate subspecies (typical form).''<br>
<font size="-1"><sup>T</sup></font>'') [[Type species]].<ref name="McD99"/>
==Taxonomy==
This genus was previously much larger and also included the following genera:<ref name="McD99"/>
* ''[[Calloselasma]]'' - The Malayan pit viper found in [[Southeast Asia]].
* ''[[Deinagkistrodon]]'' - The Hundred-pace viper found mostly in southern [[China]].
* ''[[Gloydius]]'' - Moccasins found in [[Asia]].
* ''[[Hypnale]]'' - Hump-nosed vipers found in [[India]] and [[Sri Lanka]].
==See also==
* [[List of crotaline species and subspecies]]
* {{c|Crotalinae by common name}}
* {{c|Crotalinae by taxonomic synonyms}}
* [[Snakebite]]
==References==
{{reflist}}
==External links==
{{Commons|Agkistrodon}}
* {{NRDB genus|genus=Agkistrodon|date=9 August|year=2007}}
* [http://www.herpbreeder.com/worldspecies/Snakes/vipers/agkistrodon.htm ''Agkistrodon''] at [http://www.herpbreeder.com/ Herpbreeder.com]. Accessed [[26 September]] [[2006]].
[[Category:Crotalinae]]
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