Editing Caridea (section)

==Systematics and related taxa==
{{Multiple image
| header = Difference between carideans and dendrobranchiates
| direction = horizontal
| align = right
| width = 220
| image1 = Pandborealisind.jpg
| caption1 = Carideans, such as ''[[Pandalus borealis]]'', typically have two pairs of claws, and the second segment of the abdomen overlaps the segments on either side. The abdomen shows a pronounced ''caridean bend''.
| image2 = Penaeus monodon.jpg
| caption2 = [[Dendrobranchiata]], such as ''[[Penaeus monodon]]'', typically have three pairs of claws, and even-sized segments on the abdomen. There is no pronounced bend in the abdomen.
}}

Shrimp of the infraorder Caridea are more closely related to [[lobster]]s and [[crab]]s than they are to the members of the sub-order [[Dendrobranchiata]] (prawns).<ref>{{cite web |url=http://museumvictoria.com.au/crust/caribiol.html#svp |title=Biology of Shrimps |publisher=[[Museum Victoria Australia]] |access-date=January 9, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100104102229/http://museumvictoria.com.au/crust/caribiol.html#svp |archive-date=January 4, 2010 }}</ref> Biologists distinguish these two groups based on differences in their [[gill]] structures. The gill structure is [[Lamella (zoology)|lamellar]] in carideans but branching in dendrobranchiates. The easiest practical way to separate true shrimp from dendrobranchiates is to examine the second [[Somite|abdominal segment]]. The second segment of a carideans overlaps both the first and the third segment, while the second segment of a dendrobranchiate overlaps only the third segment.<ref>{{cite web |author1=Charles Raabe |author2=Linda Raabe |year=2008 |url=http://www.chucksaddiction.com/Caridean.html |title=The Caridean shrimp: Shrimp Anatomy - Illustrations and Glossary}}</ref> They also differ in that carideans typically have two pairs of [[chela (organ)|chelae]] (claws), while dendrobranchiates have three.<ref name="Bauer_3_14">{{cite book |author=Raymond T. Bauer |year=2004 |title=Remarkable Shrimps: Adaptations and Natural History of the Carideans |volume=7 |series=Animal Natural History Series |publisher=[[University of Oklahoma Press]] |isbn=978-0-8061-3555-7 |chapter=What is a caridean shrimp? |pages=3–14 |chapter-url=https://books.google.com/books?id=b8YHIsnod3EC&pg=PA3}}</ref> A third group, the [[Stenopodidea]], contains around 70 species and differs from the other groups in that the third pairs of legs is greatly enlarged.<ref name="Bauer_3_14"/>

[[Procarididea]] are the sister group to the Caridea, comprising only eleven species.<ref name="Grave">{{cite journal|journal=[[Raffles Bulletin of Zoology]] |year=2009 |volume=Suppl. 21 |pages=1–109 |title=A classification of living and fossil genera of decapod crustaceans |author1=Sammy De Grave |author2=N. Dean Pentcheff |author3=Shane T. Ahyong |url=http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf |display-authors=etal |url-status=dead |archive-url=https://web.archive.org/web/20110606064728/http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf |archive-date=2011-06-06 }}</ref><ref name="Carideorum">{{cite journal |author=S. De Grave & C. H. J. M. Fransen |year=2011 |title=Carideorum Catalogus: the Recent species of the dendrobranchiate, stenopodidean, procarididean and caridean shrimps (Crustacea: Decapoda) |journal=[[Zoologische Mededelingen]] |volume=85 |issue=9 |pages=195–589, figs. 1–59 |isbn=978-90-6519-200-4 |url=http://www.zoologischemededelingen.nl/85/nr02/a01 |url-status=dead |archive-url=https://archive.today/20121220093841/http://www.zoologischemededelingen.nl/85/nr02/a01 |archive-date=2012-12-20 }}</ref>

The [[cladogram]] below shows Caridea's relationships to other relatives within [[Decapoda]], from analysis by Wolfe ''et al.'', 2019.<ref name="Wolfe2019">{{cite journal |last1=Wolfe |first1=Joanna M. |last2=Breinholt |first2=Jesse W. |last3=Crandall |first3=Keith A. |last4=Lemmon |first4=Alan R. |last5=Lemmon |first5=Emily Moriarty |last6=Timm |first6=Laura E. |last7=Siddall |first7=Mark E. |last8=Bracken-Grissom |first8=Heather D. |title=A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans |journal=Proceedings of the Royal Society B | date=24 April 2019 |volume=286 |issue=1901 |doi=10.1098/rspb.2019.0079 |pmc=6501934  |pmid=31014217 |doi-access=free }}</ref>

{{Decapoda cladogram}}

The below [[cladogram]] shows the internal relationships of eight selected [[family (biology)|families]] within Caridea, with the [[Atyidae]] (freshwater shrimp) being the most [[basal (phylogenetics)|basal]]:<ref name="Wolfe2019"/>

{{clade| style=font-size:85%; line-height:85%
|label1='''Caridea'''
|1={{clade
 |1=[[Atyidae]]
 |2={{clade
  |1=[[Oplophoridae]]
  |2={{clade
   |1={{clade
    |1=[[Lysmatidae]]
    |2=[[Barbouriidae]] }}
   |2={{clade
    |1={{clade
     |1=[[Thoridae]]
     |2=[[Hippolytidae]] }}
    |2={{clade
     |1=[[Alpheidae]]
     |2=[[Palaemonidae]]
}} }} }} }} }} }}