Editing Dendrobranchiata (section)

==Description==
Together with other swimming Decapoda, Dendrobranchiata show the "caridoid facies", or shrimp-like form.<ref name="TM100">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 100</ref> The body is typically robust, and can be divided into a [[cephalothorax]] (head and thorax fused together) and a [[pleon]] (abdomen).<ref name="TM100"/> The body is generally slightly flattened side-to-side.<ref name="TM100"/> The largest species, ''[[Penaeus monodon]]'', can reach a [[mass]] of {{convert|450|g}} and a length of {{convert|336|mm}}.<ref name="Dall3-4">[[#Dall1990|Dall, 1990]], pp. 3–4</ref>

===Head===
[[File:Shrimp head.jpg|right|thumb|Head]]
The most conspicuous appendages arising from the head are the [[antenna (biology)|antennae]]. The first pair are biramous (having two [[flagellum|flagella]]), except in [[Luciferidae]], and are relatively small.<ref name="TM106">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 106</ref> The second pair can be 2–3 times the length of the body and are always uniramous (having a single flagellum).<ref name="TM106"/> The [[arthropod mouthparts|mouthparts]] comprise pairs of [[Mandible (arthropod mouthpart)|mandibles]], maxillules and maxillae, arising from the head, and three pairs of maxillipeds, arising from the thorax.<ref name="TM106-8">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 106–108</ref> A pair of stalked [[eye]]s points forwards from the head.<ref name="TM102">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 102</ref>

===Thorax===
The [[carapace]] grows from the thorax to cover the cephalothorax, and extends forwards between the eyes into a [[rostrum (anatomy)|rostrum]].<ref name="TM102"/> This is only as long as the stalked eyes in [[Benthesicymidae]], [[Luciferidae]] and [[Sergestidae]], but considerably longer in [[Aristeidae]].<ref name="TM102"/>

As well as the three pairs of maxillipeds, the thorax also bears five pairs of [[pereiopod]]s, or walking legs; the first three of these end in small [[Chela (organ)|chelae]] (pincers).<ref name="TM108-10">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 108–110</ref> The last two pereiopods are absent in [[Luciferidae]] and ''[[Acetes]]'', but much longer than the preceding pereiopods in ''[[Hymenopenaeus]]'' and ''[[Xiphopenaeus]]''.<ref name="TM110">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 110</ref>

The thoracic appendages carry [[gill]]s, which are protected beneath the carapace.<ref name="TM103-5">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 103–105</ref> The gills are typically branched, and so resemble trees, lending the group its scientific name, Dendrobranchiata, from the [[Ancient Greek language|Greek]] words {{lang|el|[[:wikt:δένδρον|δένδρον]]}} (''{{lang|el|dendron}}'', [[tree]]) and {{lang|el|βράγχια}} (''{{lang|el|[[:wikt:branchia|branchia]]}}'', gills).<ref name="TM103">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 103</ref>

===Pleon===
The [[pleon]], or abdomen, is similar in length to the cephalothorax.<ref name="TM105">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 105</ref> It has six segments, the first five bearing lamellar [[pleopod]]s, and the last one bearing [[uropod]]s.<ref name="TM110-11">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 110–111</ref> The pleopods are biramous, except in [[Sicyoniidae]], where they are uniramous.<ref name="TM110"/> The uropods and [[telson]] collectively form the tail fan; the uropods are not divided by a diaeresis, as they are in many other decapods.<ref name="TM111">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 111</ref> The telson is pointed and is usually armed with four pairs of [[seta]]e or [[spine (zoology)|spines]].<ref name="TM111"/>

===Internal anatomy===
Most of the [[muscle|musculature]] of a prawn is used for bending the pleon, and almost all the space in the pleon is filled by muscle.<ref name="TM113">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 113</ref> More than 17 muscles operate each of the pleopods, and a further 16 power the tail fan in the rapid backward movement of the [[caridoid escape reaction]].<ref name="TM113-114">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 113–114</ref> These muscles, collectively, are the meat for which prawns are commercially fished and farmed.<ref>[[#KanduriEckhardt2002|Kanduri & Eckhardt, 2002]], p. 42</ref>

The [[nervous system]] of prawns comprises a dorsal [[brain]], and a [[ventral nerve cord]], connected by two [[commissure]]s around the [[oesophagus]].<ref name="TM114">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 114</ref> The chief sensory inputs are visual input from the eyes, [[chemoreceptor]]s on the antennae and in the mouth, and [[mechanoreceptor]]s on the antennae and elsewhere.<ref name="TM116-8">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 116–118</ref>

The [[digestive system]] comprises a foregut, a midgut and a hindgut, and is situated dorsally.<ref name="TM118">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 118</ref> The foregut begins at the mouth, passes through the oesophagus, and opens into a sac that contains the grinding apparatus of the [[gastric mill]].<ref name="TM118"/> The [[hepatopancreas]] feeds into the midgut, where [[digestive enzyme]]s are released, and nutrients taken up.<ref name="TM118"/> The hindgut forms faecal pellets, which are then passed out through the muscular [[anus]].<ref name="TM118-9">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 118–119</ref>

The [[circulatory system]] is based around a compact, triangular [[heart]], which pumps blood into three main [[artery|arteries]].<ref name="TM120">[[#TavaresMartin2010|Tavares & Martin, 2010]], p. 120</ref> [[Excretion]] is carried out through the gills, and by specialised [[gland]]s located at the base of the antennae, and is mostly in the form of [[ammonia]].<ref name="TM120-1">[[#TavaresMartin2010|Tavares & Martin, 2010]], pp. 120–121</ref>