Editing Notostraca (section)

==Description==
Notostracans are {{convert|2|-|5|cm|1}} long, with a broad [[carapace]] at the front end, and a long, slender abdomen.<ref name="Light">{{cite book |author=Denton Belk |chapter=Branchiopoda |editor1=Sol Felty Light |editor2=James T. Carlton |year=2007 |title=The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon |edition=4th |publisher=[[University of California Press]] |isbn=978-0-520-23939-5 |pages=414–417 |chapter-url=https://books.google.com/books?id=64jgZ1CfmB8C&pg=PA417}}</ref> This gives them a similar overall shape to a [[tadpole]], from which the [[common name]] ''tadpole shrimp'' derives.<ref name="Light"/> The carapace is dorso-ventrally flattened, smooth, and bears no [[rostrum (anatomy)|rostrum]]; it includes the head, and the two sessile [[compound eye]]s are located together on top of the head.<ref name="Light"/> The two pairs of [[antenna (biology)|antennae]] are much reduced, with the second pair sometimes missing altogether.<ref name="Lowry"/> The [[arthropod mouthparts|mouthparts]] comprise a pair of uniramous [[Mandible (arthropod mouthpart)|mandibles]] and no maxillipeds.<ref name="Lowry"/>

[[File:Triops australiensis belly.jpg|thumb|left|The ventral side of ''Triops australiensis'', showing the many pairs of phyllopodous legs]]
The trunk consists of three regions; thorax I, thorax II and the abdomen. Thorax I is made up of 11 segments, each with a pair of well-developed [[arthropod leg|limbs]] and the genital opening on the eleventh segment. In the female, it is modified to form a "brood pouch".<ref name="Pennak"/> The first one or two pairs of legs differ from the remainder, and probably function as sensory organs.<ref name="Pennak">{{cite book |author=Douglas Grant Smith |year=2001 |title=Pennak's freshwater invertebrates of the United States: Porifera to Crustacea |edition=4th |publisher=[[John Wiley and Sons]] |isbn=978-0-471-35837-4 |url=https://books.google.com/books?id=GqIctb8IqPoC&pg=PA431}}</ref>

The somites on thorax II are fused into "rings", which varies in number between species and gender and appear to be [[Segmentation (biology)|body segments]], but do not always reflect the underlying segmentation.<ref name="Light"/> Each ring is made up of 2–6 complete or partial fused segments, and the number of legs on each body ring match its number of segments.<ref>[https://academic.oup.com/book/38957/chapter-abstract/350633934?redirectedFrom=fulltext&login=false Evolution and Phylogeny of Pancrustacea: A Story of Scientific Method - 44. Notostraca and Allies (Calmanostraca)]</ref><ref name="Light"/> The legs become progressively smaller posteriorly,<ref name="Pennak"/> with the last segments being legless.<ref name="Light"/>

The limbless abdomen ends in a [[telson]] and a pair of long, thin, multi-articulate [[Caudal ramus|caudal rami]].<ref>{{cite book |title=The Invertebrata |edition=4th |year=1961 |publisher=[[Cambridge University Press]] |chapter=Subclass 1. Branchiopoda |pages=368–375 |chapter-url=https://books.google.com/books?id=7FM8AAAAIAAJ&pg=PA373}}</ref> The form of the telson varies between the two genera: in ''[[Lepidurus]]'', a rounded projection extends between the caudal rami, while in ''[[Triops]]'' there is no such projection.<ref name="Light"/>