Editing Cephalothorax (section)

{{short description|Arthropod tagma}}
{{for|cephalothoracic humans|Headless men}}
[[File:General malacostracan en.svg|thumb|''[[Bauplan]]'' of a [[malacostraca]]n; the '''cephalothorax''' is the region including cephalon and thorax, marked in yellow.|upright=1.2]]
The '''cephalothorax''', also called '''prosoma''' in some groups, is a [[Tagma (biology)|tagma]] of various [[arthropod]]s, comprising the head and the [[Thorax (arthropod anatomy)|thorax]] fused together, as distinct from the [[Abdomen#Arthropoda|abdomen]] behind.<ref name="Biology">{{cite book |author=Eldra Pearl Solomon, Linda R. Berg & Diana W. Martin |year=2004 |title=Biology |edition=7th |publisher=[[Cengage Learning]] |isbn=978-0-534-49276-2 |chapter=The animal kingdom: an introduction to animal diversity |pages=534–549 |chapter-url=https://books.google.com/books?id=UCUxpgfcoNsC&pg=PA573}}</ref> (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cephalothorax'' and ''abdomen'' in some groups. The terms ''prosoma'' and ''opisthosoma'' may be preferred by some researchers in cases such as arachnids, where there is neither fossil nor embryonic evidence animals in this class have ever had separate heads and thoraxes, and where the ''opisthosoma'' contains organs atypical of a true ''abdomen'', such as a heart and respiratory organs.<ref>{{cite book |author=Shultz, Stanley; Shultz, Marguerite |year=2009 |title=The Tarantula Keeper's Guide |publisher=Barron's |pages=23 |isbn=978-0-7641-3885-0}}</ref>) The word ''cephalothorax'' is derived from the [[Greek language|Greek]] words for head ({{lang|el|[[:wikt:κεφαλή|κεφαλή]]}}, ''{{lang|el|kephalé}}'') and thorax ({{lang|el|θώραξ}}, ''{{lang|el|[[:wikt:thorax|thórax]]}}'').<ref>{{cite book |author=Timothy J. Gibb & C. Y. Oseto |year=2006 |title=Arthropod Collection and Identification: Field and Laboratory Techniques |publisher=[[Academic Press]] |isbn=978-0-12-369545-1 |chapter=Glossary |chapter-url=https://books.google.com/books?id=qwO-9ElVPlMC&pg=PT180}}</ref> This fusion of the head and thorax is seen in [[Chelicerata|chelicerates]] and [[crustacean]]s; in other groups, such as the [[Hexapoda]] (including [[insect]]s), the head remains free of the thorax.<ref name="Biology"/> In [[horseshoe crab]]s and many [[crustacean]]s, a hard shell called the [[carapace]] covers the cephalothorax.<ref>{{cite book |author=Andrew J. Martinez |year=2003 |title=Marine Life of the North Atlantic: Canada to New England |edition=3rd |publisher=[[Aqua Quest Publications]] |isbn=978-1-881652-32-8 |chapter=Arthropoda (crabs, shrimps, lobsters) |pages=144–175 |chapter-url=https://books.google.com/books?id=dq-iIBVn4_MC&pg=PA144}}</ref>