Eubrachyura

{{Short description|Group of crabs}}

{{Automatic taxobox

| fossil_range = {{fossil_range|Cretaceous|recent}}

| image = Liocarcinus_vernalis.jpg

| image_caption = Liocarcinus vernalis

| taxon = Eubrachyura

| authority = de Saint Laurent, 1980

| subdivision_ranks = Subsections {{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 |archiveurl=https://web.archive.org/web/20110606064728/http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf |archivedate=2011-06-06 }}

| subdivision =

• Heterotremata
• Thoracotremata

}}

Eubrachyura is a group of decapod crustaceans (ranked as a "section") comprising the more derived crabs. It is divided into two subsections, based on the position of the genital openings in the two sexes. In the Heterotremata, the openings are on the legs in the males, but on the sternum in females, while in the Thoracotremata, the openings are on the sternum in both sexes. This contrasts with the situation in other decapods, in which the genital openings are always on the legs. Heterotremata is the larger of the two groups, containing the species-rich superfamilies Xanthoidea and Pilumnoidea and all the freshwater crabs (Gecarcinucoidea, Potamoidea). The eubrachyura is well known for actively and constantly building its own burrows.{{cite journal|journal=Raffles Bulletin of Zoology |year=2008 |volume=17 |pages=1–286 |title=Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world |author=P. K. L. Ng, D. Guinot & P. J. F. Davie |url=http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |url-status=dead |archiveurl=https://web.archive.org/web/20110606061453/http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |archivedate=2011-06-06 }} The fossil record of the Eubrachyura extends back to the Cretaceous;{{Cite web|url=https://gsa.confex.com/gsa/2012AM/webprogram/Paper212659.html|title = Evolution of Primitive Crabs: Insights from the Neotropics|date = 6 November 2012}} the supposed Bathonian (Middle Jurassic) representative of the group, Hebertides jurassica,{{cite journal |title=Hebertides jurassica n. gen., n. sp. (Crustacea, Decapoda, Brachyura) from the Middle Jurassic (Bathonian) of Normandy (France) |author1=Danièle Guinot |author2=Antonio de Angeli |author3=Alessandro Garassino |journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano |year=2007 |volume=148 |issue=2 |pages=241–260}} ultimately turned out to be Cenozoic in age.{{cite journal |title=The Cenozoic age of the supposed Jurassic crab Hebertides jurassica Guinot, De Angeli & Gerassino, 2007 (Crustacea, Decapoda, Brachyura) |author1=Paul D. Taylor |author2=G. Breton |author3=Danièle Guinot |author4=Antonio de Angeli |author5=Alessandro Garassino |journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano |year=2012 |volume=153 |issue=1 |pages=71–83 |doi=10.4081/nhs.2012.71 |doi-access=free }}

Here is a cladogram showing Eubrachyura's placement within Brachyura, as well as the two subgroups Heterotremata and Thoracotremata:{{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 |pmid=31014217 |pmc=6501934 |doi-access=free }}{{cite journal |title=Evolutionary History of True Crabs (Crustacea: Decapoda: Brachyura) and the Origin of Freshwater Crabs |author1=Ling Ming Tsang |author2=Christoph D. Schubart |author3=Shane T. Ahyong |author4=Joelle C.Y. Lai |author5=Eugene Y.C. Au |author6=Tin-Yam Chan |author7=Peter K.L. Ng |author8=Ka Hou Chu |journal=Molecular Biology and Evolution |publisher=Oxford University Press |volume=31 |issue=5 |year=2014 |pages=1173–1187 |doi=10.1093/molbev/msu068 |pmid=24520090 |doi-access=free}}

{{clade| style=font-size:85%; line-height:85%

|label1=Brachyura

|1={{clade

|1=Dromiacea

|2={{clade

|1={{clade

|1=Raninoida

|2=Cyclodorippoida }}

|label2=Eubrachyura

|2={{clade

|1=Heterotremata

|2=Thoracotremata }} }} }} }}