Astacidea

{{Automatic taxobox

| fossil_range = {{fossil range|279|0}} Middle Permian - present

| image = RNK jastog.jpg

| image_caption = Adriatic lobster

| image2 = Austropotamobius pallipes.jpg

| image2_caption = Crayfish: Austropotamobius pallipes

| display_parents = 2

| taxon = Astacidea

| authority = Latreille, 1802

| subdivision_ranks = Superfamilies

| subdivision = *Astacoidea

}}

Astacidea is an infraorder of decapod crustaceans including lobsters (though not "lobsters" such as the spiny lobster etc.), crayfish, and their close relatives.

Description

The Astacidea are distinguished from most other decapods by the presence of chelae (claws) on each of the first three pairs of pereiopods (walking legs), the first of which is much larger than the remaining two pairs.{{cite book |author=Gary Poore |year=2004 |title=Marine Decapod Crustacea of Southern Australia: a Guide to Identification |publisher=CSIRO Publishing |isbn=9780643099258 |chapter=Astacidea – scampi & crayfish |pages=159–167}} The last two pairs of pereiopods are simple (without claws), except in Thaumastocheles, where the fifth pereiopod may have "a minute pincer".{{cite book |url=ftp://ftp.fao.org/docrep/fao/009/t0411e/t0411e04.pdf |title=FAO species catalogue Vol. 13: Marine Lobsters of the World |author=Lipke Holthuis |author-link=Lipke Holthuis |publisher=Food and Agriculture Organization |location=Rome, Italy |year=1991 |isbn=92-5-103027-8 |chapter=Infraorder Astacidea Latreille, 1802 |pages=19–86}}

Distribution

Members of the infraorder Astacidea are found throughout the world – both in the oceans and in fresh water – except for mainland Africa and parts of Asia.{{cite web |url=http://www.crustacea.net/crustace/www/astacid.htm |archive-url=https://web.archive.org/web/20080705112826/http://crustacea.net/crustace/www/astacid.htm |archive-date=July 5, 2008 |title=Astacidea (Decapoda, Eucarida, Malacostraca) |work=Crustacea, the Higher Taxa |author=J. K. Lowry |date=October 2, 1999 |publisher=Australian Museum |access-date=October 24, 2012}}

Classification

Astacidea belongs to the group Reptantia, which consists of the walking/crawling decapods (lobsters and crabs).{{Cite book|last1=Yeo|first1=Darren|title=Advances in Freshwater Decapod Systematics and Biology|last2=Cumberlidge|first2=Neil|last3=Klaus|first3=Sebastian|publisher=BRILL|year=2014|isbn=9789004207615}} Astacidea is the sister clade to the infraorder Polychelida, a small group of crustaceans restricted to deep waters. The cladogram below shows Astacidea's placement within the larger order Decapoda, from analysis by Wolfe et al., 2019.{{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 }}

The infraorder Astacidea comprises five extant superfamilies, two of crayfish (Astacoidea and Parastacoidea), one of true lobsters (Nephropoidea), one of reef lobsters (the genus Enoplometopus), and a number of fossil taxa.{{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 |access-date=2010-02-22 |archive-date=2011-06-06 |archive-url=https://web.archive.org/web/20110606064728/http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf |url-status=dead }} {{As of|2009}}, the group contains 782 recognised species, over 400 of which are in the crayfish family Cambaridae. The members of the infraorder Glypheidea (containing numerous fossils and the two extant species Neoglyphea inopinata and Laurentaeglyphea neocaledonica) were formerly included here.

The cladogram below shows Astacidea's internal relationships and the early split between lobsters and crayfish:{{Cite journal| title = An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list| date = 2017| last1 = Crandall | first1 = Keith A.| last2 = De Grave | first2 = Sammy| journal = Journal of Crustacean Biology| volume = 37| issue = 5| pages = 615–653| doi = 10.1093/jcbiol/rux070| doi-access = free}}{{cite journal| author1=Heather D. Bracken-Grissom |author2=Shane T. Ahyong |author3=Richard D. Wilkinson |author4=Rodney M. Feldmann |author5=Carrie E. Schweitzer |author6=Jesse W. Breinholt |author7=Matthew Bendall |author8=Ferran Palero |author9=Tin-Yam Chan |author10=Darryl L. Felder |author11=Rafael Robles |author12=Ka-Hou Chu |author13=Ling-Ming Tsang |author14=Dohyup Kim |author15=Joel W. Martin |author16=Keith A. Crandall |title=The Emergence of Lobsters: Phylogenetic Relationships, Morphological Evolution and Divergence Time Comparisons of an Ancient Group (Decapoda: Achelata, Astacidea, Glypheidea, Polychelida) |journal=Systematic Biology |date=July 2014 |volume=63 |issue=4 |pages=457–479 |doi=10.1093/sysbio/syu008 |doi-access= |pmid=24562813 }}

{{clade

|label1=Astacidea

|1={{clade

|label1=clawed lobsters

|1={{clade

|label1=Enoplometopoidea

|1=Enoplometopidae

|label2=Nephropoidea

|2=Nephropidae }}

|label2=crayfish

|2={{clade

|label1=Parastacoidea