Editing Jurassic (section)

==== Crustaceans ====
[[File:Eryon cuvieri Solnhofen.jpg|thumb|''[[Eryon]],'' a [[polychelida]]n decapod crustacean from the Late Jurassic of Germany.]]
The Jurassic was a significant time for the evolution of [[Decapoda|decapods]].<ref name="Klompmaker-2013" /> The first true crabs ([[Crab|Brachyura]]) are known from the Early Jurassic, with the earliest being ''[[Eocarcinus|Eocarcinus praecursor]]'' from the early Pliensbachian of England, which lacked the crab-like morphology ([[carcinisation]]) of modern crabs,<ref>{{Cite journal|last=Scholtz|first=Gerhard|date=November 2020|title=Eocarcinus praecursor Withers, 1932 (Malacostraca, Decapoda, Meiura) is a stem group brachyuran|journal=Arthropod Structure & Development|language=en|volume=59|pages=100991|doi=10.1016/j.asd.2020.100991|pmid=32891896|doi-access=free|bibcode=2020ArtSD..5900991S }}</ref> and [[Eoprosopon|''Eoprosopon klugi'']] from the late Pliensbachian of Germany, which may belong to the living family [[Homolodromiidae]].<ref>{{Cite journal|last1=Schweitzer|first1=Carrie E.|last2=Feldmann|first2=Rodney M.|date=2010-05-01|title=The Oldest Brachyura (Decapoda: Homolodromioidea: Glaessneropsoidea) Known to Date (Jurassic)|journal=Journal of Crustacean Biology|volume=30|issue=2|pages=251–256|doi=10.1651/09-3231.1|s2cid=84707572|issn=0278-0372|doi-access=free|bibcode=2010JCBio..30..251F }}</ref> Most Jurassic crabs are known only from [[carapace]] pieces, which makes it difficult to determine their relationships.<ref name="Guinot-2019">{{Cite journal|last=Guinot|first=Danièle|date=2019-11-14|title=New hypotheses concerning the earliest brachyurans (Crustacea, Decapoda, Brachyura)|journal=Geodiversitas|volume=41|issue=1|pages=747|doi=10.5252/geodiversitas2019v41a22|s2cid=214220075|issn=1280-9659|doi-access=free|bibcode=2019Geodv..41..747G }}</ref> While rare in the Early and Middle Jurassic, crabs became abundant during the Late Jurassic as they expanded from their ancestral silty sea floor habitat into hard substrate habitats like reefs, with crevices in reefs providing refuge from predators.<ref name="Guinot-2019" /><ref name="Klompmaker-2013" /> [[Hermit crab]]s also first appeared during the Jurassic, with the earliest known being ''[[Schobertella|Schobertella hoelderi]]'' from the late Hettangian of Germany.<ref>{{Cite journal|last1=Fraaije|first1=René|last2=Schweigert|first2=Günter|last3=Nützel|first3=Alexander|last4=Havlik|first4=Philipe|date=2013-01-01|title=New Early Jurassic hermit crabs from Germany and France|journal=Journal of Crustacean Biology|language=en|volume=33|issue=6|pages=802–817|doi=10.1163/1937240X-00002191|issn=0278-0372|doi-access=free|bibcode=2013JCBio..33..802F }}</ref> Early hermit crabs are associated with ammonite shells rather than those of gastropods.<ref>{{Cite journal|last=Mironenko|first=Aleksandr|date=January 2020|title=A hermit crab preserved inside an ammonite shell from the Upper Jurassic of central Russia: Implications to ammonoid palaeoecology|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|language=en|volume=537|pages=109397|doi=10.1016/j.palaeo.2019.109397|bibcode=2020PPP...53709397M|doi-access=free}}</ref> [[Glypheidea|Glypheids]], which today are only known from two species, reached their peak diversity during the Jurassic, with around 150 species out of a total fossil record of 250 known from the period.<ref>{{Cite journal|last1=Bracken-Grissom|first1=Heather D.|last2=Ahyong|first2=Shane T.|last3=Wilkinson|first3=Richard D.|last4=Feldmann|first4=Rodney M.|last5=Schweitzer|first5=Carrie E.|last6=Breinholt|first6=Jesse W.|last7=Bendall|first7=Matthew|last8=Palero|first8=Ferran|last9=Chan|first9=Tin-Yam|last10=Felder|first10=Darryl L.|last11=Robles|first11=Rafael|date=2014-07-01|title=The Emergence of Lobsters: Phylogenetic Relationships, Morphological Evolution and Divergence Time Comparisons of an Ancient Group (Decapoda: Achelata, Astacidea, Glypheidea, Polychelida)|url=https://academic.oup.com/sysbio/article/63/4/457/2847939|journal=Systematic Biology|language=en|volume=63|issue=4|pages=457–479|doi=10.1093/sysbio/syu008|pmid=24562813|issn=1063-5157|doi-access=free}}</ref> Jurassic barnacles were of low diversity compared to present,<ref>{{Cite journal|last1=Chan|first1=Benny K K|last2=Dreyer|first2=Niklas|last3=Gale|first3=Andy S|last4=Glenner|first4=Henrik|last5=Ewers-Saucedo|first5=Christine|last6=Pérez-Losada|first6=Marcos|last7=Kolbasov|first7=Gregory A|last8=Crandall|first8=Keith A|last9=Høeg|first9=Jens T|date=2021-02-25|title=The evolutionary diversity of barnacles, with an updated classification of fossil and living forms|journal=Zoological Journal of the Linnean Society|volume=193|issue=3|pages=789–846|doi=10.1093/zoolinnean/zlaa160|issn=0024-4082|doi-access=free|hdl=11250/2990967|hdl-access=free}}</ref> but several important evolutionary innovations are known, including the first appearances of calcite shelled forms and species with an epiplanktonic mode of life.<ref>{{Cite journal|last1=Gale|first1=Andy|last2=Schweigert|first2=Günter|date=January 2016|editor-last=Hautmann|editor-first=Michael|title=A new phosphatic-shelled cirripede (Crustacea, Thoracica) from the Lower Jurassic (Toarcian) of Germany – the oldest epiplanktonic barnacle|journal=Palaeontology|language=en|volume=59|issue=1|pages=59–70|doi=10.1111/pala.12207|bibcode=2016Palgy..59...59G |s2cid=128383968 |doi-access=free}}</ref>