Pygocephalomorpha

{{Short description|Extinct order of crustaceans}}

{{automatic taxobox

| fossil_range = {{fossil range|Famennian|Early Permian}}

| image = Mangrullo Formation pygocephalomorph fossils.jpg

| image_caption = Fossil specimens of Hoplita ginsburgi

| image2 = Tealliocaris etheridgii.png

| image2_caption = Life restoration of Tealliocaris etheridgii

| taxon = Pygocephalomorpha

| authority = Beurlen, 1930

| subdivision_ranks = Families

| subdivision = *Jerometichenoriidae

• Notocarididae
• Pygocephalidae
• Tealliocarididae
• Tylocarididae

}}

The order Pygocephalomorpha is an extinct group of peracarid crustaceans. Pygocephalomorpha appeared in the Late Devonian,{{Cite journal |last=Gueriau |first=Pierre |last2=Charbonnier |first2=Sylvain |last3=Clément |first3=Gaël |date=2014 |title=First decapod crustaceans in a Late Devonian continental ecosystem |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12111 |journal=Palaeontology |language=en |volume=57 |issue=6 |pages=1203–1213 |doi=10.1111/pala.12111 |issn=1475-4983}} were abundant from the Carboniferous era until their extinction in the Early Permian era.{{cite book |editor=Elva Escobar-Briones, Fernando Alvarez |year=2002 |title=Modern approaches to the study of Crustacea |publisher=Springer |isbn=978-0-306-47366-1 |chapter=Habitat specialization and its relation to conservation policy in Crustacea |author=Marjorie L. Reaka-Kudla |pages=211–221 |chapter-url=https://books.google.com/books?id=H_u6HHgd2bMC&pg=PA215}}{{Cite journal |last=Pazinato |first=Paula Giovana |last2=Soares |first2=Marina Bento |last3=Adami-Rodrigues |first3=Karen |date=2016 |title=Systematic and palaeoecological significance of the first record of Pygocephalomorpha females bearing oöstegites (Malacostraca, Peracarida) from the lower Permian of southern Brazil |url=https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12260 |journal=Palaeontology |language=en |volume=59 |issue=6 |pages=817–826 |doi=10.1111/pala.12260 |issn=1475-4983}}

This group constituted part of the freshwater and aquatic crustacean assemblages. The carapace is relatively axially shortened, with a prominent gastric region. Laterally, a cervical groove is visible, with carapace margins which is defined by an acute spine or process, including a somewhat well developed branchiostegites"{{Cite journal |last=Jones, Feldmann, Schweitzer, Reitano, Insacco |first=Wade , Rodney, Carrie , Agatino , Gianni |date=1 September 2015 |title=New Pygocephalomorph (Peracarida) from the Permian of the Sosio Valley (Sicily, Italy) |doi=10.1163/1937240X-00002367 |journal=Journal of Crustacean Biology |volume=35 |issue=5 |pages=627–632 |via=Oxford Academic}}