Cyamocephalus

{{Short description|Extinct genus of chelicerate}}

{{Automatic taxobox

| name = Cyamocephalus

| taxon = Cyamocephalus

| fossil_range = {{fossil range|Silurian}}

| image = 20200814 Cyamocephalus loganensis.png

| image_caption = Reconstruction of Cyamocephalus loganensis

| display_parents = 3

| authority = Currie, 1927

| type_species = †Cyamocephalus loganensis

| type_species_authority = Currie, 1927

}}

Cyamocephalus is a genus of synziphosurine,{{Cite journal|last=Anderson|first=Lyall I.|date=1999-01-01|title=A new specimen of the Silurian synziphosurine arthropod Cyamocephalus|url=http://www.sciencedirect.com/science/article/pii/S0016787899800716|journal=Proceedings of the Geologists' Association|language=en|volume=110|issue=3|pages=211–216|doi=10.1016/S0016-7878(99)80071-6|bibcode=1999PrGA..110..211A|issn=0016-7878}} a paraphyletic group of fossil chelicerate arthropods.{{Cite journal|last1=Bicknell|first1=Russell D. C.|last2=Pates|first2=Stephen|date=2020|title=Pictorial Atlas of Fossil and Extant Horseshoe Crabs, With Focus on Xiphosurida|journal=Frontiers in Earth Science|language=en|volume=8|page=98|doi=10.3389/feart.2020.00098|bibcode=2020FrEaS...8...98B|issn=2296-6463|doi-access=free}} Cyamocephalus was regarded as part of the clade Planaterga.{{Cite journal|last1=Selden|first1=Paul A.|last2=Lamsdell|first2=James C.|last3=Qi|first3=Liu|title=An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China|url=https://www.academia.edu/14633144|journal=Zoologica Scripta|year=2015|volume=44|issue=6|pages=645–652|doi=10.1111/zsc.12124|s2cid=55264483|issn=0300-3256|doi-access=free}}{{Cite journal|last1=Lamsdell|first1=James C.|last2=Briggs|first2=Derek E. G.|last3=Liu|first3=Huaibao P.|last4=Witzke|first4=Brian J.|last5=McKay|first5=Robert M.|date=2015|title=A new Ordovician arthropod from the Winneshiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspidids|url=https://www.researchgate.net/publication/282127302|journal=The Science of Nature|language=en|volume=102|issue=9–10|pages=63|doi=10.1007/s00114-015-1312-5|pmid=26391849|bibcode=2015SciNa.102...63L|s2cid=8153035|issn=0028-1042}}{{Cite journal|last1=Bicknell|first1=Russell D. C.|last2=Lustri|first2=Lorenzo|last3=Brougham|first3=Tom|date=2019-12-01|title=Revision of "Bellinurus" carteri (Chelicerata: Xiphosura) from the Late Devonian of Pennsylvania, USA|journal=Comptes Rendus Palevol|language=en|volume=18|issue=8|pages=967–976|doi=10.1016/j.crpv.2019.08.002|bibcode=2019CRPal..18..967B|issn=1631-0683|doi-access=}} Fossils of the single and type species, C. loganensis, have been discovered in deposits of the Silurian-aged Patrick Burn Formation in Lesmahagow, Scotland (in the United Kingdom). Cyamocephalus is one of the two members of the family Pseudoniscidae, the other being Pseudoniscus.{{cite book|chapter-url=http://www.wsc.nmbe.ch/resources/fossils/Fossils19.0.pdf|title=World Spider Catalog|last1=Dunlop|first1=J. A.|last2=Penney|first2=D.|last3=Jekel|first3=D.|publisher=Natural History Museum Bern|year=2018|chapter=A summary list of fossil spiders and their relatives|pages=1–296}}{{cite journal|last=Lamsdell|first=James C.|year=2013|title=Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura|journal=Zoological Journal of the Linnean Society|volume=167|issue=1|pages=1–27|doi=10.1111/j.1096-3642.2012.00874.x|issn=0024-4082|doi-access=free}} Cyamocephalus differ from Pseudoniscus by the fused tergites of 6th and 7th opisthosomal segments.