Elrathia kingi is a typical ptychopariid
Elrathia kingi

ORDER PTYCHOPARIIDA

The Order Ptychopariida (yellow) arises as early as the Redlichiida and gives rise to several other orders before ending in the late Ordovician.

AGNOSTIDA | ASAPHIDA PTYCHOPARIIDA | HARPETIDA | PROETIDA | REDLICHIIDA | PHACOPIDA | LICHIDA | CORYNEXOCHIDA


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pictorial guide

Modocia
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ORDER PTYCHOPARIIDA
last revised 23 February 2009 by S. M. Gon III

Introduction: A large, heterogenous order with primitive origins and problematic classification, with specialized offshoots that are hard to frame within a general diagnosis. 
Cephalon: typically with opisthoparian facial sutures, with gently forward-tapering simple glabella bearing a broad, rounded front, usually with 3 pairs of rather narrow parallel glabellar furrows; natant hypostome.
Thorax: typically large with 8+ thoracic segments.
Pygidium: quite variable, but typically with a small pygidium bearing a border (Cambrian) or a larger pygidium with or without border (post-Cambrian). 
Occurrence: Lower Cambrian to Upper Ordovician.
Suborders: Ptychopariina, Olenina, (formerly also included Harpina, which is now treated as a full Order Harpetida).


 
 
 
 
 
 
 
 
 
 
 
 
 

Ellipsocephaloidea
Ellipsocephalidae
Ellipsocephalus

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 Ellipsocephalidae
Lermontovia

.Yunnanocephalidae
Yunnanocephalus

 
 
 
 
 
 
 
 
 
 
   
 

Ptychoparioidea
Alokistocaridae
Elrathia


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Menomoniidae
Menomonia


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Norwoodiidae
Norwoodia

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Tricrepicephalidae
Tricrepicephalus

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Conocoryphidae
Conocoryphe


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Marjumiidae
Modocia


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Suborder Ptychopariina

Introduction: Primitive Ptychopariida, a large and extremely varied group. 
Cephalon: glabella usually tapering with 3 pairs of glabellar furrows, sutures typically opisthoparian (but some proparian, and blind forms marginal); anterior sutures usually convergent to slightly divergent, posterior sections moderately to highly divergent; eyes usually present, medial, and near glabella; usually blade-like genal spines present. 
Thorax: generally long, relative to pygidium. 
Pygidium: variable, but typically smaller than thorax.
Superfamilies: Ellipsocephaloidea, Ptychoparioidea (see below)
Families: (listing those for which suborder assignment is uncertain) Ityophoridae, Catillicephalidae, Raymondinidae, Avoninidae, Plethopeltidae.

Superfamily Ellipsocephaloidea
Cephalon: glabella tapering forward, or subparallel or slightly expanding forward; up to 5 pairs of lateral furrows, eye ridges present.
Thorax: generally 12-16 thoracic segments.
Pygidium: small, unremarkable.
Other: includes some of the oldest trilobites in the fossil record (members of the Bigotinidae).
Families and Genera: Agraulidae: Agasella, Agaso, Agraulos (/Arion; /Arionius; =/Arionides /Arionellus; =Agrauloides), Batenoides, Chittidilla (=Diandongaspidella /Diandongaspis), Chondroparia, Clemenella, Conagraulos, Elankaspis, Lenagraulos, Litavkaspis, Metagraulos, Micragraulos, Mungyongia, Parachittidilla (=Amurticephalus), Paragraulos, Paraplesiagraulos, Phymaspis, Plesiagraulos, Poriagraulos, Proampyx, Protochittidilla, Pseudoeteraspis, Pseudoplesiagraulos, Qiannanagraulos, Shahaspis, Skreiaspis, Stembergaspis, Taiganella, Tetragonocephalus, Tholus, Tianjingshania, Veragraulos, Wutaishania.


Aldonaiidae: Aldonaia, Granutaspis, Ideria, Perissopyge, Planaspis, Pumilina, Repinaspis, Tuvanella (=Eleganolimba), Tuvanellus, Volonellus.
Bigotinidae: Bigotina, Bigotinella, Bigotinops, Bulaiaspis, Hupetina, Neobigotina, Ouijjania, Pruvostina, Serrania.
Chengkouiidae: Acanthomicmacca (=Chengkouia; =Jaskovitchella; =Myopsomicmacca), Bidjinella, Changyangia, Micmacca, Turkestanella, Wenganella, Xiuqiella, Zacanthellina, Zhenbaspis (=Yankongia; =Zhenxiongaspis).
Ellipsocephalidae: Acadolenus, Alueva, Antatlasia, Argunaspis, Asiatella, Bergeroniaspis, Bergeroniellus, Blayacina, Brevitermierella (=Paratermierella), Cambrunicornia, Catadoxides, Charaulaspis, Chorbusulina, Comluella, Culmenaspis, Ellipsocephalus (=Germaropyge), Ellipsostrenua, Glabrella, Hamatolenus, Hupeolenus, Issafeniella, Kadyella, Kameschkoviella, Kijanella, Kingaspidoides (=Elatius), Kingaspis (=Mesetaia), Krolina, Kymataspis, Latikingaspis, Latouchia, Latuzella, Lermontovia, Limataceps, Limouolenus, Lotzeia, Lusatiops (= Jalonella), Mohicana, Myopsolenus (=Collyrolenus), Myopsostrenua, Nelegeria, Olekmaspis, Ornamentaspis, Orodes, Ourikaia, Paramicmacca, Paraprotolenella, Pauliceps, Planolimbus, Protagraulos, Protaldonaia, Protolenella, Protolenus (/Bergeronia; =Matthewlenus), Pruvostinoides, Pseudoasiatella, Pseudokadyella, Pseudolenus, Pseudoprotolenella, Ptychoparopsis (=Berabichia), Rinconia, Sailycaspis, Sectigena, Strenuaeva (=Hindermeyeria), Strenuella, Tadakoustia, Termieraspis, Termierella, Thoralaspis, Timnaella, Triangulaspis (=Acutaspis; =Angustaeva; =Plenudiscus; =Triangullina), Yeshanaspis.
Estaingiidae: Alanisia, Chulanolenus, Coreolenus, Eomalungia, Estaingia (=Hsuaspis, =Pseudichangia; =Zhuxiella; =Sematiscus; =Strenax), Hupeia, Ichangia, Longmenshania, Longxianaspis, Madianaspis, Mundocephalina, Ningxiaspis, Olekinanellus, Paraichangia, Pararaia (=Proichangia; =Tannuolaspis), Protolenoides, Shangsiaspis, Shifangia, Shiqihepsis, Sichuanolenus, Subeia, Szechuanolenus, Yinshanaspis.
Palaeolenidae: Alataurus, Bajangoliaspis, Enammocephalus, Ferralsia, Gigoutella, Hybrocephalus, Hoffetella, Latipalaeolenus, Megapalaeolenus, Palaeolenella, Palaeolenides, Palaeolenus, Resimopsis, Schistocephalus, Torgaschina, Ulakhanella, Validaspis.
Yunnanocephalidae: Elicicola, Luaspis, Pensacola, Wangzishia, Wenganlenus, Yunnanocephalus (/Pseudoptychoparia).

Superfamily Ptychoparioidea
Cephalon: typically with well-defined border, glabella tapering forward, preglabellar field present, opisthoparian sutures, natant hypostome, and genal spines; but exceptions include eyeless forms (Conocoryphidae), proparian forms (Norwoodiidae), rounded genal angles and gonatoparian sutures (Menomoniidae).
Thorax: typically 12-17 segments.
Pygidium: typically micropygous, transverse, pleural field nearly flat, with distinct pleural grooves; but exceptionally isopygous (e.g., some Asaphiscidae, Cooselidae).
Families and Genera: Acrocephalitidae HUPE, 1953
Acrocephalella, Acrocephalinella, Acrocephalites (=Acantholenus), Acrodirotes, Afghancephalites, Asturiaspis, Brutaspis, Cermataspis, Decus, Diceratocephalina, Elatilimbus, Ijacephalus, Kepisis, Mansiella, Pseudacrocephalaspina, Siligerites, Toxotina, Trifonella.


Alokistocaridae: Alokistocare (=Pseudoalokistocare), Alokistocarella, Alokistocaropsis, Altiocculus, Amecephalina, Amecephaloides, Amecephalus (=Strotocephalus), Annamitia, Arcadiaspis, Arellanella, Atopiaspis, Beldirella, Binella, Bythicheilus, Chancia, Chanciaopsis, Danzhaiaspis, Diaoyaspis, Ehmania, Ehmaniella (=Anomalocephalus; =Clappaspis), Elrathia, Elrathiella (=Coelaspis; =Glossocoryphus), Eokaotaia, Erdoradites, Furia, Ganovexopyge (/Scottia), Huochengella, Inglefieldia, Jenkinsonia, Kailiella, Kaotaia, Katunicare, Kistocare, Langqia, Lenacare, Nelgakia, Parapachyaspis, Parehmania (=Mcnairia; =Rowia; =Thompsonaspis), Pedinocephalina, Peregrinaspis, Plesiamecephalus, Proehmaniella, Proveedoria, Pseudomexicella, Schopfaspis, Trachycheilus, Tympanuella, Utaspis.


Antagmidae: Antagmella, Antagmus, Bagradia, Bicella, Bilimbataia, Cambrophatictor, Crassifimbra, Cyphambon, Erzishania (=Oreisator), Houmengia, Katunia, Lennontoviella, Longshania, Luaspides, Mantoushania, Onchocephalina, Onchocephalus (=Litocodia), Paraantagmus, Periomma, Plesioperiomma, Shilengshuia, Sombrerella, Wanbeiaspis, Xiangqianaspis, Xiaofangshangia, Xiaomajiella, Yuehsienszella.
Asaphiscidae: Anomocarellius, Asaphiscus, Blainia, Blainiopsis, Blountiella, Blountina, Canotiana (=Williamsina), Cinnella, ?Conoides, Dunderburgella, Edithiella, Eoasaphiscus HAJRULLINA, Eokaninia (/Kaniniella SIVOV), Eoproetus, Erbenia, Eteraspis, Iniotoma, Kaninia (/Kaniniella SIVOV; =Dolgaia), Kaniniella KOBAYASHI, Lioparia (/Lorentzia, /Pseudoliostracina; =Emmrichella; =Liaoyangaspis), Luyanhaoaspis (/Luaspis PENG et al., 1995), Mindycrusta, Paraorlovia, Vega, Verkholenella.
Atopidae: Atopina, Atops (=Ivshiniellus), ?Avalonia, Pseudatops.
Bolaspididae: Acrocephalops, Bolaspidaspis, Bolaspis, Eldoradia, Rawlinsella.
Cedariidae: Bonneterrina (=Holstonia; =Piedmontia), Carinamala, Cedaria, Cedarina, Henadoparia, Jimachongia, Vernaculina.
Changshaniidae: Benxiella, Changshania (=Metachangshania; =Prochangshania), Changshanocephalus, Kazelia (=Kazellina), Mecophyrs, Narinosa, Parachangshania, Paramenomonia, Paraqingshuiheella (=Qingshuiheella), Pseudowentsuia, Suribongia, Wentsuia.
Conocoryphidae: Bailiaspis, Bailiella (=Liaotungia; =Liocephalus; =Tangshihella), Cainatops (=Comucoryphe), Conocoryphe (/Conocephalites; =Conocephalus; =Couloumania), Ctenocephalus, Elyx (/Eryx), Hartella, Parabailiella, Tchaiaspis.
Conokephalinidae: Buitella, Catuniella, Conokephalina (=Lobocephalina; =Ruzickaia/Lobocephalus), Gorskia, Maspakites, Meisteraspis, Meisterella, Miranda, Oirotella, Suludella, Westergaardella.
Crepicephalidae: Bagongshania, Beikuangaspis, Cayupania, Coosella (=Wilsonella), Coosia, Coosina, Coosinoides, Crepicephalina (=Mesocrepicephalus), Crepicephalus, Hsuchuangia, Idioura, Kasatchaspis, Neimonggolaspis, Perforina, Pseudocrepicephalus, Sinocoosella, Sinocrepicephalus, Sneedvillia, Temnoura (=Asteromajia), Tetraceroura, Uncaspis, Zaozhuangaspis.
Diceratocephalidae: Anopocodia, Aulacodigma, Cyclolorenzella, Diceratocephalus, Fenghuangella (=Cyclolorenzellina), Hwangjuella, Jiangnania, Tangshihlingia, Tholifrons (=Paraphoreotropsis), Torifera, Xiangia.
Elviniidae: Chariocephalus, Dartonaspis, Drumaspis, Dunderbergia, Dytremacephalus, Elburgia, Elvinaspis, Elvinia (=Moosia), Elviniella, Elvinioides, Elyaspis, Enshia, Irvingella (=Irvingellina; =Parairvingella; =Komaspis), Jessievillia, Kujandina, Maladioides, Maladiopsis, Megadundabergia, Metisaspina, Onchopeltis, Paraenshia, Parakomaspis, Pesaia, Protemnites (=Prismenaspis), Pseudomaladioides, Pseudosaukia, Qingshuihella, Schmidtaspis, Yunlingia.
Eulomidae: Acrocephalaspina, Altaiaspis, ?Amzasskiella (=Triplacephalus), Archaeuloma, Baikadamaspis, Bilacunaspis, Butyrinia, Crucicephalus, Dolgeuloma (/Rosovaspis/ Pseudoacrocephalites ROSOVA), Duplora, Euduplora, Euloma (=Calymenopsis), Guizhoucephalina, Iveria, Karataspis, Ketyna (=Kujandaspis), Lateuloma, Limpeina, Loparella, Lopeuloma, Luyanhaoia, Miaeuloma, ?Natmus, Pareulorna (=Gansucephalina), Pesaiina, Plecteuloma, Probilacunaspis, Proteuloma (=Mioeuloma), Pseudoacrocephalites MAKSIMOVA, Sanduspis, Spineuloma, Stigmatoa.
Ignotogregatidae: Ignotogregatus.
Inouyiidae: Catinouyia, Eoinouyia, Huainania, Inouyia, Parahuainania, Parainouyia, Parajialaopsis, Parawuania, Plesiowuania, Proinouyia, Pseudinouyia.
Isocolidae: Cyphoniscus, Effnaspis, Hanzhongaspis, Holdenia (/Tiresias), Isocolus (/Astyages), Kielanella, Liangshanocephalus, Paratiresias, Pradesia, Pseudopetigurus, Taimyraspis, Thoralocolus, Triarthroides.
Kingstoniidae: Acheilus CLARK, Ankoura, Blountia (=Homodictya; =Protillaenus; =Stenocombus), Brachyaspidion (/Brachyaspis MILLER, 1936), Bynumia, Bynumina, Calvipelta, Clelandia (/Harrisia; =Bynumiella), Ithycephalus, Kingstonella, Kingstonia (=Ucebia), Kingstonioides, Komaspidella (=Buttsina; =Ataktaspis), Larifugula, Maryvillia, Pugionicauda, Saonella, Shuizuia, Wanwanaspis, Wanwanoglobus, Yanzhuangia.
Lisaniidae: Dazhuia, Eoshcngia (=Baojingia), Extrania, Klimaxocephalus, Lisania (=Aojia), Megalisania, Metalisania, Paralisaniella, Paraojia, Parashengia, Platylisania, Quandraspis, Redlichaspis (=Lisaniella), Rinella, Shengia, Xichuania.
Llanoaspididae: Amquia, Arcuolimbus, Deiracephalus (/Asteraspis), Genevievella (=Placoscma; = Nixonella; =Torridella), Llanoaspidella, Llanoaspis, Metisaspis, Nahannicephalus, Paracedaria (/Pilgrimia), Rogersvillia, Sacha, Stenelymus, Tagenarella.
Lonchocephalidae: Amiaspis, Bolaspidellus, Calymenidius, Caulaspina, Caulaspis, Durinia, Glaphyraspis (=Raaschella), Graciella, Hawkinsaspis (/Hawkinsia), Interalia, Kuraspis, Kuraspoides, Lazarenkiura, Letniites, Lonchocephalus (=Bucksella), Monosulcatina, Neoglaphyraspis, Nordia, Olegaspis, Prolonchocephalus, Pseudotalbotina, Quebecaspis, Raaschellina, Talbotina, Terranovella, Trymataspis, Weeksina.
Lorenzellidae: Damiaoaspis, Eujinnania, Inouyops, Inoyellaspis, Jiangjunshania, Lonchinouyia, Lorenzella, Paralorenzangella (/Paralorenzella Q.Z. ZHANG), Paralorenzella LUO, Paraporilorenzella, Porilorenzella (=Jinnania), Pseudolorenzella, Ptyctolorenzella, Zhongweia.
Mapaniidae: Angsiduoa, Hualongia, Mapania, Mapanopsis, Metanomocarella, Paramapania, Pseudomapania, Quitacetra, Quitalia.
Marjumiidae: Anemocephalops, Crepichilella, Glyphopeltis, Holmdalia, Ithyektyphus, Lecanopleura, Loulania, Marjumia, Modocia (=Armonia; =Metisia; =Perioura; =Semnocephalus), Nasocephalus, Nericella, Nericia, Pearylandia, Petruninaspis, Schyilaspis, Shickshockia, Syspacheilus.
Menomoniidae: Balderia, Biaverta, Bolaspidella (= Deissella; =Howellaspis), Bridgeia, Coenaspis, Coenaspoides, Deltophthalmus, Dresbachia, Hysteropleura (=Apedopyanus), Josina, Knechtelia, Menomonia (=Densonella/Millardia), Tavsenia, Verditerrina.
Nepeidae: Ascionepea, Ferenepea, Folliceps, Loxonepea, Nepea, Penarosa (=Trinepea).
Norwoodiidae: Cedaraspis, Garbiella, Hardyoides (=Norwoodina), Holcacephalus, Levisaspis, Norwoodella, Norwoodia (=Whitfieldina), Paranorwoodia, Xenocheilos.
Papyriaspididae: Badainjaranaspis, Metapianaspis, Papyriaspis, Pianaspis, Prohedinaspis, Prohedinia (=Tosotychia), Sanduhedinaspis, Wandelella, Wangcunia, Wudangia.
Phylacteridae: Aphelotoxon (=Ponumia), Cliffia, Drabia, Phylacterus (=Liostracinoides), Westonaspis. 
Proasaphiscidae: Acanthocephalus Alomataspis, Chelidonocephalus, Dananzhuangaspis, Daopingia, Deltocephalus, Derikaspis, Dignaceps, Eoasaphiscellus (/Eoasaphiscus LU & YUAN), Eymekops (=Kolpura), Farsia, Gangdeeria, Gloria, Grandioculus (/Megalophthalmus; =Honania), Guankouia, Hadraspis, Hatangia, Heukkyoella, Holanshania, Honanaspis, Hsiaoshia, Huaibeia, Hundwarella (=Anomocaraspis), Hunjiangaspis, Iranochresterius, Iranoleesia (/Irania; =Michaspis; =Heyelingella), Itcheriella, Jiangsuaspis, Jiangsucephalus, Jiangsuia, Jiubaspis, Jixianella (/Jixiania), Koptura (=Parakoptura), Kopungiella, Kutsingocephalus, Leichuangia, Lioparella (=Zhuozishania), Luliangshanaspis, Luonanocephalus, Manchuriella, Maotunia, Memmatella, Miaobanpoia, Paofeniellus, Paragangdeeria, Parazhongtiaoshanaspis, Plectrocrania, Plesigangdeeria, Proasaphiscina, Proasaphiscus, Pseudanomocarina, Pseudonericella, Raduginella, Severina, Shanxiella, Shuangshania, Stella, Sudanomocarina, Szeaspis (=Spitiaspis), Tankhella, Tengfengia, Teratokoptura, Tylotaspis, Ulania, Urjungaspis, Wutaishanaspis, Xiangshania, Xinglongia, Yanshania, Yujinia, Zhaishania, Zhongtiaoshanaspis.
Ptychopariidae: Achlysopsis, Altikolia, Altitudella, Amecephalites, Asthenopsis, Austinvillia, Balangcunaspis, Bashania, Bathyholcus, Bathyocos, Billingsaspis, Binodaspis (=Xilingxia), Blairella, Bolaspidina, Brunswickia, Bulkuraspis, Caborcella, Callidaspina, Callidaspis, Cathayanella, Champlainia, Chengshanaspis, Chinghisicus, Chunghwaella, Conopolus, Dananzhuangia, Deltina, Douposiella (=Tongshania), Elrathina, Entsyna, Eodouposiella, Eokochaspis, Eosoptychoparia, Eospencia, Eurostina, Finecrestia, Gaotanaspis, Gaphuraspis, Gedongaspis, Gunnia (=Ellotia; =Yiliangaspis), Hadrocephalites, Hadrokraspedon, Hamptonella, Hejinaspis, Hemicricometopus, Hewenia, Holasaphus, Horbusonia, Illtydaspis, Jangudaspis, Jialaopsis, Jianchangia, Jimaoshania, Jiumenia, Kermanella, Kochaspis (/Palaeocrepicephalus), Kochiella (=Eiffelaspis), Kochiellina, Kochina, Kounamkites, Kunmingaspis (=Benxiaspis), Laminurus, Laoyingshania, Lianglangshania, Loriella, Luguoia, Luxella, Lyriaspis, Majiangia, Manailina, Meitania, Metisella, Mexicella, Monanocephalus, Mopanshania, Mrassina, Mufushania, Nangaocephalus, Nangaoia, Nangaops, Nanoqia, Nassovia, Nelsonia, Neokochina, Nyella, Olenekina, Onchocephalites, Ontoella, Orienturus, Orlovia, Orloviella, Pachyaspidella, Pachyaspis, Palmeraspis, Panacus, Paraeosoptychoparia, Paragunnia, Paramecephalus (=Parahiolites), Paraperiomma, Paraplagiura, Parapoulsenia, Parashuiyuella, Paraziboaspis, Perimetopus, Periommella, Piazella, Pingluaspis, Piochaspis, Plagiura (=Ruichengella; =Plagiurella), Pokrovskayaspis, Poulsenella, Poulsenia, Poulseniella, Probowmania, Probowmaniella (=Proshantungaspis), Probowmanops, Proliostracus, Promeitania, ?Protohedinia, Pseudoliostracus, Psilostracus, Ptychoparella (=Eoptychoparia; =Syspacephalus; =Elrathma), Ptychoparia (=Agraulopsis; =Ptychoparioides), Qiaotouaspis, Qingshuiheia, Reedus, Regina, Regius, Runnania, Salankanaspis, Sanhuangshania, Sanwania, Schistometopus, Semisphaerocephalus, Seriaspis, Shanganella, Shantungaspis, Shuiyuella, Sinoptychoparia, Spencella, Spencia (=Stauroholcus), Stoecklinia, Sujaraspis, Suluktella, Taijiangia, Taniaspidella, ?Townleyella, Trachyostracus, Trigonyangaspis (/Trigonaspis), Tukalandaspis, ?Ulrichaspis, Variopelta, Vermontella, Vica, Volocephalina, Wanhuaia, Weijiaspis, Wuhaina, Xiangshanaspis, Xingrenaspis (=Spitella; = Danzhaina; =Wuxunaspis), Yaoyiayuella, Yohoaspis, Yuknessaspis, Ziboaspidella, Ziboaspis.
Shumardiidae: Acanthopleurella, Changchowilla, Conophrys, Elaphraella, Eoshumardia, Gaoloupingia, Koldinioidia (=Akoldinioidia), Kuruktagaspis, Kweichowilla, Leioshumardia, Leoforteyia, Liriamnica, Parashumardia, Puanocephalus, Shumardia, Shumardoella (/Shumardella), Shumardops, Stigmametopus, Tarimella (=Yinganaspis), Thomondia, Trianguraspis.
Solenopleuridae: Abakanopleura, Acanthometopus, Acrocephalaspis, Aiaiaspis, Aidarella, Aikhaliella, Albansia, Aldanaspis, Badulesia, Bigranulella, Bijelina, Braintreella, Canotaspis, Catasolenopleura, Changqingia (=Austrosinia), Colliceps, Conicephalus, Crusoia, Daldynaspis, Datongites, Denaspis, Eilura, Ejinaspis, Erratojincella, Foveatella, Gonzaloia, Gushanaspis, Herse (/Solenopleurina; =Parasolenopleura WESTERGARD), Huzhuia, Hyperoparia, Jiagouia, Jincella, Kabuqiia, Kaipingella, Karagandoides, Keguqinia, Lashushania, Levisia, Lingyuanaspis, Liosolenopleura, Maiaspis, Manublesia, Markhaspis, Mataninella, Menocephalites (=Parataitzuia), Minupeltis, Mukrania, Munija, Neoacrocephalites, Neosolenopleurella, Nilegna, Ninaspis, Notocoryphe, Paracrocephalites (/Arctaspis), Paramenocephalites (=Solenoparina), Parasolenoparia, Parasolopleurena (/Parasolenopleura POLETAEVA), Parayabeia, Pardailhania, Perneraspis (/Perneria), Pingluia, Plesisolenoparia, Proavus, Protrachoparia, Pseudosolenoparia, Reillopleura, Rimouskia, Rina, Sao (=Acanthocnemis; =Acanthogramma, =Crithias; =Endogramma; =Enneacnemis; =Goniacanthus; =Micropyge; =Monadina; =Monadella; =Selenosema; =Staurogmus; =Tetracnemis), Shanghaiaspis, Sohopleura, Solenoparia, Solenoparops, Solenopleura, Solenopleurella, Solenopleuropsis, Squarrosoella, Suyougouia, Tabalqueia, Tangwangzhaia, Tjungiella, Trachoparia, Usumunaspis, Velieuxia, Wafangdiania, Xianfengia, Yabeia.
Tricrepicephalidae: Erediaspis, Meteoraspis (=Greylockia; = Coleopachys), Prometeoraspis, Tricrepicephalus (/Paracrepicephalus).
Utiidae: Amginouyia, Antagmopleura (=Poljakovia), Chondragrautina, Chondagraulos, Okunevaella, Utia.
Wuaniidae: Eotaitzuia, Houmaia, Inouyella, Jixianaspis, Latilorenzella (=Wuania), Lophodesella, Megagraulos, Pseudosolenopleura, Rencunia, Ruichengaspis, Wuanoides, Wuhushania, Yunmengshania.
Olenus

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Triarthrus

Suborder Olenina

Cephalon: with narrow border, opisthoparian sutures (exceptionally proparian), genal angle rounded or spined, glabella tapering forward with simple, sigmoid, or bifurcate furrows (furrows absent in some forms); librigenae yoked (fused by a narrow strip of cephalic doublure), or rarely, separated by anterior median suture; eyes small to medium, usually with distinct eye ridges.
Thorax: 9-24 segments.
Pygidium: micropygous to subisopygous, with or without marginal spines.
Other: typically with extremely thin cuticle.
Family: Olenidae (subfamilies Leptoplastinae, Oleninae, Triarthrinae, Pelturinae).
Genera: Olenidae: Acerocare, Acerocarina (/Cyclognathus), Aciculolenus, Anaximander, Angelina (=Keidelaspis), Apoplanias, Asilluchus, Baikonuraspis, Balnibarbi, Bienvillia (=Diatemnus; =Mendoparabolina), Boeckaspis (/Boeckia BROGGER; =Sphaerophthalmella), Bondarevites, Bulbolenus, Chekiangaspis, Cloacaspis, Ctenopyge, Cyclognathina, Danarcus, Desmetia, Eoctenopyge, Euonchonotina, Eurycare, Granitzia, Hancrania, Helieranella, Highgatella, Huangshiaspis, Hunanolenus, Hypermecaspis (=Spitsbergaspis), Inkouia (=Agalatus), Isidrella, Jujuyaspis (=Alimbetaspis), Leiobienvillia, Leptoplastides (=Andesaspis; =Beltella; =Chunkingaspis; =Parabolinopsis; =Rampartaspis), Leptoplastus, Leurostega, Magnomma, Mesoctenopyge, Moxomia, Neoolenus, Neoparabolina, Nericiaspis, Olenus (=Simulolenus), Orkekeia, Parabolina (/Odontopyge), Parabolinella, Parabolinina, Parabolinites, Paraolenus, Paraplicatolina, Peltocare, Peltura (/Anthes; =Anopocare), Pelturina, Plicatolina, Plicatolinella, Porterfieldia, Prohedinella, Protopeltura, Psilocara, Remizites, Rhodonaspis, Saltaspis, Shihuigouia, Sphaerophthalmus, Svalbardites, Talbotinella, Triarthrus (/Brongniartia EATON), ?Ullaspis, Westergaardia (=Sphaerophthalmoides), Westergaardites, Wujiajiania.


Cattilicephalidae
Pemphigaspis

Uncertain Suborder or Polyphyletic Families:

Avoninidae: Avonina, Wongia.


Catillicephalidae: Acheilops, Agelagma (?=Paradistazeris), Buttsia, Buttsiella, Catillicephala (/Cephalocoelia), Catillicephalites, Coephalocoeliaspis, Cryptoderaspis, Distazeris, Galeaspis, Lajishanaspis, Madarocephalus, Matania, Onchonotellus (=Onchonotina; =Guotangia; =Seletella), Onchonotopsis, Onchonotus, Pemphigaspis (=Hallaspis), Peracheilus (=Acheilus RAYMOND), Qilianshania, Stenochilina, Theodenisia (/Denisia; =Calculites; =Mannschreekia), Triarthropsis, Tumidulaspis, Tuojiangella, Urbanaspis, Waergangia, Welleraspis (=Avonaspis), Yukonaspis.
Ityophoridae: Frognaspis, Ityophorus.
Plethopeltidae: Arapahoia (=Hesperaspis), Exigua (=Brassicicephalus), Koldinia, Koldiniella, Kuljumbina, Lampropeltis, Leiocoryphe, Meniscocoryphe, Notaiella, Plethopeltides, Plethopeltis (=Plethometopus; =Enontioura), Plethopeltoides (=Kulyumbopeltis), Poriplethopeltis, Pseudokoldinella, Semicyclocephalus, Stenopilus, Strotocephala, Tolstotchichaspis.
ADDITIONAL CLASSIFICATION NOTES FOR PTYCHOPARIIDA:
This order is certainly most problematic. Defined largely by combinations of primitive character states (such as tapering glabella, preglabellar field, natant hypostome, small, furrowed pygidium, and subdued exoskeletal sculturing), the fate of the Ptychopariida may be to slowly dwindle as groups such as the Proetida, Asaphida, and Harpetida are defined via their shared derived characters and extracted from the Ptychopariida clade.

The origins of the Ptychopariida and other Early Cambrian trilobite lineages have been explored by Jell (2003) who noted that at least two major lineages arose independently in different parts of the Early Cambrian world out of Fallotaspididae (one of the earliest trilobite families, a member of Order Redlichiida) to produce taxa that are now referred to as members of Ellipsocephaloidea (generally recognized as the earliest of the Ptychopariida). More recently (e.g, Hollingsworth 2008), members of the ellipsocephaloid family Bigotinidae (Serrania and Hupetina) actually appear in strata lower and earlier than fallotaspidoids in Morocco and Spain! In addition, Jell 2003 suggests that another lineage gives rise to Anomocaridae (primitive members of Order Asaphida) and Proasaphiscidae (primitive Ptychoparioidea). This would make the Ptychopariida polyphyletic, and throws a complicaton into the origins of the Asaphida. Jell also questions the primacy of the conterminant hypostomal state, suggesting that the earliest trilobites were natant, and that both facial sutures and the conterminant condition arose early and  independently in several lines.

The "Librostome Orders" (Ptychopariida, Asaphida, Proetida, Harpetida, and possibly the Phacopida), have sister taxa within the Ptychopariida, making it a paraphyletic taxon. The problem is exacerbated by the inadequate diagnoses of the constituent families; even the well-accepted clades within Ptychopariida, such as the family Olenidae, are united by few shared derived characters, and, as in the Asaphida, there are primitive representatives lacking some of the derived states, and advanced representatives that have secondarily lost them. The process of clarifying the Ptychopariida is hampered by lack of complete specimens, lack of sufficient ontogenetic data, lack of hypostome and other ventral characters, etc. It will take much effort and some fortuitous breakthroughs in both data and analysis to deal with the Ptychopariida. There are a number of families and genera that are for the present considered part of the Ptychopariida, but for which additional detail is difficult to ascertain. This by definition makes the Ptychopariida a "garbage heap" taxon, an inelegant status.

The genera listed here are from Jell & Adrain 2003.


Fortey, R. A. Trilobite systematics: the last 75 years. J. of Paleontology. 75(6):1141-51.

Hollingsworth, J.S., 2008. The first trilobites in Laurentia and elsewhere. In: I.Rábano, R. Gozalo and D. García-Bellido (Eds.), Advances in trilobite research. Cuadernos del Museo Geominero, nº 9. Instituto Geológico y Minero de España, Madrid,

Jell, P.A. 2003. Phylogeny of Early Cambrina trilobites. Special Papers in Palaeontology 70:45-57.

Jell, P.A. & J.M. Adrain. 2003  Available generic names for trilobites. Memoirs of the Queensland Museum 48(2):331-553

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