Fezouata Formation

{{Infobox rockunit | name = Fezouata Formation | image = Furca mauritanica MHNT.jpg | caption = Fossil of "''Furca mauretanica''", a marrellomorph arthropod from one of the exceptionally preserved intervals. | type = Geological formation | age = {{Fossil range | Tremadocian | Floian}}<ref name="ReferenceA">{{Cite journal| doi = 10.1111/let.12240| title = Age calibration of the Lower Ordovician Fezouata Lagerstätte, Morocco| journal = Lethaia| year = 2017| last1 = Lefebvre| first1 = Bertrand| last2 = Gutiérrez-Marco| first2 = Juan C| last3 = Lehnert| first3 = Oliver| last4 = Martin| first4 = Emmanuel L. O| last5 = Nowak| first5 = Hendrik| last6 = Akodad| first6 = Mustapha| last7 = El Hariri| first7 = Khadija| last8 = Servais| first8 = Thomas| volume = 51| issue = 2| pages = 296–311| doi-access = free}}</ref> | period = Floian | prilithology = Shale | region = Drâa-Tafilalet | country = Morocco | underlies = Zini Formation | thickness = >{{convert|1000|m|ft|abbr=on}}, combined for upper and lower formations, the two exceptionally preserved intervals ~{{convert|25|m|ft|abbr=on}} and {{convert|15|m|ft|abbr=on}} respectively | coordinates = {{coord|30.6|N|5.7|W|display=inline,title}} | paleocoordinates = {{coord|73.9|S|108.1|E|display=inline}} | map = {{Location map+ | Morocco | relief = 1 | width = 250 | float = center | places = {{Location map~ | Morocco | lat_deg = 30.6 | lon_deg = -5.7 | mark = Dark Green 004040 pog.svg | marksize = 10 }} {{Location map~ | Morocco | lat_deg = 27.9 | lon_deg = -11.4 | mark = Dark Green 004040 pog.svg | marksize = 10 }} {{Location map~ | Morocco | lat_deg = 30.6 | lon_deg = -6.0 | mark = Dark Green 004040 pog.svg | marksize = 10 }} }} }} The '''Fezouata Formation''' or '''Fezouata Shale''' is a geological formation in Morocco which dates to the Early Ordovician.<ref name="FW1">[https://paleobiodb.org/classic/displayStrata?geological_group=&formation=Fezouata&group_formation_member=Fezouata Fezouata Formation] at Fossilworks.org</ref><ref name="FW2">[https://paleobiodb.org/classic/displayStrata?geological_group=&formation=Fezouata%20Shale&group_formation_member=Fezouata%20Shale Fezouata Shale] at Fossilworks.org</ref><ref name="FW3">[https://paleobiodb.org/classic/displayStrata?geological_group=&formation=Lower%20Fezouata&group_formation_member=Lower%20Fezouata Lower Fezouata Formation] at Fossilworks.org</ref><ref name="FW4">[https://paleobiodb.org/classic/displayStrata?geological_group=&formation=Upper%20Fezouata&group_formation_member=Upper%20Fezouata Upper Fezouata Formation] at Fossilworks.org</ref> It was deposited in a marine environment, and is known for its exceptionally preserved fossils, filling an important preservational window beyond the earlier and more common Cambrian Burgess shale-type deposits.<ref name="DeRoy2010">{{Cite journal |last1=Van Roy |first1=P. |last2=Orr |first2=P. J. |last3=Botting |first3=J. P. |last4=Muir |first4=L. A. |last5=Vinther |first5=J. |last6=Lefebvre |first6=B. |last7=Hariri |first7=K. E. |last8=Briggs |first8=D. E. G. |author-link8=Derek Briggs |year=2010 |title=Ordovician faunas of Burgess Shale type |url=https://www.researchgate.net/publication/44593276 |journal=Nature |volume=465 |issue=7295 |pages=215–8 |bibcode=2010Natur.465..215V |doi=10.1038/nature09038 |pmid=20463737 |s2cid=4313285}}</ref> The fauna of this geological unit is often described as the '''Fezouata biota''', and the particular strata within the formation which exhibit exceptional preservation are generally termed the '''Fezouata Lagerstätte'''.

== Biota == <gallery mode="packed" heights="250"> File:Fezouata Biota.jpg|Reconstruction of the Fezouata Biota, featuring roughly 50 different species. The largest animal, ''Aegirocassis benmoulai'' (just over 2 metres in length), is depicted swimming just above the seafloor.<ref>{{cite journal |last1=Saleh |first1=Farid |last2=Antcliffe |first2=Jonathan B. |last3=Birolini |first3=Enzo |last4=Candela |first4=Yves |last5=Corthésy |first5=Nora |last6=Daley |first6=Allison C. |last7=Dupichaud |first7=Christophe |last8=Gibert |first8=Corentin |last9=Guenser |first9=Pauline |last10=Laibl |first10=Lukáš |last11=Lefebvre |first11=Bertrand |last12=Michel |first12=Soline |last13=Potin |first13=Gaëtan J.-M. |date=6 September 2024 |title=Highly resolved taphonomic variations within the Early Ordovician Fezouata Biota |url=https://www.nature.com/articles/s41598-024-71622-w |journal=Scientific Reports |language=en |volume=14 |issue=1 |page=20807 |doi=10.1038/s41598-024-71622-w |issn=2045-2322 |pmc=11379804 |doi-access=free}}</ref> </gallery>Over 1,500 non-mineralized specimens, representing 50 distinct taxa that have a composition similar to earlier Burgess Shale type biotas, have been recovered from the formations in addition to a less abundant shelly fauna.<ref name=DeRoy2010/> The make-up of the community varies significantly through the stratigraphic sequence, with both abundances and faunal composition changing as time progresses.<ref name=DeRoy2010/> Major burrowing is not present, but there are small (1-3 mm wide) burrows in the sediment, which may indicate that there is not enough oxygen in the water or sediment.<ref name=DeRoy2010/> Particularly notable is the presence of bryozoa and graptolites,<ref name=DeRoy2010/> forms that are absent in the Cambrian period. Diverse echinoderms indicate a normal range of salinity, and the overall shelly assemblage is not significantly different from the normal shelly fauna expected in open Ordovician waters.<ref name=DeRoy2010/> The non-mineralized cohort contains a range of forms familiar from the Burgess Shale: Demosponges,<ref name=":13">{{Cite journal| pages = 737–748| year = 2007| doi = 10.1016/j.geobios.2007.02.006| first1 = J.| volume = 40| title = 'Cambrian' demosponges in the Ordovician of Morocco: Insights into the early evolutionary history of sponges| journal = Geobios| last1 = Botting| issue = 6 | bibcode = 2007Geobi..40..737B}}</ref> lobopods, barnacles, annelids, radiodonts (e.g. ''Aegirocassis''),<ref name=":19">{{Cite journal | last1 = Van Roy | first1 = P. | last2 = Briggs | first2 = D. E. G. | author-link2 = Derek Briggs | doi = 10.1038/nature09920 | title = A giant Ordovician anomalocaridid | journal = Nature | volume = 473 | issue = 7348 | pages = 510–513 | year = 2011 | pmid = 21614078 |bibcode = 2011Natur.473..510V | s2cid = 205224390 }}</ref> possible halkieriids, marrellomorphs, paleoscolecid worms, nektaspids, skaniids as well as the expected ''problematica''. Other Ordovician oddballs are also present, including mitrates,<ref>{{Cite journal| doi = 10.1016/j.annpal.2007.06.003| title = First report of the mitrate Peltocystis cornuta Thoral (Echinodermata, Stylophora) in the Lower Ordovician of central Anti-Atlas (Morocco)| year = 2007| last1 = Lefebvre | first1 = B.| last2 = Botting | first2 = J.| journal = Annales de Paléontologie| volume = 93| issue = 3| page = 183| bibcode = 2007AnPal..93..183L}}</ref> machaeridians,<ref name=":12" /> cheloniellids and xiphosurans in abundance.<ref name=DeRoy2010/>

== Depositional setting == right|250px|thumb|South Polar paleogeography of the Middle Ordovician, 460 Ma The fossiliferous strata were deposited just above storm wave base (offshore to lower shoreface transition), at between {{convert|50|and|150|m|ft}} water depth. Organisms were likely buried in situ.<ref name="MartinPittet2016">{{cite journal|last1=Martin|first1=Emmanuel L.O.|last2=Pittet|first2=Bernard|last3=Gutiérrez-Marco|first3=Juan-Carlos|last4=Vannier|first4=Jean|last5=El Hariri|first5=Khadija|last6=Lerosey-Aubril|first6=Rudy|last7=Masrour|first7=Moussa|last8=Nowak|first8=Hendrik|last9=Servais|first9=Thomas|last10=Vandenbroucke|first10=Thijs R.A.|last11=Van Roy|first11=Peter|last12=Vaucher|first12=Romain|last13=Lefebvre|first13=Bertrand|title=The Lower Ordovician Fezouata Konservat-Lagerstätte from Morocco: Age, environment and evolutionary perspectives|journal=Gondwana Research|volume=34|year=2016|pages=274–283|issn=1342-937X|doi=10.1016/j.gr.2015.03.009|bibcode=2016GondR..34..274M|doi-access=free}}</ref> Because of its placement above storm wave base, storms would have mobilized sediment that could be quickly deposited, trapping animals and leading to their preservation.<ref name=DeRoy2010/><ref>{{cite web |last1=Saleh |first1=Farid |last2=Candela |first2=Yves |last3=Harper |first3=David A. T. |last4=Polechová |first4=Marika |last5=Lefebvre |first5=Bertrand |last6=Pittet |first6=Bernard |title=Storm-Induced Community Dynamics in the Fezouata Biota (Lower Ordovician, Morocco) |url=https://pubs.geoscienceworld.org/sepm/palaios/article-abstract/33/12/535/567771/storm-induced-community-dynamics-in-the-fezouata?redirectedFrom=fulltext |website=(limited access to full article) geoscienceworld.org |publisher=Society for Sedimentary Geology PALAIOS, print edition: 21 December 2018, pp. 535-541 (Vol. 33, No. 12) |access-date=1 March 2019}}</ref> Consequently, the assemblage is dominated by benthic organisms.<ref name=DeRoy2010/>

== Preservation == Fossils of the Fezouata Formation, which are usually squashed flat (although some do retain some degree of their original three-dimensionality) are often coated with a dusting of pyrite, and tin; this aspect of the fossil preservation is very similar to that at Chengjiang.<ref name=DeRoy2010/> Non-mineralized appendages are often preserved.<ref name=DeRoy2010/> While the formation as a whole is over {{convert|1000|m|ft}} thick, only two intervals, {{convert|25|m|ft}} and {{convert|15|m|ft}} thick, provide exceptional preservation.<ref>{{cite web |last1=Saleh |first1=Farid |last2=Pittet |first2=Bernard |last3=Perrillat |first3=Jean-Philippe |last4=Lefebvre |first4=Bertrand |title= Orbital Control on Exceptional Fossil Preservation (abstract only) |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/47/2/103/567985/orbital-control-on-exceptional-fossil-preservation?redirectedFrom=fulltext |website=geoscienctworld.org (subscription w/ free abstract) |publisher=Geology (magazine published) 1 February 2019 |access-date=1 March 2019}}</ref><ref>{{cite news |title=Shifts in Earth's Orbit Increase the Chances of Spectacular Fossils |url=https://www.economist.com/science-and-technology/2019/01/26/shifts-in-earths-orbit-increase-the-chances-of-spectacular-fossils |newspaper=The Economist |publisher=The Economist, print edition: January 26th 2019, p. 72 (1/2-page based on article in Geology--in prior footnote--1/Feb/2019)|access-date=1 March 2019}}</ref> Both of these intervals are located near the top of the lower formation, corresponding to the ''Araneograptus murrayi'' and ''Hunnegraptus copiosus'' graptolite zones respectively.<ref name="MartinPittet2016" />

== Location and stratigraphy == The fossils occur within an area of {{convert|500|km2|sqmi}}, in southeast Morocco's Draa Valley, north of Zagora. Stratigraphically productive layers are found through a {{convert|1.1|km|mi}}-thick column of rock that spans the Tremadocian and Floian epochs.<ref name=DeRoy2010/> Two stratigraphic intervals of the formation are fossiliferous: the lower is Late Tremadocian and sits {{convert|260|to|330|m}} above the base of the formation; the upper, at {{convert|570|to|620|m}}, is mid-Floian in age.<ref name="ReferenceA">{{Cite journal| doi = 10.1111/let.12240| title = Age calibration of the Lower Ordovician Fezouata Lagerstätte, Morocco| journal = Lethaia| year = 2017| last1 = Lefebvre| first1 = Bertrand| last2 = Gutiérrez-Marco| first2 = Juan C| last3 = Lehnert| first3 = Oliver| last4 = Martin| first4 = Emmanuel L. O| last5 = Nowak| first5 = Hendrik| last6 = Akodad| first6 = Mustapha| last7 = El Hariri| first7 = Khadija| last8 = Servais| first8 = Thomas| volume = 51| issue = 2| pages = 296–311| doi-access = free}}</ref>

== History == The Lagerstätten were first identified in the late 1990s when a local fossil collector, Ben Moula, showed some of the finds to a PhD student who was then working in the area.<ref>{{cite conference| title= Exceptionally Preserved Faunas from the Lower Ordovician of the Anti-Atlas, Morocco |author= Van Roy, P |author2= Lefebvre, B |author3 =El Hariri, K |author4=Hafid, A | year = 2008 | conference = First international Conference and Exhibition, Marrakech, Morocco | url=http://www.searchanddiscovery.com/abstracts/pdf/2008/mapg_morocco/abstracts/vanroy.pdf }}</ref><ref>{{Cite journal| doi = 10.1038/news.2010.234| last1 = Jones | first1 = N.| title = Weird wonders lived past the Cambrian| year = 2010| journal = Nature}}</ref>

===IUGS geological heritage site=== In respect of the 'exceptional fossil preservation bridging the Cambrian Explosion and the Great Ordovician Biodiversification', the International Union of Geological Sciences (IUGS) included the 'Ordovician Fezouata Shale Fossil Site at Jbeltizagzaouine' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.'<ref>{{cite web |title=The First 100 IUGS Geological Heritage Sites |url=https://iugs-geoheritage.org/videos-pdfs/iugs_first_100_book_v2.pdf |website=IUGS International Commission on Geoheritage |publisher=IUGS |access-date=13 November 2022}}</ref>

== Paleobiota == After<ref name=":9">{{Cite journal |last1=Van Roy |first1=Peter |last2=Briggs |first2=Derek E. G. |last3=Gaines |first3=Robert R. |date=September 2015 |title=The Fezouata fossils of Morocco; an extraordinary record of marine life in the Early Ordovician |url=https://www.lyellcollection.org/doi/10.1144/jgs2015-017 |journal=Journal of the Geological Society |language=en |volume=172 |issue=5 |pages=541–549 |doi=10.1144/jgs2015-017 |bibcode=2015JGSoc.172..541V |s2cid=129319753 |issn=0016-7649|url-access=subscription |hdl=1854/LU-8714212 |hdl-access=free }}</ref> and subsequent literature:

=== Radiodonts === Apart from the four named species of Fezouata radiodonts, three other unnamed species occur in the formation: a third species of ''Pseudoangustidontus'', an aegirocassisine, and a sediment-sifting hurdiid.<ref name=":20">{{Cite journal |last1=Potin |first1=Gaëtan J.-M. |last2=Gueriau |first2=Pierre |last3=Daley |first3=Allison C. |date=2023 |title=Radiodont frontal appendages from the Fezouata Biota (Morocco) reveal high diversity and ecological adaptations to suspension-feeding during the Early Ordovician |journal=Frontiers in Ecology and Evolution |volume=11 |doi=10.3389/fevo.2023.1214109 |doi-access=free |issn=2296-701X}}</ref><ref name="meathook" /> A potential fourth species of radiodont has been found in the Floian section and is known from probable head sclerites.<ref name="meathook" /> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Radiodonts of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Aegirocassis<ref name=":21">{{Cite journal |last1=Van Roy |first1=Peter |last2=Daley |first2=Allison C. |last3=Briggs |first3=Derek E. G. |date=2015 |title=Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps |url=https://www.researchgate.net/publication/273467554 |journal=Nature |language=en |volume=522 |issue=7554 |pages=77–80 |doi=10.1038/nature14256 |pmid=25762145 |bibcode=2015Natur.522...77V |issn=1476-4687}}</ref>'' |''A. benmoulae<ref name=":21" />'' |''Araneograptus murrayi'' zone,<ref name=":20" /> ''Baltograptus minutus'' zone?<ref name=":39">{{Cite journal |last1=Saleh |first1=Farid |last2=Vaucher |first2=Romain |last3=Vidal |first3=Muriel |last4=Hariri |first4=Khadija El |last5=Laibl |first5=Lukáš |last6=Daley |first6=Allison C. |last7=Gutiérrez-Marco |first7=Juan Carlos |last8=Candela |first8=Yves |last9=Harper |first9=David A. T. |last10=Ortega-Hernández |first10=Javier |last11=Ma |first11=Xiaoya |last12=Rida |first12=Ariba |last13=Vizcaïno |first13=Daniel |last14=Lefebvre |first14=Bertrand |date=2022-12-13 |title=New fossil assemblages from the Early Ordovician Fezouata Biota |journal=Scientific Reports |language=en |volume=12 |issue=1 |page=20773 |doi=10.1038/s41598-022-25000-z |pmid=36513689 |pmc=9747710 |bibcode=2022NatSR..1220773S |issn=2045-2322}}</ref> |A giant filter-feeding aegirocassisine hurdiid radiodont. The largest known radiodont and one of the largest known panarthropods, at {{Convert|2|m|ft}} in length.<ref name=":19" /><ref name=":21" /><ref name=":20" /> |center|frameless|150x150px |- |''Falciscaris''<ref name="meathook">{{cite journal |last1=Gaëtan J.-M. |first1=Potin |last2=Claisse |first2=Pénélope |title=A new giant nektobenthic radiodont benthivore from the Early Ordovician Fezouata Biota in Morocco |journal=Acta Palaeontologica Polonica |date=2 December 2025 |volume=70 |issue=4 |pages=709–722 |doi=10.4202/app.01278.2025|doi-access=free }}</ref> |''F. mumakiana'' |''Sagenograptus (Araneograptus) murrayi'' zone |A benthivorous hurdiid radiodont around a meter long. Unlike aegirocassisines, it likely sifted through sediment to capture prey, as shown by its less fine endites<ref name=meathook/> |center|150x150px |- | rowspan="3" |''Pseudoangustidontus''<ref name=":22">{{Cite journal |last1=Van Roy |first1=Peter |last2=Tetlie |first2=O. Erik |date=2006 |title=A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco |url=https://www.app.pan.pl/archive/published/app51/app51-239.pdf |journal=Acta Palaeontologica Polonica |volume=51 |issue=2 |pages=239–246}}</ref> |''P. duplospineus<ref name=":22" />'' |''Sagenograptus (Araneograptus) murrayi'' zone and Upper Fezouata | rowspan="3" |A filter-feeding aegirocassisine hurdiid radiodont. Originally considered enigmatic until 2023, where it was redescribed as a radiodont. Like the contemporary ''Aegirocassis'', this genus was most likely a filter feeder, but it could have preyed upon larger food.<ref name=":22" /><ref name=":20" /> |center|150x150px |- |''P. izdigua<ref name=":20" />'' |''Sagenograptus (Araneograptus) murrayi'' zone |center|150x150px |- |''P. sp.<ref name=":20" />'' |''Sagenograptus (Araneograptus) murrayi'' zone | |}

=== Trilobites === The largest trilobite individuals in the Fezouata Formation tend to inhabit deep oxygenated waters with minimal influence from storms or larger predators.<ref name=":23">{{Cite journal |last1=Saleh |first1=Farid |last2=Vidal |first2=Muriel |last3=Laibl |first3=Lukáš |last4=Sansjofre |first4=Pierre |last5=Gueriau |first5=Pierre |last6=Pérez-Peris |first6=Francesc |last7=Lustri |first7=Lorenzo |last8=Lucas |first8=Victoire |last9=Lefebvre |first9=Bertrand |last10=Pittet |first10=Bernard |last11=El Hariri |first11=Khadija |last12=Daley |first12=Allison C. |date=2021 |title=Large trilobites in a stress-free Early Ordovician environment |url=https://www.cambridge.org/core/product/identifier/S0016756820000448/type/journal_article |journal=Geological Magazine |language=en |volume=158 |issue=2 |pages=261–270 |doi=10.1017/S0016756820000448 |bibcode=2021GeoM..158..261S |issn=0016-7568}}</ref> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Trilobites of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Agerina'' |''A. quadrata'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone |A leiostegiid which is common at intermediate depths in the transitional zone between shoreface and offshore sediments.<ref name=":34">{{Cite journal |last1=Martin |first1=Emmanuel L.O. |last2=Vidal |first2=Muriel |last3=Vizcaïno |first3=Daniel |last4=Vaucher |first4=Romain |last5=Sansjofre |first5=Pierre |last6=Lefebvre |first6=Bertrand |last7=Destombes |first7=Jacques |date=2016 |title=Biostratigraphic and palaeoenvironmental controls on the trilobite associations from the Lower Ordovician Fezouata Shale of the central Anti-Atlas, Morocco |url=https://linkinghub.elsevier.com/retrieve/pii/S003101821630195X |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=142–154 |doi=10.1016/j.palaeo.2016.06.003|bibcode=2016PPP...460..142M |url-access=subscription }}</ref> | |- |''Ampyx'' |''A. priscus'' |''Araneograptus murrayi'' zone up to the ?''Baltograptus jacksoni'' zone.<ref name=":34" /><ref name=":26">{{Cite journal |last1=Vannier |first1=Jean |last2=Vidal |first2=Muriel |last3=Marchant |first3=Robin |last4=El Hariri |first4=Khadija |last5=Kouraiss |first5=Khaoula |last6=Pittet |first6=Bernard |last7=El Albani |first7=Abderrazak |last8=Mazurier |first8=Arnaud |last9=Martin |first9=Emmanuel |date=2019-10-17 |title=Collective behaviour in 480-million-year-old trilobite arthropods from Morocco |journal=Scientific Reports |language=en |volume=9 |issue=1 |page=14941 |doi=10.1038/s41598-019-51012-3 |issn=2045-2322 |pmc=6797724 |pmid=31624280|bibcode=2019NatSR...914941V }}</ref> |A long-spined eyeless raphiophorid which often occurs in distinctive linear clusters.<ref name=":26" /> These clusters are interpreted as collective behavior akin to modern ''Palinurus'' lobsters, either as biological aggregations (for spawning or moulting), or migrating groups due to environmental pressures such as storms. Other trilobites occasionally become entangled with the ''Ampyx'' clusters.<ref name=":26" /> This species is widely distributed in time and is most common in relatively deep (upper offshore) sediments.<ref name=":34" /> | |- |''Anacheirurus'' |''A. adserai'' |''Araneograptus murrayi'' zone<ref name=":34" /><ref name=":23" /><ref name=":27">{{Cite journal |last1=Pérez-Peris |first1=Francesc |last2=Laibl |first2=Lukáš |last3=Vidal |first3=Muriel |last4=Daley |first4=Allison C. |date=2021 |title=Systematics, morphology, and appendages of an Early Ordovician pilekiine trilobite Anacheirurus from Fezouata Shale and the early diversification of Cheiruridae |url=https://www.app.pan.pl/archive/published/app66/app009022021.pdf |journal=Acta Palaeontologica Polonica |volume=66 |issue=4 |pages=857–877 |doi=10.4202/app.00902.2021}}</ref><ref name=":24">{{Cite journal |last1=Laibl |first1=Lukáš |last2=Drage |first2=Harriet B. |last3=Pérez-Peris |first3=Francesc |last4=Schöder |first4=Sebastian |last5=Saleh |first5=Farid |last6=Daley |first6=Allison C. |date=2023 |title=Babies from the Fezouata Biota: Early developmental trilobite stages and their adaptation to high latitudes |url=https://linkinghub.elsevier.com/retrieve/pii/S0016699523000700 |journal=Geobios |language=en |volume=81 |pages=31–50 |doi=10.1016/j.geobios.2023.06.005|bibcode=2023Geobi..81...31L |url-access=subscription }}</ref> |A small pilekiine cheirurid, up to {{Convert|4.8|cm|in}} long,<ref name=":23" /> which is common in relatively deep (upper offshore) sediments.<ref name=":34" /> Fossils of this species are known to preserve appendages similar in form to those of Cambrian trilobites.<ref name=":27" /> Known from multiple life stages, including late meraspids.<ref name=":24" /> Some specimens may have previously been misidentified as ''Lehua''<ref name=":34" /> or ''Parapilekia''.<ref name=":27" /> | |- | rowspan="2" |''Apatokephalus'' |''A. cf. incisus'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone |An uncommon remopleuridid found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> | |- |''A. sp.'' |Lower Fezouata,<ref name=":10" /> Upper Fezouata<ref name=":10" /> |A remopleuridid.<ref name=":34" /> | |- | rowspan="5" |''Asaphellus'' |''A. fezouataensis'' |''?Baltograptus jacksoni'' zone |An endemic asaphid. Associated body fossils and trace fossils help to identify this species as the tracemaker for a distinctive resting trace, ''Rusophycus carleyi''.<ref>{{Cite journal |last1=Gibb |first1=Stacey |last2=Chatterton |first2=Brian D. E. |last3=Gingras |first3=Murray K. |date=2010-11-30 |title=Rusophycus carleyi (James, 1885), Trace Fossils from the Lower Ordovician of Southern Morocco, and the Trilobites that Made Them |url=http://www.tandfonline.com/doi/abs/10.1080/10420940.2010.535452 |journal=Ichnos |language=en |volume=17 |issue=4 |pages=271–283 |doi=10.1080/10420940.2010.535452 |bibcode=2010Ichno..17..271G |issn=1042-0940|url-access=subscription }}</ref> Found at intermediate depths in the transitional zone between shoreface and offshore sediments.<ref name=":34" /> | |- |''A. aff. jujuanus'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone,

?''Baltograptus jacksoni'' zone |A small and common asaphid up to {{Convert|6.2|cm|in}} long,<ref name=":23" /> without clear preferences for specific depths.<ref name=":34" /> | |- |''A. sp.'' |''Araneograptus murrayi'' zone<ref name=":24" /> |An asaphid. Known from multiple life stages, including late meraspids.<ref name=":24" /> | |- |''A. stubbsi''<ref>{{Cite journal |last=Fortey |first=Richard A. |date=2009 |title=A New Giant Asaphid Trilobite from the Lower Ordovician of Morocco |journal=Memoirs of the Association of Australasian Palaeontologists |volume=37 |pages=9–16}}</ref> |''Araneograptus murrayi'' zone<ref name=":34" /><ref name=":23" /> |A large endemic asaphid up to {{Convert|38|cm|in}} long.<ref name=":23" /> Found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> |center|174x174px |- |''A. tataensis'' |''Araneograptus murrayi'' zone,<ref name=":34" /><ref name=":28">{{Cite journal |last1=Edgecombe |first1=Gregory D. |last2=Fortey |first2=Richard. A. |date=2023 |title=A novel antennal form in trilobites |url=https://www.researchgate.net/publication/362196019 |journal=Journal of Paleontology |language=en |volume=97 |issue=1 |pages=152–157 |doi=10.1017/jpa.2022.59 |bibcode=2023JPal...97..152E |issn=0022-3360}}</ref> Upper Fezouata<ref name=":10" /> |An uncommon medium-sized endemic asaphid. Some specimens have been fossilized with unusual flattened antennae, the only reliable attributions of these structures in asaphids. The antennae may have had a particular sensory function to assist in hunting or scavenging.<ref name=":28" /> Found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> | |- |''Asaphopsis'' |''A. sp.'' |Lower Fezouata<ref name=":10" /> |A ''Dikelokephalina''-like trilobite. | |- | rowspan="3" |''Basilicus'' |''B. destombesi'' |''Baltograptus jacksoni'' zone<ref name=":34" /> |A large asaphine asaphid up to {{Convert|33|cm|in}} long.<ref name=":29">{{Cite journal |last1=Corbacho |first1=Joan |last2=Vela |first2=Joan Antoni |date=2010 |title=Giant Trilobites from Lower Ordovician of Morocco |url=https://www.researchgate.net/publication/265168252 |journal=Batalleria |volume=15 |pages=3–34}}</ref> | |- |''B. sp.'' | |A very large asaphine asaphid up to {{Convert|51|cm|in}} long.<ref name=":29" /> |center|150x150px |- |''B. vidali'' | |A large asaphine asaphid up to {{Convert|36|cm|in}} long.<ref name=":29" /> | |- |''Bathycheilus'' |''B. gallicus'' |Upper Fezouata<ref name=":10" /> |A bathycheilid. | |- | rowspan="2" |''Bavarilla'' |''B. sp.'' |''Araneograptus murrayi'' zone<ref name=":23" /> |A small bavarillid up to {{Convert|4.1|cm|in}} long.<ref name=":23" /> | |- |''B. zemmourensis'' |''Araneograptus murrayi'' zone,<ref name=":34" /><ref name=":24" /> Upper Fezouata<ref name=":10" /> |An endemic bavarillid common in relatively shallow (lower nearshore) sediments.<ref name=":34" /> | |- |''Ceraurinella?'' |''C.? sp.'' |Upper Fezouata<ref name=":10" /> |A cheirurid. | |- | rowspan="3" |''Colpocoryphe'' |''C. pradesensis'' |?''Baltograptus jacksoni'' zone, ''Baltograptus minutus'' zone |A rare calymenid.<ref name=":34" /> | |- |''C. thorali'' |''?Cymatograptus protobalticus'' zone, ''Baltograptus minutus'' zone<ref name=":39" /> |A rare calymenid.<ref name=":34" /> | |- |''C. sp.'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone |A rare calymenid found in relatively deep (upper offshore) sediments.<ref name=":34" /> |center|150x150px |- |''Dactylocephalus'' |''D. sp.'' | |A large asaphid up to {{Convert|29|cm|in}} long.<ref name=":29" /> | |- | rowspan="2" |''Dikelokephalina'' |''D. brenchleyi''<ref name=":30">{{Cite journal |last=Fortey |first=Richard A. |date=2011 |title=Trilobites of the genus Dikelokephalina from Ordovician Gondwana and Avalonia |url=https://www.researchgate.net/publication/264332416 |journal=Geological Journal |language=en |volume=46 |issue=5 |pages=405–415 |doi=10.1002/gj.1275 |bibcode=2011GeolJ..46..405F |issn=0072-1050}}</ref> |''Araneograptus murrayi'' zone<ref name=":34" /><ref name=":23" /> |A large endemic dikelokephalinid up to {{Convert|33.7|cm|in}} long.<ref name=":23" /> Often found in mass death assemblages, possibly for spawning akin to modern horseshoe crabs.<ref name=":30" /> | |- |''D. sp.'' |Lower Fezouata<ref name=":10" /> |A large dikelokephalinid up to {{Convert|29.5|cm|in}} long.<ref name=":29" /> |center|150x150px |- |''Ectillaenus''? |''E.? sp.'' |''Baltograptus minutus'' zone<ref name=":39" /> |An illaenid. | |- |''Eoharpes'' |''E. sp.'' | |A harpetid. |center|150x150px |- |''Euloma'' |''E. sp.'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone,

?''Baltograptus jacksoni'' zone |A small eulomid up to {{Convert|3.8|cm|in}} long.<ref name=":23" /> Found at intermediate depths in the transitional zone between shoreface and offshore sediments.<ref name=":34" /> | |- |''Foulonia'' |''F. peregrina'' |''Araneograptus murrayi'' zone, ''?Baltograptus jacksoni'' zone |A cheirurid.<ref name=":34" /> | |- |''Geragnostus'' |''G. sp.'' |''Araneograptus murrayi'' zone, ''?Baltograptus jacksoni'' zone |A very rare<ref name=":34" /> artiopodan arthropod in the order Agnostida, which is often considered a group of trilobites. Very small, at up to {{Convert|0.9|cm|in}} long.<ref name=":23" /> |center|206x206px |- |''Harpides'' |''H. sp.'' | |A harpidid of questionable occurrence. |center|200x200px |- |''Indiligens'' |''I. sp.'' |''Araneograptus murrayi'' zone<ref name=":24" /> |A ptychopariid known from multiple life stages, including mid-stage meraspids.<ref name=":24" /> | |- |''Leptoplastides'' |''L. salteri'' |''Anisograptus matanensis'' zone, ''Rhabdinopora flabelliformis anglica'' zone |An olenid, the only diagnostic member of the family to be found in Africa.<ref>{{Cite journal |last1=Hopkins |first1=Melanie J. |last2=Gutiérrez-Marco |first2=Juan Carlos |last3=Di Silvestro |first3=Gianpaolo |date=2024-01-15 |title=First occurrence of well-preserved Ordovician trilobites of the family Olenidae from Africa |url=https://www.cambridge.org/core/product/identifier/S0022336023000604/type/journal_article |journal=Journal of Paleontology |language=en |pages=1–10 |doi=10.1017/jpa.2023.60 |issn=0022-3360|doi-access=free }}</ref> Previously misidentified as ''Beltella''.<ref name=":10" /> | |- |''Lichakephalus'' |''L. stubbsi''<ref name=":35">{{Cite journal |last=Fortey |first=Richard A. |date=2012 |title=The first known complete Lichakephalid trilobite, lower Ordovician of Morocco |journal=Memoirs of the Association of Australasian Palaeontologists |volume=42 |pages=1–7}}</ref> | |A large lichakephalid.<ref name=":35" /> | |- |''Megistaspis'' (''Ekeraspis'') |''M. (E.) hammondi<ref name=":29" />'' |''Araneograptus murrayi'' zone<ref name=":25">{{Cite journal |last1=Gutiérrez-Marco |first1=Juan C. |last2=García-Bellido |first2=Diego C. |last3=Rábano |first3=Isabel |last4=Sá |first4=Artur A. |date=2017-01-10 |title=Digestive and appendicular soft-parts, with behavioural implications, in a large Ordovician trilobite from the Fezouata Lagerstätte, Morocco |journal=Scientific Reports |language=en |volume=7 |issue=1 |article-number=39728 |doi=10.1038/srep39728 |issn=2045-2322 |pmc=5223178 |pmid=28071705|bibcode=2017NatSR...739728G }}</ref><ref name=":24" /> |A large isoteline asaphid up to {{Convert|28.5|cm|in}} long, not counting a pronounced spine on the pygidium.<ref name=":29" /> Some specimens preserving gut traces and appendages showing new anatomical traits not seen in other trilobites. The cephalic appendages hosted long spines capable of combing through sediment for food. This species' feeding behavior may be responsible for ''Cruziana rugosa'', a trace fossil common throughout Ordovician Gondwana.<ref name=":25" /> Known from multiple life stages, including mid to late meraspids.<ref name=":24" /> | |- |''Neseuretus'' |''N. cf. attenuatus'' |''?Cymatograptus protobalticus'' zone, ''Baltograptus minutus'' zone |A calymenid found in particularly shallow sediments.<ref name=":34" /> | |- |''Nileus'' |''N. deynouxi'' |''Araneograptus murrayi'' zone<ref name=":24" /> |A nileid known from multiple life stages, including late meraspids.<ref name=":24" /> | |- |''Nobiliasaphus?'' |''N.? sp.'' | |A large asaphine asaphid up to {{Convert|33|cm|in}} long.<ref name=":29" /> | |- | rowspan="2" |''Ogyginus'' |''O. forteyi hammondi''<ref name=":29" /> | |A very large ogygiocaridinine asaphid, up to {{Convert|45|cm|in}} long.<ref name=":29" /> | |- |''O. sp.'' |''Araneograptus murrayi'' zone<ref name=":23" /> |A very large ogygiocaridinine asaphid, up to {{Convert|49.1|cm|in}} long.<ref name=":23" /> | |- |''Orometopus'' |''O. sp.'' |''Araneograptus murrayi'' zone<ref name=":24" /> |Known from multiple life stages, including early to late meraspids.<ref name=":24" /> | |- |''Parabathycheilus'' |''P. gallicus'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone,

?''Baltograptus jacksoni'' zone |A common bathycheilid without clear preferences for specific depths.<ref name=":34" /> | |- |''Parvilichas''<ref name=":36">{{Cite journal |last1=Corbacho |first1=Joan |last2=Vela |first2=Joan A. |title=Parvilichas marochii: New genus and species of Lichidae from the Zagora region (Morocco); Early Ordovician (Floian) |url=https://www.researchgate.net/publication/265168221 |journal=Scripta Musei Geologici Seminarii Barcinonensis [Ser. palaeontologica] |volume=14 |pages=3–13}}</ref> |''P. marochii<ref name=":36" />'' |Upper Fezouata |A lichid.<ref name=":36" /> | |- |''Pharostomina?'' |''P.? sp.'' |Lower Fezouata<ref name=":10" /> |A pharostomatid. | |- |''Platycoryphe'' |''P. sp.'' |Upper Fezouata<ref name=":10" /> |A homalonotid. | |- |''Platypeltoides'' |''P. magrebiensis'' |''Araneograptus murrayi'' zone<ref name=":23" /><ref name=":24" /> |A large endemic nileid, up to {{Convert|23|cm|in}} long.<ref name=":23" /> Typically considered a single species.<ref name=":10" /><ref name=":23" /><ref name=":24" /> Known from multiple life stages, including early to late meraspids.<ref name=":24" /> Found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> |center|202x202px |- |''Pradoella'' |''P. tazzarinensis'' |''?Cymatograptus protobalticus'' zone, ''Baltograptus minutus'' zone |A calymenid.<ref name=":34" /> | |- |''Prionocheilus'' |''P. aff. languedocensis'' |''Araneograptus murrayi'' zone, ''?Baltograptus jacksoni'' zone |A pharostomatid found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> | |- |''Selenopeltis'' | | |An odontopleurid. |center|172x172px |- | rowspan="4" |''Symphysurus'' |''S. angustatus'' |''Araneograptus murrayi'' zone,<ref name=":34" /> Upper Fezouata<ref name=":10" /> |A nileid found in relatively shallow (lower nearshore) sediments.<ref name=":34" /> | |- |''S. ebbestadi''<ref name=":31">{{Citation |last1=Gutiérrez-Marco |first1=Juan Carlos |title=The nileid trilobite ''Symphysurus'' from upper Tremadocian strata of the Moroccan Anti-Atlas: taxonomic reappraisal and palaeoenvironmental implications |date=2019 |work=Fossils and Strata |volume=64 |pages=155–171 |editor-last=Owen |editor-first=Alan W. |url=https://www.idunn.no/doi/10.1002/9781119564249.ch7 |publisher=John Wiley & Sons, Ltd |language=en |doi=10.1002/9781119564249.ch7 |isbn=978-1-119-56423-2 |last2=Rábano |first2=Isabel |last3=García-Bellido |first3=Diego C. |editor2-last=Bruton |editor2-first=David L.|url-access=subscription }}</ref> |''Araneograptus murrayi'' zone<ref name=":31" /><ref name=":24" /> |A common nileid with gregarious habits, often associated with graptolite debris at multiple water depths.<ref name=":31" /> Some specimens have been fossilized in the process of a mass moulting event, including some of the few known fossils of post-moult trilobites.<ref>{{Cite journal |last1=Drage |first1=Harriet B. |last2=Vandenbroucke |first2=Thijs R.A. |last3=Van Roy |first3=Peter |last4=Daley |first4=Allison C. |date=2019 |title=Sequence of post-moult exoskeleton hardening preserved in a trilobite mass moult assemblage from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco |url=https://www.app.pan.pl/archive/published/app64/app005822018.pdf |journal=Acta Palaeontologica Polonica |volume=64 |issue=2 |pages=261–273 |doi=10.4202/app.00582.2018}}</ref> Known from multiple life stages, including mid to late meraspids.<ref name=":24" /> | |- |''S. sicardi'' |? |A small nileid up to {{Convert|4.5|cm|in}} long<ref name=":31" /> | |- |''S. sp.'' |''Araneograptus murrayi'' zone<ref name=":31" /><ref name=":23" /> |Several additional ''Symphysurus'' species, one which reaches {{Convert|7.5|cm|in}} in length,<ref name=":31" /> and another reaching {{Convert|4.2|cm|in}}.<ref name=":23" /> | |- |''Toletanaspis'' |''T. aff. borni'' |''Araneograptus murrayi'' zone, ''?Cymatograptus protobalticus'' zone,

?''Baltograptus jacksoni'' zone |A dalmanitid without clear preferences for specific depths.<ref name=":34" /> | |}

=== Other arthropods === Many arthropods of the Fezouata Biota remain unnamed and undescribed. These include synziphosurines, xiphosurans (horseshoe crabs), chasmataspidids, phyllocarids, ostracods, a canadaspidid, a leanchoiliid, a cheloniellid ("Eoduslia"),<ref name=":15">{{Cite journal |last1=Sumrall |first1=Colin D. |last2=Zamora |first2=Samuel |date=2011 |title=Ordovician edrioasteroids from Morocco: faunal exchanges across the Rheic Ocean |journal=Journal of Systematic Palaeontology |volume=9 |issue=3 |pages=425–454 |bibcode=2011JSPal...9..425S |doi=10.1080/14772019.2010.499137 |issn=1477-2019}}</ref> a possible retifaciid, and a lepadomorph barnacle.<ref name=":9" /> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Other arthropods of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Brachyaglaspis''<ref name=":16">{{Cite journal |last1=Ortega-Hernández |first1=Javier |last2=Van Roy |first2=Peter |last3=Lerosey-Aubril |first3=Rudy |date=May 2016 |title=A new aglaspidid euarthropod with a six-segmented trunk from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco |url=https://www.researchgate.net/publication/281287136 |journal=Geological Magazine |language=en |volume=153 |issue=3 |pages=524–536 |bibcode=2016GeoM..153..524O |doi=10.1017/S0016756815000710 |issn=0016-7568 |s2cid=130254788|hdl=1854/LU-8714213 |hdl-access=free }}</ref> |''B. singularis<ref name=":16" />'' |Upper Fezouata (mid-Floian) |An aglaspidid with a very large cephalon, a short trunk, and no eyes.<ref name=":16" /> |center|frameless|158x158px |- |?''Carcinosoma''<ref name="carcinosoma">{{cite journal |last1=Van Roy |first1=Peter |last2=Richards |first2=Jared C. |last3=Ortega-Hernández |first3=Javier |title=Early Ordovician sea scorpions from Morocco suggest Cambrian origins and main diversification of Eurypterida |journal=Proceedings of the Royal Society B: Biological Sciences |date=November 2025 |volume=292 |issue=2058 |doi=10.1098/rspb.2025.2061|doi-access=free |pmc=12606246 }}</ref> |?''C. aurorae'' |''Sagenograptus murrayi'' zone |The earliest known eurypterid. Known mostly from fragments. |center|frameless|158x158px |- |''Enosiaspis''<ref name=":17">{{Cite journal |last=Legg |first=David A. |date=2016 |title=An acercostracan marrellomorph (Euarthropoda) from the Lower Ordovician of Morocco |url=http://link.springer.com/10.1007/s00114-016-1352-5 |journal=The Science of Nature |language=en |volume=103 |issue=3–4 |page=21 |doi=10.1007/s00114-016-1352-5 |pmid=26922777 |bibcode=2016SciNa.103...21L |issn=0028-1042|url-access=subscription }}</ref> |''E. hrungnir<ref name=":17" />'' |''Araneograptus murrayi'' zone |An acercostracan marrellomorph with a shield-like dorsal carapace.<ref name=":17" /> |center|frameless|158x158px |- |"Furca" |"F. mauretanica" |''Sagenograptus (Araneograptus) murrayi'' zone |A marrellid marrellomorph which has not been formally named or described in detail, but has been referred to by the informal unpublished name "Furca mauretanica". It had three pairs of cephalic appendages, 13 pairs of trunk appendages, and a cephalic shield with six large setae-bearing spines. Both adult and juvenile specimens are known of this species,<ref>{{Cite journal |last1=Laibl |first1=Lukáš |last2=Gueriau |first2=Pierre |last3=Saleh |first3=Farid |last4=Pérez-Peris |first4=Francesc |last5=Lustri |first5=Lorenzo |last6=Drage |first6=Harriet B. |last7=Bath Enright |first7=Orla G. |last8=Potin |first8=Gaëtan J.-M. |last9=Daley |first9=Allison C. |date=2023 |title=Early developmental stages of a Lower Ordovician marrellid from Morocco suggest simple ontogenetic niche differentiation in early euarthropods |journal=Frontiers in Ecology and Evolution |volume=11 |doi=10.3389/fevo.2023.1232612 |doi-access=free |issn=2296-701X}}</ref> including individuals caught in the act of moulting.<ref>{{Cite journal |last1=Drage |first1=Harriet B. |last2=Legg |first2=David A. |last3=Daley |first3=Allison C. |date=2023 |title=Novel marrellomorph moulting behaviour preserved in the Lower Ordovician Fezouata Shale, Morocco |journal=Frontiers in Ecology and Evolution |volume=11 |doi=10.3389/fevo.2023.1226924 |doi-access=free |issn=2296-701X}}</ref> The name "Furca mauretanica" is an informal ''nomen nudum'' for this species, first introduced in a PhD thesis. Multiple marrellid species may be present in the formation. |center|frameless|153x153px |- |''Isoxys''? |''I''? ''giganteus''<ref>{{Cite journal|last1=Yoshino |first1=S. |last2=Oji |first2=T. |year=2026 |title=A bivalved arthropod from the lower Ordovician Fezouata Shale suggests the post Cambrian survival and gigantism of ''Isoxys'' (Isoxyda, Isoxyidae) |journal=Historical Biology: An International Journal of Paleobiology |pages=1–12 |doi=10.1080/08912963.2026.2663158 |doi-access=free}}</ref> |''Araneograptus murrayi'' zone |A bivalved arthropod possibly belonging to the genus ''Isoxys,'' if right, this interpretation would make ''I''? ''giganteus'' the largest ''Isoxys'' species by far with the holotype valve being 334 mm long. It would also be the youngest ''Isoxys'' species, extending the stratigraphic range of isoxyids by approximately 20 million years and the first isoxyd of the Ordovician. Its very large size could reflect an adaptation to the cool water of the Fezouata Formation or/and a change in ecology. | |- |''Setapedites''<ref name=":42">{{Cite journal |last1=Lustri |first1=Lorenzo |last2=Gueriau |first2=Pierre |last3=Daley |first3=Allison C. |date=2024-05-07 |title=Lower Ordovician synziphosurine reveals early euchelicerate diversity and evolution |journal=Nature Communications |language=en |volume=15 |issue=1 |page=3808 |doi=10.1038/s41467-024-48013-w |pmid=38714651 |issn=2041-1723|pmc=11076625 |bibcode=2024NatCo..15.3808L }}</ref> |''S. abundantis<ref name=":42" />'' |''Araneograptus murrayi'' zone |A small but abundant offacolid "synziphosurine" (early euchelicerate). Though most closely related to ''Dibasterium'' and ''Offacolus'' from the Silurian Herefordshire Lagerstätte, it also shows similarities to ''Habelia'' from the Cambian, and thus serves as a transitional form among Ordovician euchelicerate evolution.<ref name=":42" /> |center|frameless|153x153px |- |''Tariccoia'' |''T. tazagurtensis<ref name=":18">{{Cite journal |last1=Pérez-Peris |first1=Francesc |last2=Laibl |first2=Lukáš |last3=Lustri |first3=Lorenzo |last4=Gueriau |first4=Pierre |last5=Antcliffe |first5=Jonathan B |last6=Bath Enright |first6=Orla G |last7=Daley |first7=Allison C |date=2021 |title=A new nektaspid euarthropod from the Lower Ordovician strata of Morocco |url=https://www.cambridge.org/core/product/identifier/S001675682000062X/type/journal_article |journal=Geological Magazine |language=en |volume=158 |issue=3 |pages=509–517 |doi=10.1017/S001675682000062X |bibcode=2021GeoM..158..509P |issn=0016-7568}}</ref>'' |''Araneograptus murrayi'' zone |A liwiid nektaspid with a large cephalon and pygidium and sharply angled thorax tergites. One of the few liwiid fossils with soft tissue of the digestive system preserved.<ref name=":18" /> | |- |''Thelxiope'' |''T. sp.'' |''Araneograptus murrayi'' zone |A mollisoniid, possibly related to chelicerates.<ref>{{Cite journal |last1=Lerosey-Aubril |first1=Rudy |last2=Skabelund |first2=Jacob |last3=Ortega-Hernández |first3=Javier |date=2020-04-09 |title=Revision of the mollisoniid chelicerate(?) Thelxiope, with a new species from the middle Cambrian Wheeler Formation of Utah |journal=PeerJ |language=en |volume=8 |article-number=e8879 |doi=10.7717/peerj.8879 |doi-access=free |pmid=32296605 |pmc=7151752 |issn=2167-8359}}</ref> |center|frameless|150x150px |- |''Tremaglaspis'' |''T. sp.'' | |An aglaspidid, one of the first expectionally-preserved invertebrates found in the formation.<ref name=":16" /><ref name=":10" /> |center|frameless|158x158px |}

=== Echinoderms === Many echinoderm species of the Fezouata Biota remain unnamed and undescribed. These include representatives of chauvelicystids, other cornutes, anomalacystitids, mitrocystitids, eocrinoids, rhenopyrgids, and somasteroids.<ref name=":37">{{Cite journal |last1=Lefebvre |first1=Bertrand |last2=Allaire |first2=Ninon |last3=Guensburg |first3=Thomas E. |last4=Hunter |first4=Aaron W. |last5=Kouraïss |first5=Khaoula |last6=Martin |first6=Emmanuel L.O. |last7=Nardin |first7=Elise |last8=Noailles |first8=Fleur |last9=Pittet |first9=Bernard |last10=Sumrall |first10=Colin D. |last11=Zamora |first11=Samuel |date=2016 |title=Palaeoecological aspects of the diversification of echinoderms in the Lower Ordovician of central Anti-Atlas, Morocco |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216001395 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=97–121 |doi=10.1016/j.palaeo.2016.02.039|bibcode=2016PPP...460...97L |url-access=subscription }}</ref> Fezouata stylophoran fossils include soft tissue preserved among the skeletal elements, helping to unravel controversial details of their anatomy and ecology.<ref>{{Cite journal |last1=Lefebvre |first1=Bertrand |last2=Guensburg |first2=Thomas E. |last3=Martin |first3=Emmanuel L.O. |last4=Mooi |first4=Rich |last5=Nardin |first5=Elise |last6=Nohejlová |first6=Martina |last7=Saleh |first7=Farid |last8=Kouraïss |first8=Khaoula |last9=El Hariri |first9=Khadija |last10=David |first10=Bruno |date=2019 |title=Exceptionally preserved soft parts in fossils from the Lower Ordovician of Morocco clarify stylophoran affinities within basal deuterostomes |url=https://linkinghub.elsevier.com/retrieve/pii/S0016699518301219 |journal=Geobios |language=en |volume=52 |pages=27–36 |doi=10.1016/j.geobios.2018.11.001|bibcode=2019Geobi..52...27L |url-access=subscription }}</ref><ref name=":41" />

Specific echinoderm species may form dense fossil beds in some layers of the formation, a phenomenon which is particularly common in the mid-late Tremadocian (''Araneograptus murrayi'' graptolite zone).<ref name=":37" /> Most echinoderm beds are dominated by only a few species, often representatives of stylophorans or the eocrinoid ''Rhopalocystis'', with few other animal fossils. Through nearly the entire the formation, small ''Rhopalocystis'' species dominate "meadow"-like ecosystems in shallow waters impacted by storms. In the youngest layers of the formations, diploporites usurp this niche. Conversely, stylophorans are opportunistic colonizers of deeper low-oxygen seabeds in some intervals of the ''Araneograptus murrayi'' zone. Echinoderms are uncommon at intermediate depths, which have a higher proportion of brachiopod and trilobite fossils.<ref name=":37" />

Nevertheless, there are quite a few exceptions which contradict these broad rules. Many sites record diverse deep-water ecosystems protected from both storms and insufficient oxygen. Numerous species of echinoderms and other invertebrates coexist at these localities, even if one echinoderm species outnumbers other fossils at any given time. Large ''Rhopalocystis'' species, ''Macrocystella'', ''Plasiacystis'', and ''Balantiocystis'' are common components of these assemblages.<ref name=":37" />

Fezouata reconstructs the uneven nature of the Cambrian-Ordovician transition of echinoderm faunas. Cosmopolitan Late Cambrian hallmarks (such as cornute stylophorans) maintain their abundance in oxygen-poor areas, while newer groups (crinoids, diploporites, asterozoans) make inroads into more oxygenated waters. The rarity of carbonate platforms and hard substrates in the Gondwanan area delayed the diversification of crinoids and edrioasteroids in the region. This also provided more space for the establishment of a distinctive South Polar ecosystem dominated by eocrinoids, mitrates, solutans, and eventually diploporites.<ref name=":37" /> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Echinoderms of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Aethocrinus'' |''A. cf. moorei'' |''Araneograptus murrayi'' zone |A crinoid. | |- |''Ampelocarpus'' |''A. sp.'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''Amygdalotheca'' |''A. griffei'' |''Araneograptus murrayi'' zone |An uncommon cornute. | |- | rowspan="2" |''Anatifopsis'' |''A. escandrei'' |''Hunnegraptus copuosus'' zone |A rare mitrate. | |- |''A. trapeziiformis'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone,

?''Baltograptus jacksoni'' zone |A common eocrinoid. The dominant echinoderm at sites Z-F26 and Z-F23, which preserve diverse fossil assemblages buried in calm-water fine-grained siltstone of the ?''Cymatograptus protobalticus'' zone. Also abundant in higher-energy deposits of the ?''Baltograptus jacksoni'' zone.<ref name=":37" /> | |- |''Bohemiaecystis'' |''B. sp.'' |''Araneograptus murrayi'' zone |A locally abundant cornute with a large sample size, allowing for a reconstruction of decay pathways in stylophoran soft tissue and skeletal material.<ref name=":41">{{Cite journal |last1=Saleh |first1=Farid |last2=Lefebvre |first2=Bertrand |last3=Dupichaud |first3=Christophe |last4=Martin |first4=Emmanuel L.O. |last5=Nohejlová |first5=Martina |last6=Spaccesi |first6=Léa |date=2023 |title=Skeletal elements controlled soft-tissue preservation in echinoderms from the Early Ordovician Fezouata Biota |url=https://linkinghub.elsevier.com/retrieve/pii/S0016699523001006 |journal=Geobios |language=en |volume=81 |pages=51–66 |doi=10.1016/j.geobios.2023.08.001|bibcode=2023Geobi..81...51S }}</ref> | |- | rowspan="3" |''Chauvelicystis'' |''C. spinosa'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''C. ubaghsi'' |''Araneograptus murrayi'' zone |An uncommon cornute. | |- |''C. vizcainoi'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''Chinianocarpos'' |''C. sp.'' |"''Azygograptus'' interval" |An uncommon mitrate. | |- |''Flabellicarpus'' |''F. rushtoni'' |''Araneograptus murrayi'' zone |A rare cornute. | |- | rowspan="2" |''Galliaecystis'' |''G. ubaghsi'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''G. sp.'' |''Araneograptus murrayi'' zone |An uncommon cornute. | |- |''Hanusia'' |''H. sp.'' |''Araneograptus murrayi'' zone |An uncommon cornute. | |- |''Iocrinus'' |''I. sp.'' |?''Cymatograptus protobalticus'' zone |A rare disparid crinoid. | |- |''Lagnocystis'' |''L. pyramidalis'' |''Araneograptus murrayi'' zone |A rare mitrate. | |- | rowspan="2" |''Lingulocystis'' |''L. aff. deani'' |?''Cymatograptus protobalticus'' zone, ?''Baltograptus jacksoni'' zone |A rare eocrinoid. | |- |''L. elongata'' |''Araneograptus murrayi'' zone, ?''Baltograptus jacksoni'' zone |A rare eocrinoid. | |- |''Macrocystella'' |''M. bohemica'' |''Araneograptus murrayi'' zone, ?''Baltograptus jacksoni'' zone |A common glyptocystitid rhombiferan. Crushed but complete skeletons of this species are abundant at Oued Beni Zoli locality Z-F5, a site preserving a diverse assemblage of storm-influenced siltstone in the ''Araneograptus murrayi'' zone.<ref name=":37" /> | |- |''Nanocarpus'' |''N. cf. dolambii'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''Nimchacystis''<ref name=":38">{{Cite journal |last1=Dupichaud |first1=Christophe |last2=Lefebvre |first2=Bertrand |last3=Milne |first3=Claire H. |last4=Mooi |first4=Rich |last5=Nohejlová |first5=Martina |last6=Roch |first6=Renaud |last7=Saleh |first7=Farid |last8=Zamora |first8=Samuel |date=2023 |title=Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications |journal=Frontiers in Ecology and Evolution |volume=11 |doi=10.3389/fevo.2023.1290063 |doi-access=free |issn=2296-701X}}</ref> |''N. agterbosi<ref name=":38" />'' |''Araneograptus murrayi'' zone |An uncommon minervaecystid solutan.<ref name=":38" /> |center|frameless|150x150px |- |''Paleosphaeronites?'' |''P.? prokopi'' |''Araneograptus murrayi'' zone, ?''Baltograptus jacksoni'' zone |A rare diploporite. | |- |''cf. Pareocrinus'' | |''Araneograptus murrayi'' zone, ?''Cymatograptus protobalticus'' zone |An uncommon eocrinoid. | |- |''Peltocystis'' |''P. cornuta'' |''Araneograptus murrayi'' zone |An uncommon mitrate. | |- |''Plasiacystis'' |''P. mobilis'' |''Araneograptus murrayi'' zone<ref name=":37" /> up to the ''Baltograptus minutus'' zone<ref name=":39" /> |A common minervaecystid solutan. Paddles of this species are abundant at sites Z-F13c and Z-F24, a pair of diverse faunal assemblages emplaced in sandy storm deposits of the ''Hunnegraptus copuosus'' zone.<ref name=":37" /><ref name=":38" /> | |- |''Procothurnocystis'' |''P. sp.'' |''Araneograptus murrayi'' zone |A common cornute. | |- |''Prokopicystis'' |''P. sp.'' |''Araneograptus murrayi'' zone |A rare cornute. | |- |''Ramseyocrinus'' |''R. sp.'' |?''Cymatograptus protobalticus'' zone, ?''Baltograptus jacksoni'' zone |A rare disparid crinoid. | |- | rowspan="5" |''Rhopalocystis'' |''R. destombesi'' |''Aorograptus victoriae'' zone, ''Araneograptus murrayi'' zone,

''Hunnegraptus copiosus'' zone,

?''Baltograptus jacksoni'' zone |A common and endemic eocrinoid which can be abundant in certain layers. It is a small but robust species often found in densely jumbled fossiliferous lenses. These lenses are interpreted as debris from shallow-water "meadows", uprooted and washed down into deeper areas by storms.<ref name=":37" /><ref name=":40">{{Cite journal |last1=Allaire |first1=Ninon |last2=Lefebvre |first2=Bertrand |last3=Nardin |first3=Elise |last4=Martin |first4=Emmanuel L.O. |last5=Vaucher |first5=Romain |last6=Escarguel |first6=Gilles |date=2017 |title=Morphological disparity and systematic revision of the eocrinoid genus Rhopalocystis (Echinodermata, Blastozoa) from the Lower Ordovician of the central Anti-Atlas (Morocco) |url=https://www.cambridge.org/core/product/identifier/S0022336017000063/type/journal_article |journal=Journal of Paleontology |language=en |volume=91 |issue=4 |pages=685–714 |doi=10.1017/jpa.2017.6 |bibcode=2017JPal...91..685A |issn=0022-3360|hdl=11336/44871 |hdl-access=free }}</ref> | |- |''R. fraga'' |''Araneograptus murrayi'' zone |A rare and endemic eocrinoid, similar to ''R. destombesi'' in form and preservation style.<ref name=":37" /><ref name=":40" /> | |- |''R. grandis'' |''Araneograptus murrayi'' zone |A rare and endemic eocrinoid, similar to ''R. havliceki'' in form and preservation style.<ref name=":37" /><ref name=":40" /> | |- |''R. havliceki'' |''Araneograptus murrayi'' zone |A common and endemic eocrinoid. It is a large but fragile species which is often found disarticulated in siltstone beds. Unlike ''R. destombesi'', it was likely a deep-water specialist buried in place.<ref name=":37" /><ref name=":40" /> | |- |''R. zagoraensis'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone |A common and endemic eocrinoid, similar to ''R. destombesi'' in form and preservation style.<ref name=":37" /><ref name=":40" /> | |- | rowspan="2" |''Thoralicystis'' |''T. sp.'' |''Araneograptus murrayi'' zone |A common cornute. | |- |''T. zagoraensis'' |?''Baltograptus jacksoni'' zone |A rare cornute. | |- |''Villebrunaster'' |''V. fezouatensis<ref name=":8">{{Cite journal |last1=Blake |first1=Daniel B. |last2=Hotchkiss |first2=Frederick H. C. |date=2022-08-01 |title=Origin of the subphylum Asterozoa and redescription of a Moroccan Ordovician somasteroid |journal=Geobios |volume=72-73 |pages=22–36 |doi=10.1016/j.geobios.2022.07.002 |bibcode=2022Geobi..72...22B |issn=0016-6995|doi-access=free }}</ref>'' |''Araneograptus murrayi'' zone |A chinianasterid somasteroid, a sea star-like echinoderm with a broad pentagonal body. Originally described in a new genus, ''Cantabrigiaster,<ref>{{Cite journal |last1=Hunter |first1=Aaron W. |last2=Ortega-Hernández |first2=Javier |date=January 2021 |title=A new somasteroid from the Fezouata Lagerstätte in Morocco and the Early Ordovician origin of Asterozoa |url=https://www.researchgate.net/publication/348622592 |journal=Biology Letters |language=en |volume=17 |issue=1 |article-number=20200809 |doi=10.1098/rsbl.2020.0809 |issn=1744-9561 |pmc=7876607 |pmid=33465330}}</ref>'' but subsequently referred to ''Villebrunaster.<ref name=":8" />'' | |- |''Vizcainocarpus'' |''V. sp.'' |''Araneograptus murrayi'' zone |A rare mitrate. | |}

=== Molluscs === {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Molluscs of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Alococoncha''? |''A.? sp.'' |"''Azygograptus'' interval" |A rare ctenodontid protobranch bivalve. It was likely an infaunal deposit feeder.<ref name=":5">{{Cite journal |last=Polechová |first=Marika |date=October 2016 |title=The bivalve fauna from the Fezouata Formation (Lower Ordovician) of Morocco and its significance for palaeobiogeography, palaeoecology and early diversification of bivalves |url=https://www.researchgate.net/publication/288906976 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=155–169 |bibcode=2016PPP...460..155P |doi=10.1016/j.palaeo.2015.12.016}}</ref> | |- |''Babinka'' |''B. prima'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone,

"''Azygograptus'' interval" |A common bivalve, tentatively identified as one of the oldest lucinids (hatchet shells). It was likely an infaunal filter-feeder capable of rapid vertical movement within sediment. Like modern lucinids, it may have been a specialist in oxygen-poor environments thanks to endosymbiotic sulfide-oxidizing bacteria.<ref name=":5" /> | |- |''Bactroceras'' |''B. sp.'' |"late early to mid Floian" |A very rare baltoceratid "nautiloid" cephalopod in the order Orthocerida.''<ref name=":4">{{Cite journal |last1=Kröger |first1=Björn |last2=Lefebvre |first2=Bertrand |date=August 2012 |title=Palaeogeography and palaeoecology of early Floian (Early Ordovician) cephalopods from the Upper Fezouata Formation, Anti-Atlas, Morocco |url=https://fr.copernicus.org/articles/15/61/2012/fr-15-61-2012.pdf |journal=Fossil Record |language=en |volume=15 |issue=2 |pages=61–75 |doi=10.1002/mmng.201200004 |doi-access=free|bibcode=2012FossR..15...61K }}</ref>'' | |- | rowspan="2" |''Bathmoceras'' |''B. australe'' |"late early to mid Floian" | rowspan="2" |A very rare bathmoceratid "nautiloid" cephalopod in the order Ellesmerocerida.<ref name=":4" /> | |- |''B. taichoutense<ref name=":4" />'' |"late early to mid Floian" | |- |''Calvapilosa''<ref name=":6">{{Cite journal |last1=Vinther |first1=Jakob |last2=Parry |first2=Luke |last3=Briggs |first3=Derek E. G. |last4=Van Roy |first4=Peter |date=February 2017 |title=Ancestral morphology of crown-group molluscs revealed by a new Ordovician stem aculiferan |url=http://www.nature.com/articles/nature21055 |journal=Nature |language=en |volume=542 |issue=7642 |pages=471–474 |doi=10.1038/nature21055 |pmid=28166536 |bibcode=2017Natur.542..471V |issn=0028-0836|hdl=1983/70368bb0-c2df-490a-8b45-26e7b4397596 |s2cid=205253410 |hdl-access=free |url-access=subscription }}</ref> |''C. kroegeri<ref name=":6" />'' |''Araneograptus murrayi'' zone |A mollusc in the group Sachitida (the proposed clade containing living aculiferans and their extinct stem group relatives such as halkieriids). It had a flattened body with an extensive radula, a mantle covered in bristle-like sclerites, and a single flat calcareous shell on the head.<ref name=":6" /> | |- | rowspan="3" |''Carcassonnella'' |''C. courtessolei'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone |A common tergomyan monoplacophoran.''<ref name=":1">{{Cite journal |last=Ebbestad |first=Jan Ove R. |date=October 2016 |title=Gastropoda, Tergomya and Paragastropoda (Mollusca) from the Lower Ordovician Fezouata Formation, Morocco |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216000043 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=87–96 |bibcode=2016PPP...460...87E |doi=10.1016/j.palaeo.2016.01.003|url-access=subscription }}</ref>'' | |- |''C. sp.'' |''Araneograptus murrayi'' zone, ?''Cymatograptus protobalticus'' zone? |A common tergomyan monoplacophoran known from tiny juveniles which died in relatively deep, oxygen-poor waters.''<ref name=":1" />'' | |- |''C. vizcainoi'' |?''Cymatograptus protobalticus'' zone |A common tergomyan monoplacophoran.''<ref name=":1" />'' | |- |''Cardiolaria''? | |"''Azygograptus'' interval" |A rare afghanodesmatid protobranch bivalve. It may have been an infaunal filter-feeder.<ref name=":5" /> | |- |''Cienagomya''? |''C.? sp.'' |?''Cymatograptus protobalticus'' zone, |A very rare actinodontid bivalve in the family Intihuarellidae. It was likely an infaunal filter-feeder.<ref name=":5" /> | |- |''Coxiconchia'' |''C. guiraudi'' |?''Cymatograptus protobalticus'' zone, "''Azygograptus'' interval" |A common bivalve, tentatively identified as one of the oldest lucinids (hatchet shells). It was likely an infaunal filter-feeder capable of rapid vertical movement within sediment. Like modern lucinids, it may have been a specialist in oxygen-poor environments thanks to endosymbiotic sulfide-oxidizing bacteria.<ref name=":5" /> | |- |''Destombesiceras<ref name=":4" />'' |''D. zagorense<ref name=":4" />'' |"late early to mid Floian" |An apicrinoceratid "nautiloid" cephalopod in the order Discosorida. The least rare nautiloid found in the formation, though still uncommon.''<ref name=":4" />'' | |- |''Ekaterodonta'' |''E. courtessolei'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone |A rare afghanodesmatid protobranch bivalve. It was likely an infaunal deposit feeder.<ref name=":5" /> | |- |''Glyptarca'' |''G. sp.'' |?''Cymatograptus protobalticus'' zone, |A rare arcid bivalve. It was likely an infaunal filter-feeder.<ref name=":5" /> | |- |''Lesueurilla'' |''L. prima'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone,

''Baltograptus minutus'' zone<ref name=":39" /> |A lesuerillid gastropod.''<ref name=":1" />'' | |- |''Pelecyogyra''<ref name=":7">{{Cite journal |last1=Ebbestad |first1=Jan Ove R. |last2=Lefebvre |first2=Bertrand |date=November 2015 |title=An unusual onychochilid mollusc from the Ordovician (Tremadocian) Fezouata Formation, Morocco |url=https://linkinghub.elsevier.com/retrieve/pii/S0016699515000807 |journal=Geobios |language=en |volume=48 |issue=6 |pages=427–438 |bibcode=2015Geobi..48..427E |doi=10.1016/j.geobios.2015.09.004|url-access=subscription }}</ref> |''P. fezouataensis<ref name=":7" />'' |''Araneograptus murrayi'' zone |A common onychochilid paragastropod, an extinct group of gastropod-like molluscs with asymmetrically coiled shells. It was gregarious and primarily found in shallow oxygenated waters represented at the Oued Beni Zoli locality.<ref name=":7" />''<ref name=":1" />'' | |- |''Polymeres'' |''P. sp.'' |"late early to mid Floian" |A rare polymerid "nautiloid" cephalopod in the order Dissidocerida.''<ref name=":4" />'' | |- |''Praenucula''? |''P.? sp.'' |?''Cymatograptus protobalticus'' zone, |A very rare praenuculid protobranch bivalve known from a single specimen. It was likely an infaunal deposit feeder.<ref name=":5" /> | |- |''Protocyptendoceras'' |''P. longicameratum<ref name=":4" />'' |"late early to mid Floian" |A very rare protocameroceratid "nautiloid" cephalopod in the order Endocerida.''<ref name=":4" />'' | |- |''Redonia'' |''R. michelae'' |?''Cymatograptus protobalticus'' zone, ''?Baltograptus jacksoni'' zone,

"''Azygograptus'' interval" |A very common actinodontid bivalve in the family Redoniidae. It was likely a shallowly infaunal filter-feeder capable of rapid reburial, with the majority of the shell embedded in sediment.<ref name=":5" /> | |- |''Ribeiria'' |''R. sp.'' |Upper Fezouata |A rostroconch.<ref name=":10">{{Cite journal |last1=Lefebvre |first1=Bertrand |last2=El Hariri |first2=Khadija |last3=Lerosey-Aubril |first3=Rudy |last4=Servais |first4=Thomas |last5=Van Roy |first5=Peter |date=2016 |title=The Fezouata Shale (Lower Ordovician, Anti-Atlas, Morocco): A historical review |url=https://foreninger.uio.no/ngf/GEO3030/Litteratur/Fezouata-Lefebvre%20et%20al%202015%20-%20The%20Fezouata%20Shale%20a%20historical%20review%20-%20Palaeo3.pdf |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=7–23 |doi=10.1016/j.palaeo.2015.10.048|bibcode=2016PPP...460....7L }}</ref> | |- |''Rioceras'' |''R. sp.'' |"late early to mid Floian" |A very rare rioceratid "nautiloid" cephalopod in the order Ellesmerocerida.<ref name=":4" /> | |- |''Sinuites'' |''S. sp.'' |''?Baltograptus jacksoni'' zone |A rare bellerophontoid gastropod.''<ref name=":1" />'' | |- |''Thoralispira'' |''T. laevis'' |''?Baltograptus jacksoni'' zone |A common tergomyan monoplacophoran.''<ref name=":1" />'' | |}

=== Conodonts === Conodonts from the Fezouata Formation are mostly coniform elements of Early Ordovician species.''<ref name=":2">{{Cite journal |last1=Lehnert |first1=Oliver |last2=Nowak |first2=Hendrik |last3=Sarmiento |first3=Graciela N. |last4=Gutiérrez-Marco |first4=Juan Carlos |last5=Akodad |first5=Mustapha |last6=Servais |first6=Thomas |date=October 2016 |title=Conodonts from the Lower Ordovician of Morocco — Contributions to age and faunal diversity of the Fezouata Lagerstätte and peri-Gondwana biogeography |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216300323 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=50–61 |bibcode=2016PPP...460...50L |doi=10.1016/j.palaeo.2016.03.023|url-access=subscription }}</ref>'' Overall diversity is rather low, and species which were common in temperate and tropical seas are apparently absent. The Fezouata Formation appears to be an exemplar of the 'subpolar domain', an assemblage of cold-water coastal conodonts native to the South Polar region of the Early Ordovician. Similar conodont faunas are known from Early Ordovician deposits in Central Europe, which was also located near the South Pole. The 'subpolar domain' survived into the Middle Ordovician and expanded into areas now found in the Middle East.''<ref name=":2" />''

Fezouata conodonts are difficult to correlate to biostratigraphic systems in nearby temperate regions such as Baltica. Most species appear to correspond to the time interval stretching from the ''Oelandodus elongatus-Acodus deltatus'' subzone of the ''Paroistodus proteus'' zone (uppermost Tremadocian) up through the ''Prioniodus oepiki'' zone (lower Floian).''<ref name=":2" />'' {| class="wikitable sortable mw-collapsible" ! colspan="4" align="center" |Conodonts of the Fezouata Formation |- !Genus !Species !Notes !Images |- |''Acodus'' |''A. deltatus'' |An acodontid prioniodontid | |- |''Cornuodus'' |''C. longibasis'' |A strachanognathid | |- |''Drepanodus'' |''D. arcuatus'' |A drepanoistodontid or protopanderodontid | |- |''Drepanoistodus'' |''D. cf. forceps'' |A drepanoistodontid | |- | rowspan="2" |''Paltodus'' |''P. cf. inaequalis'' | rowspan="2" |A drepanoistodontid | |- |''P. spp.'' | |- | rowspan="2" |''Parapaltodus'' |''P. cf. flexuosus'' | rowspan="2" |An acanthodontid | |- |''P. aff. simplicissimus'' | |- | rowspan="2" |''Paroistodus'' |''P. cf. parallellus'' | rowspan="2" |A drepanoistodontid | |- |''P. proteus'' | |- | rowspan="2" |''Periodon'' |''P. cf. primus'' | rowspan="2" |A periodontid ozarkodinid | |- |''P. cf. selenopsis'' | |- |''Prioniodus'' |''P. cf. gilberti'' |A balognathid prioniodontid | |- |''Protopanderodus'' |''P. cf. leonardii'' |A protopanderodontid | |- |''Scalpellodus'' |''S. aff. gracilis'' |An acanthodontid | |- |''Scolopodus'' |''S. aff. krummi'' |A protopanderodontid | |- | rowspan="2" |''Semiacontiodus'' |''S. cf. cornuformis'' | rowspan="2" |A protopanderodontid | |- |''S. sp.'' | |- |''Stolodus'' |''S. cf. stola'' |A belodellid | |- | rowspan="2" |''Tripodus'' |''T. aff. laevis'' | rowspan="2" |An acodontid | |- |''T. cf. sweeti'' | |}

=== Graptolites === Graptolites in the Fezouata Formation are important for biostratigraphic correlation to other regions. Most species found in the formation are assigned to planktic (graptoloid) groups, though some mesh-shaped taxa (like ''Araneograptus'' and ''Rhabdinopora'') may have been transitional between sessile (dendroid) graptolites and free-floating graptoloids.''<ref name=":0">{{Cite journal |last1=Gutiérrez-Marco |first1=Juan Carlos |last2=Martin |first2=Emmanuel L.O. |date=October 2016 |title=Biostratigraphy and palaeoecology of Lower Ordovician graptolites from the Fezouata Shale (Moroccan Anti-Atlas) |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216302814 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=35–49 |bibcode=2016PPP...460...35G |doi=10.1016/j.palaeo.2016.07.026|url-access=subscription }}</ref>'' Sessile forms, such as ''Didymograptus'', ''Dictyonema'', ''Webbyites'', and rhabdopleurids, are also present but much more rare.<ref name=":32">{{Cite journal |last1=Nanglu |first1=Karma |last2=Waskom |first2=Madeleine E. |last3=Richards |first3=Jared C. |last4=Ortega-Hernández |first4=Javier |date=2023-10-11 |title=Rhabdopleurid epibionts from the Ordovician Fezouata Shale biota and the longevity of cross-phylum interactions |journal=Communications Biology |language=en |volume=6 |issue=1 |page=1002 |doi=10.1038/s42003-023-05377-x |issn=2399-3642 |pmc=10567727 |pmid=37821659}}</ref>

The graptolites of the Fezouata Formation are distributed over 10 biozones. In order, these zones are: the ''Anisograptus matanensis'' zone (1)'', Rhabdinopora flabelliformis anglica'' zone (2), "''Adelograptus''" ''tenellus'' zone (3), ''Aorograptus victoriae'' zone (4), ''Araneograptus murrayi'' zone (5), ''Hunnegraptus copiosus'' zone (6), ?''Cymatograptus protobalticus'' zone (7), ?''Baltograptus jacksoni'' zone (8), ''Baltograptus minutus'' zone (9), and the "''Azygograptus'' interval" (10). Not all of the index taxa which these zones are named for are known from the Fezouata Formation. The Tremadocian-Floian boundary is approximately at the level between the ''Hunnegraptus copiosus'' and ''?Cymatograptus probalticus'' zones.''<ref name=":0" />''

The most well-preserved fossils in the Fezouata Formation generally come from strata of the late Tremadocian (late ''Araneograptus murrayi'' zone and early ''Hunnegraptus copiosus'' zone) and the mid-late Floian (late ''Baltograptus minutus'' zone and early "''Azygograptus'' interval").''<ref name=":0" />'' {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Graptolites of the Fezouata Formation |- !Genus !Species !Graptolite biozone !Notes !Images |- |''"Adelograptus"'' |''"A." tenellus'' |"''Adelograptus''" ''tenellus'' zone |A multiramous anisograptid (basal graptoloid). | |- |''Ancoragraptus'' |''A. bulmani'' |''Aorograptus victoriae'' zone |A "psigraptid"-type anisograptid, with a small number of reclined stipes. | |- |''Anisograptus'' |''A. cf. matanensis'' |''Anisograptus matanensis'' zone |A multiramous anisograptid. Very rare, only a single fossil may indicate its presence. | |- |''Araneograptus'' |''A. murrayi'' |''Araneograptus murrayi'' zone |A common basal graptoloid with a mesh-like conical colony form. Potentially a species of ''Sagenograptus''. | |- |''Azygograptus'' |''A. eivionicus'' |"''Azygograptus'' interval" |A rare "azygograptid", a unique type of early graptoloid with a single uniserial stipe, convergently similar to the Silurian-Devonian monograptids. | |- | rowspan="4" |''Baltograptus'' |''B. deflexus'' |''Baltograptus minutus'' zone | rowspan="4" |A didymograptid graptoloid, with two subhorizontal to pendent stipes. | |- |''?B. jacksoni'' |?''Baltograptus jacksoni'' zone | |- |''?B. kurcki'' |''Baltograptus minutus'' zone | |- |''B. minutus'' |''Baltograptus minutus'' zone | |- |''Choristograptus'' |''C. louai'' |''Aorograptus victoriae'' zone |A small and rare anisograptid. | |- | rowspan="2" |''Clonograptus'' |''C. multiplex'' |?''Cymatograptus protobalticus'' zone, ?''Baltograptus jacksoni'' zone | rowspan="2" |A large and common multiramous dichograptid. | |- |''C. rigidus'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone | |- |''?Cymatograptus'' |''?C. protobalticus'' |?''Cymatograptus protobalticus'' zone |A rare didymograptid. | |- |''"Didymograptus"'' |''"D." sp.'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone |A rare didymograptid. | |- |''Expansograptus'' |''E. sp.'' |?''Baltograptus jacksoni'' zone |A rare didymograptid with two horizontal stipes. | |- |''Holograptus'' |''H. sp.'' |''Baltograptus minutus'' zone<ref name=":39" /> |A multiramous dichograptid. | |- |''Hunnegraptus'' |''H. copiosus'' |''Hunnegraptus copiosus'' zone |A multiramous anisograptid. | |- |''"Kiaerograptus"'' |''"K." supremus'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone |A "psigraptid"-type anisograptid, with a small number of reclined stipes. | |- | rowspan="2" |''Paradelograptus'' |''P. norvegicus'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone | rowspan="2" |A multiramous sigmagraptid graptoloid. | |- |''P. tenuis'' |''Araneograptus murrayi'' zone | |- |''Paratemnograptus'' |''P. magnificus'' |''Araneograptus murrayi'' zone, ''Hunnegraptus copiosus'' zone |A large and common multiramous anisograptid. | |- | rowspan="4" |''Rhabdinopora'' |''R. flabelliformis anglica'' |''Rhabdinopora flabelliformis anglica'' zone | rowspan="4" |A basal graptoloid with a mesh-like conical colony form transitional between dendroids (such as ''Dictyonema'') and early graptoloids such as anisograptids. | |- |''R. flabelliformis canadensis'' |''Anisograptus matanensis'' zone | |- |''R. flabelliformis flabelliformis'' |''Anisograptus matanensis'' zone, ''Rhabdinopora flabelliformis anglica'' zone | |- |''R. flabelliformis socialis'' |''Anisograptus matanensis'' zone | |- |indeterminate rhabdopleurid | |''Sagenopterus (Araneograptus) murrayi'' zone |Tubes of ''Rhabdopleura''-like pterobranchs have been found growing around the edge of a cephalopod shell, one of the few examples of hard substrate to be found in the formation. This association is similar to the ecology reported for ''Yuknessia'' from the Burgess Shale.<ref name=":32" /> | |- |''Schizograptus'' |''?S. sp.'' |''Baltograptus minutus'' zone |A common multiramous dichograptid, also sometimes classified as ''Holograptus''. | |- | rowspan="2" |"''Tetragraptus''" |"''T. bulmani''" |''Araneograptus murrayi'' zone | rowspan="2" |A common tetragraptid graptoloid with two to four reclined to pendent stipes. | |- |Other ''Tetragraptus'' species |''Araneograptus murrayi'' zone, ?''Baltograptus jacksoni'' zone | |- |''Webbyites'' |''W. felix<ref name=":33">{{Cite journal |last1=Muir |first1=L A |last2=Gutiérrez-Marco |first2=J C |date=2023 |title=A new species of the problematic organism Webbyites from the Early Ordovician Fezouata Biota of Morocco |url=https://kirj.ee/earth-publications/?filter[year]=2023&filter[issue]=1468&filter[publication]=12591 |journal=Estonian Journal of Earth Sciences |language=en |volume=72 |issue=1 |page=74 |doi=10.3176/earth.2023.24 |issn=1736-4728|doi-access=free |hdl=10261/348447 |hdl-access=free }}</ref>'' |"probable late Tremadocian" |An enigmatic feather-shaped organism identified as a sessile graptolite.<ref name=":33" /> | |}

=== Brachiopods === {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Brachiopods of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Acrothele'' |''A. sp.'' |Lower Fezouata<ref name=":10" /> |An acrothelid linguliform. | |- |''Angusticardinia'' |''A. sp.'' |Upper Fezouata<ref name=":10" /> |An angusticardiniid orthid. | |- |''Lingula'' |''L. salteri'' |Upper Fezouata<ref name=":10" /> |A lingulid linguliform. | |- |''Orbithele'' |''O. vana'' |Upper Fezouata<ref name=":10" /> |An acrothelid linguliform. | |- |''Paurorthis'' |''P. tadristensis'' |Upper Fezouata<ref name=":10" /> |A paurorthid orthid. | |- |''Plectorthis'' |''P. simplex'' |Lower Fezouata<ref name=":10" /> |A plectorthid orthid. | |- |''Ranorthis'' |''R. fasciata'' |Lower and Upper Fezouata<ref name=":10" /> |A ranorthid orthid.<ref name=":9" /> | |- |''Tarfaya'' |''T. marocana'' |Upper Fezouata<ref name=":10" /> |A heterorthid orthid. | |}

=== Sponges === Many sponges from the Fezouata biota remain unnamed, including protomonaxonid demosponges (leptomitids, "choiids", hamptoniids, piraniids), a hazeliid, reticulosan hexactinellids (asthenospongiids,''<ref name=":13" />'' etc.), and other indeterminate forms.<ref name=":14">{{Cite journal |last=Botting |first=Joseph P. |date=2016 |title=Diversity and ecology of sponges in the Early Ordovician Fezouata Biota, Morocco |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216301584 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=75–86 |doi=10.1016/j.palaeo.2016.05.018|bibcode=2016PPP...460...75B |url-access=subscription }}</ref> Many of the sponges have affinities with Cambrian taxa common in Burgess Shale-type faunas.''<ref name=":13" />'' Though at least 27 sponge species have been recorded in the biota, nearly all occurrences are monospecific death assemblages, with the exception of ''Pirania auraeum'', which has a broader and less dense distribution in the formation. Periodic unstable seafloor conditions (potentially related to seasonal disruptions) would have favored species-poor colonization events over short time periods, rather than a stable and diverse equilibrium.<ref name=":14" />

This is unusual relative to other Ordovician sponge ecosystems, such as the Builth Inlier of Wales. Another difference is how Fezouata's sponge fauna consists mostly of protomonaxonids, with a few reticulosans occupying course-grained shallow seabeds. Conversely, in Wales there is a clear succession of diverse and sturdy lithistids and thick-walled hexactinellids in shallow reefs and other energetic areas, with protomonaxonids at intermediate depths, and reticulosans in the deepest and calmest environments.<ref name=":14" /> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Sponges of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Choia'' |''C. sp.'' |Upper Fezouata |A "choiid".''<ref name=":13" />''<ref name=":14" /> |center|frameless|150x150px |- |''Choiaella'' |''C. sp.'' | |A "choiid".<ref name=":14" /> | |- |''Hamptonia'' |''H. sp.'' | |A hamptoniid.<ref name=":14" /> | |- |''<nowiki/>'Hamptonia''' |''<nowiki/>'H.' christi<ref name=":13" />'' |Upper Fezouata |An indeterminate protomonaxonid. Previously considered a species of ''Hamptonia'',''<ref name=":13" />'' but likely belongs to a new genus.<ref name=":14" /> | |- |''Pirania'' |''P. auraeum<ref name=":13" />'' |Upper Fezouata |A piraniid.''<ref name=":13" />''<ref name=":14" /> | |- |''Valospongia?'' |''V.? sp.'' | |A reticulosan.<ref name=":14" /> | |}

=== Other animals === Many animals from the Fezouata biota remain unnamed and undescribed, including bryozoans, chordate "dermal plates", annelid worms, priapulids, problematica, and at least five new species of lobopod, including an armored form.<ref name=":9" /><ref name="DeRoy2010" /> {| class="wikitable sortable mw-collapsible" ! colspan="5" align="center" |Other animals of the Fezouata Formation |- !Genus !Species !Stratigraphy !Notes !Images |- |''Archaeoconularia'' |''A. sp.'' |Lower and Upper Fezouata |A common large conulariid, up to {{Convert|50|cm|in}} tall.''<ref name=":3">{{Cite journal |last1=Van Iten |first1=Heyo |last2=Muir |first2=Lucy |last3=Simões |first3=Marcello G. |last4=Leme |first4=Juliana M. |last5=Marques |first5=Antonio C. |last6=Yoder |first6=Naomi |date=October 2016 |title=Palaeobiogeography, palaeoecology and evolution of Lower Ordovician conulariids and Sphenothallus (Medusozoa, Cnidaria), with emphasis on the Fezouata Shale of southeastern Morocco |url=https://repositorio.unesp.br/server/api/core/bitstreams/76ba63d3-a5fa-484a-b927-f95dffdbdb92/content |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=170–178 |bibcode=2016PPP...460..170V |doi=10.1016/j.palaeo.2016.03.008 |hdl-access=free |hdl=11449/161915}}</ref>'' |- |''Cavernolites'' |''C. senex'' |Upper Fezouata<ref name=":10" /> |A hyolith. |- |''Elegantilites'' |''E. sp.'' |Upper Fezouata<ref name=":10" /> |A hyolith. |- |''Eoconularia'' |''E. sp.'' |Lower and Upper Fezouata |An abundant small conulariid (less than {{Convert|5|cm|in}} tall). Frequently found attached to brachiopods or even other conulariids.''<ref name=":3" />'' |- |''Gamalites?'' |''G.? sp.'' |Upper Fezouata<ref name=":10" /> |A hyolith. |- |''Gompholites'' |''G. sp.'' |Upper Fezouata<ref name=":10" /> |A hyolith. |- |''Nephrotheca'' |''N. sp.'' |Upper Fezouata<ref name=":10" /> |A hyolith. |- |''Palaeoscolex?'' |''P.? tenensis'' |''Araneograptus murrayi'' zone |A palaeoscolecid worm. Though most palaeoscolecids are inferred to be burrowing carnivores, remains from the Fezouata Formation are more consistent with an opportunistic epibenthic lifestyle, patrolling for organic matter on the surface of the seabed.<ref>{{Cite journal |last1=Martin |first1=Emmanuel L.O. |last2=Lerosey-Aubril |first2=Rudy |last3=Vannier |first3=Jean |date=October 2016 |title=Palaeoscolecid worms from the Lower Ordovician Fezouata Lagerstätte, Morocco: Palaeoecological and palaeogeographical implications |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216300621 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=130–141 |bibcode=2016PPP...460..130M |doi=10.1016/j.palaeo.2016.04.009|url-access=subscription }}</ref><ref>{{Cite journal |last1=Kouraiss |first1=Khaoula |last2=El Hariri |first2=Khadija |last3=El Albani |first3=Abderrazak |last4=Azizi |first4=Abdelfattah |last5=Mazurier |first5=Arnaud |last6=Vannier |first6=Jean |date=2018 |title=X-ray microtomography applied to fossils preserved in compression: Palaeoscolescid worms from the Lower Ordovician Fezouata Shale |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018218301627 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=508 |pages=48–58 |doi=10.1016/j.palaeo.2018.07.012|bibcode=2018PPP...508...48K |url-access=subscription }}</ref> |- |''Pauxillites'' |''P. thaddei<ref name=":11">{{Cite journal |last=Valent |first=Martin |date=2015-10-31 |title=Pauxillites thaddei a new lower Ordovician hyolith from Morocco |url=http://fi.nm.cz/wp-content/uploads/2016/05/sbB_c1_2_2015_valent_corbacho_web.pdf |journal=Acta Musei Nationalis Pragae, Series B, Historia Naturalis |language=en |pages=51–54 |doi=10.14446/AMNP.2015.51 |issn=1804-6479}}</ref>'' |Upper Fezouata |A medium-sized pauxillitid hyolith.<ref name=":11" /> |- |''Plumulites'' |''P. bengtsoni<ref name=":12">{{Cite journal |last1=Vinther |first1=Jakob |last2=Van Roy |first2=Peter |last3=Briggs |first3=Derek E. G. |date=2008 |title=Machaeridians are Palaeozoic armoured annelids |url=https://www.nature.com/articles/nature06474 |journal=Nature |language=en |volume=451 |issue=7175 |pages=185–188 |doi=10.1038/nature06474 |pmid=18185586 |bibcode=2008Natur.451..185V |issn=1476-4687|url-access=subscription }}</ref>'' |''Araneograptus murrayi'' zone |A machaeridian (armored annelid worm). This species is the only machaeridian known to preserve soft tissue and jaw material, helping to demonstrate their affinities with aphroditiform polychaetes (scaleworms and kin).<ref name=":12" /><ref>{{Cite journal |last1=Parry |first1=Luke A. |last2=Edgecombe |first2=Gregory D. |last3=Sykes |first3=Dan |last4=Vinther |first4=Jakob |date=2019-07-24 |title=Jaw elements in Plumulites bengtsoni confirm that machaeridians are extinct armoured scaleworms |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=286 |issue=1907 |article-number=20191247 |doi=10.1098/rspb.2019.1247 |issn=0962-8452 |pmc=6661337 |pmid=31337310}}</ref> |center|frameless|150x150px |- |''Sphenothallus'' |''S. spp.'' |Lower and Upper Fezouata |A tubular organism likely closely related to conulariids.''<ref name=":3" />'' |}

=== Other organisms === Chitinozoans, acritarchs, and algae have been recorded from the formation.<ref name=":9" /><ref name=":10" /><ref>{{Cite journal |last1=Nowak |first1=Hendrik |last2=Servais |first2=Thomas |last3=Pittet |first3=Bernard |last4=Vaucher |first4=Romain |last5=Akodad |first5=Mustapha |last6=Gaines |first6=Robert R. |last7=Vandenbroucke |first7=Thijs R.A. |date=2016 |title=Palynomorphs of the Fezouata Shale (Lower Ordovician, Morocco): Age and environmental constraints of the Fezouata Biota |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216001693 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=460 |pages=62–74 |doi=10.1016/j.palaeo.2016.03.007|bibcode=2016PPP...460...62N |url-access=subscription }}</ref>

== References == {{reflist}}

Category:Fezouata Formation Category:Ordovician System of Africa Category:Lower Ordovician Series Category:Tremadocian Category:Floian Category:Shale formations Category:Paleontology in Morocco Category:First 100 IUGS Geological Heritage Sites Category:Lagerstätten