{{Short description|Devonian fossil locality in Canada}} {{Infobox landform |name=MOTH |type=Geologic site |coordinates={{coord|62.55|-127.75|display=it}} |location=Northwest Territories, Canada |image=File:'Wonder Block' cast (8 fossil fish individuals, of 7 species)..jpg |caption=A cast of the "Wonder Block", a rock slab from MOTH with 7 different species (8 fish in total) in one place:<ref name=":102"/> <br />an unnamed ischnacanthid (center left), an unnamed osteostracan (top left), ''Brochoadmones'' (two largest fish near the center), ''Lupopsyrus'' (above the left ''Brochoadmones''), ''Drepanolepis'' (bottom center), ''Obtusacanthus'' (top right), ''Furcacauda'' (bottom right) |pushpin_map=Canada |pushpin_relief=1 |age=Lochkovian (Early Devonian) |map_caption= }} The '''Man-on-the-hill''' ('''MOTH''') locality is a fossil site in the Northwest Territories of Canada renowned for its incredibly well-preserved Early Devonian fish fossils. Discovered in the Mackenzie Mountains in the 1960s, MOTH accumulated greater prestige in the late 20th century, with many fossil fish species only known from this one site. The fauna consists of both jawed fish (mostly acanthodians, the "spiny sharks") and jawless fish (armored osteostracans and pteraspidomorphs, as well as distinctive fork-tailed furcacaudiform thelodonts). The geology of MOTH reconstructs the area as a calm marine environment with mixed sediment sources along the western coast of Laurussia.<ref name=":8" />
== History == In the mid-1960s, geological mappers from the Geological Survey of Canada (GSC) discovered well-preserved fish fossils on a steep mountainside in the Mackenzie Mountains, about {{Convert|70|km|mi|abbr=on}} northeast from the mining town of Tungsten, Northwest Territories. At the time, the site was known as '''GSC locality 69014'''.<ref>{{Cite journal |last=Dineley |first=David L. |date=1967 |title=Palaeontology: Mackenzie Mountains, District of Mackenzie |url=https://emrlibrary.gov.yk.ca/gsc/papers/68-1A.pdf |journal=Geological Survey of Canada Report of Activities |volume=68 |issue=1 |page=101}}</ref><ref>{{Cite journal |last=Gabrielse |first=H. |last2=Blusson |first2=S.L. |last3=Roddick |first3=J.A. |date=1973 |title=Geology of Flat River, Glacier Lake and Wrigley Lake map areas, District of Mackenzie, Northwest Territories |url=https://emrlibrary.gov.yk.ca/gsc/memoirs/366/memoir.pdf |journal=Geological Survey of Canada Memoirs |volume=366 |pages=1–268}}</ref><ref name=":9" /> By the late 1970s, it had gained renown among Canadian paleoichthyologists, initiating a long list of new species discovered at the site.<ref name=":9" /><ref name=":20">{{Cite journal |last=Bernacsek |first=G.M. |last2=Dineley |first2=D.L. |date=1977 |title=New acanthodians from the Delorme Formation (Lower Devonian) of N.W.T., Canada |journal=Palaeontographica, Abteilung A |volume=159 |pages=1–25}}</ref>
The University of Alberta Laboratory for Vertebrate Paleontology (UALVP), which catalogues the site as '''UALVP locality 129''', handled most subsequent collecting efforts. UA paleontologists Brian D.E. Chatterton and Mark V.H. Wilson led expeditions in 1983, 1990, 1996, 1998, and 2013, greatly increasing the volume of fossils recovered from the site.<ref name=":0" /> A nearby rock landmark, resembling a man sitting on the ridge, inspired a persistent nickname for the site: '''Man-on-the-hill''' (MOTH).<ref name=":5" /><ref name=":10" /><ref name=":70" /> The main fossiliferous section of MOTH is an Early Devonian horizon at the level of 180 meters, and fossils are also found on the talus slope of the mountainside.<ref name=":8">{{Cite journal |last=Zorn |first=Marilyn E |last2=Caldwell |first2=Michael W |last3=Wilson |first3=Mark VH |date=2005-05-01 |title=Lithological analysis of the Lower Devonian vertebrate-bearing beds at the MOTH locality, N.W.T., Canada: insights to taphonomy and depositional setting |url=http://www.nrcresearchpress.com/doi/10.1139/e05-015 |journal=Canadian Journal of Earth Sciences |language=en |volume=42 |issue=5 |pages=763–775 |doi=10.1139/e05-015 |issn=0008-4077}}</ref> Though MOTH is the most productive fish site in the Mackenzie Mountains, it is not alone: well-preserved Silurian fish are also known from lower layers of the site (known as B-MOTH),<ref name=":21">{{Cite journal |last=Soehn |first=Kenneth L. |last2=Hanke |first2=Gavin F. |last3=Märss |first3=Tiiu |last4=Wilson |first4=Mark V.H. |date=2000 |title=Preliminary vertebrate biostratigraphy of the Avalanche Lake sections (Wenlock, Silurian), southern Mackenzie Mountains, N.W.T., and review of northwestern Canadian vertebrate localities of Silurian Age |journal=Courier Forschungsinstitut Senckenberg |volume=223 |pages=129–156}}</ref><ref>{{Cite journal |last=Hanke |first=Gavin F |last2=Wilson |first2=Mark VH |last3=Lindoe |first3=L Allan |date=2001 |title=New species of Silurian acanthodians from the Mackenzie Mountains, Canada |url=https://cdnsciencepub.com/doi/abs/10.1139/e01-039 |journal=Canadian Journal of Earth Sciences |volume=38 |issue=11 |pages=1517–1529 |doi=10.1139/e01-039 |issn=0008-4077}}</ref> strata in the vicinity of Avalanche Lake,<ref>{{Cite journal |last=Soehn |first=Kenneth L. |last2=Wilson |first2=Mark V. H. |date=1990-12-20 |title=A complete, articulated heterostracan from Wenlockian (Silurian) beds of the Delorme Group, Mackenzie Mountains, Northwest Territories, Canada |journal=Journal of Vertebrate Paleontology |volume=10 |issue=4 |pages=405–419 |doi=10.1080/02724634.1990.10011825 |issn=0272-4634 |jstor=4523341}}</ref><ref name=":16" /><ref name=":10" /><ref name=":21" /> and elsewhere in the range.<ref name=":9" />
== Geology == MOTH corresponds to a transitional zone between the clastic shales of the Road River Formation and the shelf carbonates of the Delorme Group.<ref name=":8" /> An earliest Devonian (Lochkovian) age is established by its fossil fauna, with distinctive Lochkovian fish such as ''Waengsjoeaspis'', ''Canadapteraspis'', ''Romundina'', ''Altholepis'', ''Polymerolepis'', and ''Seretolepis''. Brachiopod and conodont fossils also agree with this age estimate.<ref name=":5" /> At the time, the area would have been the tropical western continental shelf of Laurussia, fractured into many smaller basins and platforms by rifting along the Cordilleran front.<ref name=":8" />
The vertebrate-bearing layers of MOTH are mainly composed of finely layered light grey argillaceous (clay-rich) limestone and dark grey silty calcareous shale. Fine grains of dolomite, calcite, and quartz are the predominant minerals in the sediment, reflecting a mixture of carbonate and siliciclastic inputs, including sharp grains sourced from airborne dust. The layers are flat-lying and undisturbed apart from subtle bioturbation, indicating perpetually calm waters. Older studies advocated for a shallow-water (tide pool or lagoon) environment, based on the assumption that its fish and invertebrates preferred coastal or freshwater habitats.<ref name=":9" /> A 2005 overview instead supported a more offshore environment, below storm wave base. In any case, the presence of pyrite indicates that bottom waters were anoxic (oxygen-deprived), allowing for high-fidelity fossil preservation. The exact cause of death is unknown for the fauna, as there is no evidence for turbidites (underwater mudslides) or seasonal water column disruptions.<ref name=":8" /> MOTH can be considered a lagerstätte.<ref name=":8" />
== Paleobiota == More than 72 vertebrate species are known from MOTH as of 2015, though only around half have been formally named and described.<ref name=":0">{{Cite journal |last=Blais |first=Stephanie A. |last2=Hermus |first2=Chelsea R. |last3=Wilson |first3=Mark V. H. |date=2015-01-02 |title=Four new Early Devonian ischnacanthid acanthodians from the Mackenzie Mountains, Northwest Territories, Canada: an early experiment in dental diversity |url=http://www.tandfonline.com/doi/full/10.1080/02724634.2014.948546 |journal=Journal of Vertebrate Paleontology |language=en |volume=35 |issue=1 |article-number=e948546 |doi=10.1080/02724634.2014.948546 |issn=0272-4634}}</ref>
=== Acanthodii === A few fully articulated ischnacanthiform fossils cannot be assigned to a specific species, as their diagnostic teeth are obscured by scales. Various MOTH ischnacanthid fossils have been referred to ''Ischnacanthus gracilis'', though later studies refuted these claims.<ref>{{Cite journal |last=Gagnier |first=Pierre-Yves |last2=Wilson |first2=Mark V. H. |date=1995-01-01 |title=New evidences on jaw bones and jaw articulations in acanthodians |url=https://www.sciencedirect.com/science/article/pii/S0016699595801014 |journal=Geobios |series=Premiers Vertandébrandés et Vertandébrandés Infandérieurs |volume=28 |pages=137–143 |doi=10.1016/S0016-6995(95)80101-4 |issn=0016-6995}}</ref><ref name=":0" /> A 2001 UA biology dissertation by Gavin Hanke provides many new species names for MOTH specimens, but some of these names are yet to be published in a peer-reviewed journal.<ref name=":11">{{Cite thesis |last=Hanke |first=Gavin Frank |date=2001 |title=Comparison of an early Devonian acanthodian and putative chondrichthyan assemblage using both isolated and articulated remains from the Mackenzie Mountains, with a cladistic analysis of early gnathostomes |url=https://era.library.ualberta.ca/items/1229f847-4b57-4017-8d8c-aa1db56abf20 |publisher=University of Alberta |doi=10.7939/r3-cqef-jh86 |doi-access=free |type=PhD Thesis}}</ref> {| class="wikitable" align="center" ! colspan="4" align="center" |'''Acanthodians''' '''("spiny sharks") and acanthodian-like fish of MOTH''' |- !Genus !Species !Notes !Images |- |''Altholepis'' |''A.'' spp. |Three new species from MOTH have scales resembling ''Altholepis'', though these species have yet to be formally named and described.<ref name=":12">{{Cite book |last=Wilson |first=M.V.H. |title=Pan-Arctic Palaeozoic Tectonics, Evolution of Basins and Faunas |last2=Hanke |first2=G.F. |last3=Soehn |first3=K.L. |publisher=IGCP 406 |year=2000 |editor-last=Antoshkina |editor-first=A. |series=Ichthyolith Issues Special Publication 6 |location=Syktyvkar |pages=137–141 |chapter=Diversity and age of the Devonian vertebrate assemblage at MOTH, Mackenzie Mountains, Northwest Territories, Canada |editor-last2=Malysheva |editor-first2=E. |editor-last3=Wilson |editor-first3=M.V.H. |chapter-url=https://www.researchgate.net/publication/258697419}}</ref><ref name=":11" /><ref>{{Cite journal |last=Burrow |first=Carole J. |last2=Turner |first2=Susan |date=2018 |title=Stem chondrichthyan microfossils from the Lower Old Red Sandstone of the Welsh Borderland |url=https://www.researchgate.net/publication/328042230 |journal=Acta Geologica Polonica |volume=68 |issue=3 |pages=321–334 |doi=10.1515/agp-2018-0010}}</ref> | |- |''Brochoadmones<ref name=":20" />'' |''B. milesi'' |A deep-bodied acanthodian with many small spiny "finlets" on its underside.''<ref name=":18">{{Cite journal |last1=Gagnier |first1=Pierre-Yves |last2=Wilson |first2=Mark V.H. |date=1996 |title=Early Devonian acanthodians from northern Canada |url=https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_39/vol39_part2_pp241-258.pdf |journal=Palaeontology |volume=39 |issue=2 |pages=241–258}}</ref>''<ref name=":102">{{Cite journal |last1=Hanke |first1=Gavin F. |last2=Wilson |first2=Mark V. H. |date=2006-09-11 |title=Anatomy of the early Devonian acanthodian ''Brochoadmones milesi'' based on nearly complete body fossils, with comments on the evolution and development of paired fins |url=https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282006%2926%5B526%3AAOTEDA%5D2.0.CO%3B2 |journal=Journal of Vertebrate Paleontology |volume=26 |issue=3 |pages=526–537 |doi=10.1671/0272-4634(2006)26[526:AOTEDA]2.0.CO;2 |issn=0272-4634 |s2cid=86378747 |url-access=subscription}}</ref> |center|150x150px |- |''Cassidiceps<ref name=":18" />'' |''C. vermiculatus'' |A deep-bodied acanthodian with a head covered in thick densely-textured scales.''<ref name=":18" />'' | |- |''Erymnacanthus<ref name=":0" />'' |''E. clivus'' |An ischnacanthid with small teeth and deep jaws.<ref name=":0" /> |center|150x150px |- |''Euryacanthus<ref name=":0" />'' |''E. rugosus'' |An ischnacanthid with large, robust teeth.<ref name=":0" /><ref name=":3">{{Cite journal |last=Blais |first=Stephanie A. |date=2017-01-01 |editor-last=Evans |editor-first=David C. |title=Precise occlusion and trophic niche differentiation indicate specialized feeding in Early Devonian jawed vertebrates |url=https://facetsjournal.com/doi/10.1139/facets-2016-0030 |journal=FACETS |language=en |volume=2 |pages=513–530 |doi=10.1139/facets-2016-0030 |issn=2371-1671}}</ref> | |- |''Gladiobranchus<ref name=":20" />'' |''G. probaton'' |A toothless gladiobranchid diplacanthiform. Potentially a junior synonym of ''Uraniacanthus spinosus'', an English acanthodian which is exceedingly similar to ''Gladiobranchus''.''<ref name=":62">{{Cite journal |last1=Hanke |first1=Gavin F. |last2=Davis |first2=Samuel P. |last3=Wilson |first3=Mark V. H. |date=2001-12-14 |title=New species of the acanthodian genus ''Tetanopsyrus'' from northern Canada, and comments on related taxa |url=https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282001%29021%5B0740%3ANSOTAG%5D2.0.CO%3B2 |journal=Journal of Vertebrate Paleontology |volume=21 |issue=4 |pages=740–753 |doi=10.1671/0272-4634(2001)021[0740:NSOTAG]2.0.CO;2 |issn=0272-4634 |jstor=20062014 |s2cid=86098457 |url-access=subscription}}</ref>''<ref name=":32">{{Cite journal |last1=Hanke |first1=Gavin F. |last2=Davis |first2=Samuel P. |date=2008 |title=Redescription of the acanthodian ''Gladiobranchus probaton'' Bernacsek & Dineley, 1977, and comments on diplacanthid relationships |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2008n2a3.pdf |journal=Geodiversitas |volume=30 |issue=2 |pages=303–330}}</ref><ref name=":31">{{Cite journal |last1=Newman |first1=Michael J. |last2=Davidson |first2=Robert G. |last3=Blaauwen |first3=Jan L. Den |last4=Burrow |first4=Carole J. |date=2012 |title=The Early Devonian Acanthodian ''Uraniacanthus curtus'' (Powrie, 1870) n. comb. from the Midland Valley of Scotland |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2012n4a2.pdf |journal=Geodiversitas |volume=34 |issue=4 |pages=739–759 |doi=10.5252/g2012n4a2 |issn=1280-9659 |s2cid=54811929}}</ref> | |- |''Kathemacanthus<ref name=":18" />'' |''K. rosulentus'' |A deep-bodied acanthodian with a "necklace" of artichoke-shaped scales similar to more typical chondrichthyans.''<ref name=":18" /><ref name=":1">{{Cite book |last1=Hanke |first1=Gavin F. |title=Morphology, Phylogeny and Paleobiogeography of Fossil Fishes |last2=Wilson |first2=Mark V.H. |publisher=Verlag Dr. Friedrich Pfeil |year=2010 |location=Munich |pages=159–182 |chapter=The putative stem-group chondrichthyans ''Kathemacanthus'' and ''Seretolepis'' from the Lower Devonian MOTH locality, Mackenzie Mountains, Canada |chapter-url=https://www.researchgate.net/publication/258487908}}</ref>'' | |- |''Lupopsyroides''<ref name=":15">{{Cite book |last=Hanke |first=Gavin F. |title=Recent Advances in the Origin and Early Radiation of Vertebrates |last2=Wilson |first2=Mark V.H. |publisher=Verlag Dr. Friedrich Pfeil |year=2004 |isbn=3-89937-052-X |editor-last=Arratia |editor-first=Gloria |location=München |pages=189–216 |chapter=New teleostome fishes and acanthodian systematics |editor-last2=Wilson |editor-first2=Mark V.H. |editor-last3=Cloutier |editor-first3=Richard}}</ref> |''L. macracanthus'' |A toothless fish with simple scales and no apparent bony skeleton apart from fin spines.<ref name=":11" /><ref name=":15" /> | |- |''Lupopsyrus<ref name=":20" />'' |''L. pygmaeus'' |An enigmatic acanthodian with simple scales and two rows of large keeled scutes on each side of its body.<ref name=":45">{{Cite journal |last1=Hanke |first1=Gavin F. |last2=Davis |first2=Samuel P. |date=September 2012 |title=A re-examination of ''Lupopsyrus pygmaeus'' Bernacsek & Dineley, 1977 (Pisces, Acanthodii) |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2012n3a1.pdf |journal=Geodiversitas |volume=34 |issue=3 |pages=469–487 |doi=10.5252/g2012n3a1 |issn=1280-9659 |s2cid=85622590}}</ref> | |- |''Nostolepis'' |''N. striata'' |A weathered specimen with ''Nostolepis''-type scales, yet to be formally described.<ref name=":12" /><ref name=":11" /> The specimen may be referable to ''Nostovicina laticristata''.<ref>{{Cite journal |last=Burrow |first=Carole Jan |last2=Murphy |first2=Michael |last3=Turner |first3=Susan |date=2023-06-06 |title=Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U.S.A. |url=https://escholarship.org/uc/item/6bb3q574 |journal=PaleoBios |volume=40 |issue=4 |pages=1-32 |doi=10.5070/P940454153 |issn=2373-8189}}</ref> | |- |''Obtusacanthus<ref name=":15" />'' |''O. corroconis'' |An acanthodian-like fish with enlarged needle-like lip scales and no true teeth.<ref name=":11" /><ref name=":15" /><ref name=":83">{{Cite journal |last1=Blais |first1=Stephanie A. |last2=MacKenzie |first2=Lindsay A. |last3=Wilson |first3=Mark V. H. |date=2011 |title=Tooth-Like Scales in Early Devonian Eugnathostomes and the 'Outside-In' Hypothesis for the Origins of Teeth in Vertebrates |url=https://bioone.org/journals/journal-of-vertebrate-paleontology/volume-31/issue-6/039.031.0611/Tooth-Like-Scales-in-Early-Devonian-Eugnathostomes-and-the-Outside/10.1080/039.031.0611.full |journal=Journal of Vertebrate Paleontology |volume=31 |issue=6 |pages=1189–1199 |doi=10.1080/02724634.2011.607992 |doi-broken-date= |issn=0272-4634}}</ref> | |- |''Paucicanthus<ref name=":50">{{cite journal |last1=Hanke |first1=Gavin F. |year=2002 |title=''Paucicanthus vanelsti'' gen. et sp. nov., an Early Devonian (Lochkovian) acanthodian that lacks paired fin-spines |journal=Canadian Journal of Earth Sciences |volume=39 |issue=7 |pages=1071–1083 |bibcode=2002CaJES..39.1071H |doi=10.1139/e02-023}}</ref>'' |''P. vanelsti'' |A narrow-bodied acanthodian lacking spines on its pectoral and pelvic fins.''<ref name=":50" />'' | |- |''Polymerolepis'' |''P. whitei'' |An enigmatic fish with "bradyodont"-like scales. Fossils from MOTH show that it had an anal fin spine, like acanthodians.<ref>{{Cite journal |last=Hanke |first=Gavin F. |last2=Wilson |first2=Mark V. H. |last3=Saurette |first3=Fernand J. |date=2013 |title=Partial articulated specimen of the Early Devonian putative chondrichthyan Polymerolepis whitei Karatajūtė-Talimaa, 1968, with an anal fin spine |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2013n3a2.pdf |journal=Geodiversitas |language=en |volume=35 |issue=3 |pages=529–543 |doi=10.5252/g2013n3a2 |issn=1280-9659}}</ref> | |- |''Promesacanthus<ref name=":70">{{Cite journal |last=Hanke |first=Gavin F. |date=2008 |title=''Promesacanthus eppleri'' n. gen., n. sp., a mesacanthid (Acanthodii, Acanthodiformes) from the Lower Devonian of northern Canada |url=https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2008n2a2.pdf |journal=Geodiversitas |volume=30 |issue=2 |pages=287–302}}</ref>'' |''P. eppleri'' |A mesacanthid acanthodiform which retains small prepectoral spines, akin to "climatiiform" acanthodians.''<ref name=":70" />'' | |- |''Seretolepis'' |''S. elegans'' |A chondrichthyan-like fish closely related to ''Kathemacanthus''.''<ref name=":1" />'' | |- | rowspan="2" |''Tetanopsyrus<ref name=":2">{{Cite journal |last1=Gagnier |first1=P. |last2=Hanke |first2=G. |last3=Wilson |first3=M. |date=1999 |title=Tetanopsyrus lindoei gen. et sp. nov., an Early Devonian acanthodian from the Northwest Territories, Canada |url=https://geojournals.pgi.gov.pl/agp/article/view/10325/8837 |journal=Acta Geologica Polonica |language=EN |volume=49 |issue=2 |pages=81–96 |issn=0001-5709}}</ref>'' |''T. breviacanthias<ref name=":62" />'' |A stocky diplacanthiform with broad crushing plates instead of teeth. This species has relatively short pectoral spines.''<ref name=":62" />'' | |- |''T. lindoei<ref name=":2" />'' |A stocky diplacanthiform with broad crushing plates instead of teeth.''<ref name=":2" />'' This species has relatively long pectoral spines.''<ref name=":62" />'' |center|150x150px |- | rowspan="2" |''Tricuspicanthus<ref name=":0" />'' |''T. gannitus'' |A common but small ischnacanthid with three rows of teeth.''<ref name=":0" /><ref name=":3" />'' | |- |''T. pisciculus'' |A tiny ischnacanthid with two rows of teeth.''<ref name=":0" />'' | |}
=== Placoderms === {| class="wikitable" align="center" ! colspan="4" align="center" |Placoderms '''of MOTH''' |- !Genus !Species !Notes !Images |- |''Romundina'' |''R. stellina'' |An acanthothoracid placoderm. A single skull found at MOTH in 1990 has yet to be fully described.<ref name=":5" /><ref name=":12" /><ref>{{Cite journal |last=Johanson |first=Zerina |last2=Smith |first2=Moya M. |date=2003 |title=Placoderm fishes, pharyngeal denticles, and the vertebrate dentition |url=https://www.researchgate.net/publication/10685592 |journal=Journal of Morphology |language=en |volume=257 |issue=3 |pages=289–307 |doi=10.1002/jmor.10124 |issn=0362-2525}}</ref> |center|184x184px |}
=== Osteostraci === A 2011 UA biology thesis by Bradley Scott provides several new species names for MOTH osteostracan specimens, but some of these names are yet to be published in a peer-reviewed journal.<ref name=":13">{{Cite thesis |last=Greeniaus |first=Jeffrey |title=Description of Devonian tessellate heterostracans from the Northwest Territories, Canada and the growth of Lepidaspis |date=2004 |type=MS Thesis |publisher=University of Alberta |url=https://ualberta.scholaris.ca/items/3432fb81-e0ee-49d0-8673-7e68f5af9ba4 |doi=10.7939/r3-evpd-6918 |doi-access=free}}</ref> {| class="wikitable" align="center" ! colspan="4" align="center" |Osteostracans '''of MOTH''' |- !Genus !Species !Notes !Images |- |''Dentapelta<ref name=":4">{{Cite journal |last=Scott |first=Bradley R |last2=Wilson |first2=Mark V H |date=2015-03-04 |title=The Superciliaspididae, a new family of Early Devonian Osteostraci (jawless vertebrates) from northern Canada, with two new genera and three new species |url=http://www.tandfonline.com/doi/abs/10.1080/14772019.2013.863809 |journal=Journal of Systematic Palaeontology |language=en |volume=13 |issue=3 |pages=167–187 |doi=10.1080/14772019.2013.863809 |issn=1477-2019}}</ref>'' |''D. loefflerae'' |A superciliaspidid zenaspid with tooth-like denticles on its headshield.<ref name=":4" /> | |- |''"Diademaspis"'' |''"D." mackenziensis<ref name=":5">{{Cite journal |last=Adrain |first=Jonathan M. |last2=Wilson |first2=Mark V. H. |date=1994-09-07 |title=Early Devonian cephalaspids (Vertebrata: Osteostraci: Cornuata) from the southern MacKenzie Mountains, N.W.T., Canada |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.1994.10011561 |journal=Journal of Vertebrate Paleontology |language=en |volume=14 |issue=3 |pages=301–319 |doi=10.1080/02724634.1994.10011561 |issn=0272-4634 |jstor=4523572}}</ref>'' |A small zenaspid which is probably not a species of ''Diademaspis''.<ref>{{Cite journal |last=Voichyshyn |first=Victor |date=2006 |title=New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine |url=https://www.app.pan.pl/archive/published/app51/app51-131.pdf |journal=Acta Palaeontologica Polonica |volume=51 |issue=1 |pages=131–142}}</ref><ref>{{Cite journal |last=Keating |first=Joseph N. |last2=Sansom |first2=Robert S. |last3=Purnell |first3=Mark A. |date=2012 |title=A new osteostracan fauna from the Devonian of the Welsh Borderlands and observations on the taxonomy and growth of Osteostraci |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.2012.693555 |journal=Journal of Vertebrate Paleontology |language=en |volume=32 |issue=5 |pages=1002–1017 |doi=10.1080/02724634.2012.693555 |issn=0272-4634}}</ref> | |- | rowspan="2" |''Glabrapelta<ref name=":4" />'' |''G. cristata'' |A superciliaspidid zenaspid with a smooth headshield.<ref name=":4" /> | |- |''G. minima'' |A small superciliaspidid zenaspid with a smooth headshield.<ref name=":4" /> | |- |''Machairaspis'' |''M. serrata<ref name=":6">{{Cite journal |last=Scott |first=Bradley R. |last2=Wilson |first2=Mark V.H. |date=2013 |editor-last= |editor-first= |title=A new species of osteostracan from the Lochkovian (Early Devonian) of the Mackenzie Mountains, with comments on body size, growth, and geographic distribution in the genus Machairaspis |url=http://www.nrcresearchpress.com/doi/10.1139/cjes-2012-0100 |journal=Canadian Journal of Earth Sciences |language=en |volume=50 |issue=2 |pages=127–134 |doi=10.1139/cjes-2012-0100 |issn=0008-4077}}</ref>'' |A small scolenaspidine zenaspidid with a tall serrated spine in the middle of its headshield.<ref name=":6" /> | |- |''Superciliaspis''<ref name=":5" /> |''S. gabrielsei<ref name=":9">{{Cite journal |last=Dineley |first=D.L. |last2=Loeffler |first2=E.J. |date=1976 |title=Ostracoderm faunas of the Delorme and associated Siluro-Devonian formations North West territories Canada |url=https://palass.org/sites/default/files/media/publications/special_papers_in_palaeontology/number_18/spp18_pp1-214.pdf |journal=Special Papers in Palaeontology |volume=18 |pages=1–214}}</ref>'' |A superciliaspidid zenaspid with prominent spines on its headshield. Previously considered a species of ''Cephalaspis''.<ref name=":9" />''<ref name=":5" />''<ref>{{Cite journal |last=Hawthorn |first=Jessica R. |last2=Wilson |first2=Mark V. H. |last3=Falkenberg |first3=Armin B. |date=2008-12-12 |title=Development of the dermoskeleton in Superciliaspis gabrielsei (Agnatha: Osteostraci) |url=http://www.tandfonline.com/doi/abs/10.1671/0272-4634-28.4.951 |journal=Journal of Vertebrate Paleontology |language=en |volume=28 |issue=4 |pages=951–960 |doi=10.1671/0272-4634-28.4.951 |issn=0272-4634 |jstor=20491029}}</ref><ref name=":4" /> | |- | rowspan="2" |''Waengsjoeaspis'' |''W. nahanniensis<ref name=":5" />'' |An osteostracan related to Benneviaspidida.''<ref name=":5" />''<ref name=":7">{{Cite journal |last=Scott |first=Bradley R. |last2=Wilson |first2=Mark V. H. |date=2012 |title=A new species of Waengsjoeaspis (Cephalaspidomorpha, Osteostraci) from the Early Devonian of northwestern Canada, with a redescription of W. nahanniensis and implications for growth, variation, morphology, and phylogeny |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.2012.694514 |journal=Journal of Vertebrate Paleontology |language=en |volume=32 |issue=6 |pages=1235–1253 |doi=10.1080/02724634.2012.694514 |issn=0272-4634}}</ref> | |- |''W. platycornis<ref name=":7" />'' |An osteostracan related to Benneviaspidida.<ref name=":7" /> | |}
=== Thelodonti === All of the thelodonts present at MOTH belong to the order Furcacaudiformes, a group characterized by small heads, humpbacked bodies which are deep and laterally flattened, and equally deep fork-shaped tails.<ref name=":16">{{Cite journal |last=Wilson |first=Mark V. H. |last2=Caldwell |first2=Michael W. |date=1993 |title=New Silurian and Devonian fork-tailed 'thelodonts' are jawless vertebrates with stomachs and deep bodies |url=https://www.nature.com/articles/361442a0 |journal=Nature |language=en |volume=361 |issue=6411 |pages=442–444 |doi=10.1038/361442a0 |issn=1476-4687}}</ref><ref name=":10">{{Cite journal |last=Wilson |first=Mark V. H. |last2=Caldwell |first2=Michael W. |date=1998-04-10 |title=The Furcacaudiformes: a new order of jawless vertebrates with thelodont scales, based on articulated Silurian and Devonian fossils from northern Canada |journal=Journal of Vertebrate Paleontology |volume=18 |issue=1 |pages=10–29 |doi=10.1080/02724634.1998.10011031 |issn=0272-4634 |jstor=4523870}}</ref> {| class="wikitable" align="center" ! colspan="4" align="center" |Thelodonts '''of MOTH''' |- !Genus !Species !Notes !Images |- |''Cometicercus<ref name=":10" />'' |''C. talimaaae'' |A small, rare, and relatively slender furcacaudid furcacaudiform.<ref name=":10" /> | |- |''Drepanolepis<ref name=":10" />'' |''D. maerssae'' |A tiny drepanolepidid<ref>{{Cite journal |last=Wilson |first=M V |last2=Märss |first2=T |date=2009 |title=Thelodont phylogeny revisited, with inclusion of key scale-based taxa |url=https://kirj.ee/public/Estonian_Journal_of_Earth_Sciences/2009/issue_4/earth-2009-4-297-310.pdf |journal=Estonian Journal of Earth Sciences |language=en |volume=58 |issue=4 |page=297 |doi=10.3176/earth.2009.4.08 |issn=1736-4728}}</ref> furcacaudiform with sickle-shaped scales.<ref name=":10" /> |center|210x210px |- | rowspan="2" |''Furcacauda<ref name=":10" />'' |''F. fredholmae'' |A medium-sized furcacaudid furcacaudiform with a pronounced dorsal fin.<ref name=":10" /> |center|197x197px |- |''F. heintzae<ref name=":9" />'' |A medium-sized furcacaudid furcacaudiform with a pronounced dorsal fin. Previously considered a species of ''Sigurdia''.<ref name=":9" /><ref name=":10" /> |center|150x150px |- |''Sphenonectris<ref name=":10" />'' |''S. turnerae'' |A relatively large furcacaudid furcacaudiform without a dorsal fin.<ref name=":10" /> |center|150x150px |}
=== Pteraspidomorphi === A 2004 UA biology thesis by Jeffrey Greeniaus provides several new species names for MOTH pteraspidomorph specimens, but these names are yet to be published in a peer-reviewed journal.<ref name=":13" /> {| class="wikitable" align="center" ! colspan="4" align="center" |Pteraspidomorphs '''of MOTH''' |- !Genus !Species !Notes !Images |- |''Aserotaspis<ref name=":9" />'' |''A. canadensis'' |A tesselate heterostracan with many small armor plates, each bearing a mesh of irregular ridges.<ref name=":9" /> | |- |''Canadapteraspis<ref name=":9" />'' |''C. alocostomata'' |A medium-sized pteraspidiform.<ref name=":9" /> | |- |''Dinaspidella'' |''D. elizabethae'' |A common medium-sized irregulareaspidine cyathaspidid.<ref name=":9" /><ref name=":17">{{Cite journal |last=Pellerin |first=Nicole M. |last2=Wilson |first2=Mark V.H. |date=1995 |title=New evidence for structure of Irregulareaspididae tails from Lochkovian beds of the Delorme Group, Mackenzie Mountains, Northwest Territories, Canada |url=https://linkinghub.elsevier.com/retrieve/pii/S0016699595800859 |journal=Geobios |language=en |volume=28 |pages=45–50 |doi=10.1016/S0016-6995(95)80085-9}}</ref><ref name=":19">{{Cite journal |last=Greeniaus |first=Jeffrey W. |last2=Wilson |first2=Mark V. H. |date=2003-06-17 |title=Fossil juvenile Cyathaspididae (Heterostraci) reveal rapid cyclomorial development of the dermal skeleton |url=http://www.tandfonline.com/doi/abs/10.1671/0272-4634%282003%29023%5B0483%3AFJCHRR%5D2.0.CO%3B2 |journal=Journal of Vertebrate Paleontology |language=en |volume=23 |issue=2 |pages=483–487 |doi=10.1671/0272-4634(2003)023[0483:FJCHRR]2.0.CO;2 |issn=0272-4634 |jstor=4524340}}</ref> | |- |''Lepidaspis<ref name=":9" />'' |''L. serrata'' |A tesselate heterostracan with many small armor plates, each bearing a single serrated ridge.<ref name=":9" /> |center|150x150px |- |''Nahanniaspis'' |''N. mackenziei<ref name=":9" />'' |A common small irregulareaspidine cyathaspidid.<ref name=":9" /><ref name=":17" /><ref name=":19" /> | |- |''Pionaspis'' |''P. amplissima<ref name=":9" />'' |A rare relatively large cyathaspidid.<ref name=":9" /> |center|150x150px |- |''Poraspis'' |''P. polaris'' |A medium-sized poraspidine cyathaspidid.<ref name=":9" /> | |}
=== Other fossils === Conodonts are found at MOTH, including the Silurian-Pragian index fossil ''Ozarkodina remscheidensis''.<ref name=":12" /><ref name=":11" /> The most abundant invertebrates at MOTH are leperditiid ostracods which cluster together in mass death assemblages, sometimes around vertebrate remains. Various brachiopods can also be found at the site. Eurypterids are rare but well-preserved.<ref name=":9" /><ref name=":8" /> Conulariids and phyllocarids have also been reported.<ref name=":5" /> Tiny fragments of typical shallow marine invertebrates (crinoids, brachiopods, bryozoans, corals) make up a minor component of the sediment.<ref name=":8" />
== References == {{reflist}}
Category:Lochkovian Category:Devonian paleontological sites Category:Lagerstätten Category:Paleontology in the Northwest Territories Category:Paleozoic life of the Northwest Territories Category:Devonian Northwest Territories