Aethaspis is an extinct genus of arthrodire placoderm fish from the Devonian period. Two species were described by Denison in 1958: Aethapsis major and Aethapsis utahensis. It is one of the more basal members of the order Arthrodira, as shown in the cladogram below:

Eurycaraspis incilis Lunaspis broilii Arthrodira Yujiangolepis liujingensis Antarctaspis mcmurdoensis Wuttagoonaspidae Wuttagoonaspis fletcheri Yiminaspis shenme Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae BrachythoraciActinolepidoidei Phlyctaeniina
Eurycaraspis incilis Lunaspis broilii Arthrodira Yujiangolepis liujingensis Antarctaspis mcmurdoensis Wuttagoonaspidae Wuttagoonaspis fletcheri Yiminaspis shenme Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Eurycaraspis incilis
Lunaspis broilii
ArthrodiraYujiangolepis liujingensis Antarctaspis mcmurdoensis Wuttagoonaspidae Wuttagoonaspis fletcheri Yiminaspis shenme Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Yujiangolepis liujingensis
Antarctaspis mcmurdoensis Wuttagoonaspidae Wuttagoonaspis fletcheri Yiminaspis shenme Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Antarctaspis mcmurdoensis
Wuttagoonaspidae Wuttagoonaspis fletcheri Yiminaspis shenme Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
WuttagoonaspidaeWuttagoonaspis fletcheri Yiminaspis shenme
Wuttagoonaspis fletcheri
Yiminaspis shenme
Aethaspis major Aethaspis utahensis Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Aethaspis major Aethaspis utahensis
Aethaspis major
Aethaspis utahensis
Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Lehmanosteus hyperboreus Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Lehmanosteus hyperboreus
Aleosteus eganensis Simblaspis cachensis Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Aleosteus eganensis Simblaspis cachensis
Aleosteus eganensis
Simblaspis cachensis
Kujdanowiaspis buczacziensis Kujdanowiaspis podolica Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Kujdanowiaspis buczacziensis Kujdanowiaspis podolica
Kujdanowiaspis buczacziensis
Kujdanowiaspis podolica
Erikaspis zychi Sigaspis lepidophora Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Erikaspis zychi Sigaspis lepidophora
Erikaspis zychi
Sigaspis lepidophora
Eskimaspis heintzi Baringaspis dineleyi Proaethaspis ohioensis Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Eskimaspis heintzi
Baringaspis dineleyi Proaethaspis ohioensis
Baringaspis dineleyi
Proaethaspis ohioensis
Anarthraspis chamberlini Heightingtonaspis anglica Phyllolepida Gavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Anarthraspis chamberlini
Heightingtonaspis anglica
PhyllolepidaGavinaspis convergens Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Gavinaspis convergens
Austrophyllolepis sp. Cowralepis mclachlani Phyllolepis orvini Placolepis budawangensis
Austrophyllolepis sp.
Cowralepis mclachlani
Phyllolepis orvini
Placolepis budawangensis
Actinolepidae Bollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
ActinolepidaeBollandaspis woschmidti Actinolepis spinosa Actinolepis magna Actinolepis tuberculata
Bollandaspis woschmidti
Actinolepis spinosa Actinolepis magna Actinolepis tuberculata
Actinolepis spinosa
Actinolepis magna Actinolepis tuberculata
Actinolepis magna
Actinolepis tuberculata
Bryantolepis brachycephalus Phlyctaenioidei Phlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Bryantolepis brachycephalus
PhlyctaenioideiPhlyctaeniidae Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Phlyctaeniidae
Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae Brachythoraci
Groenlandaspidae Arctaspidae Dicksonosteus arcticus Arctolepidae
Groenlandaspidae
Arctaspidae Dicksonosteus arcticus Arctolepidae
ArctaspidaeDicksonosteus arcticus
Arctolepidae
Brachythoraci