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Trilobite Genera / Species I Trilobite Formations I Trilobite Locations

for Genera beginning with letter A

Achlysopsis (Fritz, 1968)

Achlysopsis liokata (Fritz, 1968)
Achlysopsis hemitora (Fritz, 1968)
Achlysopsis typicum (unconfirmed please contact us if you know this species)
Achlysopsis sp [Chisholm Shale]
Achlysopsis n. sp. [Spence Shale]
Achlysopsis sp. [Spence Shale]

Aciculolenus (Palmer, 1965)

Aciculolenus palmeri (Chatterton & Ludvigsen, 1998)

Acidiphorus (Raymond, 1925) [Goniotelus (Ulrich, 1927) is a junior synonym of Acidiphorus, fide (Brett & Westrop, 1996)]

Acidiphorus ? lineotuberculatus Fortey and (Droser, 1999)
Acidiphorus sp. (mentioned in Ross, 1951) (formerly Goniotelus sp.)

Agnostotes (Opik, 1963)

Agnostotes clavata (Lu in Wang, 1964)

Agnostus (Brongniart, 1822) [This genus is not recognized in Cambrian of Western North America]

Agnostus bonnerensis (Resser, 1938) [is now Peronopis]
Agnostus brevispinus (Deiss, 1939) [is now Peronopis]
Agnostus hastatus (Deiss, 1939) [reassigned to Peronopis montis]
Agnostus robustus (Deiss, 1939) [reassigned to Peronopis montis]

Albertella (Walcott, 1908)

Albertella fritzi (Eddy and McCollum, 1998)
Albertella helena (Walcott, 1908)
Albertella highlandensis (Eddy and McCollum, 1998)
Albertella longwelli (Palmer in Palmer & Halley, 1979)
Albertella microps (Rasetti, 1951)
Albertella proveedora (Lochman 1952)
Albertella schenki (Resser, 1945)
Albertella spectrensis (Palmer in Palmer & Halley, 1979)
Albertella ? sp. [Langston Formation, Spence Shale Formation]
Albertella sp. [Pioche Shale Formation - not sure which species this is]
Albertella ? sp. (Metaline Formation)

Albertellina (Palmer in Palmer & Halley, 1979)

Albertellina aspinosa (Palmer in Palmer & Halley, 1979)

Albertelloides (Fritz, 1968)

Albertelloides dispar (Resser, 1939b)
Albertelloides kitai (Eddy and McCollum, 1998)
Albertelloides maladensis (Resser, 1939b)
Albertelloides mischi (Fritz, 1968)
Albertelloidespandispinata (Fritz, 1968)
Albertelloides rectimarginatus (Palmer in Palmer & Halley, 1979)
Albertelloides cf. rectimarginatus (Palmer in Palmer & Halley, 1979)
Albertelloidessp. [Twin Knobs Formation]

Alokistocare (Lorenz, 1906)

Alokistocare charax
Alokistocare harrisi (see Altiocculus harrisi)
Alokistocare idahoense (see Amecephalus idahoense)
Alokistocare laticaudum (see Amecephalus laticaudum)
Alokistocare pananotatum (Rasetti, 1951)
Alokistocare scapegoatensis (Deiss, 1939a [Montana])
Alokistocare septum (Resser, 1939a)
Alokistocare spencense
Alokistocare subcoronatum (Hall & Whitfield, 1877)
Alokistocare swasii (Sundberg, 1994)
Alokistocare sp. [Wheeler Shale]
Alokistocare. sp. [Chisholm Formation]

Alokistocarella (Resser, 1938b)

Alokistocarella brighamensis (Resser 1939b)
Alokistocarella mexicana (Lochman, 1952 [Arrojos Formation, Caborca, Mexico])
Alokistocarella occidens (Resser 1939b)
Alokistocarella spencei (Resser, 1939a)

Altiocculus (Sundberg, 1994)

Altiocculus concavus (Sundberg, 1994)
Altiocculus drumensis (Sundberg, 1994)
Altiocculus harrisi (Robison, 1971)
Altiocculus sp. [Wheeler Shale]
Altiocculus sp. [Marjum Formation]

Amblycranium (Ross, 1951)

Amblycranium cornutum (Ross, 1951)
Amblycranium ? populus (Ross, 1951)
Amblycranium variabile (Ross, 1951)

Amecephalites (Eddy and McCollum, 1998)

        Amecephalites sundbergi (Eddy and McCollum, 1998)

Amecephalus Walcott, 1924 (includes Strotocephalus Resser, 1935)

Amecephalus agnesensis (Walcott, 1917b)
Amecephalus alta (Fritz, 1968)
Amecephalus althea (Walcott, 1916) [Arrojos Formation, Caborca, Mexico]
Amecephalus arrojosensis (Lochman, 1952) [Arrojos Formation, Caborca, Mexico; Carrara, Emigrant, Monola, and Pioche formations in the southern Great Basin]
Amecephalus cleora (Walcott, 1917b)
Amecephalus diffundatus
Amecephalus gordonensis (Resser, 1935) [=S. gordonensis Resser, 1935]
Amecephalus idahoense (Resser 1939a) (not idahoensis)
Amecephalus laticaudum (Resser 1939a)
Amecephalus modestum (Lochman, 1952) [Arrojos Formation, Caborca, Mexico]
Amecephalus packi (Resser, 1935)
Amecephalus piochensis (Walcott, 1886)
Amecephalus sp. A (Sundberg and McCollum, 2000)
Amecephalussp. unident.
Amecephalus sp. [Chisholm Shale Formation]
Amecephalus sp. (Glossopleura Zone, Washington)
Amecephalus n. sp. aff. Piochaspis [Chisholm Shale Formation]
Amecephalus n. spp. [Spence Shale Formation]
Amecephalussp. 1 [Spence Shale Formation]
Amecephalus ? sp. [Twin Knobs Formation]

Amechilus Ross, 1951

        Amechilus palaora (Ross, 1951)


Ameropiltonia perplexa (Brezinski, 2000)


Ameura sangamonensis (Meek & Worthen)

Ammagnostus (Opik, 1967)

Ammagnostus beltensis

Ampyxina (Ulrich, 1922 or Ampyxoides ?, Whittington, 1965)

Ampyxina n. sp. [Antelope Valley / Ninemile Formation]

Ampyxoides (Whittington, 1965)

Ampyxoidescf. occipitalis (Dean, 1973)
Ampyxoides trigranulatus (Palmer, 1960)

Anomalocephalus (Deiss, 1939; [Montana] [= Ehmaniella, fide Howell in Moore, 1959]

Anomalocephalus ornatus Deiss, 1939 [= Ehmaniella ornatus (Deiss, 1939)] [Montana]

Anomocare (Angelin, 1851)

Anomocaresp. [Langston Formation, Spence Shale]

Anoria (Walcott, 1924)

Anoria baton (Walcott, 1916b) [Montana]
Anoria tontoensis (Walcott, 1916) [Arizona]

Apatolichas (Whittington, 1963)

Apatolichas cf. jukesi (Billings, 1865)
Apatolichas sp. [Antelope Valley Formation]

Aphelaspis (Labiostria is a junior synonym of Aphelaspis, fide PALMER, 1965, although this is debated; see Chatterton & Ludvigsen, 1998)

Aphelaspis westropi (= Labiostria westropi) [McKay Group]


Arapahoia sp. (Weeks Formation)

Archaeaspis (Repina in Khomentovskii and Repina, 1965)

Archaeaspis macropleuron (Lieberman, 2002)
Archaeaspis nelsoni (Lieberman, 2002)

Arcuolenellus (Palmer & Repina, 1993)

Arcuolenellus arcuatis (Palmer, in Palmer & Halley 1979)
Arcuolenellus cf. megafrontalis (Vaccari)

Asaphellina (Munier-Chalmas & Bergeron in Bergeron, 1889)

Asaphellina ? sp. (Ross, 1951)

Asaphellus (Callaway, 1877)

Asaphellus ? eudocia (Walcott, 1925)
Asaphellus ? sp. A (Ross, 1951)
Asaphellus ? sp. B (Ross, 1951)

Asaphiscus (Meek, 1873)

Asaphiscus wheeleri (Meek, 1873)


Aspidagnostus sp. (Weeks Formation)

Athabaskia (Raymond, 1928)

Athabaskia belus (Walcott, 1916b) [Montana]
Athabaskia bithus (Walcott, 1916)
Athabaskia howelli (Walcott, 1886)
Athabaskia wasatchensis (Resser, 1939b)
Athabaskian. sp.
Athabaskian sp. [Spence Shale]


Australosutura llanoensis (Brezinski, 1998)
Australosutura sp. (in Brezinski, 2000)