Species: americanus WALCOTT, 1892
Etymology:

Holotype: USNM 336105

Locality: Harding Quarry, Canon City, Fremont County, Colorado.

Horizon: Harding Sandstone Formation.

Biostratigraphy:

Age: Caradoc Epoch, Late Ordvocian.

Material: 7 small slabs.

Referred material:

LETHOLA, 1983/DENISON, 1967

Locality: Canon City, Fremont County, Colorado.

Horizon:

Biostratigraphy:

Age: Ordovician.

Material:

Number: Not given: Partially articualted rostral head shield.

SANSOM & SMITH, 2004

Locality: Bighorn Moutains, Wyoming.

Horizon: South Piney Member, Winnipeg Formation.

Biostratigraphy:

Age: Mid Mohawkian, Mid-Caradoc Epoch, Late Ordvocian.

Material:

BU 3657-3659: Fragmentary plates.
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Species: orvigi DEINSON, 1967
Etymology:

Holotype: FMNH PF 5438b

Locality: Bear Rocks NW 1/4, NE 1/4, NW 1/4, sec. 26, T55N, R89W, Sheridan County, Wyoming.

Horizon: Bed 19, Harding Sandstone Formation.

Biostratigraphy:

Age: Caradoc Epoch, Late Ordvocian.
.

Material: Large plate fragments.

Paratypes:

FMNH 4635, 4637, 4646, 4648, 4649, 4682, 4698, 4699, 4701: Slides.

FMNH PF 5424f: Scales and plates.

FMNH PF 5425b, 5431d: Scales and plates.

FMNH PF 5425d, 5427b, 5427f-h, 5428, 5429, 5433b, 5434a, 5434b-d, 5435b, 5436h: Plates.

FMNH PF 5426, 5436c, 5440, 5441: Plate fragments.

FMNH PF 5432, 5439a, 5439c, 5439d: Scales.

FMNH PF 5437a-j, 5442c: Marginal plates.
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Species: leipnitzae SCHALLREUTER, 1983
Etymology:

Holotype: GPIMH 2708

Locality: Vastorf near Luenburg, Lower Saxony State, North west Germany.

Horizon:

Biostratigraphy: Ahtiella jentzxchi-conglomerate.

Age: Oelandium, Arenig Epoch, Late Early Ordovician.

Material: Scales.

Partaypes: GPIMH 2702, 2706, 2707, 2694, 2695: Scales.
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