Species: deltae LOMBARD & BOLT, 1995
Etymology: In reference to Delta Quarry, Keokuk County, Iowa.

Holotype: FM PR 1700

Locality: Sink fill, Delta Quarry, on land owned by Mr. Jasper Hiemstra, near Delta, SW 1/4, SW 1/4, section 15, T75N, R13W, Keokuk County, Iowa.

Horizon: Fills within two adjacent collapse structures formed in the Waugh and Verdi Members of the Iowa ‘St Louis” Limestone.

Biostratigraphy:

Age: Correlative with Lower Carboniferous Visean V3b of Europe, Lower Chesterian, Asbian Stage, Lower Upper Visean Epoch, Middle Mississippian, Lower Carboniferous.

Material: Skull in association with pre-sacral vertebral column, partial shoulder girdle, ribs and partial hindlimb.

Referred material:

FM PR 1634: Skull with lower jaws, nearly complete through crushed, atlas, axis, and several additional vertebrae and ribs, part of dermal shoulder girdle.

FM PR 1635: Skull with lower jaws, articulated partial column 2 scapulocoracoids, humerus, radius and ulna and other appendicular elements: all severely crushed.

FM PR 1636: Partial skull with several crushed and disarticulated vertebrae.

FM PR 1642: Fragmentary right mandible.

FM PR 1644: Block with right and left lower jaw, clavicle, rib and other elements.

FM PR 1651: Skull table with frontals, postfrontals, dorsal and ventral sides prepared free.

FM PR 1652: Partial skull roof with frontals broken off and area around parietal foramen broken out; crushed and incomplete otic capsules present; braincase and both steps crushed up onto underside of skull roof.

FM PR 1665: Crushed left mandible.

FM PR 1666: Anteriorone-quarter of mandible.

FM PR 1692: Fragmentary left mandible.

FM PR 1701: Braincase associated with first 3 vertebrae.

FM PR 1704: Left scapulocoracoid with cleithrum.

FM PR 1705: Left and right mandible.

FM PR 1712: 2 isolated pleurocentra.

FM PR 1740: Right half of pelvis plus interclavicle.

FM PR 1745: 7 articulated vertebrae.

FM PR 1755: Left adn right mandible.

FM PR 1766: Left scapulocoracoid with partial cliethrum.

FM PR 7792: Fragmentary skull with right and left mandible.

FM PR 1809: Large skull with lower jaws, occiput preserved in 3 dimensions.

FM PR 1813: Skull and vertebral column, with scattered girdle elements and limbs.

FM PR 1814: Partial skull with lower jaw.

FM PR 1816: Articulated vertebral column, from cervicals approximately through first fifteen caudals, plus limb and girdle elements, numerous ribs, some in articulation; associated with braincase and posterior half of skull table.

FM PR 1819: Fragmentary right mandible.

FM PR 1880: Left scapulocoracoid with cleithrum, left ilium and ischium, 15 articulated vertebrae and 2 disarticulated ribs.

FM PR 1887: Nearly complete articulated vertebral column plus associated pelvis and femur.

FM PR 1888: Partial skull with fragmentary right mandible of a juvenile.

FM PR 1889: Complete rib from mid-presacral region, associated with fragmentary postcranial elements on limestone block.

FM PR 1955: Right mandible.

FM PR 1957: Interclavicle.

FM PR 1958: Left femur.

FM PR 1988: Fragmentary right mandible.

FM PR 2105: Small left mandible.

FM PR 2245: Left articulated angular and surangular.

FM PR 2246: Fragmentary skull and left and right dentary.

SMU 52010: 5 intercentra, five pleurocentra, including some small complete intercentra.

WHITNEY, OTOO, ANGIELCZYK & PIERCE, 2022

FMNH PR 5021: Fragmentary specimen, size class II.

FMNH PR 5022: Fragmentary specimen, size class 1.

FMNH PR 5023: Fragmentary specimen, size class IV.

FMNH PR 1962: Fragmentary specimen, size class II.