Cardioceras (Scarburgiceras)
Species
Cardioceras (Scarburgiceras) bighornense Imlay, 1982
Similar to C. (S.) wyomingense in shape and coiling and in the ribbing of the smallest septate whorls, but has totally different ribbing on intermediate and largest whorls.
Occurrence:Redwater Shale Member in Wyoming; Swift Formation in Montana
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) bighornense
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras) cordiforme (Meek and Hayden, 1858)
Compressed discoidal form, traingular whorl cross-section slightly higher than wide in small to medium whorls but becoming slightly wider than high in larger whorls. Relatively narrow umbilicus. Ribbing well developed until diameter of at least 85 cm. Ribs are broad, low, closely spaced, form chevrons on venter. Some bifurcate near or below middle of flanks, but many are simple and separated by short ribs.
Occurrence: Redwater Shale Member in Wyoming and Utah
Originally named Ammonites cordiformis
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) cordiforme
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras) crookense Reeside, 1919
Differs from immature C. (S.) cordiforme by having rounded rather than abrupt umbilicial shoulders, and by having ribs branching at various heights.
Occurrence: Redwater Shale Member in Wyoming and South Dakota. Small pyritized specimens in north-central Montana.
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) crookense
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras?) mathiaspeakense Imlay, 1982
Occurrence: Redwater Shale Member in South Dakota
Reference: Imlay, 1982
Cardioceras (Scarburgiceras?) mathiaspeakense
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras) schucherti Reeside, 1919
Has stout whorls, narrow umbilicus. Has straight, narrow, widely spaced primary ribs, some of which terminate in tubercles. Also has about five weaker secondary ribs for each primary rib.
Occurrence:Redwater Shale Member in Wyoming; Stump Formation in northwest Colorado; Swift Formation in Montana
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) schucherti
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras) wyomingense Reeside, 1919
Similar to C. (S.) hyatti, but has slightly wider umbilicus, secondary ribs that arch forward higher on the flanks, primary ribs that are relatively stronger than the secondary ribs, and a faint shoulder at the edge of venter.
Occurrence: Redwater Shale Member in Wyoming and South Dakota; Swift Formation in Montana; Stump Formation in Utah and western Wyoming
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) wyomingense
Photograph from Imlay, 1982
Cardioceras (Scarburgiceras) reesidei Maire, 1938
Based only on immature specimens, and may not be a distinct species
Occurrence: Redwater Shale Member in Wyoming
Reference: Imlay, 1982
Cardioceras (Scarburgiceras) reesidei
Photograph from Imlay, 1982
