Cardioceras (Cardioceras)
Species
Cardioceras (Cardioceras) auroraense Reeside, 1919
Has coarse ribbing and prominent lateral tubercles. Differs from C. (C.) cordatum by having more compressed whorls, slightly narrower umbilicus, shorter primary ribs, and lacking square shoulders and tertiary ribs.
Occurrence: Redwater Shale Member in Wyoming and South Dakota
Reference: Imlay, 1982
Cardioceras (Cardioceras) auroraense
Photograph from Imlay, 1982
Cardioceras (Cardioceras) distans (Whitfield, 1880)
Very similar to C. (C.) cordatum, but “apparently” differs by retaining coarse ribbing to a diameter of at least 100 cm.
Occurrence: Redwater Shale Member in Wyoming and South Dakota
Originally named Ammonites cordiformis var. distans
Reference: Imlay, 1982
Cardioceras (Cardioceras) distans
Photograph from Imlay, 1982
Cardioceras (Cardioceras) hyatti Reeside, 1919
Similar to C. (S.) wyomingense but differs by having a slightly smaller umbilicus, straight ribbing on more of the flanks, stronger and sharper secondary ribs that curve forward closer to the keel, weaker crenulations on the keel, and by lacking a weak shoulder on the sides of the venter.
Occurrence: Redwater Shale Member in Wyoming, Utah, and South Dakota; Swift Formation in Montana
Reference: Imlay, 1982
Cardioceras (Cardioceras) hyatti
Photograph from Imlay, 1982
Cardioceras (Cardioceras) albaniense (Reeside, 1919)
Similar to G. (P.) incertum but has proportionately wider whorls, larger size, and more persistent and finer sculpture. Imlay states that it might be within range of variation of G. (P.) incertum or G. (P.) crassum; known from only one specimen and occurs with both of those species.
Occurrence: Redwater Shale of Wyoming
Originally named Cardioceras (Pachycardioceras) albaniense; also called Goliathiceras (Pachycardioceras) albaniense
Reference: Imlay, 1982
Cardioceras (Cardioceras) albaniense
Photograph from Imlay, 1982
Cardioceras (Cardioceras) bellefourchense Reeside, 1919
Similar to G. (P.) crassum, but has broader inner septate whorls at diameters of 70–75 cm, an angular instead of sharp venter, somewhat stronger ribs, and by furcation of primary ribs a little lower on flanks. Imlay states that it may be a stout, coarsely ribbed variant of G. (P.) crassum; known from only two specimens.
Occurrence: Redwater Shale of Wyoming, possibly Swift Formation of Montana
Also called Goliathiceras (Pachycardioceras) bellefourchense
Reference: Imlay, 1982
Cardioceras (Cardioceras) bellefourchense
Photograph from Imlay, 1982
Cardioceras (Cardioceras) crassum Reeside, 1919
Differs from C. (C.) russelli by its sharper venter, stronger and more persistent ribbing, and stouter whorls.
Occurrence: Redwater Shale of Wyoming and South Dakota
Also called Goliathiceras (Pachycardioceras) crassum
Reference: Imlay, 1982
Cardioceras (Cardioceras) crassum
Photograph from Imlay, 1982
Cardioceras (Cardioceras) incertum Reeside, 1919
Has narrowly rounded but not sharp venter, and by low, weak ribs, which form chevrons near the midventral line. Has much weaker ribbing than C. (C.) crassum and C. (C.) bellefourchense.
Occurrence: Redwater Shale of Wyoming
Also called Goliathiceras (Pachycardioceras) incertum
Reference: Imlay, 1982
Cardioceras (Cardioceras) incertum
Photograph from Imlay, 1982
Cardioceras (Cardioceras) russelli Reeside, 1919
Is moderately stout, with relatively strong nearly straight ribs, narrow umbilicus, and triangular whorl cross-section.
Occurrence: Redwater Shale of Wyoming and South Dakota, Stump Formation of northeast Utah
Also called Goliathiceras (Pachycardioceras) russelli
Reference: Imlay, 1982
Cardioceras (Cardioceras) russelli
Photograph from Imlay, 1982
