Cyclonema inflatum

Phylum: Mollusca
Class: Gastropoda
Order: Euomphalina
Family: Platyceratidae
Genus: Cyclonema
Species: Cyclonema inflatum (Ulrich, 1897)

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Stratigraphic Occurrences


Geographic Occurrences

Map point data provided by iDigBio.
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Sequences (Formations)

  • C2 Sequence (Fairview: Fairmount, Mount Hope)

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Identification in Hand Sample

  • Two orders of spiral, fine lines running down the sides of the shell
  • Inflated body whorl
  • Aperture rounded to polygonal
  • Narrow spire
  • Two turns at the apex coiled in a very wide angle

Cyclonema inflatum from the McMillan Formation of Maysville, Kentucky (OUIP 779 & CMC 19829)

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Davis (1998):

  • This species characterized by two orders of spiral lirae (as opposed to one in C. gracile and three in C. bilix). Fairview.

Thompson (1970):

  • Diagnosis. — Trochiform, slender spire, ventricose body whorl, coarse ornament of two orders, cords separated on upper half of whorl.
  • Description. — Trochiform shell, nucleus of four slender conical whorls, fifth whorl expands to typical juvenile whorl; slender spire, body whorl inflated, whorl profiles usually convex, sometimes straight, never concave; sutures impressed to incised, rarely channeled with angular shoulders, knobs on final shoulder caused by growth wrinkles may be present; aperture rounded to polygonal, outer lip thin and usually rounded, but rarely straight and oblique inner margin straight to concave, columellar exceedingly thick and deeply grooved; coarse second order ornament of eight to nine cords separated by threads of mature body whorl, cords are widely spaced on upper half of whorl but closer at midwhorl, cords on juvenile whorls fewer in number and finer but always separated on upper portion of whorl; collabral lirae long and recurved, ornament extending over half of basal surface.

Ulrich & Scofield (1897):

  • Shell of medium size, consisting, as usually found, of about four rounded whorls; with the apex entire there are in all about seven whorls, the first four forming a narrow truncated cone, the two turns at the apex being coiled in a very wide angle; succeeding whorls spreading more rapidly, the angle increasing in some extreme cases from 40° to 90°; mouth rounded, quadrangular; surface strongly carinated spirally, the carinae on the upper half of the whorls more distant than those on the lower, fifteen to twenty in all on the body whorl. This species agrees closely in its surface markings with certain varieties of C. mediale; and perhaps it also should be regarded as an extreme variety of that species. Generally it is readily distinguished by its more convex whorls.

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