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Species / Orthaulax Gabbi

Orthaulax Gabbi

Stromboidea


Original description of Orthaulax gabbi by Dall, 1890:

  • "Shell large, solid, many-whorled; in the very young smooth and polished, except for incremental lines and a few faintly impressed spiral lines anteriorly; nucleus small, polished, glassy, not differentiated from the rest of the shell; early whorls with a very distinct, not channelled suture; the whorl in front of it slightly turrited; each whorl after the third has three slightly elevated, narrow, rounded varices, somewhat irregularly spaced, so that they do not follow each other continuously down the slope of the spire; about the end of the eighth whorl the posterior edge of the outside whorl begins to be prolonged backward more and more as the shell grows, so that the suture thus formed makes an irregular spiral line ascending the spire over the antecedent whorls until by about the tenth turn the whole of the spire is enveloped, as well as any barnacles, vermetus, or other semiparasitic growth which may have become attached to the surface of the spire; the anterior part of the shell has the shape of Leiorhynus, the pillar is rather thick and slightly recurved, with a moderately distinct fasciole; the canal moderately wide, shorter than the pillar; the outer lip simple, sharp, a little thickened at the resting-stages, but not lirate internally; body with a moderate callus, which at the resting-stages is considerably enlarged, so that when the whorl comes to grow over it (as it is not absorbed) it produces an irregularity somewhat like a varix; the whorls are ovately rounded, smooth, except for occasional transverse undulations due to irregularities of growth, and polished; no indications of color-pattern have been observed. The adolescent form a good deal resembles a Strombus, except that the anterior sulcus of the outer lip behind the canal is absent or represented only by the faintest wave in the margin; the spire is entirely enveloped by the backward prolongation of the last whorl, except at the tip, where the envelope is usually a little eroded or defective; there appears to be a resting-stage at every two-thirds of a revolution of the whorl around the axis, for which reason, looking down on the spire, the outline of the shell transverse to the axis is subtriangular or three-sided; the outer lip is simple, rather sharp-edged, and very slightly, if at all, recurved; it extends backward to the tip of the spire, near which it recedes somewhat from its parallelism with the axis; at the shoulder, also, it is slightly excavated and thickened; the body is smooth, with a moderate callus, which becomes thicker near the shoulder; at the shoulder, in front of the excavation above noted, it becomes very thick, and is continued on to the spire parallel with the outer lip, and very near it, so that between the two is a narrow, flexuous groove of considerable depth; when the shell begins to grow again the whorl is carried over this ridge, which is not absorbed, and the surface is thus rendered, as it were, varicose; the canal is short, strongly recurved, with a remarkably deep siphonal sulcus, so that the end of the pillar stands forward in a marked way; on the shoulder, half way around the shell, is an ill-defined, narrow ridge, which ceases a little way behind the lip. The adult form differs from the adolescent by the disproportionate strength of the ridge at the shoulder, by which the surface behind the ridge has become flattish as in a Cassis, but more irregular, and the width at the shoulder has increased in proportion to the total length. No entirely complete specimen of the adult has been found, but from the numerous fragments the proportions can be approximately determined."

Locus typicus: Alum Bluff and Chipola, Calhoun County, West Florida, USA

Stratum typicum: Chipola Formation, lower Miocene


Specimens from private collections

Orthaulax gabbi Dall, 1890; Chipola Formation, lower Miocene; Tul. Uni. loc. 821: Farley Creek, Calhoun County, Florida, USA (0,1 mile east of bridge Florida Highway 275 (SW 1/4 Sec. 21, T1N, R9W); Ex-coll. E.H. Vokes; Coll. Gijs Kronenberg no. 3850

Orthaulax gabbi Dall, 1890; Chipola Formation, lower Miocene; Farley Creek, Calhoun County, Florida, USA; 77 mm; Coll. Rupert Hochleitner

Orthaulax gabbi Dall, 1890; Chipola Formation, lower Miocene; Coll. Ulrich Wieneke

  1. Chipola River, Calhoun County, Florida, USA; 59,0 mm; no. UW2439
  2. Briston ?, Florida, USA; 60,5 mm; no. UW2433
  3. Ten Mile Creek, Calhoun County, Florida, USA; 61,3 mm; no. UW2440

Orthaulax gabbi Dall, 1890; juvenile; Chipola Formation, lower Miocene; Ten Mile Creek, Chipola River, Calhoun County, Florida, USA; Coll. Elmar Mai

  1. 15,2 mm
  2. 33,6 mm
  3. 61,9 mm
  4. 34,0 mm
  5. 44,5 mm
  6. 57,4 mm

References


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