Spondylus colombiensis Weisbord, 1929
WEISBORD, N. E. 1929. Miocene Mollusca of Northern Colombia. Bulletins of American Paleontology, 14 (54): 235-306, pls. 1-9. [p. 246, pl. 2, figs. 10, 11]
1929 Spondylus colombiensis Weisbord, 1929
N. E. Weisbord, 1929, plate 2.
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«This species is represented in the collection by a well preserved right valve. Shell rather large, moderately convex, slightly inequilateral. Beak elevated, rather narrow, and twisted. Cardinal area prominent, about 12 mm. in altitude and 35 mm. in length, with a deeply incised, narrow, triangular resilium. Area marked with rather fine vertical striae. Ears subequal, the anterior sculptured with sinuous, transverse growth lines and crossed by radial lines giving the whole an imbricated appearance. The posterior ear only has the transverse striae. The valve is ornamented with seven or eight strong radii rather heavily spined. Between these are secondary smaller ribs, profusely studded with projecting spines, and a third and fourth series of riblets. The smallest are the most abundant and are also closely set with small rectangular nodes. On the other ribs the spines project downward and show a tendancy to be tubular.
Ventral margin well rounded; posteriorly the valve is slightly swollen. Inner margin with elongated denticles; muscular scar large. Interior of the shell chocolate colored. Dimensions: Alt. 75 mm; Long. 65 mm.
The Colombian shell is closely allied to S. falconensis Harris [18] from Venezuela and S. chiriquiensis Olsson [14] from Costa Rica. The Venezuelan species has a greater number of larger, subequal secondary radii than the Colombian form has. With the exception of this slight variance in sculpture the two forms are strikingly similar. S. chiriquensis is also quite similar in its general characteristics but here again the stronger secondary radii and less spinose character of the tertiary threads serve to differentiate the two forms. The minor ribs on the well known S. bostrychites Guppy are less spiny than on S. colombiensis.
Locality.— Near Tubera, Dept. of Atlantico. Age.— Miocene.» [13] Bull. Amer. Pal., Vol. 13, No. 49, P. 40, PI. 23, Figs. 4, 5, 1927
[14] Ibid, Vol. 9, No. 39, P. 206, PI. 20, Figs. 1,2 5, 6, 1922. NORMAN EDWARD WEISBORD, 1929
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