Conus canalis (Conrad, 1858)

Liopeplum canalis (Conrad, 1858)

Conus canalis. Pl. 35, fig. 22 ⁽¹⁾.

Spire prominent, volutions profoundly angular in consequence of a deep channel revolving at the suture ⁽¹⁾.
A very remarkable species, in its profoundly channelled suture presenting a strong contrast to more modern fossil or recent cones ⁽¹⁾.

Shell fairly large and subbiconic in outline, length of aperture greater than the elevation of the spire; whorls of conch five or six, increasing regularly in size and rather markedly; sculpture absent, external surlace covered with a glaze and all ornamentation obliterated except for incremental lines, which show through the glaze; suture impressed and covered with a prominent well-rounded spiral ridge of callus, which occurs over the shoulder of the whorl and the area of the whorl between the shoulder and the suture of a subsequent volution, the suture itself being covered by this ridge; this spiral callus ridge forms a deep concave canal 'with the shoulder of the subsequent whorl; body flattened dextro-ventrally, slightly inflated medially, abruptly constricted posteriorly, and sloping gently toward "the anterior into a broad, short anterior canal; aperture long and narrow, produced anteriorly into a short, straight canal and marked posteriorly by a shallow sub angular siphonal notch; outer lip simple and smooth; inner lip broadly excavated; columella marked by two or three very oblique plaits, the anterior two the more prominent; columella and parietal wall washed with callus; pillar broad and short, marked by a wide anterior fasciole, which shows through the enamel-like glaze of the shell. Several imperfect specimens in the Tennessee collection have been assigned to this species with some hesitation, fm. Conrad's type has apparently been lost. In general features this species resembles Liopleplum carinatum, but that species is n1ore slender and does not possess an abruptly constricted shoulder like that of Liopeplum canalis.

Occurrence; Ripley formation, Dave Weeks place on Coon Creek, NcNairy County, Tenn.

Collection: U.S. National Museum.

Outside distribution: Ripley formation, Owl Creek, Tippah County, Miss ⁽²⁾.

Discussion ⁽³⁾. The holotype of Liopeplum canalis (Conrad) is not present in the collections of the Academy of Natural Sciences of Philadelphia and is evidently lost. Conrad's description is short and his illustration is of an incomplete specimen. The speci-men here figured on plate 43, figure 23, from the type locality on Owl Creek, Tippah County, Miss. (loc. 46), appears to be close to the type specimen as illustrated. Other specimens, however, show a gradation to a some-what slimmer more elongate form, as is exemplified by the topotype figured on plate 43, figure 17. Despite the disparity in proportions these specimens all show affinities in the possession of the strong callus ridge that overhangs the shoulder of the succeeding whorl and thus develops a deep channel. The closest related form to this species appears to be Liopeplum tabulatum Stephenson, from the Nacatoch Sand of Texas, but that species is shorter and proportionally broader with a less well developed channel. Though L. thoracicum Stephenson, from the Black Creek Formation of Texas, has a deep channel and a well-developed callus ridge, its body is constricted anteriorly to a narrower siphonal canal and has a more strongly developed shoulder.

Liopeplum canalis (Conrad) is restricted to the Owl Creek Formation of northern Mississippi and Tennessee.

Types: Holotype (lost); hypotypes USNM 130703; 130704; hypotype USNM 20437.

Occurrence: Mississippi: Owl Creek Formation at locs. 42, 45, 46. Tennessee: Clayton Formation (Owl Creek reworked at base) at loc. 40.


Conus canalis ⁽¹⁾ Tav. 35 – fig.22	Liopeplum canalis (Conrad) Plate XLII, Figures 5, 6 ⁽²⁾

Liopeplum canalis (Conrad) Plate 43 – fig. 17, 18, 23

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