Conus regularis (Sowerby II, 1833)

Conus regularis (Gabb, 1872)

Costa Rica

An abundant fossil of Costa Rica which agrees with the descriptions and figures as well as with recent specimens from the Gulf of Nicoya, except that the surface is described as smooth. I find, however, that some of the recent shells are grooved and even marked by moniliform ribs, especially on the anterior end. The fossils vary from more nearly smooth than some of the recent specimens, to a form covered over the entire surface with large ribs, with equal, deep interspaces (fig. 45: simile al Conus gaza ma le linee spirali sono molto più distanziate).

C. marginatus, Sby. (fossil in Santo Domingo), seems to be only an older form of the same species. It is smaller and more robust than the recent shell, though approached in this respect by some of the Costa Rican fossils. Its surface is regularly marked by square revolving ribs, with equal squarely sunken interspaces, and even this character is approached by some of the specimens before us,

Ecuador

The fossils are much larger and coarser than the average recent specimens of this species. Occurrence. - Jama formation, Puerto Jama (Ecuador) ⁽⁵⁾.

California

The above name is applied to the Coyote Mountain fossils with the meaning attached to it given by Dall in the publication, cited above (pag. 221), and not as defined by Tryon. Most of the above specimens show traces of bold square maculations very distinctly. In the fossils, the color of these spots is brown, in the living shells, red ⁽⁷⁾.

This is a shorter and wider shell with a. short conical spire, longitudinal brown nebulous streaks and spiral articulated lines, which tend to be alternately darker and lighter. I have not found in our large scries an exact duplicate in color pattern of Sowerby's original figure in the Conchological Illustrations, but the mass of specimens approach it. As a. whole the color effect is darker than in the previously mentioned forms of the group, and there is a notable tendency of the color markings to form groups in the spiral sense. Another form closely allied to this, which is listed as C. dispar Sowerby, in the Thesaurus, though not the original C. dispar of the Conchological Illustrations, is characterized by a bluish or livid ground color, which gives a very different aspect to a shell not otherwise separable from C. regularis. This has been collected from Topolobampo, Mexico, to the Gulf of California ⁽⁸⁾.

California.

Bibliografia

• (1) - Sowerby (ii), G. B. Jr., 1833. The Conchological Illustrations

• (2) - Gabb, W. M., 1872. Descriptions of New Species of Fossils from the Pliocene Clay Beds between Limon and Moen, Costa Rica, Together with Notes on Previously known Species from there and elsewhere in the Caribbean Area. Journal of the Academy of Natur

• (3) - “Early Pliocene gastropod diversity from the central eastern Pacific Ocean, Mexico (Guerrero) and their paleogeographical interpretation” Catalina Gómez-Espinosa, & Claudia Gabriela Ortíz-Jerónimo & Frank Raúl Gío-Argaez & Luis Antonio Flores de Dio

• (4) - Dall, W. H., and Ochsner, W. H., 1928. Tertiary and Pliestocene Mollusca from the Galapagos Islands. Proceedings of the California Academy of Sciences, ser. 4. vol. 17 (4 ): 89 -139

• (5) - “A Pliocene Fauna from Western Ecuador” Henry A. Pilsbry and Axel A. Olsson Proceedings of the Academy of Natural Sciences of Philadelphia Vol. 93 (1941), pp. 1-79 (99 pages)

• (6) - “CATALOGUE OF THE MARINE Pliocene and Pleistocene Mollusca of California and adjacent regions”, Grant & Gale, 1931

• (7) - Hanna, 1926 “Paleontology of Coyote Mountain, Imperial County, California, Proceedings of the California Academy of Sciences 14 18, 427-503 “

• (8) - SUMMARY OF THE SHELLS OF THE GENUS CONUS FROM THE PACIFIC COAST OF AMERICA IN THE U. S. NATIONAL MUSEUM. By William Healey Dall