Conus (Ximeniconus) corrugatus (Gardner, 1937)

Conus gardnerae (Hoerle, 1976)

Description.

Shell rather small, biconic, the sharply angulated periphery of the body forming the base of each cone. Spire rather high, approximately one-third the altitude of the entire shell. Whorls 10 or more, including 3 or 4 turns of the protoconch. Nuclear turns small, polished, laterally compressed, and very gradually increasing in size; line of differentiation between conch and protoconch marked by the abrupt initiation of the angulated shoulder and the incremental sculpture. Whorls of conch increasing in size with a moderate degree of rapidity, the sides of the spire serrated by the projecting peripheries of the successive volutions. Shoulder behind the periphery conspicuously flattened as a rule, a broad spiral fillet being thus formed, which is persistent in some individuals almost to the nucleus. Sculpture of the spire restricted to arcuate incremental striations that mark the former presence of the posterior siphonal notch and restricted, in those individuals that are conspicuously flattened upon the front part of the shoulder, to the area between the fillet and posterior suture. Sutures distinct, even a little impressed. Body whorl sculptured with 12 or more low, broad spiral bands and in front of these upon the anterior canal 4 to 6 crowed lirae; interspirals linear in most individuals and finely striated by then incrementals. Aperture more than half the altitude of the entire shell, rather narrow, with subparallel margins. Outer lip thin, sharp, deeply indented upon the shoulder for the protusion of the posterior siphon. Inner lip oblique, parietal wall smooth. Anterior canal slightly flaring, obliquely truncate.

Dimension: maximum height 15,5 mm; height of the spire 5 mm; maximum diameter 7,9 mm.

Discussion.

The specific name C. corrugatus of Gardner is preoccupied by that of the recent species, C. corrugatus (Sowerby, 1870) (Proc. Zool. Soc., p. 257, pl. 22, fig. 7 . Habitat unknown. Type in British Museum.) . The new name C. gardnerae is here proposed for this species ⁽³⁾.

Gardner (1937) noted that the species " has a meager distribution in the Chipola, but in the Oak Grove sand it is abundant and widely distributed." Of the 110 specimens in the writer's collection, 85% were taken from Ten Mile Creek; however, the species is also represented at Chipola River and Farley Creek localities ⁽³⁾.

C. gardnerae can be readily distinguished from C. chipolanus by its stouter outline, smaller size , and lack of the curved-rib stage that is noted on C. chipolanus. Pustules have been observed on a few specimens. They are positioned medially along the broad spiral bands whereas those on C. chipolanus are smaller and placed on the adapical edge of the bands. Although the size and outline of C. gardnerae are nearly in agreement with those of the Recent Caribbean C. jaspideus Gmelin the nuclei and details of the spire whorls are totally different. The nucleus of the recent species has fewer whorls and the summits of the spire whorls do not have the flattened area seen on C. gardnerae ⁽³⁾.

Type: USNM 349864 – Yellow River, Okaloosa Co., Florida – Late Lower Miocene

The Alum Bluff Group is a geologic group in the states of Georgia, Florida, and Alabama.

Epoch: Miocene

The Chipola Formation is a Burdigalian geologic formation in the Florida Panhandle and member of the Alum Bluff Group.

Conus (Ximeniconus) corrugatus

Plate XLIII fig. 9

mm. 15,5 x 7,9

Conus gardnerae ⁽³⁾

mm. 13,8 x 6,9

Conus cf. gardnerae

Upper Oligocene (Chattian) Haywood Landing Member of the Belgrade Formation

Onslow County, North Carolina, USA

mm. 22

Michael Reagin, I thank Melanie Briskin for inviting me to join this group and thus giving me the opportunity to analyze this specimen.

As I mentioned in my previous comment, this specimen is very different from both Conus alveatus and Conus postalveatus, even though it comes from the same area and the same period.

Kellum points out that in Conus postalveatus “sides of outer whorl are longitudinally nearly straight”, while in this specimen sides of the outer whorl are ventricous. In Conus postalveatus, whorls are somewhat excavated on top, spirally sculptured with fine grooves, and bounded by an angular shoulder; early whorls faintly nodulated at the shoulder: a description that is clearly very far from the characteristics of this specimen.

This specimen is clearly worn by time and bad weather, which have altered its morphological characteristics, however it is still possible to observe that the body whorl is sculptured with low, broad spiral bands, just like in the description of Conus corrugatus, now Conus gardnerae, from the Alum Bluff Group of Florida. The Alum Bluff Group is a geologic group from Late Oligocene to Early Miocene (Faunal stage: Chattian through Hemphillian). It is also interesting to note that Conus marylandicus is also reported in Virginia in the Miocene.

It is difficult to say that this specimen could be a Conus gardnerae, but it is certainly very similar: Gardner noted that Conus corrugatus " has a meager distribution in the Chipola formation”, a geologic group from Late Oligocene to Early Miocene, but for this reason this specimen is very interesting.

Conus sp.