Conus ambonos (Hoerle, 1976)

 

 

Diagnosis (1):

 

Shell thin; moderately low spire; attenuated basally. Adult specimens consisting of eight teleoconch whorls plus three slender nuclear whorls; sides of first three post-nuclear whorls axially costate. Summits of spire whorls concave, marked by strong, moderately arcuate growth lines; shoulders elevated, forming a ridge; sutures ad pressed. Anal fasciole concave; outer lip slightly arched. Aperture uniformly narrow. Anterior third of last whorl ornamented with twelve to fifteen unequal-sized and unevenly-spaced flattened cords.

 

Dimensions of holotype: height 34.6 mm, diameter 18.2 mm.

Holotype: USNM 220106.

Type locality: TU 546, Ten Mile Creek, about 1 Y2 miles west of Chipola River (NW Y4 Sec. 12, T1N, R10W), Calhoun County, Florida (?=USGS

2212, "one mile west of Bailey's Ferry").

Occurrence: Chipola Formation, Florida; late lower Miocene.

 

Figured specimen: USNM 220106 (holotype).

Other occurrences: TU locality nos. 547, 554, 830,

950,951,998.

 

Discussion: C. ambonos is an uncommon species in the Chipola Formation and has a limited geographic range. With the exception of three juveniles taken from river localities, all of the specimens were collected along Ten Mile Creek. The shell is delicate and extremely fragile, consequently, the final whorl is always damaged. The elevated, rimmed shoulder and concave summits of the spire whorls are similar to those of a more massive shell, C. dodona Gardner, from the Oak Grove Sand (see pl. 4, fig. 8). However, the early postnuclear whorls of C. dodona show no axial costae, a characteristic feature of C. ambonos. Also, the Oak Grove species has a more excavated anal fasciole and is not as attenuated and constricted basally. This species derives its name from the Greed word ambonos meaning "rim" or "ridge".

 

 

 

 

Conus ambonos(1)

USNM 220106

mm. 34,6 x 18,2

 

 

 

 

 

 

 

Bibliografia Consultata

 

·         (1) - Hoerle, S. E., 1976. The Genus Conus (Mollusca: Gastropoda) from the Alum Bluff Group of Northwestern Florida. Tulane Studies in Geology and Paleontology, 12 (1 )