Conus zambaensis (Hendricks, 2015)

Description ⁽¹⁾

Shell size. Shell medium sized (largest observed specimen, PRI 66173, is 43.2 mm). Last whorl. Typically conical, but sometimes ventricosely conical (RD 0.56–0.61; μ = 0.59; PMD 0.84–0.88, μ = 0.86; n = 7); outline convex, except at anterior quarter, which may be slightly concave. Shoulder angulate, smooth. Widest part of shell below shoulder. Aperture slightly wider at base than near shoulder. Siphonal notch absent. Spiral threads on anterior half, diminishing towards shoulder ⁽¹⁾.

Spire whorls. Spire height low (RSH 0.06–0.09; μ = 0.08); outline typically concave to sigmoidal, sometimes convex; whorls may be stepped. Protoconch diameter ca. 0.7 mm (based on PRI 67488), number of whorls unknown. First 2 postnuclear whorls tuberculate, diminishing thereafter. Sutural ramp flat to slightly sigmoidal, several spiral threads present on all but the last couple of whorls in mature specimens. Subsutural flexure nearly symmetrical, depth about 1.2x width ⁽¹⁾.

Coloration pattern. Two weakly interacting patterns present. The primary (base) pattern consists of a nearly solid ground pattern, with the exception of thin band near the middle of the last whorl where this pigmentation is discontinuous, resulting in a band of unpigmented, irregularly shaped blotches. The secondary pattern—visible only on a portion of the ventral surface of PRI 67491 (Fig. 25G)—consists of at least 12 spiral rows of dots; spaces between these are sometimes unpigmented, including when they intersect the primary pattern (these unpigmented spaces are the evidence that a weak interaction between the two patterns is present). The two patterns differ in the color of emitted light. Sutural ramp with blotches that sometimes correspond with the shape of the subsutural flexure ⁽¹⁾.

Etymology

Named for the type locality, Cañada de Zamba, Dominican Republic ⁽¹⁾.

Remarks

Conus zambaensis is somewhat similar in shell morphology to Conus franklinae sp. nov.; for differences separating the two species, see remarks for the latter taxon. The shell shape of C. zambaensis, as well as the presence of spiral threads covering much of the last whorl, are also reminiscent of the extinct species Conus miamiensis Petuch, 1986, which is known from the Plio-Pleistocene of Florida. Conus miamiensis, however, has a different coloration pattern. Among extant taxa, C. daucus has a shape and coloration pattern that resembles C. zambaensis.

All of the morphometric values reported here for C. zambaensis (RD, PMD, and RSH) are within the ranges given for C. daucus by Kohn. Furthermore, C. daucus—as circumscribed by Kohn —also exhibits a solid base color that is interrupted by an unpigmented, narrow band in the middle of the last whorl, as well as spiral rows of dots. One difference between C. zambaensis and C. daucus is that the fossil species has spire whorls that are often stepped, while this is not typical in C. daucus. Puillandre et al. assigned C. daucus to the subgenus Dauciconus, a designation that is tentatively followed here for C. zambaensis. ⁽¹⁾.

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Fig 25. Conus (Dauciconus?) zambaensis Hendricks sp. nov.

All specimens are from locality station TU 1354 (Gurabo Fm.)

(A-F) PRI 67488 (holotype), SL 34.8 mm;

(G-I) PRI 67491 (paratype), SL 32.5 mm;

(J) PRI 66173 (paratype), SL 43.1 mm.

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Bibliografia Consultata

· (1) - Hendricks (2015) “Glowing Seashells: Diversity of Fossilized Coloration Patterns on Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells from the Neogene of the Dominican Republic”