Hendricks—Miocene Conidae from the Gatun Formation of Panama


(Puillandre et al., 2014)—justifying assignment of this taxon to the same subgenus, Pyruconus Olsson, 1967. The pyriform shells of members of the Pyruconus I clade are distinctive and the establishment here of C. recognitus in the lower Gatun Formation provides a potentially useful calibration date for future molecular phylogenetic studies. Given its unique shell shape, especially its rounded shoulder, C. recognitus cannot be easily confused with co-occurring fossil species in the Gatun Formation.


Conus (Pyruconus II) molis Brown and Pilsbry, 1911 Figure 12.1–12.12


1911 Conus molis Brown and Pilsbry, p. 343, pl. 23, fig. 1.


1911 Conus concavitectum Brown and Pilsbry, p. 341, pl. 23, figs. 5, 6.


1911 ?Conus haytensis; Brown and Pilsbry, p. 341 (not Sowerby I, 1850).


1917 Not Conus molis; Maury, p. 200 (likely=Conus haytensis Sowerby I, 1850).


1970 Conus molis; Woodring, 1970, p. 350, pl. 55, figs. 8–10. 1993 Not Conus cf. molis Brown and Pilsbry; Pitt and Pitt, p. 10, pl. 4, fig. 2 (= Conus spurius Gmelin, 1791).


Holotype.—USNM 636043, “excavations for the locks at Gatun” (Brown and Pilsbry, 1911, p. 336), Panama Canal Zone. Woodring (1970, p. 350) stated that the type locality is posi- tioned in the “middle part of the Gatun [F]ormation.”


Occurrence.—Woodring (1970) reported that Conus molis spans the lower to upper Gatun Formation.He also reported that the species occurs in the Limón Formation of Panama, the Tubará Formation of Colombia, and unnamed deposits in Costa Rica; these records require confirmation. Maury’s (1917) report of the species from the Dominican Republic is considered incorrect (see below).


Description.—Maximum shell size: large. The largest nearly complete observed specimen (UF 256531) from UF locality YN020 has SL 98.2mm. Woodring (1970, pl. 55, fig. 8) figured a specimen (USNM 645742) from the upper Gatun Formation (Woodring locality 185) that he reported as having an SL of 160mm. Last whorl.—Shape broadly and ventricosely conical,


broadly conical, or conical (RD 0.68–0.74, x=0:71; PMD 0.84–0.94, x=0:89; values based on three specimens, two of which are slightly damaged); outline convex on posterior half, slightly concave to nearly straight on anterior half, resulting in sigmoidal to slightly convex profile. Shoulder sharply angulate or angulate, rarely forming an adaxially slanting carinate ridge; smooth. Widest part of shell below shoulder. Aperture nearly uniform in width from base to shoulder. Siphonal notch absent. Spiral threads present on anterior half of last whorl of immature specimens, sometimes diminishing towards shoulder and occasionally forming beads (e.g., UF 270981); weak and slightly wavy spiral threads on anterior quarter of mature specimens, with very fine spiral threads sometimes extending to the shoulder.


827 Spire whorls.—Spire low to moderate (RSH 0.10–0.13;


whorls are stepped. Sutural ramp concave to nearly flat. Four or five spiral grooves separate threads on the ramps of immature specimens; mature individuals may have several more grooves and threads, though spiral ornamentation sometimes becomes obsolete on the final intervals of growth. Subsutural flexure nearly symmetrical (ASSF 0.7–0.9; x=0:7; N=4), depth typi- cally slightly greater than width (DWSSF 0.9–1.7; x=1:4; n=4). Coloration pattern.—Two occasionally interacting patterns


x=0:12; values based on three specimens, two of which are slightly damaged); outline concave to nearly straight. Proto- conch unknown. Most specimens have poorly preserved apices, but two observed specimens (UF 259776 and UF 271034) show evidence of weakly tuberculate early postnuclear whorls. Early


present that vary in the color of emitted light. The primary pat- tern consists of fine to wide axial streaks that are often separated into two (e.g., Fig. 12.7, 12.8, 12.12) or three (e.g., Fig. 12.6) regions along the length of the last whorl. The streaks range from nearly straight (e.g., 12.7, 12.11) to irregular (e.g., Fig. 12.8), sometimes forming diagonal streaks composed of sub- triangular elements (e.g., Fig. 12.10). Several rows of spiral dots and dashes are visible on the anterior half of one large specimen (Fig. 12.11) and the primary pattern is nearly absent from another large specimen (Fig. 12.12). The secondary pattern usually consists of at least two nearly continuous spiral bands; a third band is present just below the shoulder in some specimens, though it tends to be weaker than the bands positioned at the midline and on the anterior third of the last whorl. The immature specimen shown in Figure 12.7 does not show evidence of the secondary pattern. In one specimen (Fig. 12.10), the secondary pattern has the appearance of smearing the primary pattern, suggesting a degree of interaction between the two layers. Sutural ramp with diffuse radial blotches (Fig. 12.9).


Materials.—USNM 645743 (one specimen, figured by Woodring, 1970; Fig. 12.1); ANSP 1684, syntype of Conus concavitectum Brown and Pilsbry, 1911 (Fig. 12.2); and 81 specimens from UF locality YN020.


Remarks.—The holotype of Conus molis was part of the Princeton University invertebrate paleontology collection (formerly PU 5502), but now resides in the Smithsonian col- lection (USNM 636043). Woodring (1970) considered Conus concavitectum Brown and Pilsbry (1911) to represent a juvenile C. molis; on this basis, he conferred taxonomic precedence to C. molis over C. concavitectum. The syntypes of C. con- cavitectum, one of which is figured here (Fig. 12.2), were observed and Woodring’s conclusion that this species is synonymous with C. molis is accepted here. Brown and Pilsbry (1911, p. 341) reported, but did not figure, a “perfect but small specimen” of Conus haytensis Sowerby I, 1850 from the Gatun Formation; this unknown specimen is presumed to instead be C. molis, which is very similar (see below). Conversely, Maury (1917) reported C. molis from the Neogene of the Dominican Republic, but Woodring (1970, p. 351) noted, “[i]t is likely that Maury’s C. molis is an immature C. haytensis.” Pending future study, Maury’s reported occurrence of this taxon in the Dominican Republic is considered incorrect. The specimen of Conus cf. molis figured by Pitt and Pitt (1993, pl. 4, fig. 2) has a


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