Conus woodringi (Hendrick, 2018)

Descrizione e caratteristiche:

Holotype⁽¹⁾.

—UF 259874, UF locality YN020 (“San Judas 01”), lower Gatun Formation, Cativa, Colón Province, Panama (latitude and longitude: 9.3521170° N, 79.8368540° W (WGS84); determined using Google Earth Pro) (Fig. 8.1–8.5)⁽¹⁾.

Paratypes⁽¹⁾.

—UF 271017 (Fig. 8.6), UF 271018 (Fig. 8.7), UF 259753 (Fig. 8.8), UF256535 (Fig. 8.9), and UF 271019 (all from UF locality YN020, same as holotype)⁽¹⁾.

Diagnosis⁽¹⁾.

—Shell moderately large; spire low to moderate; spire tuberculate; subsutural flexure asymmetrical and deep; two sometimes interacting coloration patterns present, one often consisting of zig-zagging axial streaks⁽¹⁾.

Occurrence⁽¹⁾.

—Based on records here and in Woodring (1970), the species spans the lower to upper Gatun Formation. It may also occur in the lower Pliocene Araya Formation of Cubagua Island, Venezuela (see remarks)⁽¹⁾.

Description⁽¹⁾.

—Shell size: moderately large. The holotype specimen (UF 259874) from UF locality YN020 has SL 50.2 mm, while a middle Gatun Formation specimen (USNM 645746; Fig. 8.11, 8.12) figured by Woodring (1970) has SL 61.7 mm. Last whorl.—Shape conical (RD 0.65–0.70, x= 0:68; PMD 0.88–0.95, x= 0:91; N= 4); outline convex on posterior half, nearly straight on posterior half, resulting in a slightly convex profile. Shoulder sharply angulate to angulate and forming a posterior-pointing ridge; smooth in mature individuals. Widest part of shell below shoulder. Aperture uniform in

width from base to shoulder. Siphonal notch absent. Fine to strong spiral threads on anterior half, diminishing towards shoulder; threads are frequently beaded. Spire whorls.—Spire low to moderate (RSH 0.10–0.20, x= 0:15; N= 4); outline concave to slightly concave. Protoconch unknown. Early postnuclear whorls unknown, but at least seven of the teleoconch whorls bear large, elongate tubercles that diminish thereafter. Sutural ramp of early whorls convex, sigmoidal on later whorls; several spiral grooves present, with threads in between. Subsutural flexure asymmetrical (ASSF 0.4– 0.7, x= 0:6, N=3), depth often nearly twice width (DWSSF 1.2– 2.1, x= 1:8, N=3) (Fig. 8.2, 8.12). Coloration pattern.—Two sometimes interacting patterns present that vary in the color of emitted light. The primary pattern usually consists of two discontinuous bands made up of bold, zig-zagging axial streaks; the bands are usually divided at the midline by a narrow, unpigmented spiral band. In one specimen (Fig. 8.9), the primary bands are continuous, though an unpigmented region at the midline remains. The secondary pattern consists of numerous spiral rows of dots, dashes, or chevron-shape spots that extend from the base to the spire. Interactions between the two patterns are sometimes evident in cases where spaces between the elements of the secondary pattern overlap the primary pattern and result in small, unpigmented dots or spots. Sutural ramp with irregular blotches⁽¹⁾.

Etymology⁽¹⁾.

—Named for Dr. Wendell P. Woodring (1891–1983) in honor of his important contributions to Cenozoic tropical American paleontology (see Moore, 1992)⁽¹⁾.

Remarks⁽¹⁾.

—Conus consobrinus Sowerby I, 1850 was describedfrom the Neogene of the Dominican Republic (the most recentformal treatment of this material was by Pflug, 1961). Occurrencesof C. consobrinus have been widely reported fromthroughout tropical America (see Woodring, 1970). Based on ANSP 1682, Brown and Pilsbry (1911) were the first to report C. consobrinus from the Gatun Formation of Panama, but Woodring (1970) considered this specimen to instead represent C. tortuosostriatus Toula, 1911 and included it in his circumscription of that species; ANSP 1682 was viewed and Woodring’s assignment is accepted here⁽¹⁾.

Woodring (1970) nevertheless recognized C. consobrinus consobrinus as occurring in the Gatun Formation on the basis of other material: “two specimens from the lower part, two from the middle part, and one from the upper part” (Woodring, 1970, p. 353). Following Woodring (1970), Pitt and Pitt (1993) applied the name C. consobrinus consobrinus to a specimen (CASG 66695.09) that shows a fluorescing coloration pattern under UV light (Pitt and Pitt, 1993, pl. 4, fig. 1). Thus, the reported occurrence of C. consobrinus in the Gatun Formation is based on a total of six specimens⁽¹⁾.

While some aspects of shell form (perhaps most notably the presence of large tubercles on most spire whorls and commonly beaded spiral threads on the last whorl) support an association between specimens of C. consobrinus from the Dominican Republic and somewhat similar, older material from the Gatun Formation, coloration patterns revealed under UV light and comparison of shell shape parameters instead better support the hypothesis that the Gatun material represents a species—Conus woodringi n. sp.—distinct from younger C. consobrinus from the early Pliocene of the Dominican Republic⁽¹⁾. While the coloration pattern of C. consobrinus from its type region remains unpublished, it differs markedly from that of the new species (Hendricks, 2017, personal observation of specimens in the collections of the PRI from Tulane University locality TU 1219, lower Pliocene Gurabo Formation of the Dominican Republic). Most notably, the coloration pattern of C. consobrinus seems to lack the distinctive, zig-zagging axial streaks that are present on most of the specimens of C. woodringi n. sp. from UF locality YN020⁽¹⁾. The shell morphology of C. consobrinus from the Dominican Republic also differs substantially from the specimens assigned here to C. woodringi n. sp. In particular, measurements collected from 13 specimens of C. consobrinus in lot PRI 65989 from TU locality 1219 show that shells of C. consobrinus are narrower (RD 0.60–0.64, x= 0:62) and have higher spires (RSH 0.22–0.28, x =0:25) than shells of C. woodringi n. sp. from the Gatun Formation (compare with values above, which do not overlap with these simple metrics). It is therefore concluded that C. consobrinus does not occur in the Gatun Formation of Panama and that reports of this species by Woodring (1970) and Pitt and Pitt (1993) should instead be referred to C. woodringi n. sp⁽¹⁾.

Woodring (1970) considered Conus lavillei Cossmann, 1913 to be a junior synonym of C. consobrinus. The type specimen figured by Cossmann (1913) has a much narrower shell and higher spire than specimens assigned here to C. woodringi n. sp., and it is therefore considered to be a different species. Conus lavillei is much more similar in shell form to Conus tortuosostriatus Toula, 1911, a species known from the Gatun Formation (Woodring, 1970), but not found at UF locality YN020⁽¹⁾.

A specimen (NHMW 2010/0038/0214) from the lower Pliocene Araya Formation of Cubagua Island, Venezuela that was assigned by Landau and Silva (2010) to Conus spurius instead appears to be consistent in several respects with Conus woodringi n. sp. In particular, this specimen (see Landau and da Silva, 2010, pl. 21, fig. 6a–c) exhibits a similar overall shell shape, large tubercles on its early postnuclear whorls, and a visible coloration pattern that shows some evidence of the zig-zagging axial streaks of C. woodringi n. sp. Importantly, specimens of C. spurius never have large tubercles on early postnuclear whorls, negating the possibility that NHMW 2010/0038/0214 belongs to that species.

The specimen from the Araya Formation, however, is somewhat younger (early Pliocene) than the new species from the Gatun Formation (late Miocene). Because of this, the assignment of NHMW2010/0038/0214 to Conus woodringi n. sp. is considered tentative at the present time, pending study of additional material from the Araya Formation⁽¹⁾.

The assignment of C. woodringi n. sp. to the subgenus Stephanoconus is supported in large part by its overall shell shape, presence of large tubercles on most spire whorls, deep subsutural flexure, and especially its complex, two-element coloration pattern. Indeed, C. woodringi n. sp. is very similar in shell morphology to the extant eastern Pacific species Conus (Stephanoconus) archon Broderip, 1833, which has a known phylogenetic position (Puillandre et al., 2014, 2015). In addition to similarities shared with C. consobrinus, C. woodringi n. sp. is also somewhat similar to two additional Neogene tropical American species of Stephanoconus, both from the late Miocene and early Pliocene of the Dominican Republic: Conus sewalli Maury, 1917 and C. bellacoensis Hendricks, 2015⁽¹⁾.

Notable differences, however, include the lack of pigmented zig-zagging axial streaks on C. sewalli and that shells of C. bellacoensis are narrower (mean RD 0.57) and have higher spires (mean RSH=0.28) (Hendricks, 2015) than specimens of C. woodringi⁽¹⁾.

It is anticipated that future study of C. consobrinus will also support its assignment to the Stephanoconus clade⁽¹⁾.

The shell features of Conus woodringi (Hendricks, 2018) agree closely with those of the extant eastern Pacific species Conus (Stephanoconus) archon (Broderip, 1833) ⁽²⁾.

Risultati immagini per "conus taphrus"

Conus woodringi ⁽¹⁾

Gatun Formation

Upper Miocene - Panama

locality YN020: San Judas 01 - Lower Gatun Formation, Cativa, Colón Province, Panama

(9.3521170° N, 79.8368540° W, WGS84) ⁽²⁾

Figure 8. Conus (Stephanoconus) woodringi new species ⁽¹⁾

(1, 2, 11, 12) photographed under regular light

(3–10) photographed under UV light

all specimens are from UF locality YN020 (lower Gatun Formation) unless otherwise indicated.

(1–5) UF 259874, holotype, SL 50.2 mm, MD 28.0 mm

(6) UF 271017, SL 44.0 mm;

(7) UF 271018, preserved portion of SL 33.7 mm;

(8) UF 259753, SL 38.7 mm;

(9) UF 256535, SL 41.7 mm;

(10) USNM 645745, specimen figured by Woodring (1970, pl. 56, figs. 3, 7), Panama Canal Zone, Woodring locality 138c, lower Gatun Formation, SL 47.7 mm;

(11, 12) USNM 645746, specimen figured by Woodring (1970, pl. 56, fig. 9), Panama Canal Zone, Woodring locality 161b, middle Gatun Formation, SL 61.7 mm.

Scale bar to left of (1) is 10mm and pertains to all specimens.