Paskentana anistratenkorum, Kiel & Campbell & Gaillard, 2010

Kiel, Steffen, Campbell, Kathleen A. & Gaillard, Christian, 2010, New and little known mollusks from ancient chemosynthetic environments, Zootaxa 2390 (1), pp. 26-48 : 34-35

Paskentana anistratenkorum sp. nov.

( Fig 5C )

2008 Paskentana n. sp.; Kiel & Peckmann 2008, fig. 6F.

Diagnosis: Littoriniform shell; at least three convex whorls; suture deeply incised; fine spiral sculpture of narrowly spaced spiral cords that are stronger near suture, weaker and more widely spaced on periphery.

Holotype: USNM 535873 , H = 22 mm, W = 16 mm.

Type locality and strata: The Hauterivian Peregrinella -limestone in the Planerskoje section, southeastern Crimea, Ukraine (35°12’E 44°585’N), described by Kiel and Peckmann (2008) .

Description: Shell globular, littoriniform, three whorls preserved; whorls strongly and evenly convex; about 20 flat-topped spiral cords with very narrow interspaces on early whorls; on last whorl about ten such cords near suture, cords much weaker and broader on periphery; growth lines prosocyrt below suture, almost straight on periphery. Aperture and base unknown. Largest specimen 39 mm high, 30 mm wide; apical angle 65°.

Remarks: Paskentana anistratenkorum n. sp. differs from the Oxfordian Paskentana umbilicata n. sp. from Beauvoisin by lacking the fine axial ornament on the upper part of the whorls, and by having a more deeply incised suture. Of the three Californian species of Paskentana , P. globosa with its evenly convex, spirally ornamented whorls is the most similar one to P. anistratenkorum (see Kiel et al. 2008, fig. 7D–F). It differs from P. anistratenkorum by having closely spaced spirals on the periphery, in contrast to the widely spaces spirals of Paskentana anistratenkorum .

Ascher (1906) described four gastropod species from Peregrinella -bearing carbonates at ‚Koniakauer Schloss’ (Koniakov Castle) in eastern Czech Republic that could potentially belong to Paskentana . Most similar to Paskentana anistratenkorum is Natica (Amauropsis) euxina Retowski, 1894 . But like Retowski’s late Jurassic (Tithonian) original species from the southeastern Crimea ( Retowski 1893: pl. 14, figs. 8a, b), Ascher’s species has narrowly spaced spirals also on the periphery, in contrast to Paskentana anistratenkorum , which has widely spaced spirals on the periphery. Among the other three potential Paskentana species , Natica grodischtana Ascher, 1906 has a smooth shell, N. (Amauropsis) aff. suprajurensis Buvignier, 1843, has a subsutural ramp, and N. (A.) uhligi Ascher, 1906, shows a fine cancellate pattern. Another similar early Cretaceous species with narrowly spaced spirals on the periphery is Natica cassisiana d’Orbigny, 1842 ( d’Orbigny, 1842: p. 166, pl. 175, figs. 1, 4). Cossmann (1925) placed this species in Vanikoropsis Meek, 1876 , and Kollmann (2005) hesitantly followed this classification.

Distribution: Type locality only.

Etymology: For Olga and Vitaliy Anistratenko, Kiev.

Figures

FIGURE 5. A, B. Paskentana umbilicata n. sp. from Oxfordian (Late Jurassic) seep carbonates at Beauvoisin, southeastern France; A, holotype (FSL 286 456), B, specimen with broad last whorl (FSL 286 457). C. Paskentana anistratenkorum n. sp. from a Hauterivian (Early Cretaceous) seep carbonate in the Planerskoje section, Crimea, Ukraine; holotype (USNM 535873).