Provanna pelada, Kiel & Hybertsen & Hyžný & Klompmaker, 2020

Kiel, Steffen, Hybertsen, Frida, Hyžný, Matúš & Klompmaker, Adiël A., 2020, Mollusks and a crustacean from early Oligocene methane-seep deposits in the Talara Basin, northern Peru, Acta Palaeontologica Polonica 65 (1), pp. 109-138 : 124-125

Provanna pelada sp. nov.

Fig. 15.

Zoobank LCID: urn:lsid:zoobank.org:act:A2B18082-B13C-40BF-88DE-6C36E6AFC742

Etymology: For the type locality at Cerros El Pelado.

Type material: Holotype: NRM Mo187052 . Paratypes: NRM Mo187053 , NRM Mo187058.

Type locality: Cerros El Pelado block 2, Talara Basin, Peru .

Type horizon: The presumably early Oligocene part of the Heath shale.

Material.—The type material and several unnumbered specimens from the type locality.

Dimensions.—The largest specimen, H = c. 8 mm.

Diagnosis.—Slender provannid with at least two whorls and incised suture; whorls with basal constriction; shell surface nearly smooth, or with faint spiral threads or indistinct spiral cords, axial ornament consists either of fine or rough, prosocline, growth increments or indistinct prosocline ribs.

Description.—Shell small, slender, at least two whorls, suture deeply incised; whorl profile evenly convex or with slight subsutural constriction; base with constriction and bulge underneath; surface sculpture of fine, prosocline growth increments, sometimes also irregular, rough and irregular, low prosocline ribs, spiral sculpture ranging from absent to indistinct, low cords.

Remarks.—Compared to smooth (or nearly smooth) specimens of P. antiqua , Provanna pelada is slightly taller, its whorls are less convex, and the suture is less distinct. Also, its growth lines are prosocline, whereas those of P. antiqua are opisthocline or straight. The early Oligocene P. urahoroensis Amano and Jenkins, 2013 , from a seep deposit in eastern Hokkaido, Japan, has a similar range of ornamentation, but differs from P. pelada by having lower whorls with a more convex profile, and by lacking the constriction and bulge at the base ( Amano and Jenkins 2013). The two Miocene species Provanna marshalli Saether, Little, and Campbell, 2010a (from New Zealand) and Provanna hirokoae Amano and Little, 2014 (from Japan) differ from Provanna pelada by having a broader apical angle and by having both spiral and axial sculpture ( Saether et al. 2010a; Amano and Little 2014). There are three smooth Recent species; among them, Provanna glabra Okutani, Fujikura, and Sasaki, 1993 is taller, P. subglabra Sasaki, Ogura, Watanabe, and Fujikura, 2016 has slightly less convex whorls, and P. laevis ( Warén and Ponder 1991) has slightly more convex whorls. Provanna fortis Hybertsen and Kiel, 2018 , from the middle Eocene Humptulips Formation in western Washington state, USA ( Hybertsen and Kiel 2018), has stronger ornamentation and a much more angular whorl profile compared to that of Provanna pelada .

Stratigraphic and geographic range.— Type locality and horizon only.