Papposilenus utriculus, DeVries, 2019

DeVries, Thomas J., 2019, Early Paleogene brackish-water molluscs from the Caballas Formation of the East Pisco Basin (Southern Peru), Journal of Natural History 53 (25), pp. 1533-1584 : 1560-1561

Papposilenus utriculus sp. nov.

( Figure 4 (u, v, x))

Diagnosis

Characters as for genus; two anterior spiral cords on earliest teleoconch whorls unbeaded.

Description

Estimated shell length about 30 mm, stoutly conical, spire angle about 35°. Protoconch unknown. Spire with about nine whorls. Whorls flat-sided or slightly convex, sutures thinly incised, recessed. All preserved whorls with three spiral cords. Posteriormost spiral cord strongest, beaded on very early whorls, beads rhombohedral, flattened or nodular, with long axis parallel to shell axis and sides prosocline. Two anterior spiral cords slightly narrower, equal in size to each other, divided by thin incision on early whorls, not beaded. Last three or four whorls with all cords fully beaded; beads aligned, producing orthocline to slightly prosocline axial groove, broadly sulcate medially. Spire varices absent. Base poorly preserved; with at least four unbeaded or weakly beaded spiral cords separated by equally wide interspaces. Columella without folds. Outer lip flared from posterior attachment point but mostly not preserved. Anterior canal strongly recurved but mostly not preserved.

Remarks

Specimens of the early Eocene Papposilenus utriculus sp. nov. differ in few respects from the widely distributed Miocene P. suprasulcatus . The Eocene species usually has a more strongly opisthocyrt growth line, wider interspaces between the beaded cords, and beads that are more spirally elongate.

Etymology

‘ Utriculus ’, wineskin, a leather bag made from goat hide used to dispense wine; its profile is like that of the shell of Papposilenus .

Material

UWBM 107589 , holotype, B8772 (type locality), L (25.5), W (15.0) ; remainder are paratypes: UWBM 107590 , B8770, L (17.6), W (12.5); UWBM 107592, B8772, L (18.7), W (12.0);

MUSM INV 253, B8770, L (25.3), W (12.9); MUSM INV 254, B8769, L (22.6), W (12.9).

Occurrence

Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.

Figures

Figure 4. Gastropods from the Caballas Formation. (a–e) Nerita squatina sp. nov., B8771. (a) UWBM 107577, holotype, W 5.7 mm, spire. (b) UWBM 107648, paratype, W 8.5 mm, shoulder of last whorl. (c) UWBM 107649,paratype, W 10.1 mm, anterior of outer lip.(d) UWBM 107647,paratype,W 7.8 mm,inner surface of outer lip. (e) UWBM 107646, paratype, W 6.2 mm, columnar teeth. (f) Calyptraea cf. C. aperta Solander, 1766, UWBM 107578, B8772,W (diameter) 9.9 mm, external mould. (g) Ampullina ortoni Gabb, 1870, UWBM 107,627, B8772, L 36.8 mm, abapertural view, last whorl mostly missing; left margin annotated. (h–l) Melanella indicaformis sp. nov. (h) UWBM 107620, paratype, B8772, L 8.2 mm, apertural view. (i) UWBM 107619, paratype, B8769, L 9.4 mm, apertural/lateral view. (j) UWBM 107623, paratype, B8769,L 8.2 mm, apertural view. (k) UWBM 107618, paratype, B8772, L 10.6, abapertural view. (l) UWBM 107617, holotype, B8769, L 11.1 mm, abapertural view. (m–q) Potamides henryi sp. nov. (m) UWBM 107582, holotype, B8772, L 17.8 mm, lateral view. (n) UWBM 107582, W 6.9 mm, basal view. (o) UWBM 107586, paratype, B8771, L 11.2 mm, lateral view. (p) UWBM 107587, paratype, B8769, L 9.5 mm, abapertural view. (q) UWBM 107650, paratype, B8770, L 15.4 mm, lateral view, shell compressed. (r–t) Potamides janeae sp. nov., B8771.(r) UWBM 107579, holotype, L 9.0 mm, lateral view. (s) MUSM INV 249, L 8.8 mm, lateral and columellar view. (t) UWBM 107580, L 9.5 mm, layeral and columellar view. (u, v, x) Papposilenus utriculus gen.nov., sp. nov. (u) UWBM 107592,paratype, B8772, L 18.7 mm, oblique view of base. (v) UWBM 107589, holotype, B8772, L 25.5 mm, lateral view. (x) UWBM 107590, B8770, L 17.6 mm, lateral view.(w, y,z,jj) Rhinotamides everriculum sp.nov. (w) UWBM 107598,paratype, B8772,L 23.5 mm, abapertural view, juvenile. (y) UWBM 107593, holotype, B8769, L 21.1 mm, abapertural view. (z) UWBM 107594, paratype, B8772, L 19.4 mm, apertural view, posterior and anterior missing. (jj) UWBM 107593, apertural view.(aa,bb) Terebralia pauli gen. nov.sp.nov., UWBM 107599,holotype,B8771, L 9.2 mm.(aa) Abapertural view. (bb) Apertural view, outer lip missing. (cc) Terebralia marki gen. nov. sp. nov., UWBM 107600, holotype, B8771, L 9.8, lateral view. (dd–ii). Nodifaunus gainesi sp. nov. (dd) UWBM 107609, holotype, B8769, L 42.4 mm, apertural view. (ee) MUSM INV 264, paratype, B8772, L 31.0 mm, apertural view, anterior missing. (ff) UWBM 107609, abapertural view. (gg) UWBM 107612, paratype, B8770, L 14.2 mm, abapertural view, juvenile. (hh) UWBM 107612, apertural view. (ii) UWBM 107610, paratype, B8769, L 25.9 mm, apertural view, anterior missing.