Potamides henryi, 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 : 1557-1558

Potamides henryi sp. nov.

( Figure 4 (m – q))

Diagnosis

Shell with narrow spire. Whorls with four beaded primary spiral cords, posteriormost strongest; later whorls often with additional one to three beaded secondary spiral cords. Varices and ventrolateral varix absent. Columella with single fold.

Description

Estimated shell length 15 – 20 mm; elongate, spire slightly convex, spire angle about 16°. Protoconch poorly preserved. Spire with about eight whorls. Whorls flat-sided, sutures thinly incised, recessed. Earliest teleoconch whorls with three beaded spiral cords. Later whorls with four beaded spiral cords: posteriormost widest, adjacent to posterior suture, with axially elongate beads; anteriormost cord, nearly adjacent to suture, second widest, with spherical or spirally elongate oval beads; second cord from the anterior suture third widest, with small, partly separated spherical beads; and second cord from the posterior margin most narrow, with separated spirally elongate oval beads; lattermost spiral cord strengthens on last whorls to match strength of second most anterior cord. Secondary beaded spiral cord usually present between two posteriormost primary spiral cords; rarely with intercalation of other beaded secondary spiral threads. Anterior suture bordered with barely visible beaded spiral cord marking edge of base; latter spiral cord bordered adaxially by rounded groove with medial thread, strong spiral cord with radially elongate beads, at least one thin spiral cord near axis, and convex axial threads. Varices and ventrolateral varix absent. Columella with single fold posterior to midpoint. Inner lip with erect flange arising from parietal area; anterior end not preserved. Outer lip flaring with terminal varix but poorly preserved.

Remarks

Specimens of Potamides henryi sp. nov., which occur together with specimens of P. janeae sp. nov., are generally more elongate and the spires more convexly conical than those of P. janeae . Specimens of P. henryi have four or more beaded primary cords, rather than the three beaded spiral cords on specimens of P. janeae , and have beaded spiral cords on the base.

Material

UWBM 107582 , holotype, B8772 (type locality), L (17.8), W (6.9) ; remainder are paratypes: UWBM 107583 , B8772, L (14.9), W (6.3) ; UWBM 107584 , B8772, L (15.2), W (6.6) ; UWBM 107585 , B8772, L (12.6), W (6.0) ; UWBM 107586 , B8771, L (11.2), W (6.0) ; UWBM 107587 , B8769, L (9.5), W 6.9 ; UWBM 107588 , B8769, L (11.7), W (5.7) ; UWBM 107650 , B8770, L (15.4), W (7.4) ; MUSM INV 250 , B8772, L (14.0), W (7.9) ; MUSM INV 251 , B8772, L (15.8), W (7.7) ; MUSM INV 252 , B8772, L (10.0), W (5.6

).

Etymology

Named in honour of Henry R. DeVries, father of the author.

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.