Rhinotamides everriculum DeVries 2019, sp. nov.
Creators: name: DeVries, Thomas J.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Rhinotamides
Rhinotamides everriculum

description: Rhinotamides everriculum sp. nov.
(Figure 4 (w), 4(y), 4(z), 4(jj))
Diagnosis
Reticulate sculpture of three thin primary spiral cords and bluntly spinose axial ribs on later teleoconch whorls.
Description
Shell length estimated about 35 mm, cerithiform, spire angle about 25° for early whorls, 15° for later whorls. Protoconch unknown. Spire about 11 whorls, flat-sided to weakly convex. Sutures impressed. Earliest teleoconch whorls with reticulated sculpture produced by three strong spiral cords and about eight stronger axial ribs that extend suture to suture. Subsequent whorls with stronger, more nodular, and more numerous axial ribs (11), three distinct primary spiral cords and on some specimens, an additional basal peripheral cord; the three to four cords cross axial ribs to produce raised nodes; a secondary spiral cord inserted between each pair of primary spiral cords and between anterior and posterior primary cords and the respective sutures. Mid-spire whorls with more numerous axial ribs (14), insertion of intercalated tertiary spiral threads between three primary spiral cords; and posteriormost spiral cord with nodes becoming larger and bluntly spinose. Last whorl with smooth anterior primary spiral cord, reduced middle spiral cord, varying losses of tertiary spiral threads, and bluntly spinose posterior primary spiral cord; axial ribs diminished anteriorly. Varices, ventrolateral varix absent. Base with peripheral primary spiral cord, flattened adaxially with at least one additional strong spiral cord. Outer lip flaring, extended posteriorly adjacent to suture, producing subsutural blunt spine, but without posterior canal. Parietal area with callus; columella short, without fold. Anterior canal twisted abaxially, with keeled posterior margin; poorly preserved.
Remarks
The Caballas Formation specimens attributed to Rhinotamides differ from the Late Cretaceous species from the Tortuga Formation, R. rudis, in having axial ribs that become increasingly numerous with each spire whorl, thus preventing axial ribs on successive whorls from remaining axially aligned, as they do on the spire of R. rudis. Specimens of R. everriculum share more characters with early Eocene specimens of a species herein transferred to Rhinotamides, Potamides occidentalis Woods, 1922, from the Talara Basin of northern Peru. Those shared characters include a short smooth columella adjacent to an abaxially twisted anterior canal with a keeled posterior margin. Specimens of Rhinotamides occidentalis, however, have less sharply defined spiral cords on later whorls.
Etymology
‘ Everriculum ’, Latin for ‘ fishing net ’, referencing the reticulate sculpture of this species.
Material
UWBM 107593, holotype, B8769 (type locality), L (21.1), W (14.7); remainder are paratypes: UWBM 107594, B8772, L (19.4), W (17.0); UWBM 107595, B8769, L (29.7), W (17.6);
UWBM 107596, B8772, L (25.4), W (15.4); UWBM 107597, B8769, L (12.2), W (8.9); UWBM 107598, B8772, L (23.5), W (11.0); MUSM INV 255, B8769, L (24.8), W (15.2); MUSM INV 256, B8769, L (28.4), W (15.0); MUSM INV 257, B8769, L (13.6), W (9.0); MUSM INV 258, B8772, L (14.4), W (9.8).
Occurrence
Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.
description: Published as part of DeVries, Thomas J., 2019, Early Paleogene brackish-water molluscs from the Caballas Formation of the East Pisco Basin (Southern Peru), pp. 1533-1584 in Journal of Natural History 53 (25) on pages 1561-1562, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/3670229