107,526 research outputs found
Potamides janeae DeVries 2019, sp. nov.
No full text<i>Potamides janeae</i> sp. nov. (Figure 4 (r <i>–</i> t)) <p> <i>Diagnosis</i></p> <p>Shell with broadly conical spire. Whorls with three beaded spiral cords. Varices and ventrolateral varix absent. Columella with single fold.</p> <p> <i>Description</i></p> <p>Estimated shell length 15 mm; conical, spire angle about 25°. Protoconch unknown. Spire with at least eight whorls. Whorls flat-sided, sutures thinly incised, recessed. All preserved whorls with three beaded spiral cords. Medial spiral cord narrow, with smallest beads, and close to anterior cord. Beads nodular, spherical, aligned axially in nearly orthocline rectilinear ribs. Base of whorl demarcated by weakly beaded strong spiral cord, with adaxially adjacent, smooth, strong, quadrate spiral cord and weak third spiral cord close to axis. Remainder of base with convex axial threads. Columella with single fold anterior to midpoint. Anterior and posterior canal, if present, and outer lip not preserved.</p> <p> <i>Etymology</i></p> <p>Named in honour of Jane Cody DeVries, mother of the author.</p> <p> <i>Material</i></p> <p>All material from B8771 (type locality). UWBM 107579, holotype, L (9.0), W (5.1); remainder are paratypes: UWBM 107580, L (9.5), W (5.0); UWBM 107581, L (4.1), W (5.0); UWBM 107634, L (4.9), W (4.6); MUSM INV 248, L (8.0), W (5.0); MUSM INV 249, L (8.8), W (4.1)</p> <p>.</p> <p> <i>Remarks</i></p> <p> Specimens of <i>Potamides janeae</i> sp. nov. differ from those of <i>P. henryi</i> sp. nov. by having only three spiral cords, instead of four, and by having unbeaded spiral cords on the base.</p> <p> <i>Occurrence</i></p> <p>Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.</p>Published as part of <i>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)</i> on page 1558, DOI: 10.1080/00222933.2018.1524032, <a href="http://zenodo.org/record/3670229">http://zenodo.org/record/3670229</a>
Terebralia marki DeVries 2019, sp. nov.
No full text<i>Terebralia marki</i> sp. nov. (Figure 4 (cc)) <p> <i>Diagnosis</i></p> <p>Spiral ribs strongly opisthocline; six primary spiral cords weakly crossing axial ribs; no peripheral cord exposed near anterior suture.</p> <p> <i>Description</i></p> <p>Shell fragment small, length less than 10 mm, thick. Elongate, pleural angle about 15°. Protoconch partly preserved but windblasted; probably multispiral, conical. Evidence of five whorls preserved; flat-sided, sutures impressed. All spire whorls with six rounded primary spiral cords lightly crossing about 14 very strong rounded axial ribs; ribs straight, opisthocline. Spiral cords interspaces V-shaped, much narrower than spiral cords; axial rib interspaces almost as wide as axial ribs. Anterior end of last whorl, base unknown. Aperture circular. Columella without folds. Varices and ventrolateral varix absent. Inner and outer lip unknown.</p> <p> <i>Remarks</i></p> <p> This single specimen of <i>Terebralia marki</i> sp. nov. has more than the four spiral cords that are present on the specimen of <i>T. pauli</i> and that are typically present on species of <i>Terebralia</i> (but see extant <i>T. semistriata</i> (Mörch, 1852), which has five or six spiral cords).</p> <p> <i>Etymology</i></p> <p>Named in recognition of Mark C. DeVries, brother of the author.</p> <p> <i>Material</i></p> <p>UWBM 107600, holotype, B8771 (type locality), L (9.8), W (5.1).</p> <p> <i>Occurrence</i></p> <p>Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.</p>Published as part of <i>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)</i> on pages 1563-1564, DOI: 10.1080/00222933.2018.1524032, <a href="http://zenodo.org/record/3670229">http://zenodo.org/record/3670229</a>
Caballasea segmentata DeVries 2019, sp. nov.
No full textCaballasea segmentata sp. nov. (Figure 5 (a – e)) Diagnosis As for genus. Description Shell length about 20 mm, cerithiform, spire angle about 12°. Protoconch unknown. Teleoconch of six or seven weakly convex whorls. Sutures impressed. Shoulder canaliculate. Spiral sculpture on spire whorls of six evenly spaced, rounded, primary spiral cords; interspaces quadrate, at least half as wide as spiral cords. Base of last whorl with additional four primary spiral cords, equally spaced and equally strong. Axial sculpture of about nine primary ribs on each whorl, variably rounded to flange-like, orthocline to slightly opisthocline, often extending to anterior end, weakly sinuate posteriorly, sometimes aligned across sutures. Thin growth lines between primary axial ribs. Varices and ventrolateral varix absent. Aperture axially elongate. Outer lip thin. Columella smooth, thickened, without folds; anterior portion of lip produced with very shallow anterior canal. Etymology ‘ Segmentata ’, Latin adjective for ‘ frilled ’, referencing the frilled axial ribs of this species. Material UWBM 107606, holotype, B8769 (type locality), L 12.6, W 5.6; remainder are paratypes, B8769: UWBM 107607, L 12.4, W 5.7; UWBM 107608, L (15.3), W (5.7); MUSM INV 261, L (11.5), W (5.3); MUSM INV 262, L (8.3), W (5.2). Occurrence Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.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 1567-1568, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
Cristispira caballasensis DeVries 2019, sp. nov.
No full textCristispira caballasensis sp. nov. (Figure 5 (i)) Diagnosis Hypercampanulate; three strong keeled spiral cords on anterior two-thirds of spire whorls; finely spirally threaded interspaces. Description Shell small; pleural angle about 12°. Whorls hypercampanulate, sutural area deeply concave. Protoconch unknown, number of whorls in spire cannot be estimated. Spiral cords keeled; spiral formula dCBAr; primary cords about equally strong. Spacing formula C14B45A67; n = 1). Interspaces with microscopic spiral threads. Lateral growth line orthocline; posterior inflexion absent, anterior inflexion barely discernible. Lateral sinus moderately deep, apex close to spiral cord B. Base and aperture not preserved. Allmon formula?-1-M-B-OR. Remarks The elements of the spiral sculpture of Cristispira caballasensis sp. nov., evident even from the partial single specimen available, are nearly identical with those of two Peruvian species, the Late Cretaceous C. prechira (Olsson, 1944) and the middle Eocene C. paracasensis (Rivera, 1957): three keeled primary spiral cords, a deeply con- cave sutural area, wide concave interspaces with microscopic spiral threads, and in some specimens a secondary spiral cord or thread near the posterior suture. The spacing formula for C. caballasensis (C14B45A67; n = 1) does differ from that of the younger C. paracasensis (C35B58A72; n = 8; DeVries 2007) but is the same as that for the older C. prechira (C14B40A69; n = 1). The strength of the anteriormost primary spiral cord of C. caballasensis, however, is like that of C. paracasensis, i.e. much stronger than the anteriormost primary spiral cord of C. prechira. Material UWBM 107605, holotype, B8769 (type locality), L (5.1), W (4.4). Occurrence Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.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 page 1570, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
Nodifaunus gainesi DeVries 2019, sp. nov.
No full textNodifaunus gainesi sp. nov. (Figure 4 (dd – ii)) Diagnosis Early teleoconch whorls smooth; later whorls with tubercles or tuberculate axial ribs situated near posterior suture. Base smooth, separated from side of whorl by single spiral cord. Anterior canal short. Description Shell length to about 45 mm, high-spired, cerithiform, spire angle about 35° for early whorls, 15° for later whorls. Protoconch unknown. Teleoconch of nine or 10 slightly convex whorls; sutures impressed; sutures of early teleoconch whorls weakly canaliculate to turriculate. Spiral sculpture on earliest five or six whorls smooth; later whorls with spiral row of tubercles along posterior margin, present as blunt spines or developed as coarse prosocline, orthocline, or opisthocline axial ribs (variable orientation between and within individual shells) with blunt erect spines rising above posterior suture and extending partly or entirely to anterior suture; as many as 12 tubercles/axial ribs per whorl at first appearance, as few as eight on last whorl. No varices or ventrolateral varix. Faint spiral lines may be diagenetic artefacts. Growth lines orthocline to opisthocyrt. Base poorly preserved; steeply rounded, smooth, separated from side of whorl by spiral cord. Aperture rhombohedral; parietal area with broad callus, raised above body whorl; columella straight, thickened, without folds; anterior canal very short, slightly recurved abaxially. Outer lip mostly missing, posterior portion adjacent to suture extended abaxially with extension aligned with last subsutural tubercle; shallow posterior canal present. Remarks Nodifaunus gainesi sp. nov., with one spiral row of tubercles, differs from the early Eocene species, N. dimorphica, from the Talara Basin of northern Peru, which has a second row of nodes at the angled boundary of the base. Nodifaunus gainesi differs from N. propinqua and N. venusta, both also from the Talara Basin, which have one row of tubercles, but medially located. All three northern Peruvian species also have spiral cords or threads on the base and on the early whorls. The posterior suture-hugging single row of tubercles on specimens of N. gainesi most resembles the sculpture of specimens of Late Cretaceous N. nodosus, which also lack spiral cords, but the number of tubercles on the earliest nodose teleoconch whorls of N. gainesi (about 12) is double the number on the Late Cretaceous species. Juvenile specimens of Nodifaunus gainesi have a widely flaring aperture with a thickened outer lip. Both a twisted anterior canal and posterior canal are present. Etymology ‘ Gainesi ’, in recognition of Arthur G. Gaines, Oceanographer Emeritus, of the Woods Hole Oceanographic Institution, Woods Hole, MA, USA, and ocean sciences mentor to the author in the early 1970s. Material UWBM 107609, holotype, B8769 (type locality), L (42.4), W (19.1); remainder are paratypes: UWBM 107591, B8769, L (31.8), W (19.9); UWBM 107610, B8769, L (25.9), W (17.0); UWBM 107611, B8770, L (36.9), W (18.2); UWBM 107612, B8770, L 14.2, W 7.4; UWBM 107613, B8769, L 18.0, W 8.0; UWBM 107614, B8772, L (11.9), W 7.4; UWBM 107615, B8769, L (22.0), W (13.7); UWBM 107616, B8769, L (11.9), W (6.0); MUSM INV 263, B8769, L (33.0), W (15.8); MUSM INV 264, B8772, L (31.0), W (16.5); MUSM INV 265, B8769, L 15.9, W 8.1. Occurrence Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.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 1565-1566, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
Potamides henryi DeVries 2019, sp. nov.
No full text<i>Potamides henryi</i> sp. nov. (Figure 4 (m <i>–</i> q)) <p> <i>Diagnosis</i></p> <p>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.</p> <p> <i>Description</i></p> <p> Estimated shell length 15 <i>–</i> 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.</p> <p> <i>Remarks</i></p> <p> Specimens of <i>Potamides henryi</i> sp. nov., which occur together with specimens of <i>P. janeae</i> sp. nov., are generally more elongate and the spires more convexly conical than those of <i>P. janeae</i>. Specimens of <i>P. henryi</i> have four or more beaded primary cords, rather than the three beaded spiral cords on specimens of <i>P. janeae</i>, and have beaded spiral cords on the base.</p> <p> <i>Material</i></p> <p>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</p> <p>).</p> <p> <i>Etymology</i></p> <p>Named in honour of Henry R. DeVries, father of the author.</p> <p> <i>Occurrence</i></p> <p>Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.</p>Published as part of <i>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)</i> on pages 1557-1558, DOI: 10.1080/00222933.2018.1524032, <a href="http://zenodo.org/record/3670229">http://zenodo.org/record/3670229</a>
Papposilenus utriculus DeVries 2019, sp. nov.
No full textPapposilenus 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.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 1560-1561, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
Melanella indicaformis DeVries 2019, sp. nov.
No full textMelanella indicaformis sp. nov. (Figure 4 (h – l)) Diagnosis Shell small, elongate. Whorls smooth, flat-sided. Aperture oval, elongate, without anterior or posterior canals. Columella smooth, umbilicus absent. Description Shell length less than 15 mm, elongate, spire angle about 15°. Protoconch conical, about two smooth whorls. Teleoconch with about five whorls; whorls smooth, glossy, flat-sided to slightly convex, sometimes weakly turreted, thick; spire sometimes bent. Sutures adpressed; short crimped sutural collar sometimes overlaps preceding whorl. No spiral or axial sculpture. Base smooth, evenly rounded, set apart from rest of whorl by weak or moderately strong angulation. Aperture oval, twice as long as wide. Parietal callus strong; columellar callus thin; basal lip thickened, continuous with base of columella. Outer lip moderately thick, without teeth. Umbilicus absent. Remarks Species of Melanella have been reported from Paleocene rocks in New Zealand (Finlay and Marwick 1937) and Antarctica (Stillwell et al. 2004) and Eocene and Oligocene strata from North America (MacNeil and Dockery 1984; Garvie 1996) and New Zealand (Maxwell 1992). A species similar to Melanella indicaformis was provisionally assigned to Pseudomelania by Olsson (1944): P. simplex Olsson, 1944, found in upper Campanian beds of the Tortuga Formation in the Sechura Basin of northern Peru. The Tortuga Formation species is longer than the Caballas Formation species (length 18 mm vs 12 mm) and has nearly microscopic spiral threads, but the convexity of the spire, the glossy surface, and thickened inner lip are shared characters. A late Eocene species with a similar form, Bayania epelys Woodring, 1973 from the Canal Zone of Panama, differs from the Caballas Formation Melanella indicaformis by having faint spiral sculpture on the last whorl and a very shallow recurved siphonal notch. An early Oligocene species from the Talara Basin of northern Peru, Pachychilus canoaensis Olsson, 1931, from the estuarine and freshwater Bravo Grits of the Mancora Formation, also resembles M. indicaformis and may be referable to Melanella. Modern species of Eulimidae, including Melanella, are noted for their parasitism of echinoderms (Warén 1983). Echinoderms are noted for their intolerance of brackish conditions, although some extant brackish-water echinoderms do exist (Turner and Meyer 1980). No echinoderms have been encountered in beds of the Cuenca Member, despite an abundance of Melanella shells. Etymology ‘ Indica ’, referencing the long-grained variety of rice that this species resembles. Material UWBM 107617, holotype, B8769 (type locality), L 11.1, W 4.1; remainder are paratypes: UWBM 107618, B8772, L 10.6, W 4.1; UWBM 107619, B8769, L 9.4, W 3.6; UWBM 107620, B8772, L 8.2, W 3.1; UWBM 107621, B8772, L 8.7, W 3.2; UWBM 107622, B8769, L (8.4), W (4.7); UWBM 107623, B8769, L 8.2, W 3.3; UWBM 107624, B8772, L 6.0, W 2.8; UWBM 107625, B8772, L 5.0, W 2.6; UWBM 107626, B8770, L 4.5, W 2.4; MUSM INV 266, B8772, L 8.4, W 3.3; MUSM INV 267, B8769, L (9.0), W 3.4; MUSM INV 268, B8772, L 6.1, W 2.6 . Occurrence Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.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 1555-1556, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
Rhinotamides everriculum DeVries 2019, sp. nov.
No full textRhinotamides 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.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/367022
Pleuriocardia (Incacardium) schneideri DeVries 2019, sp. nov.
No full textPleuriocardia (Incacardium) schneideri sp. nov. (Figure 3 (l – q)) Diagnosis Shell ovate to elongate. Broad posterior sulcus extends from umbones to ventral margin. Ribs numerous with bulbous spines centred on ribs. Description Shell thin, to about 25 mm long, trapezoidal, H:L = 0.75. Subequilateral, umbones highly inflated; remainder of valves convex, excepting broad sulcus in front of weak posterior umbonal ridge and excepting irregular commarginal inflexions of curvature, especially ventrally. Beaks orthocline, orthogyrate on juveniles, overhanging hinge line; prosocline on adults. Posterior ligament narrow, less than half the length of posterodorsal margin. Dorsal margin sloping sharply anteriorly, less steeply posteriorly. Anterior broadly rounded; posterior with angled umbonal ridge. Anterodorsal and umbonal areas with 18 – 20 strong radial ribs, triangular in cross section, broader across middle of valve. U-shaped interspaces with weakly and irregularly raised commarginal growth lines. Posterodorsal flattened surface with 5 – 6 smaller triangular ribs, equal to each other in size. Circular or elongate bulbous spines or knobs rise from tops of radial ribs across middle three-fifths of valve; knobs more common at inflexions points, intersections with strong commarginal growth lines, and on specific radial ribs; other knobs randomly placed. Hinge plate and teeth not visible. Remarks Specimens of Pleuriocardia (Incacardium) schneideri sp. nov. differ from the Late Cretaceous type species, P. (Incacardium) mellisum Olsson, 1944, in having fewer ribs in front of the posterior umbonal ridge (20 – 22, rather than 28) and interspaces that have a rounded profile, not triangular. The Caballas Formation species differs from the late Campanian to early Maastrichtian Pleuriocardia (Incacardium) trechmanni Schneider, 1999, from Jamaica, in being longer than high, having fewer ribs anterior to the posterior umbonal ridge (20 – 22, rather than 25), and having nodes that are smaller, less bulbous, and more often aligned on the intersection of radial ribs with strong commarginal growth lines. Etymology Named in recognition of Jay A. Schneider, authority on the phylogeny of Incacardium and other cardiids. Material UWBM 107573, holotype, left valve, B8772 (type locality), L (21.5), H 20.6, W (12.3); remainder are paratypes: UWBM 107574, B8770, L 25.0, H 25.4, W 14.4 (pair); UWBM 107575, B8769, L (13.7), H 11.8, W 11.5 (pair); UWBM 107576, mould of left valve, B8769, L (25.5), H (19.4), W (4.9); MUSM INV 245, B8772, L (19.1), H (19.1), W (9.2) (pair); MUSM INV 246, mould of right valve, B8772, L (20.4), H (18.9), W (6.0) (pair); MUSM INV 247, B8772, L (21.1), H (16.9), W (11.8) (pair). Occurrence Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.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 1550-1551, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/367022
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