Vertipecten fucanus (Dall, 1898)
DALL, W. H. 1898. Contributions to the Tertiary fauna of Florida. Silex Beds of Tampa and the Pliocene Beds of the Caloosahatchie River. Part IV. I. Prionodesmacea: Nucula to Julia. 2. Teleodesmacea: Teredo to Ervilia. Transactions of the Wagner Free Institute of Science of Philadelphia, 3 (4): viii, 571-947 p., pls. 23-35 (pls. 36 and 37 in part 5, 1900). [p. 704, pl. 26, fig. 7]
1898 Pecten (Chlamys) fucanus Dall, 1898
W. H. Dall, 1898, plate 26.
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«Found in concretions from the Miocene sandstones of Clallam Bay, twenty-five miles eastward from Cape Flattery, on the south shore of Fuca Strait, Washington, by Mr. J. S. Diller, of the United States Geological Survey. Another specimen was received from J. G. Swan, collected in the same vicinity.
This is a rather large species of the type of P. Hindsii var. strategus, both valves moderately convex and with a fine subsidiary surface tessellation; sixteen squarish ribs, of which the median one in the left valve is stronger than the rest and surmounted by prominent imbricated scales; the others are simply radially striated, as are the interspaces, which carry a mesial elevated thread; the submargins are radially threaded, as are the subequal ears, which also bear marked concentric lamellae; the resilial pit is of moderate size and the cardinal edge is deeply grooved parallel to and just below the margin; the interior reflects the external ribbing. Alt. 85, lat. 80, convexity of left valve 16 mm. Types in the National Museum. This interesting form is represented by very perfect internal and external casts of the left valve and other less perfect examples. It is doubtless the precursor of the recent P. hericeus group.» WILLIAM HEALEY DALL, 1898
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«This large pectinid is found in the early Miocene Nye Mudstone.
Vertipecten fucanus also occurs in the uppermost part of the Yaquina Formation, but it is not found in the early to middle Miocene Astoria Formation. It is therefore a useful guide to distinguish these rock units. The right-valve sculpture is more irregular than on Patinopecten, and on the left valve the center rib is rounded and raised to protrude above the others. The genus Vertipecten is now extinct.» MOORE, E. J. 2000. Fossil shells from Western Oregon. A guide to identification. Chimtimini Press. Corvallis, Oregon. [p. 68, 69]
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Vertipecten fucanus
(Dall); E. J. Moore, 2000, Fossil shells from Western Oregon, figure page 69. |
«Holotype.— USNM 107790, external mold of a cracked young adult left valve, 8.4 cm high, 8.9 cm long, hinge 5.2 cm, with a single imbricated key rib.
Plastotypes.— UCMP 14525; USNM 107790. Type locality.— Clallam County, Wash., south shore of Strait of Juan de Fuca (USGS loc. 2464). Type found in concretion in sandstones at Clallam Bay, 25 mi east of Cape Flattery. Miocene. Weaver (1942) refined the locality (Univ. Washington 490) to NEV4 , SEV4 sec. 22, T. 32 N., R. 12 W. and referred the sandstones to the Astoria Formation, middle Miocene. Addicott (1976b) revised the biostratigraphy and recognized the unit as the Clallam Formation of late early Miocene age, the type section of the Pillarian Stage, whose index species are figured in Moore and Addicott (1987). Significant hypotypes.— CAS 60984, from the Olcese Sand, Poso Creek area, Kern County, Calif, (loc. CAS 1452). USNM 563294 from the Astoria Formation, Astoria, Oreg. (loc. CAS 2275) (Moore, 1984b, pl. 27, fig.1). Description (based on California specimen).— Valves relatively flat, left valve more convex than right valve. Height equals length; auricles equal, radially costate. Byssal notch deep. Hinge length greater than half shell length. Right valve with 16-17 flat-topped ribs of varying width flanking a wide central space opposite the raised key rib of the left valve. Left valve with 15-16 narrow ribs, more rounded than in right valve, a central raised "key rib" ornamented with imbricated flanges. Ribbing more irregular in lateral areas. Fine sculpture obsolete to fine, right valves with a medial groove on ribs, radial thread in spaces. Left valve interspaces smooth or with as many as three fine radials in addition to the fine shagreen microsculpture preserved in some specimens. Specimens from southwestern Washington tend to be larger, 12-13 cm high, than those from California. Hypotype CAS 60984 from Kern County, Calif., measured 10.5 cm high, 10 cm long (incomplete). Comparative morphology.— Right valves of V. fucanus are distinguished with difficulty from right valves of V. bowersi; V. bowersi has rounded, higher ribs and wider interspaces. Vertipecten kernensis has more ribs than V. fucanus, imbricated fine sculpture, and interribs. Patinopectens (for example, P. propatulus) usually have thinner shells, flatter ribs, smaller auricles, and a shallower byssal sinus than do Vertipectens. Addicott (1976b) noted that V. fucanus has relatively larger auricles (longer than half the shell length), a flat to slightly concave profile in juvenile right valves, and more irregular ribbing, especially in lateral areas, than Patinopecten propatulus. Left valves of V. fucanus from California have a single central key rib, (Moore, 1984b, reported 1-3 key ribs in specimens from Oregon), whereas V. bowersi has 1-3 key ribs, none with the imbrications of V. fucanus. Vertipecten kernensis (= V. nevadanus auctt.), which is morphologically closest to V. fucanus in rib profiles and spacing, has 17-19 imbricated ribs of two or three strengths. Phylogenetic affinities.— Primarily from western Washington and Oregon, V. fucanus may have evolved from V. kernensis in Kern County, Calif. Morphologic and chronostratigraphic evidence for this bioseries comes from specimens of V. fucanus in the Olcese Sand exposed after rare flash floods in tributary canyons north of Poso Creek (localities CAS 1452, UCMP B-1673). Vertipecten may be ancestral to Patinopecten, a relation supported by biostratigraphic ranges and right valve morphologic characters of California taxa but not verified for taxa from the Pacific Northwest. A transitional form examined for this study was described as Pecten (Patinopecten) haywardensis calaverasensis Hall, 1958, middle Miocene "Temblor" Stage fossil from the Diablo Range east of San Francisco, Calif. Left-valve fragments have Patinopecten ribbing and no trace of the raised key ribs found in the youngest Vertipectens, but right valves resemble Vertipecten in rib number, profile, and arrangement. Geographic and stratigraphic distributions.— Gulf of Alaska; Clallam County, northern Olympic Peninsula, and southwestern Wash.; western Oregon near Astoria and Newport; Kern County, Calif. Poul Creek Formation, upper part, from the Gulf of Alaska Yakataga District (Kanno, 1971; Addicott, 1976b). Northwestern Washington, along the Strait of Juan de Fuca: Clallam Formation, type section of the Pillarian Stage [uppermost part of the Clallam Formation of Arnold (1906)]. Representative localities include M4049, M4675, and M6029. Addicott called Vertipecten fucanus the most characteristic mollusk found throughout the 600-800 m section of the Clallam Formation exposed in sea cliffs and the intertidal zone between Slip Point at Clallam Bay and Pillar Point, north of the Pysht River. Hoh rock assemblage, western Olympic Mountains (M4146, M4415). Astoria Formation of western Oregon, Nye Mudstone, as mapped by Snavely and others (1976), Newport Embayment, coastal Oregon (Addicott, 1976b), and upper part of the Yaquina Formation south of Newport, Oreg. (E.J. Moore, written commun., 1984). Olcese Sand, Knob Hill 7½-minute quadrangle, Kern County, Calif. Locality GAS 1452, west of Borel Canyon and about 4 mi north of Poso Creek. This important specimen was collected in 1928 by G D. Hanna, who noted that Aturia was also found in the same unit, and who referred the outcrop to "zone B" of Anderson (1911). A field check for this project in 1974 turned up no trace of fossils in the gray siltstone and sandstone covered by soil and grass, but material may be buried in stream beds. Considered the middle Miocene Temblor Formation by early workers, the locality probably falls in the upper part of the Olcese Sand in the Kern River area that was discussed in detail by Addicott (1970b). The locality, originally plotted on the old Woody quadrangle (1952 ed.), is about 7 mi northwest of the Barker's ranch locality and type section of Anderson's B zone (north side of the Kern River between Hart Memorial Park and the south end of Round Mountain). Until more specimens are collected and the stratigraphic unit confirmed, the possibility remains that the strata in which V. fucanus is found are part of the undivided Freeman Silt-Jewett Sand unit. The species was misidentified from the middle Miocene Temblor Formation near Coalinga, Calif. (Adegoke, 1969). Geologic age.— Early Miocene. Biostratigraphic range.— Upper "Vaqueros" Stage in California; Pillarian Stage of the Pacific Northwest (Addicott, 1976b, 1977; Moore, 1984a; Moore and Addicott, 1987). Vertipecten fucanus is a good zonal index fossil correlating the lower Miocene Clallam Formation and Nye Mudstone, the lower part of the Astoria Formation, and the upper part of the Yaquina Formation of Oregon (E.J. Moore, written commun., 1984); these units are equivalent to the upper "Vaqueros" Stage formations of California and "***presumably, the uppermost part of the Poul Creek Formation in the Gulf of Alaska" (Addicott, 1976b). Moore (1984c) showed the Vertipecten fucanus Molluscan Zone equivalent to the Pillarian Stage; it is underlain by the Liracassis apta Molluscan Zone of late Oligocene to early Miocene age, and overlain by the Patinopecten propatulus Molluscan Zone of late early Miocene to middle Miocene age. Paleoecology.— Associated molluscan taxa in Washington and Oregon indicate a nearshore environment of shallow to moderate depths with both cool and warm water forms. Addicott (1976b) considered the Clallam Formation assemblages to be inner sublittoral, less than 100 m deep and shallower during the later depositional stages.» SMITH, J. T. 1991. Cenozoic Giant Pectinids from California and the Tertiary Caribbean Province: Lyropecten, "Macrochlamis", Vertipecten, and Nodipecten species. United States Geological Survey Professional Paper, 1391: v + 1-155, figs. 1-18, pls. 1-38. [p. 80, 81]
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Vertipecten fucanus
(Dall. 1898); J. T. Smith, 1991, Cenozoic Giant Pectinids from California and the Tertiary Caribbean Province, plate 33, figures 2-4. |
«The median rib on the left valve of Vertipecten fucanus is always elevated above the others; the fourth rib on either side may also be elevated, but to a lesser degree; and in some places the second rib on the anterior and posterior side of the median rib is elevated. The ribs on the left valve are usually strong, narrow, and rounded, and the median rib is less rounded than the others. An imbricated, lamellar microsculpture is often preserved on the left valve and is usually particularly apparent on the elevated median rib. This is the same sculpture (see p. 63) that is present on left valves of Patinopecten propatulus (pI. 16, fig. 2) and P. oregonensis cancellosus. This microsculpture may be seen also on some places on the left valve ears of V. fucanus. There is usually one interrib in each interspace on the left valve, but there may be as many as 2 or 3. On the right valve of V. fucanus there are about 15 or 16 slightly rounded flat-topped finely striated ribs in some places with a median groove. The interspaces seem to be smooth, without any interribs.
Holotype: USNM 107790, pI. 19, figs. 1, 2.
Type locality: In shaly sandstone in cliff of beach section 11,000 ft southeast of Slip Point and 13,000 ft due east of the town of Clallam Bay, Clallam County, NE¼SE¼ sec. 22, T. 32 N., R. 12 W., Astoria formation, Washington (Weaver, 1942, p. 88); USGS 2464, Clallam Bay, on the Strait of Juan de Fuca, about 25 miles east of Cape Flattery, Clallam County, Wash. J. S. Diller, collector, 1892 (V.S. Geol. Survey Cenozoic loc. book). The holotype of V. fucanus is the external cast of a left valve (pI. 19, fig. 2). A gutta-percha impression was made to show the characters of the shell more clearly (Arnold, 1906a, pI. 10, figs. 2, 2a); and a latex impression is figured herein (pI. 19, fig. 1). The holotype is 81.8 mm wide, 84.3 mm high, and approximately 12 mm thick (left valve).
In the original type lot of Patinopecten propatulus there is a single incomplete specimen (USNM 3558), figured by Arnold (1906, pI. 9, figs. 1, 1a, 2, 2a) and Dall (1909, pI. 15, figs. 1, 1a, 2, 20,), which should be assigned to Vertipecten fucanus (pI. 22, figs. 1, 4). V. fucanus may be closely related to V. nevadanus (Conrad). On the basis of a comparison of the type and topotype specimens of V. fucanus with specimens of V. nevadanus possibly from near the type locality, they are considered separate species. The right valve of V. nevadanus is usually much more highly sculptured and has numerous interribs. The left valve of V. nevadanus seems to have more ribs and more interribs than V. fucanus. As discussed under Patinopecten propatulus (p. 65), when only a right valve of V. fucanus is preserved it is often difficult to distinguish from P. propatulus (pI. 19, fig. 3; pI. 21, fig. 4). Localities: 1a, 2, 181, 181a, 184, 185, 185a; cf. 48-50.
Occurrence elsewhere: Astoria (?) formation, Washington» MOORE, E. J. 1963. Miocene Marine Mollusks from the Astoria Formation in Oregon. United States Geological Survey Professional Paper, 419: 1-109, pls. 1-32. [p. 66, 67]
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Vertipecten fucanus (Dall); E. J. Moore, 1963, Miocene Marine Mollusks from the Astoria Formation in Oregon, plate 19, figures 1, 2; plate 20, figure 8; plate 21, figures 1, 3; plate 22, figures 1, 4.
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