Chlamys hodgei (Hertlein, 1925)
HERTLEIN, L. G. 1925. New species of marine fossil Mollusca from western North America. Southern California Academy of Sciences Bulletin, 24 (2): 39-46, pls. 3, 4. [p. 42, pl. 4, figs. 1, 2]
L. G. Hertlein, 1925, plate 4.
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«Shell of medium size, higher than long, slightly compressed, equilateral. Right valve ornamented by over 19 radiating ribs which are largely bifid and often have a small riblet on each side of the large ribs, the ribs toward the margins, become finer, interspaces somewhat rounded, showing very fine pitted surfaces, sculptured by a small intercalary riblet, ribs and riblets bearing fine, scattered, sharp, imbricating spines; sides of valve nearly straight, ventral margin regularly rounded; ears unequal, the anterior much larger than the posterior, anterior ear ornamented by about 5 or 6 coarse, radiating riblets which are crossed by concentric lines of growth, byssal notch large; posterior ear small in proportion to the large anterior ear, ornamented by about 9 small, radiating riblets which are crossed by concentric lines of growth. The ornamentation of the left valve consists of alternating large and small ribs but the ribbing is much finer than on the right valve. Height 47 mm.; length 40 mm.; diameter of right valve approximately 8 mm.; length of hinge line of right valve 25 mm.; apical angle of right valve approximtaely 87°.
Type: Right valve No. 20 (L. S. J. U. Type collection); Paratype: left valve No. 21 (L. S. J. U. Type collection), from Loc. F-6 (L. S. J. U. Geol. Surv.), Coalinga Region, Sec. 20, T. 19 S, R. 15 E, California; F. P. Vickery and P. L. Henderson collectors. Santa Margarita, Miocene. Pecten hodgei appears to be closely related to P. halimensis Makiyama from the Pliocene of Japan, but it differs in that it has less numerous ribs which are more distinctly bifid, than in the species described by Makiyama. From P. opuntia Dall, P. hodgei differs in having the ribs bifid and arranged in pairs, rather than numerous, closely but irregularly spaced, rounded, and not bifid; the margins of P. opuntia are rounded and not straight as in the present species. From P. jordani Arnold, P. hodgei differs in having more numerous, rounder ribs, which on the right valve become bifid much earlier in the growth of the shell. From P. hericius Gould, P. hodgei differs in having less numerous ribs, narrower, less high, and generally finer, and the shell possesses straighter margins in the present species. From P. egregius Nomland, P. hodgei is distinguished by having more numerous ribs which are differently ornamented in the present species. Pecten hodgei at the type locality is associated with Ostrea titan Conrad, Pecten crassicardo Conrad, Pecten raymondi Clark. This species is named in honor of Dr. E. T. Hodge, professor of Geology at the University of Oregon.» LEO GEORGE HERTLEIN, 1925
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«Comments.— The holotype of Chlamys hodgei is an inequilateral right valve with wide ribs that may bifurcate when the shell is 10 mm high and that are separated by narrower interspaces that have an interrib. Remnants of spines are present on the ribs near the ventral margin. The right anterior auricle has six riblets; the left anterior auricle about eight, which are finer.
The paratype of Chlamys hodgei is a markedly inequilateral left valve that has much finer ribs than the right valve. The ribs are closely spaced, and the narrow interspaces bear 1 or 2 interribs. The left anterior auricle has 13 riblets of almost equal size. On the basis of the holotypes, I can find no characters to differentiate Chlamys durhami from Chlamys hodgei. Chlamys durhami is probably a juvenile specimen of C. hodgei, which was also collected from the Santa Margarita Formation. Geographic range.— Middle and southern California. Geologic range.— Miocene. Occurrence in California.— Castaic (Stanton, 1966) and Santa Margarita Formations. MOORE, E. J. 1984. Tertiary Marine Pelecypods of California: Propeamussidae and Pectinidae. United States Geological Survey Professional Paper, 1228-B: iv + B1-B112, figs. 1-2, pls. 1-42. [p. B22]
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Chlamys hodgei (Hertlein); E. J. Moore, 1984, Tertiary Marine Pelecypods of California: Propeamussidae and Pectinidae, plate 4, figures 5, 9; plate 5, figure 2.
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Chlamys hodgei (Hertlein) (PI. 3, fig. 2; PI. 4, figs. 3, 4) occurs in the basal part of the Empire Formation at the southwest tip of Cape Blanco (USGS loc. M3965). This species occurs in both the "Margaritan" and "Jacalitos" Stages, successive upper Miocene units in the California Coast Ranges. It was recorded from the Pancho Rico Formations of the Salinas Valley, central California, as Chlamys n. sp. aff. C. nipponensis Kuroda by Durham and Addicott (1965) (PI. 3, figs. 4, 5).
ADDICOTT, W. O. 1981. Significance of pectinids in Tertiary biochronology of the Pacific Northwest. Geological Society of America, Special Papers, 184: 17-38, pls. 1-4. [p. 24]
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Chlamys hodgei (Hertlein); W. O. Addicot, 1981, Significance of pectinids in Tertiary biochronology of the Pacific Northwest, plate 3, figures 2, 4, 5; plate 4, figures 3, 4.
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«Two articulated specimens and a single right valve, all unworn, have been found in pebbly sandstone. The specimens agree with the original description of the species. The right valves are ornamented with about 20 bifid ribs; interspaces contain a median riblet, and, in a few instances, one or two tertiary riblets. The left valves bear about 22 flatly rounded ribs; interspaces contain a median riblet one-third to one-fourth as wide as the primary rib and in some interspaces ter- tiary ribs lie along the sides of the primary ribs. The sculpture of the right valve is variable. On one specimen all the ribs are bifid; on another, only a few are bifid; and on the third, most ribs are bifid but the two parts of the ribs are not equally wide. Dimensions, in mm., of the three specimens are
Height 52 49 44
Length 49 43 40 Diameter 19 18 8 (single right valve)» STANTON JR., R. J. 1966. Megafauna of the upper Miocene Castaic Formation, Los Angeles County, California. Journal of Paleontology, 40 (1): 21-40, figs. 1-2, pls. 5-7. [p. 27]
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Chlamys hodgei (Hertlein); R. J. Stanton Jr., 1966, Megafauna of the upper Miocene Castaic Formation, Los Angeles County, California, plate 5, figures 4, 5.
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