Leopecten diegensis (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. Transactions of the Wagner Free Institute of Science of Philadelphia, 3(4): i-viii, 571-947 [p. 710]
Pecten (Pecten) diegensis Dall; R. Arnold, 1906, The Tertiary and Quaternary pectens of California, plate 51, figures 1, 1a, 1b.
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«Pecten floridus Hinds, Zool. Sulph. Voy., p. 60, pl. 17, fig. 6, 1844; not Ostrea (= Pecten) florida Gmelin, 1792.
Pleistocene of San Diego; Hemphill. Living on the adjacent shores from Monterey, California, southward.» WILLIAM HEALEY DALL, 1898 |
«Additional description: Shell averaging about 60 millimeters in altitude, longer than high, inequivalve, plano-convex, or nearly so, equilateral and with smooth margins; base evenly rounded; sides slightly concave above. Right valve somewhat convex (more pronounced near the umbo), and ornamented by about 22 or 23 prominent T-rail-shaped ribs, flattened, and generally longitudinally ridged or sulcated on top, which overhang deep, narrow, flat-bottomed interspaces; whole surface sculptured by numerous fine, sharp, incremental lines; hinge line slightly less than one-half length of disk; ears equal, slightly convex, rectangularly truncated, sculptured by fine, sharp, incremental lines; anterior ear with small byssal notch. Left valve flat or nearly so, generally concave near apex, ornamented by 21 or 22 prominent, narrow, convex-topped ribs, which are separated by concave-bottomed interspaces about equal in width to the ribs; whole surface prominently sculptured by numerous regular, fine, sharp, concentric, raised lines; ears concave, convexly truncated, and ornamented by the same concentric sculpture as the disk. Color, red and reddish brown, the left valve always being much darker than the right. (Amold, 1906, p. 128)
Additional descriptive notes: The average adult specimen is 90 mm in height, 110 in length and 20 in diameter. After his own description of this species Amold commented, "Mrs. Oldroyd has two specimens taken from fishermen's nets at San Pedro, which measure over 150 miIIimeters (6 inches) in length, and are exceptionally high colored for this species." Although Arnold said the right valve has 22 or 23 ribs and the left 21 or 22. such specimens must be quite uncommon; all that the author has ever seen had 18 to 21 on the right valve and 17 to 20 on the left. The commensal gastropod Capulus californicus Dall is often attached to the anterior side of the umbo of the right valve, as in Chlamys hastata (Sowerby), and lives only on these two species, never alone or on any other mollusca. Remarks: Although closely related to Pecten sericeus Hinds, this species is quite distinct and differs in the following respects: less orbicular (length considerably greater than height); ribs of right valve always squarish, flat-topped, and often longitudinally ridged; ribs of left valve wider and rounded; interspaces of both valves narrower (especially left); auricular margins perpendicular (or nearly so) rather than oblique; hinge line relatively longer; concentric lamellae on disks and auricles only half as numerous. Geographical range: CordelI Bank, off Bodega Bay, northern California, to Gorda Banks, off Cape San Lucas, Lower California. Also recorded from Guadalupe Island, Mexico, 180 miles west of central Lower California. Geochromological range: ?Pliocene, Pleistocene, Recent. Bathymetric range: 5 to 200 fathoms. Ecological data: Usually found 011 or swimming above the following varieties of bottom: shale, rock, gravel, gray sand, green sand, mud; associated with coralline, nullipores, kelp, sponge.» GRAU, G. 1959. Pectinidae of the eastern Pacific. Allan Hancock Pacific Expeditions, 23: i-viii, 1-308, 57 pls. University of Southern California Press. Los Angeles, California. [p. 143-145]
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Pecten diegensis Dall 1898; G. Grau, 1959, Pectinidae of the eastern Pacific, plates 52, 53.
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