Leptopecten praevalidus (Jordan & Hertlein, 1926)
JORDAN, E. K. & L. G. HERTLEIN. 1926. Expedition to the Revillagigedo Islands, Mexico, in 1925, VII. Contribution to the Geology and Paleontology of the tertiary of Cedros Island and aqdjacent parts of lower California. Proceedings of the California Academy of Sciences [4th Series], 15(14): 409-464 [p. 435, pl. 29, figs. 2-3]
1926 Pecten (Leptopecten) praevalidus Jordan & Hertlein, 1926
E. K. Jordan & L. G. Hertlein, 1926, plate 29.
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«Shell of moderate size, somewhat inflated, elongated posteriorly giving an oblique outline, the hinge line four-fifths the length of the shell. Right valve nearly flat, ornamented by about 13 or 14 flat-topped radiating ribs which are often longitudinally sculptured by one or two slight sulci; ribs separated by interspaces about as wide as the ribs, the bottoms of some of the interspaces lightly, longitudinally striate; anterior ear large, cut by a large byssal notch, and ornamented by four or five radiating ribs crossed by concentric lines of growth; left ear larger than right, sloping acutely from hinge line to posterior margin of shell, ornamented by six to nine unequal radiating riblets. Left valve somewhat more arched than right, ornamented by 15 or 16 moderately rounded radiating ribs some of which show a fairly well defined medial sulcus; interspaces as wide as ribs; both ribs and interspaces finely longitudinally striate, and crossed by concentric lines of growth; ears much as those of right valve, and similarly ornamented, except that the anterior ear of the left, carries six or seven radiating riblets between which are intercalated minute raised lines. Length 50 mm.; height 48 mm.; diameter approximately 15 mm.; length of hinge line approximately 40 mm.; apical angle 103º.
Type: No. 2101, paratypes Nos. 2102, 2103, 2104, 2105, and 2106, Mus. Calif. Acad. Sci., from Loc. 945, Southeast of Turtle Bay, Lower California; upper Pliocene; G. D. Hanna and E. K. Jordan, collectors. 30 other specimens were examined from the same locality. The large size, the flattish right valve, the flat-topped ribs of the right valve and the striations of the ribs of both valves characterize this large Leptopecten. Some specimens attain a length of about 70 mm., and a height of about 60 mm., or more.» ERIC KNIGHT JORDAN & LEO GEORGE HERTLEIN, 1926
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