Pecten (Plagioctenium) subdolus Hertlein, 1925
HERTLEIN, L. G. 1925. Pectens from the Tertiary of Lower California. Proceedings of the California Academy of Sciences [4th Series], 14 (1): 1-35, pls. 1-6. [p. 20, pl. 5, figs. 2, 4, 7].
15. Pecten (Plagioctenium) subdolus Hertlein, new species
Plate 5, figures 2, 4 and 7 «Shell of medium size, the valves moderately convex. Right valve ornamented by about 21 rounded, radiating ribs which become broader toward the ventral margin, the ribs separated by round-bottomed, narrower interspaces, the whole surface ornamented by very fine radial striations and by concentric lines of growth; anterior and posterior margins sculptured only by concentric incremental lines; ventral margin rounded; ears unequal, the anterior with a well defined byssal notch, and sculpture of about six radiating riblets crossed by incremental lines; the posterior also sculptured by about six or seven slight radiating riblets crossed by lines of growth, a very slight notch present. Left valve more arched than right and somewhat one-sided in appearance, ornamented by about 21 rounded, radiating ribs separated by round-bottomed interspaces about as wide as the ribs, the whole surface finely longitudinally striate and crossed by concentric lines of growth; ears slightly concave, the posterior sculptured by very slight radiating riblets and concentric lines of growth, the anterior with a rounded notch, the surface sculptured by a few very slight radiating riblets and by concentric growth lines, the ornamentation indistinct on weathered specimens. Altitude 50 mm.; longitude 50 mm.; diameter approximately 17 mm.; apical angle in each valve approximately 105°.
Type: No. 51 (L.S.J.U. type collection), from Loc. 115 (L.S.J.U.), Pacific Beach, San Diego, California; Paratypes: No. 52 (L.S.J.U. collection), and No. 1777 (C.A.S. collection), C. H. Sternberg collector; San Diego, Pliocene. This species also occurs at Loc. 116 (L.S.J.U.), in the Pliocene of Cedros Island, from which locality a specimen attains an approximate height of 110 mm.; length 110 mm.; diameter 30 mm. From P. cerrosensis, P. subdolus differs in its more numerous rounded ribs, large byssal notch, sculptured rather than smooth ears and usually smaller size. It differs from P. callidus in its rounded ribs which are not as high as those of the latter, in the presence of fine radial striae on the disk, and in the less strong sculpture of the ears in the present species». LEO GEORGE HERTLEIN, 1925
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L. G. Hertlein, 1925, plate 5.
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