Euvola archon (Maury, 1925)
MAURY, C. J. 1925. A further contribution to the Paleontology of Trinidad (Miocene Horizons). Bulletins of American Paleontology, 10 (42):159-402, pls. 1-43. [p. 236, pl. 16, figs. 2, 3, 5]
1925 Pecten (Pecten) archon Maury, 1925
C. J. Maury, 1925, plate 16.
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«Shell large, rather sparsely, but very prominently ribbed. Right valve convex, but not extremely so; left valve flat or slightly concave. Both valves have about sixteen ribs of which the anterior and posterior three are small and closely crowded, while the ten or eleven over the center are very much larger. On the right valve they are very bold, high, squarish, and the five or six central ribs are distally medially grooved; but this character does not appear until the shell is more than half grown. Interspaces deep, very narrow proximally, but on old shells at the basal margin nearly as wide as the ribs. Both ribs and interspaces are crossed by fine growth lines. Ears equal. On the right valve the anterior ear has five coarse, equal, radiating threads, the posterior is less strongly and regularly radiately striate. Notch beneath the anterior ear rather shallow. A convex valve is 70 mm. in length, 62 in altitude and 20 in semidiameter. Two flat valves measure 68 x 58 and 65 X 53 mm.
This is probably the Springvale Pecten that Dr. Guppy referred approximately to the Californian Pecten crassicardo Conrad. But that is a Lyropecten, with both valves convex, while this is a true Pecten. The strong ribbing is, however, somewhat alike in the Californian and Trinidad shells. The distinctive features by which this species is at once separated from the more abundant shells of P. demiurgus Dall, with which it is associated, are the dissimilar valves, and the very strong central ribs, lightly medially cleft in later stages of growth. Locality.— Springvale. Horizon.— Upper Miocene.» CARLOTTA JOAQUINA MAURY, 1925
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«Lectotype (herewith selected). — Paleont. Research Inst., Ithaca, N.Y., No. 798 (specimen figured by Maury, 1925, pl. 16, fig. 2).
Dimensions of lectotype. — Length 63.7 mm, height 53 mm (incomplete). Type locality. — Springvale Quarry, Trinidad. This species is represented from the base of the Melajo Clay by one right and several left valves. They are indistinguishable from topotypes. Rutsch (1942, p. 114) compared P. archon with related species. P. archon has been assigned by Rutsch to the subgenus Notovola Finlay (1926, p. 451), type species, Pecten novaezelandiae Reeve. Notovola, however, is considered as a synonym of Pecten s. str. by Fleming (1957, p. 18) . In Euvola Dall [1890-1903 (1898), p. 694] , type species, Ostrea ziczac Linné, the radial sculpture is much weaker and the interspaces of the ribs reduced to grooves, whereas Pecten maximus (the type species of Pecten) has strong radial sculpture. On the other hand P. archon lacks secondary riblets on the primary radials and their interspaces, which are typical in P. maximus. It has only a medial groove on the radials near the ventral margin of adult specimens, which approaches it again in P. ziczac. Occurrence. — USGS 18411, USGS 18634. Distribution. — Savaneta Glauconitic Sandstone Member and Melajo Clay Member, both of Springvale Fm.» JUNG, P. 1969. Miocene and Pliocene mollusks from Trinidad. Bulletins of American Paleontology, 55 (247): 293-697, pls. 13-60. [p. 344]
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Pecten (Pecten) archon Maury; P. Jung, 1969, Miocene and Pliocene mollusks from Trinidad, plate 19, figures 3, 4.
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