Aequipecten zenonis Cowper-Reed, 1935
COWPER REED, F. R. 1935. Notes on the Neogene Faunas of Cyprus. III. The Pliocene faunas. The Annals and Magazine of Natural History [10th Serie], 16: 489-524, pls. 13-17. [p. 492, pl. 14, figs. 1, 1a, 1b]
1935 Pecten (Aequipecten) zenonis Cowper-Reed, 1935
1935 Pecten (Aequipecten) zenonis var. horridula Cowper-Reed, 1935
1935 Pecten (Aequipecten) zenonis var. nicosiensis Cowper-Reed, 1935
1935 Pecten (Aequipecten) insularis Cowper-Reed, 1935
1935 Pecten (Aequipecten) gaudryi Cowper-Reed, 1935
1935 Pecten (Aequipecten) larnacensis Cowper-Reed, 1935
1935 Pecten (Aequipecten) zenonis var. horridula Cowper-Reed, 1935
1935 Pecten (Aequipecten) zenonis var. nicosiensis Cowper-Reed, 1935
1935 Pecten (Aequipecten) insularis Cowper-Reed, 1935
1935 Pecten (Aequipecten) gaudryi Cowper-Reed, 1935
1935 Pecten (Aequipecten) larnacensis Cowper-Reed, 1935
F. R. Cowper Reed, 1935, plate 15.
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«Shell subcircular; apical angle about 90°. Body gently convex, bearing 18-22 main, subequal straight, equidistant ribs with 5-6 much smaller, closely placed riblets on anterior and posterior lateral borders. Ribs sharply rounded to subtriangular, having a more or less elevated, distinct, narrow, median flattened or slightly excavated band forming the crest, and steep sloping sides which are slightly concave proximally, but become convex distally and bear numerous fine, regular, equidistant, linear, lamellose, concentric chevrons arched backwards, but on crossing the median band they become usually weaker, less numerous, and arch sharply forwards and occasionally on lateral ribs they develop on the crest into weak imbricating scales; a fine lateral riblet may occur on each flank of the ribs; marginal riblets with small numerous scabrosities. Interspaces between main ribs gently concave, crossed by regular, transverse, equidistant, delicate curved, lamellose lines, fewer in number and more widely spaced than the chevrons on the ribs and meeting them along a very fine longitudinal line at the base of the ribs. A few (3-5) fine linear riblets or thread-like lines are usually developed in the distal parts of the interspaces, especially in the lateral parts of the valves, and produce a minute granular cancellation on crossing the transverse lines. Auricles with 8-10 small riblets bearing small spinules which project on the upper edge. Internal ribs strongly developed over whole interior of valves.
Dimensions.— Height 37 mm.; width 37. Localities.— ¾ mile south of mile-post 3 on road from Nicosia to Limassol (Locality k, bed 2) [I, p. 264, Pecten opercularis]. Middle Pliocene. On the Pyroi-Athienou Road (Locality l, beds 1 and 3). Middle Pliocene. Remarks.— This species, which was previously referred to the variable P. opercularis, appears to be hardly separable from P. ventilabrum Goldf., with which Ugolini (4, p. 167, t. xi. fig. 2) would associate P. sowerbyi Nyst (5, P. 293, pl. xxii. fig. 3, pl. xxii. bis, fig. 3). But some of the shells figured by Cerulli-Irelli as P. opercularis var. audouini Payr. (II, p. 92, t. v. fig. 12) bear a considerable resemblance to our species. Dollfuss and Dautzenberg would put P. ventilabrum as a variety of P. seniensis Lam. (5, pp. 411-417, pl. xxxviii, figs. 8-19), a species which they would not separate from P. scabrellus Lam. But the specific names P. opercularis and P. scabrellus have been used in such a wide and variable manner by different authors that to avoid further confusion and indefiniteness a new name is here applied to these Cyprus shells, since they possess certain individual features which distinguish them from the types of both of the above-mentioned species, having a different ornamentation from the former and more numerous ribs and flatter valves than the latter. As regards the ornamentation we may draw attention to its resemblance to that of P. nux Reeve as figured by Cox (16, p. 124, pl. xiv. fig. 11) from Kenya. P. plebeius Lam., in the collection of Lamarck at Geneva (45, pl. xi. figs. 35-37) seems to be very similar to our species, which we may name after the philosopher Zeno, who was a native of Cyprus.» FREDERICK RICHARD COWPER REED, 1935
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«Description.-- Valve is slightly convex, suborbicular in outline, slightly inequilateral; posterodorsal margin is longer than the anterodorsal one. Small, orthogyrate beak is placed at the midlength of the straight hinge margin. The ears are preserved only on the left valve; the anterior one is provided with indentation at its base, while the posterior is ended perpendicularly.
External surface of the valve is covered with 20 narrow, triangular ribs, one of which, placed near the suture of the ear and disc, is narrower than the others. Grooves are wider than the ribs, sculptured with straight lamellae which are spaced more sparsely than on the ribs. Distinct scales are formed on the ribs by the ventrally bent lamellae. At the rib base weak slates, parallel to the ribs, are formed. Anterior ear is scultpured with 6 ribs, the upper three of which are wider, more spa rsely spaced, and bear weaker scales than the remaining ribs. Posterior ear is covered with 5 ribs; the width of the grooves in between decreases toward s the hinge margin. Concentric lamellae are distinct on both the ears. Scales on the ears are more prominent than those on the disc surface. The internal surface of the ears is partly damaged. Preserved are: cardinal crura c.c.AIV and c.c.PIV, one posterior auricular crus and two anterior auricular crura. Remarks.-- The investigated specimens from Rybnica are almost entirely consistent with the Pliocene species Ch. zenonis presented by ROGER (1939), except for the ornamentation of the ears. The specimens from Syria, described by ROGER ( 1939), as well as those from the Pliocene of the Cyprus described by COWPER-REED (1935; fide ROGER 1939) have their ears sculptured with 8-10 delicate ribs each, except for the anterior ear in the right valve bear ing 5 coarser ribs. The specimens from Rybnica resemble Ch., (A.) radians NYST, 1939, in the number, shape and ornamenta tion of the ribs, but differ from the latter in shape of posterior ear, number of ribs on the posterior ear (5 instead of 8- 10, respectively), as well as in absence of fine, oblique lines on the margin al part of the valve. The form under discussion is also similar to Ch. (A.) opercularis (LINNÉ 1758), especially to its variety lateocostata MONTEROSATO, the shell of which, however, shows more rectangular ribs, covered with scales weaker than in the former species. Furthermore, Ch. (A .) opercularis has its posterior ear in the left valve oblique and nearly twice shorter than the anterior ear, the surface of the former being covered with densely spaced, line riblets; while the specimens from Rybnica have their ears subequal, straight, sculptured each with 5 wide ribs. Stratigraphic range.-- Middle Miocene (this paper).» STUDENCKA, B. 1986. Bivalves from the Badenian (Middle Miocene) marine sandy facies of Southern Poland. Paleontologia Polonica, 47: 3-128, pls. 1-18. [p. 40]
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Chlamys (Aequipecten) aff. zenonis Cowper-Reed, 1935; B. Studencka, 1986, Bivalves from the Badenian (Middle Miocene) marine sandy facies of Southern Poland,
plate. 4, figure 11. |