Chagrepecten cactaceus (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. I. Prionodesmacea: Nucula to Julia. 2. Teleodesmacea: Teredo to Ervilia. Transactions of the Wagner Free Institute of Science of Philadelphia, 3 (4): i-viii, 571-947, pls. 23-35. pl. 34, fig. 2]
1898 Pecten (Chlamys) cactaceus Dall, 1898
W. H. Dall, 1898, plate 34.
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«Tertiary of St. Domingo, Gabb; Pliocene of Tehuantepec, seventy kilometres west of eastern terminus of the railway, near the foot-hills of the elevated country, Spencer.
Shell thin, fragile, compressed, nearly equilateral and equivalve, with ten to twelve sharp, narrow-keeled ribs, with much wider shallow interspaces, in which there are five or six fine, sharp radial threads; whole surface, when perfect, covered with imbricating scales, those on the ribs triangular, apices basally directed, and similarly on a smaller scale, on the threads, between the keels and threads the imbrication is looped in an umbonal direction, sharp and rasp-like; ears subequal, with close, sharp, concentric, elevated lines and a few subspinose radial threads; interior grooved in harmony with the external ribs, the margins of the channels reinforced by lirae in the adult; crura developed, notch shallow. Alt. 47, lat. 46, diam. about 8 mm. This is quite a distinct species, not particularly like any other described from this region and apparently a deep-water shell. The specimens in Gabb's collection are mixed with others identified by him as oxygonnm Sby., and their horizon is not definitely settled.» WILLIAM HEALEY DALL, 1898
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«Woodring (1982: 594) placed Pecten cactaceus from the Upper Miocene of Mexico and Panama in the genus Cryptopecten, noting similarities in sculpture with extant C. alli Dall, Bartsch, & Rehder, 1938 [= Pecten (Chlamys) bullatus Dautzenberg & Bavay, 1912] from the Hawaiian Islands and C. phrygium from the western Atlantic. In a thorough review of Cryptopecten in the world's oceans, however, Hayami (1984: 90) regarded the placement of Pecten cactaceus in Cryptopecten as debatable, noting that this species differs considerably from other Cryptopecten in having an "undeveloped ctenolium, well-developed and persistent intercostal threads, relatively shallow byssal notch, and unusually thin shells."»
WALLER, T. R. 2011. Neogene Paleontology of the Northern Dominican Republic. 24. Propeamussiidae and Pectinidae (Mollusca: Bivalvia: Pectinoidea) of the Cibao Valley. Bulletins of American Paleontology, 381: 1-197 [p. 67]
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Chagrepecten cactaceus (Dall, 1898); T. R. Waller, 2011, Neogene Paleontology of the Northern Dominican Republic, plate 8, figures 6, 7.
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«This characteristic species of the Chagres sandstone is represented by 42 specimens. One is articulated and the range in length is 21.9 to 51.9 mm. An exceptional small right valve (length 22.2 mm, locality 206) has 16 ribs and is more convex than other small valves. It is the only valve that has a
rib count of more than 14. The part of the outermost crust is shown on plate 124, figure 9. The sculpture revealed when it is effaced is shown on the same illustration. With further effacement, the microscopic sculpture is lost. Though the lectotype is immature (pI. 124, fig. 1), a somewhat damaged mature left valve (practically complete length 44.8 mm) is among the syntypes collected by Spencer. In his description, Dall recorded the approximate dimensions of the mature valve. Bose illustrated a mature left topotype. Mexican geologists do not use Spencer's name: Coatzacoalcos formation (Spencer, 1897, p. 23). Whether the moderately deep-water strata of late Miocene age, so designated by Spencer, can be fitted into the late Tertiary stratigraphic units now recognized in the Tehuantepec area is uncertain. Spencer's and Bose's fossils were collected in railroad cuts, which now are weathered and overgrown. Dall recorded Pecten cactaceus from the Dominican Republic on the basis of the Gabb collection, but it was not found by Pilsbry when he restudied that collection (Pilsbry, 1922, p. 410). As a matter of fact, a closely related species, or possibly a subspecies of Cryptopecten cactaceus, is represented by four small valves (maximum length 31.5 mm) from the Gurabo formation of that country (USGS 8586, 8735). Fossil species of Cryptopecten are unknown in America outside the Caribbean region. The genus survives, however, in western Atlantic waters, where it is represented by Pecten phrygium (Dall, 1886, p. 217; 1889, pI. 40, fig. 1). That species ranges from Massachusetts to the Gulf of Mexico and the Lesser Antilles and has a considerable depth range—7 to 156 fathoms. Though most of the some 70 available lots clearly were dead shells, the type, dredged at a depth of 95 fathoms in the Gulf of Mexico, was alive. C. phrygium (maximum length 42 mm) is somewhat smaller than C. cactaceus and is less thin shelled, and its interrib radial threads are finer and more closely spaced. Occurrence: Chagres sandstone (late Miocene or early Pliocene), localties 206, 206a, 206b, 208. Spencer's Coatzacoalcos formation (late Miocene), Tehuantepec area, Vera Cruz, México.» WOODRING, W. P. 1982. Geology and paleontology of Canal Zone and adjoining parts of Panama. United States Geological Survey Professional Paper, 306-F: 1-759, pls. 83-124. [p. 595]
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Cryptopecten cactaceus (Dall); W. P. Woodring, 1982, Geology and paleontology of Canal Zone and adjoining parts of Panama, plate 124, figures 1, 9-11.
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