Interchlamys interlineata interlineata (Gabb, 1873)
GABB, W. M. 1873. On the topography and geology of Santo Domingo. American Philosophical Society Transactions, n. s., 15: 49-259. [p. 256]
1973 Pecten interlineatus Gabb, 1873
1898 Pecten (Plagioctenium) gabbi Dall, 1898
1919 Pecten (Plagioctenium) crucianus Cooke, 1919
1898 Pecten (Plagioctenium) gabbi Dall, 1898
1919 Pecten (Plagioctenium) crucianus Cooke, 1919
Chlamys (Lyropecten) interlineatus (Gabb); I. Tucker-Rowland, 1938, The Atlantic and Gulf Coast
Tertiary Pectinidae of The United States, plate 5, figure 18.
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«Shell slightly convex, nearly equilteral, base and sides evemly rounded; ears large, radiately ribbed; surface marked by about eighteen round or sub-angulated ribs, wich a single small line in each interspace. Length 1 inch.
About the size of the preceding [P. augusticostatus Gabb, n. s.], this shell is longer and flatter, with a marqued difference in the character of ribs.» WILLIAM MORE GABB, 1873
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«Original description.— "Shell slightly convex, nearly equilateral, base and sides evenly rounded; ears large, radiately ribbed; surface marked by ca. eighteen round or sub-angulated ribs, with a single small line in each interspace. Length 1 inch" (Gabb, 1873: 256).
Description.— Shell reaching 47 mm Ht, length and height approximately equal throughout ontogeny, slightly prosocline with posterior slightly more extended from midline than anterior, equiconvex with convexity of closed, articulated shell ca. 20-30% of Ht, disk gapes absent. Disks with 17-21 radial plicae, most commonly 18 or 19, on LV originating at ca. 4 mm Ht after early pre-radial stage bearing coarse antimarginal striae; ribs broader than interspaces and rounded in profile in early ontogeny but becoming trigonal, with narrow crest and sloping flanks; single scabrous costa present on narrow rib crests beginning in mid-ontogeny with additional secondary costae forming on rib flanks and on either side of medial costae near margin; single scabrous medial costa forming in rib interspaces early in ontogeny. Commarginal lamellae looping ventrally across crests of secondary costae, forming distally pointing blunt scales, with scales more prominent on lateral ribs and interspaces. Disk flanks low but steep, all but the right anterior flank bearing fine scabrous costellae. Auricles small relative to size of disk, total hl ca. 50-60% L, ahl slightly longer than phl. Right anterior auricle with 4 or 5 strong, scabrous costae and deep byssal notch with active ctenolium; other auricles with more numerous, finer costae; anterior margin of left anterior auricle sigmoidal, with shallow byssal sinus, overall trend forming acute angle with dorsal margin; posterior margins of posterior auricles nearly straight, forming obtuse angle of ca. 112-116° with dorsal margin. Hinge dentition of RV dominated by strong dorsal tooth on each side of resilifer, bordered dorsally by deep groove for outer ligament. Internal plicae with carinate edges near shell margin. Muscle scars and extent of internal shell layers not accessible. Type material.— Holotype, ANSP 2846, an articulated shell illustrated by Pilsbry (1922: pl. 45, fig. 3), 24.7 mm Ht, 23 mm L. Type locality.— Dominican Republic. Although Gabb (1873) did not furnish locality data other than "Santo Domingo," the type specimen possibly came from the vicinity of locality TU 1245, a road cut in the Mao Adentro Limestone, just south of the bridge at Guayubín, on the road to Sabaneta, northern Dominican Republic, where the species is abundant and well preserved. H. & E. Vokes (1992: 12) remarked that locality TU 1245 is almost certainly an area visited by Gabb, because the geology conforms closely to Gabb's description. Other material.— Northern Dominican Republic, Mao Adentro Limestone: TU 1245 (the designated type locality), 17 articulated DV, 1 RV; TU 1438, road cut 0.5 km south of bridge at Guayubín, on road to Sabaneta, 3 RV, 2 LV; USGS 8724, Gurabo hills, province of Santiago, ca. 2 mi northeast from Santiago near rock-crushing site for road metal, 1 RV. Southeastern Cuba, La Cruz Formation, Pliocene: USGS 3439, Jurauga railroad road cut, La Cruz, 1 LV; USGS 3440, northeastern portion of Santiago, marl on hillside, 1 LV [holotype of Pecten (Plagioctenium) crucianus Cooke, 1919]; USGS 3441, east of La Cruz, near railroad crossing of road to Morro Castle, 1articulated DV (paratype of P. crucianus). Remarks.— The presence of almost all articulated shells filled with fine lime mud at TU 1245 suggests that these specimens were buried alive, perhaps as a result of a storm that moved them off of a shallow, coral-rich carbonate bank or patch reef into much finer sediment, such as might be expected in a backreef lagoon. The presence of numerous small, solitary serpulid worm tubes and occasional immature scleractinian corals and oysters attached to either valve suggests that burial was not rapid, and that the dead articulated shells served as a substratum within the photic zone, probably in very shallow water. The articulated shell of Pecten crucianus from Cuba, regarded as a junior synonym of Interchlamys interlineata, has a similar association of matrix and epifauna. De Huelbes (1988: 31), in his study of Chlamys cruciana (= I. interlineata), reported that 42 of the 103 specimens from the La Cruz Formation were articulated. Comparisons.-- Interchlamys interlineata differs from I. jacobiana in having higher ribs and a medial costa in interspaces. Interchlamys aidei, although having a medial costa filling rib interspaces, has rounded rather than trigonal ribs and lacks pointed scales atop secondary costae. (See also the preceding section on the genus Interchlamys n. gen.) Dimarzipecten crocus (Cooke, 1919), of the late Early to early Middle Miocene Anguilla Formation of Anguilla, has a medial costa in interspaces that begins much later than in I. interlineata. Furthermore, D. crocus is chlamydiform, with a narrow umbonal angle and asymmetric auricles, and has a coarse oblique antimarginal microsculpture that is prominent in rib interspaces and on disk flanks in early ontogeny. Although I. interlineata superficially resembles large specimens of Spathochlamys vaginula, the former species is more equilateral than the latter. The radial ribs of all Spathochlamys species begin abruptly much closer to the beak than in Interchlamys n. gen. Evolution.— See remarks for the genus Interchlamys n. gen. Occurrence.— In the Dominican Republic, Interchlamys interlineata is known only from the Mao Adentro Limestone Member of the Mao Formation, Pliocene. Distribution.— Outside of the Dominican Republic, Interchlamys interlineata has been reported from the La Cruz Formation in the vicinity of Santiago de Cuba (Cooke, 1919; de Huelbes, 1988) and an unnamed formation of probable Pliocene age in Guadeloupe (Mongin, 1968).» 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. 31, 32]
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Interchlamys interlineata (Gabb, 1873); T. R. Waller, 2011, Neogene Paleontology of the Northern Dominican Republic, plate 2, figures 10-13.
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«Diagnose [Chlamys cruciana (Cooke)]. — Coquille de taille moyenne, très peu convexe, portant 18 côtes élevées à section ronde ou plus ou moms losangique, suivant l'usure des costules; intervalles aussi larges que les côtes, et contenant une costule squameuse. Surface de toute la coquille parcourue par des stries d'accroissement très fines se réunissant sur le dos de la côte et dans l'intervalle en dormant des squames arrondis en forme de tuile. Oreillette droite de la valve droite longue, portant les cinq ou six costules des Chlamys ainsi que l'échancrure byssale à la base. Oreillettes de la valve gauche grandes droites, portant dix fines costules squameuses. Sur les aires latérales des valves, les côtes sont beaucoup plus ornées, plus squameuses et les costules peuvent se dédoubler.
Rapports et différences. — Cette espèce, quand les coquilles sont usées, peut s'apparenter à Chlamys interlineata Gabb (1873, p. 256) (in Pilsbry, 1921, pl. 45, fig. 3, type), mais celui-ci a les intervalles plus étroits avec parfois deux ou trois costules et il n'a pas de squames sur les côtes, caractère visible sur la figuration de Tucker et Wilson (1932, pl. 4, fig 7). De plus, C. interlineata est plus petit et l'ornementation des oreillettes différentes. On peut le comparer aussi avec C. interlineata var. aidii Hodson et Harris (1927, pl. 15, fig. 9) du Miocene due Venezuela. Cette espèce, C. cruciana n'a pas d'affine en Europe. Gisements. — Janagua Railroad à la Cruz et au N. E. de Santiago, à Cuba (Miocène moyen). A la Guadeloupe, colline de C. R. S., niveau mc (gis. 0).» MONGIN, D. 1968. Les Pectinides du Miocène de La Guadaloupe (Antilles Francaises). Bulletins of American Paleontology, 54 (245): 471-510. [p. 483]
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Chlamys cruciana (Cooke); D. Mongin, 1968, Les Pectinides du Miocène de La Guadaloupe, plate 41, figure 3.
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«On the left valve there are 15 or 16 rounded and not very hiigh major ribs, a riblet running in each interval; close to the base there are two or three in each interval. Anterior submargin with about six riblets, posterior ribs and riblets are granose. The anterior ear has few fine riblets, posterior ear coarse ribs. There is a fine concentric sculpture of regular hair-lines. but more or less wholly worn from the summits of the ribs. The right valve is a trifle less convex with the same sculpture except that both ears have fine. riblets. Four well-developed teeth in the short ctenolium.
Length 23, alt. 24.7, diam. 7.2 mm. Type no. 2856 A. N. S. P.» PILSBRY. H. A. 1922. Revision of W. M. Gabb's Tertiary Mollusca of Santo Domingo. Proceedings of the Academy of Natural Sciences of Philadelphia, 73: 305-435. [p. 411]
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Pecten interlineatus Gabb; H. A. Pilsbry, 1922, Revision of W. M. Gabb's Tertiary Mollusca of Santo Domingo, plate 45, figure 3.
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