Catalog - Globigerina hybrida

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Globigerina hybrida

Citation: Globigerina hybrida McCulloch 1977

Type specimens: holotype (fig. 7), AHF 2571; paratype (fig. 5), AHF 2569; hypotypes (figs. 4, 6, 15), nos. AHF 2568, 2570, 2579.

Type locality: Holotype (fig. 7) and paratype (fig. 5) in 49-63 fms. on Velero Station 1004, 32°13'N, 119°19'W, off San Nicolas Island; hypotype (fig. 4) in 147 fms. on Station 82, off Long Point, hypotype (fig. 6) in 175 fms on Station 1205, and hypotype (fig. 15) in 255 on Station 1247, off Long Point; Catalina Island; California; also in shallow water to 600 fms. on more than 200 other Stations in the Eastern Pacific Ocean.

Type repository: Los Angeles, Univ Southern California, Allan Hancock Foundation

Test free, calcareous, circular in contour, slightly compressed, trochospiral, biconvex, periphery lobulated, broadly rounded; wall some what smooth, coarsely perforate, slightly hispid, opaque, com paratively thick; dorsal side presenting a low spire of two and a half to three whorls of medium sized subglobose in flated chambers, 5 or 6 somewhat variable in size and shape chambers in last formed whorl; chambers embracing; all sutures depressed curved to radiate dorsally, radiate ventrally; ventral side involute presenting an umbilicus more or less open; aperture interiomarginal extraumbilical umbilical with a narrow rim or lip outlining its periphery usually visible.

Size. - Holotype (fig. 7) 0.54 x 0.515 x 0.415mm; hypotype (fig. 4) 0.498 x 0.476 x 0.415mm; paratype (fig. 5) 0.511 x 0.498 x 0.341mm; hypotype (fig. 6) 0.541 x 0.476 x 0.498mm; hypotype (fig. 15) 0.642 x 0.561 x 0.415mm.

Banner and Blow (1960, p. 11, pl. 2, figs. 1, 4) redefined the taxa Globigerina eggeri Rhumbler, 1901, and Globigerina dutertrei D’Orbigny, 1839, on the basis of their research, the original descriptions and type figures, the present series of forms seems to be different from both the above taxa. G. eggeri is a species with more depressed sutures, a higher, off-center apex, sharply defined spiral suture chambers which are smaller, more inflated, and more uniform in size and shape. The overall shape and position of final chamber and umbilicus of test are distinctive. The present forms are less globose tending to be flatter as shown in the edge views. The taxon of G. dutertrei d’Orbigny is less sharply defined. d’Orbigny’s original illustrations point to an outer whorl of chambers deeply lobulate chambers increasing in size to a large last formed one dorsally. Banner and Blow’s lectotype does not present the same characters as above. It presents a more globose form, less lobulate with an infilled ‘umbilicus with out a rim or lip.’ The series of five forms herein illustrated show variation in number of, shape of and organization of chambers dorsally along with considerable variation of structure, size of last formed chamber and umbilicus. Globigerina conglomerata Schwager, 1866, G. dutertrei d’Orbigny, and G. eggeri Rhumbler have been reported in Eastern Pacific waters.”

References:

Banner, F. T. & Blow, W. H. (1960a). Some primary types of species belonging to the superfamily Globigerinaceae. Contributions from the Cushman Foundation for Foraminiferal Research. 11: 1-41. gs

McCulloch, I. A. (1977). Qualitative observations on Recent foraminiferal tests with emphasis on the eastern Pacific (3 vols). University of Southern California, Los Angeles. -. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina hybrida McCulloch 1977

Globigerina hybrida

References:

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