Catalog - Recurvoides

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Recurvoides

Citation: Recurvoides Earland, 1934

Type species: Recurvoides contortus Earland, 1934

[Earland 1934]: Test free, arenaceous, composed of several convolutions, each containing many chambers. The convolutions are planospiral and partially embracing but arranged in two series, the axis of winding of the second series being approximately at right angles to that of the first or earlier series. The second series therefore envelops the first, but leaves the peripheral edge of the final convolution of the first series visible on one of the faces as a raised line of chambers, extending across the umbilical portion of the adult test. The umbilical portion of the opposite face is more depressed. Composed of sand grains of varying sizes with a considerable amount of ferruginous cement. Aperture small, on the inner edge of the final chamber, sometimes having protruding lips.

[Earland 1934 emend. Uchio 1960]: The test is free, arenaceous, composed of several convolutions, each containing many chambers. The convolutions are planispiral and partially embracing but arranged in two series, the axis of winding of the second series being oblique (not necessarily at right angles) to that of the previous or earlier series. Therefore, the second series envelops the first, but leaves the peripheral edge of the final convolutions of the first series visible on one of the faces as a raised line of chambers extending across the umbilical portion of the adult test. Composed of sand grains of varying sizes. Aperture a narrow slit slightly above the base of the apertural face of the last chamber, frequently with a distinct lip.

[Earland 1934]: Recurvoides has many points of resemblance to Haplophragmoides Cushman, but differs from that genus, which is planospiral throughout growth, in its variable axis. It thus bears much the same relationship to Haplophragmoides as Glomospira to Ammodiscus. Trochamminoides Cushman, 1910, of which the genotype is Trochammina proteus Karrer, 1866, has sometimes a varying axis but is quite distinctive in its irregular chambering and construction. The genotype is Recurvoides contortus Earland, 1934, which is based on the specimens recorded and figured in the South Georgia report under the name “Haplophragmoides scitulus Brady, oval variety” (1933, Discovery Repts., vol. 7, no. 112, pl. 3, figs. 11, 12). Their real structure did not become apparent until sections were made. Apart from their oval contour due to the change of axis, which becomes less apparent after more than one convolution of the second series has become completed, specimens of Recurvoides contortus and Haplophragmoides scitulus [Lituola (Haplophragmium) scitulum Brady, 1881] are externally in close agreement, and the two species often occur together. Horizontal sections of the two forms are quite different. That the two organisms are not zoologically related is proved by the fact that both megalospheric and microspheric specimens of each have been found.

[Earland 1934 emend. Uchio 1960]: Remarks. – Earland did not describe the apertural character of the genus in detail, nor that of the type species, Recurvoides contortus. Dr. C.G. Adams, curator at the Foraminifera Section, British Museum (Natural History), has kindly examined Earland’s type material. According to his personal communication to the writer “Earland’s type slide 2F3470 contains 30 specimens, 13 of which are illustrated in Discovery Report volume 10, plate 10. No holotype was designated, the 13 figured specimens thus becoming syntypes, and the 17 unfigured specimens paratypes.” Adams has selected a lectotype and intends to publish a short description, together with photographs. The photograph of the proposed lectotype shows a 30° change in the axis of winding of the second series from that of the first series rather than a right angle change; the aperture is a narrow slit a little above the base of the apertural face of the last chamber, with a protruding lip. The apertural character of the other 5 specimens, which Adams sketched for the writer, shows that the apertures are slightly above the base of the apertural face.

References:

Earland, A. (1934). Foraminifera, Part III: the Falklands sector of the Antarctic (excluding South Georgia). Discovery Reports. 10: 1-208. gs

Uchio, T. (1960b). Ecology of living benthonic foraminifera from the San Diego, California area. Cushman Foundation for Foraminiferal Research, Special Publication. 5: 1-72. gs

			Recurvoides nadvornensis Myatlyuk, 1970 = Conglophragmium irregulare
			Recurvoides anormis Myatlyuk, 1970 = Recurvoides anormis
			Recurvoides azuaensis Bermúdez, 1949 = Recurvoides azuaensis
			Recurvoides contortus Earland, 1934 = Recurvoides contortus
			Recurvoides contortus subsp. gurgitis Saidova 1961 = Recurvoides contortus
			Recurvoides laevigatum Höglund, 1947 = Recurvoides contortus

CATALOG OF ORIGINAL DESCRIPTIONS: Recurvoides Earland, 1934

Recurvoides

References:

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