Catalog - Reticulophragmium

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Reticulophragmium

Citation: Reticulophragmium Maync, 1955

Type species: Reticulophragmium venezuelanum (Maync) = Alveolophragmium venezuelanum Maync, 1952

In their important paper entitled “Studies of Arctic Foraminifera” (1953, Smithsonian Misc. Coll., vol. 121, no. 7), A.R. Loeblich and H. Tappan briefly discuss the genus Alveolophragmium Stschedrina, 1936, which was based on the Recent species Alveolophragmium orbiculatum Stschedrina (1936, Zool. Anz., vol. 114).

The new genus Labrospira was erected in 1947 by H. Höglund, with Haplophragmium crassimargo Norman as genotype (Höglund, 1947, Uppsala Univ., Zool. Bidrag, vol. 26, p. 141). Labrospira is stated to differ from Haplophragmoides Cushman in showing an interio-areal aperture instead of an interio-marginal one (ibid., p. 133).

Being convinced that Alveolophragmium orbiculatum Stschedrina “is without doubt the same (species) as the common Arctic species Haplophragmium crassimargo Norman” (Loeblich and Tappan, 1953, p. 29), the authors concluded that Labrospira is a junior synonym of Alveolophragmium.

The genus Alveolophragmium had been established for Haplophragmoides-like forms that reveal an alveolar (labyrinthic) wall structure (Stschedrina, 1936, p. 312; Maync, 1952, Cushman Found. Foram. Res., Contr., vol. 3, pt. 2, p. 48; Maync, 1952, ibid., vol. 3, pts. 3-4, p. 141; Loeblich and Tappan, 1953, p. 28). According to Loeblich and Tappan, however, the type species, Haplophragmium crassimargo Norman, 1892, does not possess such an alveolar wall structure, for the apparent alveoles are “merely the gaps left between the coarse fragments used in constructing the test” (Loeblich and Tappan, 1953, p. 29). This being the case, Alveolophragmium does not belong to the labyrinthic group (Spirocyclininae) of the Lituolidae. (It must be stressed that the above conclusions rest on the assumption that Haplophragmium crassimargo Norman and Alveolophragmium orbiculatum Stschedrina are identical.)

Some time ago, the writer described a Haplophragmoides-like foraminifer from the Oligo-Miocene of Venezuela which positively possesses a reticulate-alveolar wall structure. Since Alveolophragmium was the only representative of Haplophragmoides with a reportedly alveolar wall structure, the Venezuelan form was named Alveolophragmium venezuelanum Maync. No topotype material of Alveolophragmium orbiculatum was, of course, available to the writer, and the only reference was the figures given by Stschedrina (1936, tfs. 1-3). Two other species were also referred by the writer to the genus Alveolophragmium because of their labyrinthic wall structure, viz. Alveolophragmium peruvianum Maync and Alveolophragmium reticulatum (Boomgaart) [Haplophragmoides reticulatus, 1949].

As Alveolophragmium orbiculatum Stschedrina (= Haplophragmium crassimargo Norman, fide Loeblich and Tappan) now is reported to disclose a simple arenaceous test, whereas the species of Alveolophragmium described by the writer show a true alveolar (labyrinthic) wall structure (Maync, 1952, Cushman Found. Form. Res., Contr., vol. 3, pts. 3-4, pp. 141-144), the mentioned forms obviously cannot be accommodated in the same genus. Since Alveolophragmium is considered to be a valid genus, though it does not exhibit an alveolar wall structure, contrary to its etymology, the truly labyrinthic forms of Haplophragmoides have to be included in a new genus. In order to emphasize the presence of the diagnostic reticulate-alveolar wall structure as revealed by the type species, Alveolophragmium venezuelanum Maync, the new name Reticulophragmium is herewith proposed.

[The following species were included in the genus Reticulophragmium by Maync in 1955 (loc. cit.)]:

Reticulophragmium peruvianum (Maync) = Alveolophragmium peruvianum Maync, 1952;
Reticulophragmium reticulatum (Boomgaart) = Haplophragmoides reticulatus Boomgaart, 1949;
Reticulophragmium venezuelanum (Maync) = Alveolophragmium venezuelanum Maync, 1952.

References:

Maync, W. (1955). Reticulophragmium, n. gen., a new name for Alveolophragmium Stschedrina, 1936 (pars),. Journal of Paleontology. 29: 557-558. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Reticulophragmium Maync, 1955

Reticulophragmium

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