Miliammina obliqua Heron-Allen and Earland, 1930

Camacho, S, Moura, D, Connor, S, Scott, DB & Boski, T, 2015, Taxonomy, ecology and biogeographical trends of dominant benthic foraminifera species from an Atlantic-Mediterranean estuary (the Guadiana, southeast Portugal), Palaeontologia Electronica 52 (4), pp. 1-37 : 19

Miliammina obliqua Heron-Allen and Earland, 1930

Figure 2.27-2.28

1930 Miliammina obliqua Heron-Allen and Earland : p. 42, pl. 1, figs. 7, 12.

1999a Miliammina obliqua Heron-Allen and Earland ; Hayward, Grenfell, Reid and Hayward, p. 82, pl. 1, figs. 7, 8.

2005 Miliammina obliqua Heron-Allen and Earland ; Horton, Whittaker, Thomson, Hardbattle, Kemp, Woodroffe and Wright, p. 3, pl. 1, fig. 2.

2006 Glomospira sp. Debenay and Luan: pl. 1, fig. 9.

Morphological description. Broadly ovate, quinqueloculine test with early chambers oblique to main axis; thin wall composed of well-cemented fine silt grains, with a smoothly finished, light brown shinning surface; aperture is an interio-marginal arch ( Figure 2.27 ); smaller than M. fusca .

Occurrence. Reported for the first time in Guadiana, where it is common, with higher incidence in winter, at middle elevations of the northernmost positions and at upper elevations with a more confined position.

Remarks. Strong morphological similarities with M. fusca may prevent accurate identification, not only in Portuguese estuarine systems, but also worldwide; rarely mentioned in the literature.

Figures

FIGURE 2. Scanning electron micrographs of the foraminifera specimens. Scale bar equals 100 µm. 1-3- Three different specimens of Polysaccammina ipohalina Scott, 1976b, illustrating the differences in size and form. In all specimens it is possible to see attached organic matter; 4-5- Polysaccammina hyperhalina Medioli, Scott, and Petrucci, 1983. 4- complete specimen of P. hyperhalina; 5- aperture view; 6- specimen with several side branches; 7-10- different sized specimens of Ammovertellina sp.; 11-14- various specimens of Reophax nana Rhumbler, 1913; 15-17- Leptohalysis scottii (Chaster, 1892); 15 and 16- side view of two complete specimens; 17- detail on the agglutination of the last chamber; 18- complete specimen of Ammobaculites exiguus Cushman and Brönnimann, 1948b; 19- Ammobaculites sp. with the uncoiled portion broken; 20-22- Ammotium salsum (Cushman and Brönnimann, 1948a); 20- best specimen; 21- smaller specimen; 22- aperture detail; 23- Ammotium sp.; 24-26- different specimens of Miliammina fusca (Brady, 1870); 27-28- Miliammina obliqua Heron-Allen and Earland, 1930; 27- view of the interio-marginal arch of the aperture; 29-30- Arenoparrella mexicana (Kornfeld, 1931); 29- ventral side with view to main aperture and supplementary apertures; 30- dorsal side with view to supplementary apertures; 31-32- Deuterammina eddystonensis Brönnimann and Whittaker, 1990; 31- dorsal view; 32- ventral view; 33-35- Jadammina macrescens (Brady, 1870); 33- dorsal view; 34- ventral view; 35- dorsal view of a deformed test.