Smithsonian National Museum of Natural History

Original Description
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"Astochoporella cassidula nom. nov. (Fig. 4 E, F)

Pemmatoporella marginata: Hayward and Taylor 1984: 76, Fig. 2A, B.
Material
Holotype BMNH 1987.9.20.16, "Discovery" stn. 1652, 23.1.1936, 567 m.

Description
Autozooids elongate, rectangular, flat, separated by thin, raised sutures. Frontal wall finely granular, with well marked marginal septula, interspersed with thickened, nodular ridges. Aperture relatively large, slightly wider than long, its proximal border straight, slightly convex or sometimes with a distinctly angular lip simulating a lyrula. Avicularium situated close to proximal edge of aperture; elongate oval, with the rostrum slightly uplifted distally. Ovicell a short hemisphere, about as long as aperture, not very protuberant; with relatively large, irregular foramen in ectooecium; granular ooecial cover developing in early ontogeny.
Measurements, means and standard deviations of 20 values, mm: Autozooid length 1.84 ± 0.01 Aperture length 0.32 ± 0.04 Autozooid width 0.90 ± 0.04 Aperture width 0.41 ± 0.02

Geographical distribution
The material figured by Hayward and Taylor (1984) was from the Ross Sea. The present material consists of eight samples, one from the Palmer Archipelago ("Discovery" stn. 190), and the rest from the Ross Sea (National Antarctic Expedition, Coulman Isd., "Terra Nova" stns. 295, 316, 339, 355; "Discovery" stns. 1652, 1660)." (Hayward and Thorpe, 1988b:292)