Buryella pentadica Foreman

Buryella pentadica Foreman, 1973, p.433, pl.8, fig.8, pl.9, figs.15- 16

DESCRIPTION

Shell of five segments, subovate, smooth, with none of the strictures expressed externally. Cephalis subspherical with a few circular pores, bearing a short, bladed or smooth conical horn. Collar stricture with four collar pores internally and a vertical pore expressed as a short, horizontally directed tube. Thorax and third segment conical, with circular pores in approximately transverse rows. Fourth segment largest, inflated, with greatest dimension medianly or in the distal half. Uniform circular pores are arranged in longitudinal and four to six, generally five, transverse rows. Area between longitudinal rows raised. Last segment truncate, inverted-conical, with thinner wall and three to five transverse rows of circular to elliptical pores. Distal margin scalloped or even, without a differentiated rim (Foreman, 1973).

DIMENSIONS

Based on 15 specimens. Length overall, exclusive of horn, 130-150 m, length of cephalis and thorax together 20-25 m, of third segment 20-25 m, of fourth segment 45-60 m, of last segment 30-50 m; greatest width 65-90 m (Foreman, 1973).

DISTINGUISHING CHARACTERS

See Buryella tetradica.

DISTRIBUTION

This species is found as far north as 40N (DSDP Site 384) in the North Atlantic, in the tropical Indian Ocean (DSDP Site 237) and in the Caribbean. Its morphotypic first appearance lies below the oldest defined Paleocene zone, the Bekoma campechensis Zone. Its morphotypic last appearance lies within the Bekoma campechensis Zone.

PHYLOGENY

Ancestor of B. tetradica

NEXT