N47

Pterocanium grandiporus Nigrini

Pterocanium grandiporus Nigrini, 1968, p. 57, pl. 1, fig. 7

DESCRIPTION

"Similar in size and shape to P. trilobum but shell may be heavier and rougher, cephalic pores better defined, and apical horn usually longer. Thoracic pores larger than those of P. trilobum, 9-11 across the widest part of the segment.

"Abdomen often quite well developed and attached to the feet for at least most of its length. Pores large, subcircular, having no definite arrangement; those adjacent to the feet larger than the others. Termination always ragged." (from Nigrini, 1968).

DIMENSIONS

"Length of apical horn 45-81m, of cephalis 14-27 m, of thorax 63-90 m, of feet 108-240 m. Maximum breadth of cephalis 23-27 m, of thorax 90-127 m." (from Nigrini, 1968).

Plate 23, figure 5

N48

RECENT DISTRIBUTION

1. Nigrini, 1968, text-fig. 8; "Few in 2 samples near the coast of Central America and in 2 equatorial samples near the coast of South America, rare or absent in all other samples examined.

2. Molina-Cruz, 1975, Code N6; used in factor analysis of southeast Pacific assemblages; cf. Appendix 10 for percent N6 at each station.