N85

Pterocorys hertwigii (Haeckel)

Eucyrtidium hertwigii Haeckel, 1887, p. 1491, pl. 80, fig. 12

Theoconus hertwigii (Haeckel), Nigrini, 1967, p. 73, pl. 7, figs. 4a, b

DESCRIPTION

"Shell conical to ovate, thin-walled, smooth except for longitudinal ridges at irregular intervals. Cephalis trilocular with numerous subcircular pores, heavier than rest of shell. Stout three-bladed apical horn usually about the same length or a little longer than cephalis. Primary lateral and dorsal spines aligned with the ribs in the thoracic wall.

"Thorax campanulate with subcircular pores arranged in longitudinal rows. Lumbar stricture distinct. Abdomen broader than thorax, but with similar pores. In complete specimens abdomen slightly constricted distally with a smooth termination, but most specimens are incomplete.

"Both thorax and abdomen ornamented by poreless ridges which run more or less longitudinally, irregularly spaced and not necessarily continuous for entire shell length. On the thorax some of the ridges frequently bear 1 or 2 small spines." (from Nigrini, 1967).

"Some specimens lacked ribs." (from Renz, 1976).

DIMENSIONS "Total length (excluding apical horn) 119-191 microns. Length of apical horn 2-45 microns; of cephalis 23-32 microns; of thorax 45-63 microns; of abdomen up to 109 microns. Maximum breadth of cephalis 27-32 microns; of thorax 81-100 microns; of abdomen 100-136 microns." (from Nigrini, 1967).

REMARKS

1. Benson's (1966) description and dimensions of this species (Phormocyrtis fatuosa (Ehrenberg) in Benson, p. 485) are generally consistent with the above except for a greater thoracic length (64-80 microns).

Plate 25, figure 9

N86

RECENT DISTRIBUTION

1. Benson, 1966 (Phormocyrtis fatuosa); "... very rare in the Gulf [of California]... indicates its preference for oceanic waters."

2. Nigrini, 1967 (Theoconus hertwigii), fig. 38; "Indian Ocean occurrences - T. hertwigii is very sparsely distributed in low latitudes, and does not occur in samples from south of 35 degrees S."

3. Molina-Cruz, 1975, Code N39 (Theoconus hertwigii); not used in factor analysis of southeast Pacific assemblages; cf. Appendix 10 for percent N39 at each station.