Stichocorys johnsoni Caulet

Stichocorys johnsoni Caulet, 1986, p.851, pl.6, figs.5-6

DESCRIPTION

Shell with four (or more?) segments, distinctly separated by constrictions, the first three segments together forming a conical section. Cephalis subspherical, rough, poreless, and bearing a slightly curved apical horn generally longer than the first segment. Thorax subspherical, well developed, having 20-30 irregularly arranged subcircular pores. Third segment conical, longer and broader than any other, bearing two kinds of pores: ordinary small pores on the whole surface and a single row of pores twice as large as the others just below the lumbar stricture. Fourth segment generally ragged with smaller pores irregularly arranged. Entire apertural margin never observed (Caulet, 1986).

DIMENSIONS

Length of first, second and third segments 120-130 µm. Thoracic length 40 µm. Abdominal length 50-60 µm (Caulet, 1986).

DISTINGUISHING CHARACTERS

Eucyrtidium diaphanes (Sanfilippo et al., 1973, p.221, pl.5, figs.12-14) also has a single row of large pores just below the lumbar stricture and is thus similar to this form, but its shell has a different shape and the stratigraphic range is quite different.

VARIABILITY

This species was first described from Indian Ocean material. Pacific Ocean forms of this species generally lack an indentation on the third segment.

DISTRIBUTION

First occurrence has not been recognized, but is at least as old as the Didymocyrtis antepenultima Zone. Its morphotypic last appearance lies within the Stichocorys peregrina Zone.