Turriplaca brevispina (Nicholls, 2013)

Diagnosis: Cells about 10-15 µm in diameter. Plate-scales oval in outline with parallel sides and rounded ends, about 3 µm wide and 4 µm long. Distal surface of the plate-scales with a series of 7-9 holes 0.2-0.3 µm in diameter forming a ring located about 1/4 of the scale width from the margin of the scale; 1-2 additional smaller holes 0.15-0.2 µm in diameter are located near the center of the scale. Spine-scales are short (0.9-1.3 µm), hollow tubes with a marked mid-length constriction where spine shaft diameter = about 0.04 µm. The flared circular base of the spine-scale has a concave outer surface 0.06-0.08 µm in diameter, above which are a series of depressions around the spine base giving a scalloped edge appearance to the base in a polar view of the scale. The flared distal ends of the spine-scales are characterized by a septµm that divides the opening to the internal colµmn of the spine shaft into two separate cavities with entrance holes of about 0.15 µm in diameter.
Type locality. Pacific Ocean beach near Gillatt (Grassy) Island, Haida Gwaii (Queen Charlotte Islands, British Colµmbia, Canada (53.241ON, 131.898OW).

Remarks: T. brevispina joins a small group of Turriplaca species with spine-scales having septate, flared distal ends; the others being T. thomseni, T. minima and T. emarginata. The spine-scales of T. thomseni are 2-6 X larger than those of T. brevispina and have much more elaborately structured terminal septa. T. emarginata plate-scales have fewer and larger holes on the distal surfaces and margins with marked lateral incisements; spine-scales are 2-3 X larger with differently structured spine ends.