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.