Male Morphological Description: Valves boxy in shape with deep incisur and a straight dorsal margin. Male valve length = 1.52-1.85 mm. Male valve height = 0.91-1.10mm. Color: Transparent, except for yellow-brown rectangular light organ and orangish-brown to tan abdomen. Eye: is brown to maroon-brown with about 12 ommatidia. Lateral eye length=0.23-0.30 mm. Infold setae: Rostral Row (RR) with about 22-33 double bristles; 4-12 double bristles posterior to RR; 0-2 double bristles anterior to RR; 3-8 dorsal to incisur; 1-3 tiny bristles posterodorsal to inner edge of incisur; Anterior edge of incisur with 4-5 double bristles. Anteroventral Row (AVR) of 38-53 double bristles; 20-69 double setae posterior to AVR; 3-8 widely spaced bristles anterior edge of incisur. 7th limb: Distal comb with 1-2 bristles; terminal comb with 3-4 bristles; distal peg with 3 bristles; terminal peg with 3 bristles. Furca: with 9 claws. Claws 2 and 4 are fused to lamella.
Male Bioluminescent Display: rapid flashing upward display of 8-12 pulses. Display train length= 1.5-2m. Bright, blue pulses that are <1 sec in duration; train duration about 18 sec. Displays occur 3-10m depth over grassbeds.
Female Morphological Description: Valves are oval in shape with deep incisur and a rather straignt dorsal margin. Valve length = 1.80-2.25 mm. Valve height = 1.18-1.43 mm. Color: Mostly transparent, except for yellow-brown rectangular light organ and orangish-brown to tan abdomen. Eye:Lateral eye length = 0.21-0.26 mm. Infold setae: Rostral row (RR) with 19-30 bouble bristles; 7-10 double bristles posterior to RR; 0-1 bristle anterior to RR. Anteroventral Row (AVR) with 38-51 double bristles; 34-36 double bristles posterior to AVR. 7th limb: Distal comb with 4-5 bristles; terminal comb with 5 bristles; distal peg with 4-5 bristles; terminal peg with 3 bristles. Furca: with 9 claws. Claws 2 and 4 are fused to lamella.