Male Morphological Description: Valves are oval in shape with deep incisur. Valve length = 1.95-2.12 mm. Valve height = 1.08-1.25 mm. Color: Mostly transparent, except for yellow light organ and rich brown to orange-brown gut Eye: brown to maroon-brown color with 16 ommatidia. Infold setae: Rostral Row (RR) with 17-24 bristles; 0 or 1 bristle anterior to RR. Anteroventral Row (AVR) with 20-31 bristles; 0 bristles anterior to AVR; 1-5 bristles posterior to AVR. # of tiny suckers on 1st antenna: 5-7 on proximal filament of b-bristle; 4-8 on distal filament of b-bristle; 4-6 on proximal filament of c-bristle; 3-7 on distal filament of c-bristle. 7th limb: with 8-12 bristles. Furca: with 9 claws (few with 8 or 10 claws). Only claw 2 is fused.
Male Bioluminescent Display: Produce short, downward displays 0.2-2 m above the reef. Displays occur 45 min after sunset. Composed of 1 or 2 (rarely 3-5) bright pulses, very rarely followed by a trill of 3-7 dim pulses. Train length is about 2-6 cm (10 cm if a trill occurs), and train duration is 6-7s.
Female Morphological Description: Valves are egg-shaped with a dorsal margin that is steeply arched posteriorly. Valve length = 2.87-2.96 mm. Valve height = 1.80-1.90 mm. Infold setae: Rostral Row with 22-29 bristles; 0 or 1 bristle anterior to RR. Anteroventral Row (AVR) with 36-45 bristles; 0 bristles anterior to AVR; 16-32 bristles posterior to AVR. 7th limb: with 22-24 bristles. Furca: with 9 claws (few with 8 or 10 claws). Only claw 2 is fused.