The body of metamorphosed females is short and globular, its depth 50–60% SL. The length of the head is 46–67% SL, the length of the lower jaw, 32–57% SL. The caudal peduncle is unusually short, the dorsal and anal fins terminating nearly at the base of the caudal-fin rays. The sphenotic spines are prominent. The dorsolateral margin of the frontals is smooth, without spines or projections. The lower jaw is without a symphysial spine. The posterior tip of the angular forms a sharp spine. The anterior end of the pterygiophore of the illicium protrudes slightly from the snout. The relative length of the illicium increases with growth: it measures 35.7% SL in a 42-mm specimen, 67.9% SL in a 56-mm specimen, and 70.5% SL in a 105-mm specimen. The escal bulb is relatively large (its width 6.2–8.2% SL) and bears a single, unpigmented distal appendage, 2.3–35.7% SL. Additional escal appendages and filaments are absent. The skin of the head and body is uniformly black to dark red-brown, except for the distal part of the escal bulb and escal appendage.
The teeth are relatively few: there are only 6 or 7 on each premaxilla and 9 on each dentary in a 42-mm specimen; 15 on each premaxilla and 10–12 on each dentary in a 56-mm specimen; and 25 or 26 teeth on each premaxilla and 16 on each dentary in a 105-mm specimen. The longest premaxillary tooth measures 5.0–14.9% SL, the longest dentary tooth, 8.8–19.6% SL. The dorsal and anal fins each contain 3 rays, the pectoral-fin, 16–19 rays. Pelvic fins are absent. There are 9 caudal-fin rays, the ninth ray (the ventral-most) about one-half the length of the eighth caudal-fin ray.
Metamorphosed females of Acentrophryne differ from those of all other genera of the family in lacking a spine on the preopercle. They differ further in having the following combination of character states: Frontal, epiotic, and posttemporal spines are absent. Jaw teeth are few in number (6–26 on each premaxilla, 9–16 on each dentary), extremely long (longest about 20% SL), and arranged in two or three overlapping, oblique longitudinal series. There are 2–6 vomerine teeth. The ninth caudal-fin ray is about one-half the length of the eighth. The length of the illicium is 35.7–70.5% SL. The esca bears a single, unpigmented distal appendage. A hyoid barbel is absent. The skin is uniformly black except for distal parts of the esca. Material is unavailable for internal anatomical examination.
Pietsch TW. 2009. Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea. Berkley: University of California Press. 638 p.
Acentrophryne is known only from five metamorphosed female specimens, all of which have small undeveloped ovaries. Based on this and the reproductive characteristics of other memebers of the family, one must assume males of the genus also attach to the female as sexual parasites.
