#alepocephaliformes

[bestanimal]

Round 3 - Actinopterygii - Alepocephaliformes

(Sources - 1, 2, 3, 4)

Order: Alepocephaliformes

Common Name: “slickheads” and “tubeshoulders”

Families: 2 - Alepocephalidae (“slickheads”) and Platytroctidae (“tubeshoulders” or “searsids”)

Anatomy: reduced ossification in the skeleton as an adaptation to deep-sea life; no swim bladder; scaleless head, body has small cycloid scales; small, sharp teeth; large eyes; spineless fins; single dorsal fin; a tube above the base of pectoral fin connects to a luminous gland on the shoulder girdle; some species have bioluminescent photophores

Diet: plankton, small crustaceans, small fish, tunicates, or detritus (ingests sediment from the seafloor, filtering out microfauna such as foraminiferans)

Habitat/Range: bathypelagic layer of oceans worldwide, at 300 to 3,000 meters (1.9 miles) below the surface

Evolved in: Early Eocene

(source)

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Voting ended onJun 27, 2025

Propaganda under the cut:

The largest known Alepocephaliform is the Yokozuna Slickhead (Narcetes shonanmaruae) (see gif above), which is also the largest known completely deep-sea actinopterygiian. The Yokozuna Slickhead can grow over 2.5 metres (8.2 ft) long. The common name refers to the highest rank in sumo wrestling, Yokozuna (横綱).

Two slickheads are known from Oligocene fossils, one in the genus Bathyprion and one in the genus Carpathichthys. Today, the only Bathyprion species alive is the Fangtooth Smooth-head (Bathyprion danae). Carpathichthys appears to be closely related to the living genus Rouleina.