Aulostomus medius

Aulostomus medius Weiler 1920

    Oligocene

    Wiesloch near Heidelberg

    Germany

    Length 4 cm / 1.5"

    The species of the family Aulostomidae belong to the order Syngnathiformes. The name "Syngnathiformes" means "conjoined-jaws". Syngnathiformes is an order of ray-finned fishes that includes among others pipefishes and seahorses (Syngnathidae), razorfishes (Centriscidae), trumpetfishes (Aulostomidae) and cornetfishes (Fistulariidae). Fishes of this order have elongate, narrow, bodies surrounded by a series of bony rings, and small, tubular mouths. The tubular mouth shows that these members of the Syngnathiformes fed on small Crustaceans and such, much as their modern-day relatives Seahorses and Pipefishes. The family Aulostomidae includes the genus Aulostomus with currently three species. The name Aulostomus means "Flutemouth".

    The species of the subfamily Aulostomidae (trumpetfishes) have elongated, thin, snake-like bodies with a highly modified skeleton formed into armored plating.  The head is elongate with a long and slender, tubular snout; the mouth being small and toothless. Dorsal and anal fins are almost closely adjacent to the tail.  Aulostomids are highly carnivorous fish. They stalk their prey by hovering almost motionlessly a few inches above the substrate, inching their way towards unsuspecting prey. Once close enough, they rapidly dart in, and expand their jaws rapidly. Opening their tube-like mouths in quick succession creates a strong suction force, which draws prey straight into the mouth. Aulostomids are known to feed almost exclusively on small, schooling reef fishes. Aulostomids are found in tropical waters worldwide. They can reach almost 1m in length.

    Parin, N.N., Micklich, N. Two aulostomoid fish (aulostomidae, syngnathiformes) from the Lower Oligocene of Germany (1996) Paleontological Journal, 30 (1), pp. 61-66.