Thaumatichthys

Thaumatichthys, the wonderfish or trapjaw anglerfish, is a genus of deep-sea anglerfish in the family Thaumatichthyidae, with three known species. Its scientific name means "wonder-fish" in Greek; oceanographer Anton Bruun described these fishes as "altogether one of the oddest creatures in the teeming variety of the fish world." In contrast to other anglerfishes, the bioluminescent lure (called the "esca") of Thaumatichthys is located inside its cavernous mouth. They are worldwide in distribution and are ambush predators living near the ocean floor.

Nomenclature

Taxonomy

The first specimen of Thaumatichthys was collected by an American expedition in Indonesia in 1908 and given the species name pagidostomus ("trap-mouthed"). A subsequent specimen from the north Atlantic was placed by Regan and Trewavas (1932) into a new genus, Amacrodon, based on differences in dentition. Bruun assigned a specimen collected by the Galathea Expedition of 1950–52 to a third genus, Galatheathauma ("Galathea's wonder"), as it was much larger than the previous specimens. However, a later examination of the then-32 known specimens showed that these differences were attributable to age, and thus there was only one valid genus, Thaumatichthys, with three species; the two aforementioned genera were lumped and became its synonym.

Historically, the closest relative of Thaumatichthys was thought to be Lasiognathus, which also possesses enlarged, hinged premaxillaries, denticles on the esca, and a branched upper operculum. However, significant differences were noted between the two genera, and Lasiognathus shares many more traits with members of the family Oneirodidae than does Thaumatichthys. A study using total-evidence revised the classification of anglerfish, and this team confirmed that Lasiognathus was in fact an Oneirodid, leaving Thaumatichthyidae as a monotypic family.