Wednesday, July 7, 2010

July 7, 2010 : Wolf-Trap Anglerfish

Wolf-Trap Anglerfish (Lasiognathus)

Lasiognathus is a genus of deep-sea anglerfish in the family Thaumatichthyidae, with five species known from the Atlantic and Pacific Oceans. It has been called a "compleat angler", in that its lure apparatus consists of a fishing rod (the projecting basal bone or pteropterygium), a fishing line (the illicium, a modified dorsal fin ray), bait (the bioluminescent esca), and hooks (large dermal denticles). It is also distinctive for an enormous upper jaw with premaxillaries that can be folded down to enclose the much shorter lower jaw. 

The closest relative of Lasiognathus is Thaumatichthys, which also has enlarged and hinged premaxillaries, escal denticles, and a branched upper operculum. However, there are significant differences between those two taxa as well, which includes characters that Lasiognathus shares with the oneirodids not found in Thaumatichthys. Bertelsen and Struhsaker (1977) noted that, given the undefined cladistics of the Oneirodidae, it was somewhat subjective whether Lasiognathus and Thaumatichthys were placed in their own family, in separate families, or in the Oneirodidae. Lasiognathus comes from the Ancient Greek lasios, meaning "hairy", and gnathos, meaning "jaw".

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