Anotopterus

The daggertooths (genus Anotopterus) are a genus of marine mesopelagic fish in the order Aulopiformes, the sole genus of the family Anotopteridae. They are found in oceans worldwide, but prefer cooler waters.

==Description== Daggertooths are similar in appearance to the related lancetfishes and barracudina. They are elongate, silvery, predatory marine fishes that lack scales and have sharp teeth likely used for hunting fishes. However, as their scientific name (meaning "without fins on its back") suggests, they lack dorsal fins which easily differentiates them from their close allies, especially the similar-looking lancetfishes. Another feature that distinguishes daggertooths from lancetfishes is the placement of the large, fang-like teeth. In lancetfishes, the fangs appear on both the upper and lower jaws while in daggertooths the fangs are only seen along the upper jaw. Whether the fangs or the distinctly protruding mandible inspired the common name "daggertooth" remains unclear. Anotopterus spp. have been reported to grow to as long as . The skin of daggertooths makes them highly refractive to light. Like their close relatives, they lack swim bladders. thumb|A daggertooth trawled from the mesopelagic near Bear's Seamount in the North Atlantic. The Yellow coloration in this photo is the yellow of a hi-vis life jacket reflecting off this fish's silvery skin. Photo by Dr. Jon A. Moore