The bighead searsid (''Holtbyrnia anomala'') is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
tubeshoulder
The tubeshoulders are a family, Platytroctidae, of ray-finned fish belonging to the order Alepocephaliformes. They are found throughout the world, except for the Mediterranean Sea. Tubeshoulders live at moderate depths of , and some have light-pr ...
fish.
Description
It maximum length is . Its head is large, making up over a third of the fish's length. It has 25–31
gillrakers
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...
; 5–11
pyloric caecae
Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology co ...
. The snout is pointed, with premaxillary tusks pointing forward.
It is dark red in colour. Its
photophores are rudimentary (except for the shoulder organ), hence its specific name ''anomala'' ("unusual").
Habitat
The bighead searsid lives in the
North Atlantic Ocean; it is a
mesopelagic fish, living at depths of .
References
{{Rayfinned-fish-stub
Platytroctidae
Fish described in 1980
Bioluminescent fish