hammerjaw

The hammerjaw, Omosudis lowii, is a small deep-sea aulopiform fish, found worldwide in tropical and temperate waters to 4,000 m (13,000 ft) depth. It is the only representative of its family, Omosudidae (from the Greek omo, "shoulder", and Latin sudis, either "esox, fish of the Rhine" or "stake").

==Description== thumb|left|Illustration of a hammerjaw The large head is dominated by a massive, truncated lower jaw and large, high-set eyes. The lower jaw has a dark, almost black distal end, "chin". The lower jaw possesses at least one pair of oversized, transparent, and dagger-like teeth; the palatines possess 1–4 pairs of slightly smaller teeth. The body itself is scaleless and laterally compressed; it is covered in iridescent, silvery-gray guanine with the dark peritoneum peeking through in places. Dark smoky gray dorsally, the body tapers strongly towards a thin caudal peduncle (which has a dermal keel) and deeply forked caudal fin. The caudal peduncle is a smoky black color, darker than the body and tail. All fins are spineless; both the low-slung pectoral fins (with 11–16 soft rays) and abdominal pelvic fins (with eight soft rays) are fairly small.