The razorback scabbardfish, ''Assurger anzac'', is a rare species of

cutlassfish The cutlassfishes are about 45 species of predatory ray-finned fish in the family Trichiuridae of the order Scombriformes found in seas throughout the world. Fish of this family are long, slender, and generally steely blue or silver in colour, ...

, family Trichiuridae, and the only member of its

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

. It has been caught from scattered locations worldwide: in the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

it is known from off

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

, and the Walvis Ridge, in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

it is known from off western

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, and in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

it is known from off

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, southern

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Midway Island Midway Atoll (colloquial: Midway Islands; ; ) is a atoll in the North Pacific Ocean. Midway Atoll is an insular area of the United States and is an unorganized and unincorporated territory. The largest island is Sand Island, which has housi ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, and the Nazca and Sala y Gomez Ridges. Adults are thought to be

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

, occurring at a depth of , while juveniles are found near the surface or in midwater. Assurger anzac head

This fish has a very long and thin body, measuring 25 to 28 times as long as deep and 12 to 14 times as long as the head. The dorsal profile of the head is straight or slightly convex, with a prominent sagittal crest. The

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

diameter is about one-eighth the head length. The

lower jaw In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

juts out past the upper, and both jaws are tipped with a short dermal process. There are three pairs of fangs at the front of the jaws. The

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

is very long, containing a few weak spines at the front followed by 116-123

soft rays 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 origin of the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

lies beneath the 42nd to 44th dorsal fin ray; the anal fin contains 74-87 elements but only 14-17 have external rays, led by 2 small spines. The

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s are reduced to only 1 scale-like spine and 1 soft ray, placed beneath the 8th or 9th dorsal fin ray. A tiny forked

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

is present. The coloration is silver, with the front of the dorsal fin membrane black until the 3rd or 4th soft ray. The razorback scabbardfish attains a maximum length of . Its diet consists of

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

es, such as the

Californian anchovy The Californian anchovy or northern anchovy (''Engraulis mordax'') is a species of anchovy found in the Eastern Pacific Ocean, ranging from Mexico to British Columbia. It is a small, Clupeiformes, Clupeoid fish with a large mouth and a long, late ...

(''Engraulis mordax'') and the

North Pacific hake The North Pacific hake, Pacific hake, Pacific whiting, or jack salmon (''Merluccius productus'') is a ray-finned fish in the genus '' Merluccius'', found in the northeast Pacific Ocean from northern Vancouver Island to the northern part of the Gu ...

(''Merluccius productus''), and

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

. The only known

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

of the razorback scabbardfish is the

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

''Avitocaligus assurgericola''. Reproduction is presumably

oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

with pelagic

eggs An egg is an organic vessel in which an embryo begins to develop. Egg, EGG or eggs may also refer to: Biology * Egg cell, the female reproductive cell (gamete) in oogamous organisms Food * Eggs as food Places * Egg, Austria * Egg, Switzerland ...

and larvae as with other members of the family, though eggs and newly hatched

larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

have not been described. Flexion (the bending of the

notochord The notochord is an elastic, rod-like structure found in chordates. In vertebrates the notochord is an embryonic structure that disintegrates, as the vertebrae develop, to become the nucleus pulposus in the intervertebral discs of the verteb ...

as part of caudal fin formation) occurs at around a length of . Post-flexion larvae have slender bodies and pointed heads, with the pelvic and first dorsal spines elongated. They can be distinguished by the presence of pigment on the top of the head, snout, and opercles. This species is not targeted by

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

; it is sometimes hooked or netted, or found washed ashore.

References

{{Taxonbar, from=Q941173 Trichiuridae Fish described in 1916 Taxa named by Wilfred Backhouse Alexander