Horned lantern fish
Encyclopedia
The horned lantern fish or prickly seadevil, Centrophryne spinulosa, is a deep-sea anglerfish found worldwide. It is the sole species
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 in the family Centrophrynidae, distinguished from other deep-sea anglerfishes by various characters including four pectoral radials, an anterior spine on the subopercular bone, and a short hyoid (chin) barbel in both sexes.

Distribution

The horned lantern fish occurs in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 from Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...

 south to the Marquesas Islands
Marquesas Islands
The Marquesas Islands enana and Te Fenua `Enata , both meaning "The Land of Men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. The Marquesas are located at 9° 00S, 139° 30W...

 and the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

. Specimens have also been captured in other locations, including New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

, the South China Sea
South China Sea
The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around...

, Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

, and the Mozambique Channel
Mozambique Channel
The Mozambique Channel is a portion of the Indian Ocean located between the island nation of Madagascar and southeast Africa, primarily the country of Mozambique. It was a World War II clashpoint during the Battle of Madagascar...

, suggesting a wide oceanic distribution in tropical and subtropical waters. Specimens were caught at depths from 650 to over 2000 meters, while larvae have been recovered close to the surface to a depth of 35 meters.

Description

The female horned lantern fish measures up to 23 cm in length and is long and slender, with a large head and jaws of equal length. The jaws are filled with slender, recurved, depressible teeth of mixed large and small sizes. There is a large oval pit in front of each eye in specimens larger than 42 mm. The eye itself lies beneath the skin and appears through a translucent patch. The fish is reddish brown to black in color; its skin is covered with numerous close-set spines. The illicium ("fishing rod") and esca (lure) are attached to the snout. The esca has a fan-shaped appendage in front and another short appendage on the back; the tip is white with scattered large melanophores. There is a small hyoid barbel, although it is vestigial in adult females.

The males are much smaller
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

 and dark brown in color, measuring up to 1.6 cm long and lacking the illicium and esca. The known specimens are all immature, though already with large olfactory organs and well-developed denticular plates on the tip of the snout bearing 3-4 curved teeth each. Their hyoid barbel distinguishes them from the males of all other deep-sea anglerfish. The two known larvae measure 4.2 mm and 7.5 mm long and have short, stout bodies with moderately inflated skin.

Biology

Unlike other deep-sea anglerfish, female horned lantern fish have only a single ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

 lined with villi-like epithelial projections rather than epithelial folds. All known female specimens have had immature oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...

s, suggesting that sexually mature individuals have yet to be captured. It is unknown whether the males of the horned lantern fish are parasitic. A female horned lantern fish has been found with a parasitic male Melanocetus johnsonii attached, though the coupling was likely in error (possibly occurring while the two fish were in the net) and there was no fusion of tissues.

The function of the hyoid barbel in the horned lantern fish is unknown. The only other deep-sea anglerfishes that have a hyoid barbel are the linophrynids, where it occurs only in the females and is often elaborate and/or bioluminescent.
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