Blackmouth lanternshark

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The blackmouth lanternshark is a species of dogfish shark within the family Etmopteridae. This species is part of a subgroup that includes one other species from within the family. It is known to inhabit the benthic zones of the Eastern Indian Ocean and the Arafura Sea. [1] These sharks were first described in a 2002 issue of Cybium, and there is still much unknown about the species.

Contents

Blackmouth lanternshark
Etmopterus evansi Last, Burgess & Seret, 2002.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Squaliformes
Family: Etmopteridae
Genus: Etmopterus
Species:
E. evansi
Binomial name
Etmopterus evansi
Etmopterus evansi distmap.png
Range of the blackmouth lanternshark (in blue)

Taxonomy and phylogeny

The blackmouth lanternshark belongs to a subgroup of the genus Etmopterus that also includes the lined lanternshark, Etmopterus dislineatus. The genus name can be broken down into its Greek roots: "ethmos" refers to the sharks' ethmoid bone in the skull and "pteron" refers to sharks' fins. The species name evansi comes from the Australian fishery scientist, David Evans, who has spent years studying specimens of the species. [3]

Distribution and habitat

Within the Indian ocean, the blackmouth lanternshark can be found in the continental slopes off the northwest coast of Western Australia. The species is also found in the continental slopes of the Arafura Sea south of the Tanimbar Islands in Indonesia. [4] There are additional records of the species found off the coast of Papua New Guinea. [5] Generally these lanternshark are found between 430 and 550 meters below sea level. [1] [5] More specifically, the sharks tend to inhabit shoals and reefs within these locations and depths. [6] It is not known to have a preference for hard or soft substrate environments. [1]

Description

The Blackmouth lanternshark is known to reach 30 cm in length. Knowledge on the species general description is limited due to its recent discovery and the limited samples currently being studied. Females tend to be larger than males, and the males are known to be mature at roughly 26 cm long. [3] The longest individual found was 32 cm. [5]

These lanternsharks are fusiform and approximately cylindrical in shape with a soft trunk. Compared to other species within the genus, evansi's head and snout are relatively short and its nostrils are relatively small. The species has relatively large, narrow eyes. [3] [5] Its mouth is narrow and moderately arched with four sets of functional teeth. The upper jaw contains three of the fours sets with small teeth usually having five cusps, and the lower jaw contains the fourth set with interlocking blade-like teeth with one cusp. [3] The gills of the Blackmouth lanternfish are relatively large, approximately oblique, and roughly all the same size. [3] Individuals have two dorsal fins, one pectoral fin, one pelvic fin and one caudal fin. The first fin is low and small compared to the second, and the pectoral fin is also relatively small. The caudal peduncle is long and thin. The caudal fin is very short, usually roughly the same size as the head. [3]

Blackmouth lanternsharks have a light gray/brown dorsal half and a significantly darker ventral half separated by fine black lines. Individuals have denticles covering most of their body. [3] There are a few bare spots but for the most part the denticles are dense and thin throughout, and are arranged in imperfect longitudinal rows. [5] There are well defined melanophores and luminescent markings throughout the sharks' bodies as well. [3]

Diet

The diet of the Blackmouth lanternshark has yet to be studied in depth but many species from the genus Etmopterus are known to feed on nekton such as krill, cephalopods, small crustaceans, and small teleost fish. [7] [8]

Behavior and ecology

The blackmouth lanternshark is ovoviviparous. [5] The eggs are hatched within the female's uterus and sustained on a yolk sac until they are ready to hatch. The gestation period varies for many other species of Etmopterus but is generally longer than other sharks. [9] These sharks require two reproductive seasons for one full reproductive cycle: one for reproductive organ development and gamete production and one for embryological development. [9] Females within the Etmopterus genus produce anywhere from 2 to 20 young in one reproductive cycle. [9] [10] The Blackmouth lanternshark's mating behavior includes distinct pairing and a courtship embrace. [5]

The blackmouth lanternshark is recognized as Least Concern in terms of conservation status. It is not known to be threatened by human activity due to its habitat. [1]

Related Research Articles

<span class="mw-page-title-main">Blackbelly lanternshark</span> Species of shark

The blackbelly lanternshark or lucifer shark is a shark of the family Etmopteridae found around the world in tropical and temperate seas at depths between 150 and 1,250 meters – the mesopelagic zone. Compared to other mesopelagic fish predators and invertebrates, the blackbelly lanternshark is thought to reside in shallower, more southern waters. E. lucifer can reach up to 47 centimeters in length and consumes mesopelagic cephalopods, fish, and crustaceans. Blackbelly lanternsharks are bioluminescent, using hormone controlled mechanisms to emit light through ventral photogenic organs called photophores and are presumed to be ovoviviparous. The blackbelly lanternshark has been classified as "Not Threatened" within the New Zealand Threat Classification System.

<span class="mw-page-title-main">New Zealand lanternshark</span> Species of shark

The New Zealand lanternshark is a shark of the family Etmopteridae mainly found off the coast of New Zealand. It can also be found in the Southern areas of Australia and Africa, inhabiting water depths between 500-1500m. These sharks can be commonly known as Baxter's dogfish and giant lantern shark. According to the New Zealand Threat Classification System (NZTCS), this species conservation status is considered non-threatened.

<span class="mw-page-title-main">Viper dogfish</span> Species of shark

The viper dogfish or viper shark is a rare species of dogfish shark in the family Etmopteridae, and the only extant member of its genus. It has been found in the Pacific Ocean off southern Japan, the Bonin Islands, Pacific Ocean off northern Taitung County and the Northwestern Hawaiian Islands. This species inhabits upper continental slopes and seamounts. It may migrate vertically, shifting between bottom waters 270–360 m (890–1,180 ft) deep during the day and upper waters less than 150 m (490 ft) deep at night. A slender, black shark reaching 54 cm (21 in) in length, the viper dogfish can be recognized by its narrow, triangular jaws and well-spaced, fang-like teeth. It also has two spined dorsal fins, dermal denticles with faceted crowns, and numerous light-emitting photophores concentrated on its ventral surface.

<i>Etmopterus</i> Genus of sharks

Etmopterus is a genus of lantern sharks in the squaliform family Etmopteridae. They are found in deep sea ecosystems of the Atlantic, Indian and Pacific Oceans.

<span class="mw-page-title-main">Blurred lanternshark</span> Species of shark

The blurred lanternshark is a little-known species of dogfish shark in the family Etmopteridae, found around the world in benthic and pelagic habitats from a depth of 110 m (360 ft) to over 1 km (0.62 mi) down. This shark forms the E. pusillus species group with the smooth lanternshark, which are distinguished from other members of its family by having irregularly arranged, flat-topped dermal denticles that give them a "smooth" appearance. Both species are slender-bodied with long heads, two dorsal fins bearing spines, no anal fins, and light-emitting photophores. The blurred lanternshark is larger, reaching 67 cm (26 in) or more in length. This species feeds on small squid, fishes, and fish eggs, and is ovoviviparous. It has been assessed as of Least Concern by the International Union for Conservation of Nature, because of its wide distribution and lack of threat from fishing pressure.

<span class="mw-page-title-main">Smooth lanternshark</span> Species of shark

The smooth lanternshark or slender lanternshark is a species of dogfish shark in the family Etmopteridae, found widely in the Atlantic and Pacific Oceans. It inhabits benthic environments at a depth of 274–1,000 m (899–3,281 ft), and pelagic environments at a depth of 0–708 m (0–2,323 ft). The smooth lanternshark forms a species group with the larger blurred lanternshark, both of which are distinguished from other members of their family by small, irregularly arranged dermal denticles with a truncated shape. This species has a slender, dark brown body with an indistinct black band on the sides over the pelvic fins, and reaches 50 cm (20 in) in length. This slow-growing, ovoviviparous shark feeds on smaller squid, fishes, and fish eggs. Smooth lanternsharks are often caught as bycatch in eastern Atlantic and Japanese commercial fisheries. The International Union for Conservation of Nature (IUCN) has evaluated this species as of Least Concern because of its wide distribution and limited threats.

<span class="mw-page-title-main">Velvet belly lanternshark</span> Species of shark

The velvet belly lanternshark is a species of dogfish shark in the family Etmopteridae. One of the most common deepwater sharks in the northeastern Atlantic Ocean, the velvet belly is found from Iceland and Norway to Gabon and South Africa at a depth of 20–2,490 m (66–8,169 ft). A small shark generally no more than 45 cm (18 in) long, the velvet belly is so named because its black underside is abruptly distinct from the brown coloration on the rest of its body. The body of this species is fairly stout, with a moderately long snout and tail, and very small gill slits. Like other lanternsharks, the velvet belly is bioluminescent, with light-emitting photophores forming a species-specific pattern over its flanks and abdomen. The ventral photophores are thought to function in counter-illumination, which camouflages the shark against predators and prey. The bioluminescent flank markings may play a role in intraspecific communication.

<span class="mw-page-title-main">Blackmouth catshark</span> Species of shark

The blackmouth catshark is a species of deepwater catshark, belonging yo the family Pentanchidae, common in the northeastern Atlantic Ocean from Iceland to Senegal, including the Mediterranean Sea. It is typically found over the continental slope at depths of 150–1,400 m (490–4,590 ft), on or near muddy bottoms. The youngest sharks generally inhabit shallower water than the older juveniles and adults. This slim-bodied species is characterized by the black interior of its mouth, a marbled pattern of pale-edged brownish saddles or blotches along its back and tail, and a prominent saw-toothed crest of enlarged dermal denticles along the upper edge of its caudal fin. It reaches lengths of 50–79 cm (20–31 in), with sharks in the Atlantic growing larger than those in the Mediterranean.

<span class="mw-page-title-main">Green lanternshark</span> Species of shark

The green lanternshark is a species of dogfish shark in the family Etmopteridae, found in the western central Atlantic Ocean. This species usually occurs on the upper continental slope below a depth of 350 m (1,150 ft). Reaching 26 cm (10 in) in length, the green lanternshark has a slender body with a long, thin tail and low, conical dermal denticles on its flanks. It is dark brown or gray with ventral black coloration, which contain light-emitting photophores that may serve a cryptic and/or social function. Green lanternsharks are thought to be gregarious and may attack their prey, squid and octopus often larger than themselves, in packs. Reproduction is aplacental viviparous, with females giving birth to litters of one to three young. This relatively common shark is an occasional, valueless bycatch of commercial fisheries; currently it does not appear to be significantly threatened by human activities.

<span class="mw-page-title-main">Hawaiian lanternshark</span> Species of shark

The Hawaiian Lanternshark is a species of small squaliform shark in the family Etmopteridae.

<span class="mw-page-title-main">Dwarf lanternshark</span> Species of shark

The dwarf lanternshark is a species of dogfish shark in the family Etmopteridae and is the smallest shark in the world, reaching a maximum known length of 20 cm (8 in). It is known to be present only on the upper continental slopes off Colombia and Venezuela, at a depth of 283–439 m (928–1,440 ft). This species can be identified by its small size at maturity, long flattened head, and pattern of black ventral markings and a mid-dorsal line. Like other members of its genus, it is capable of producing light from a distinctive array of photophores. Reproduction is aplacental viviparous, with females gestating two or three young at a time. The dwarf lanternshark is not significant to commercial fisheries, but could be threatened by mortality from bycatch; the degree of impact from human activities on its population is unknown.

<span class="mw-page-title-main">Fringefin lanternshark</span> Species of shark

The fringefin lanternshark is a shark of the family Etmopteridae found in the western central Atlantic from Texas to Florida, northern Gulf of Mexico, and Mexico. It is endemic to this area. It is a deep water shark and is found about 220 to 915 meters below the surface, on the upper continental slopes of the Gulf. E. schultzi is a small shark, about 27–30 cm long and feeds on squid. It is also bioluminescent, which counter-illuminates it and helps with intraspecific interaction. Due to its limited range and the difficulty of collecting deep water species, it has not been evaluated by the IUCN Red List, but due to recent oil spills in the Gulf of Mexico, it is likely that fringefin lanternsharks have decreased in population.

<span class="mw-page-title-main">Slendertail lanternshark</span> Species of shark

The slendertail lanternshark or Moller's lanternshark is a shark of the family Etmopteridae found in the western Indian Ocean between latitudes 34°N and 46°S at depths between 250 and 860 m. It can grow up to 46 cm in length.

<span class="mw-page-title-main">Great lanternshark</span> Species of shark

The great lanternshark is a shark of the family Etmopteridae found in the northeast and northwest Atlantic. Its name was given because, at the time of its discovery, it was thought to be bioluminescent, but this has been challenged.

<span class="mw-page-title-main">Splendid lanternshark</span> Species of shark

The splendid lanternshark is a shark of the family Etmopteridae found in the western Pacific at depths between 120 and 210 m. Through the classification of Etmopterus species into several clades based on the positioning of their bioluminescent photophores, the splendid lanternshark can be considered a member of the Etmopterus pusillus clade.

<span class="mw-page-title-main">Brown lanternshark</span> Species of shark

The brown lanternshark or bristled lanternshark is a little-known species of deep-sea dogfish shark in the family Etmopteridae. It is found off Japan and New Zealand, and possibly also South Africa and Australia, typically deeper than 300 m (980 ft). This species can be distinguished from other lanternsharks by its coloration, which is a uniform dark gray or brown without the ventral surface being much darker and clearly delineated from the rest of the body. The brown lanternshark feeds on small bony fishes, cephalopods, and crustaceans. Reproduction is ovoviviparous, with females giving birth to 9–18 young. An unusually high proportion of individuals in Suruga Bay are hermaphrodites, with both male and female characteristics.

<i>Etmopterus dislineatus</i> Species of shark

Etmopterus dislineatus, sometimes called the lined lanternshark, is a shark of the family Etmopteridae found in the central Coral Sea at depths of between 590 and 800 m. Its length is up to 45 cm.

<span class="mw-page-title-main">Pygmy lanternshark</span> Species of shark

The pygmy lanternshark is a shark of the family Etmopteridae found in the eastern Indian Ocean from northern Western Australia and possibly Java, at depths of between 430 and 550 m. Its length is up to 26 cm.

<span class="mw-page-title-main">Ninja lanternshark</span> Species of shark

The ninja lanternshark is of the family Etmopteridae, found in the eastern Pacific Ocean from Nicaragua, south to Panama and Costa Rica. The depth range of collections is from 836 to 1443 meters along the continental slope. E. benchleyi is the only Etmopterus species presently known from the Pacific Coast of Central America.

<span class="mw-page-title-main">Barrie's lanternshark</span> Species of lanternshark

Barrie's lanternshark is a species of lanternshark of the family Etmopteridae, found in the Southwest Indian Ocean and Southeast Atlantic Ocean. It lives on seamounts and continental slopes at depths of 480–1,200 m (1,570–3,940 ft). This deep-water shark was previously misidentified with sculpted lanternshark and also resembles blackbelly lanternshark in having linear rows of dermal denticles.

References

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  2. Kyne, P.M.; Cavanagh, R.D. (2015). "Etmopterus evansi". IUCN Red List of Threatened Species . 2015: e.T41807A68622556. doi: 10.2305/IUCN.UK.2015-4.RLTS.T41807A68622556.en . Retrieved 18 November 2021.
  3. 1 2 3 4 5 6 7 8 Bernard, Last, P.R. Burgess, G.H. Séret (2002). Description of six new species of lantern-sharks of the genus Etmopterus (Squaloidea: Etmopteridae) from the Australasian region. OCLC   882933216.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. Last, P. R. (2009). Sharks and rays of Australia. J. D. Stevens (2nd ed.). Cambridge, Mass.: Harvard University Press. ISBN   978-0-674-03411-2. OCLC   262430748.
  5. 1 2 3 4 5 6 7 "Etmopterus evansi, Blackmouth lanternshark". www.fishbase.de. Retrieved 2022-04-19.
  6. "Etmopterus evansi: Kyne, P.M. & Cavanagh, R.D." 2015-04-28. doi: 10.2305/iucn.uk.2015-4.rlts.t41807a68622556.en .{{cite journal}}: Cite journal requires |journal= (help)
  7. Hallett, Chris S.; Daley, Ross K. (2010-09-08). "Feeding ecology of the southern lanternshark (Etmopterus baxteri) and the brown lanternshark (E. unicolor) off southeastern Australia". ICES Journal of Marine Science. 68 (1): 157–165. doi: 10.1093/icesjms/fsq143 . ISSN   1095-9289.
  8. Besnard, Lucien; Duchatelet, Laurent; Bird, Christopher S.; Le Croizier, Gaël; Michel, Loïc; Pinte, Nicolas; Lepoint, Gilles; Schaal, Gauthier; Vieira, Rui P.; Gonçalves, Jorge M.S.; Martin, Ulrich (April 2022). "Diet consistency but large-scale isotopic variations in a deep-sea shark: The case of the velvet belly lantern shark, Etmopterus spinax, in the northeastern Atlantic region and Mediterranean Sea". Deep Sea Research Part I: Oceanographic Research Papers. 182: 103708. Bibcode:2022DSRI..18203708B. doi: 10.1016/j.dsr.2022.103708 . ISSN   0967-0637. S2CID   246522469.
  9. 1 2 3 Coelho, Rui; Erzini, Karim (August 2007). "Population parameters of the smooth lantern shark, Etmopterus pusillus, in southern Portugal (NE Atlantic)". Fisheries Research. 86 (1): 42–57. doi:10.1016/j.fishres.2007.04.006. ISSN   0165-7836.
  10. IUCN (2019-07-01). "Etmopterus perryi: Pollom, R., Lasso-Alcalá, O., Mejía-Falla, P.A., Navia, A.F. & Herman, K.: The IUCN Red List of Threatened Species 2020: e.T60240A124455061". doi: 10.2305/iucn.uk.2020-3.rlts.t60240a124455061.en . S2CID   242088588.{{cite journal}}: Cite journal requires |journal= (help)