Snubnosed eel | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Anguilliformes |
Family: | Synaphobranchidae |
Subfamily: | Simenchelyinae |
Genus: | Simenchelys T. N. Gill in Goode and Bean, 1879 |
Species: | S. parasitica |
Binomial name | |
Simenchelys parasitica | |
Synonyms | |
Conchognathus grimaldii Collett, 1889 Contents |
The snubnosed eel, Simenchelys parasitica, also known as the pug-nosed eel, slime eel, or snub-nose parasitic eel, is a species of deep-sea eel and the only member of its genus. Some authors classify it as the sole member of the subfamily Simenchelyinae of the family Synaphobranchidae, or cutthroat eels, while others place it in its own monotypic family, the Simenchelyidae. [1] It is found in the Atlantic and Pacific Oceans, typically at a depth of 500–1,800 m (1,600–5,900 ft) near the bottom. Although typically a scavenger, it is better known for using its powerful jaws and teeth to burrow into larger fishes as a parasite. [2] This species is harmless to humans and of no interest to fisheries. [2] The generic name Simenchelys translates literally as "pug-nosed eel". [3]
In the eastern Atlantic, the snubnosed eel is known from France to Madeira and the Azores, as well as from off Cape Verde and South Africa. In the western Atlantic, it has been captured off the coast of the United States. In the Pacific, it occurs off Japan, Australia, New Zealand, and Hawaii. They have been recorded from 136 to 2,620 m (446 to 8,596 ft), but are usually found between 500 and 1,800 m (1,600 and 5,900 ft) on the continental slope, in water temperatures of 4–9 °C (39–48 °F). [2] At some locations, large numbers of snubnosed eels have been caught over a short time, indicating local abundance or schooling behavior. [4]
The snubnosed eel has a long, stout body that is strongly compressed posterior of the vent. The head is thick and cylindrical, with a short, blunt snout. The mouth is distinctive, consisting of a tiny horizontal slit surrounded by strongly plicate lips. The jaws are short and strong, with the premaxillaries and maxillaries fused into a single piece. The jaws are equipped with a single row of small, rounded, close-set teeth; the vomerine teeth are absent. The eyes are small and round; the anterior pair of nostrils are short tubes and the posterior pair are slit-like. The gill openings are small and located below the pectoral fins, which are small and triangular. The dorsal, caudal, and anal fins are merged, the dorsal fin base originating over the tip of the pectoral fins and the anal fin originating behind the vent. The scales are similar in appearance to those of Anguilla and are arranged in a right-angle basketweave pattern. The coloration is gray to grayish brown, becoming darker at the fin margins and along the lateral line. This species attains a length of 61 cm (24 in). [2] [3] [5]
Early juvenile snubnosed eels feed on epibenthic copepods ( Tharybis spp.) and amphipods. [6] Adults appear to be specialized hagfish-like scavengers, using their powerfully muscled jaws and short, stout teeth to tear away chunks of flesh from carcasses that have fallen to the sea floor. [7] However, this eel is more notorious for its parasitic habits, which are often repeated in literature. Frank Thomas Bullen, in the 1904 Denizens of the Deep, wrote that the eel "attaches himself to the bodies of the larger, fleshier fish, such as halibut, and by sheer force of suction and boring withal works his ravenous way right into their bodies, at what misery to his involuntary hosts can only be imagined." [8] Spencer Fullerton Baird reported that the eels are "not unfrequently found nestling along the backbone of the halibut and cod, where they seem to have the power of abiding for some time without actually causing death." Baird also made note of the eels' supposed habit of burrowing into the abdominal cavities of netted, gravid shad and eating their eggs within the span of "a few minutes". [9]
In 1992, two snubnose eels were discovered inside the heart of a 395 kg (871 lb) shortfin mako shark (Isurus oxyrhinchus) landed at Montauk, New York. The two eels, both immature females, measured 21 and 24 cm (8.3 and 9.4 in) long and had fed on blood, with histiological evidence suggesting that they had been there long enough for arteriosclerosis and hyperplasia (indicative of circulatory obstruction or toxicity from metabolic wastes), and tissue regeneration to occur. The authors speculated that the eels had burrowed into the shark through the gills or throat (the precise path of entry could not be determined, possibly obscured by damage caused by the tow rope) after it had been weakened on the capture line, entered the circulatory system, and then made their way to the heart. Despite records of its parasitic behavior, submersible encounters with free-swimming juveniles and adults, and their capture in baited traps, suggest that this species is at most a facultative parasite that opportunistically enters sick and dying fish. [4]
Reproduction is oviparous. The eggs are likely pelagic, measuring at least 2 mm (0.079 in) across, and lack an oil globule. An ovary from one 51 cm (20 in) female examined contained about 30,000 eggs. Like all other eels, the snubnosed eel undergoes a leptocephalus larval stage that metamorphoses into a juvenile form resembling the adult. Leptocephali belonging to this species have yet to be identified, but based on the appearance of the metamorphic stage, they likely have long bodies with short heads and small mouths, and little to no body pigmentation. Metamorphic fish are white, with the black peritoneum clearly visible; one known metamorphic specimen measured 11 cm (4.3 in) long. Sexual maturation is attained at around a length of 50–53 cm (20–21 in). [6] The trematode Hypertrema ambovatum is a known parasite of this species, infesting the intestines. [4]
In 2002, Koyama et al. reported that they had cultured cells from the pectoral fin of a snubnosed eel and maintained them in vitro for over a year. This represents one of the first cases of successful long-term tissue culture derived from a deep-sea multicellular organism, and has implications for a range of biotechnological fields. [10]
The frilled shark, also known as the lizard shark, is one of the two extant species of shark in the family Chlamydoselachidae. The frilled shark is considered a living fossil, because of its primitive, anguilliform (eel-like) physical traits, such as a dark-brown color, amphistyly, and a 2.0 m (6.6 ft)–long body, which has dorsal, pelvic, and anal fins located towards the tail. The common name, frilled shark, derives from the fringed appearance of the six pairs of gill slits at the shark's throat.
Moray eels, or Muraenidae, are a family of eels whose members are found worldwide. There are approximately 200 species in 15 genera which are almost exclusively marine, but several species are regularly seen in brackish water, and a few are found in fresh water.
Combtooth blennies are blenniiformids; percomorph marine fish of the family Blenniidae, part of the order Blenniiformes. They are the largest family of blennies with around 401 known species in 58 genera. Combtooth blennies are found in tropical and subtropical waters in the Atlantic, Pacific and Indian Oceans; some species are also found in brackish and even freshwater environments.
The shortfin mako shark, also known as the shortfin mako, blue pointer, or bonito shark, is a large mackerel shark. It is commonly referred to as the mako shark, as is the longfin mako shark. The shortfin mako can reach a size of 4 m (13 ft) in length and weigh 570 kg (1,260 lb). The species is classified as Endangered by the IUCN.
The black dogfish is a species of dogfish shark in the family Etmopteridae. It is common over the outer continental shelf and continental slope at depths of 180–2,250 m (590–7,380 ft). Females generally inhabit deeper water than males, and depending on the region, smaller sharks may occur at different depths than larger ones. This species is distributed widely in the Atlantic Ocean, from Greenland and Iceland to Virginia and West Africa in the north, and off southwestern Africa and Argentina in the south. The largest member of its family, the black dogfish, typically measures 60–75 cm (24–30 in) long. It has a stocky, dark brown body that is darker below than above, and bears scattered, minute bioluminescent organs. Its two dorsal fins are preceded by stout spines, and the anal fin is absent.
The serpent eel or sand snake-eel is an eel found in the eastern Atlantic Ocean, western Mediterranean Sea, western Indian Ocean, western Pacific Ocean and the north-east and west coast of North Island in New Zealand. It is an elongated, slender fish with a length of up to 250 centimetres. It spends the day with its body immersed in the sediment, emerging into the open water at night.
The horn shark is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring 1 m (3.3 ft) in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large spines, and a brown or gray coloration with many small dark spots.
The silvertip shark is a large species of requiem shark, in the family Carcharhinidae, with a fragmented distribution throughout the tropical Indian and Pacific Oceans. It is often encountered around offshore islands and coral reefs, and has been known to dive to a depth of 800 m (2,600 ft). The silvertip shark resembles a larger and bulkier grey reef shark, but can be easily identified by the prominent white margins on its fins. It attains a maximum length of 3 m (10 ft).
The longfin mako shark is a species of mackerel shark in the family Lamnidae, with a probable worldwide distribution in temperate and tropical waters. An uncommon species, it is typically lumped together under the name "mako" with its better-known relative, the shortfin mako shark. The longfin mako is a pelagic species found in moderately deep water, having been reported to a depth of 220 m (720 ft). Growing to a maximum length of 4.3 m (14 ft), the slimmer build and long, broad pectoral fins of this shark suggest that it is a slower and less active swimmer than the shortfin mako.
The smalltooth sand tiger or bumpytail ragged-tooth is a species of mackerel shark in the family Odontaspididae, with a patchy but worldwide distribution in tropical and warm temperate waters. They usually inhabit deepwater rocky habitats, though they are occasionally encountered in shallow water, and have been known to return to the same location year after year. This rare species is often mistaken for the much more common grey nurse shark, from which it can be distinguished by its first dorsal fin, which is larger than the second and placed further forward. It grows to at least 4.1 m (13 ft) in length. They have also been recently sighted in Irish and English waters.
The Japanese bullhead shark is a species of bullhead shark in the family Heterodontidae found in the northwestern Pacific Ocean off the coasts of Japan, Korea, and China. This benthic shark occurs at depths of 6–37 m (20–121 ft) over rocky bottoms or kelp beds. Measuring up to 1.2 m (3.9 ft) long, it can be identified by its short, blunt head, two high dorsal fins with anterior spines, and pattern of irregularly shaped, vertical brown bands and stripes. The Japanese bullhead shark is a docile, slow-swimming species that feeds mainly on shelled invertebrates and small bony fishes. Reproduction is oviparous, with females laying spiral-flanged eggs in communal "nests". This species is of little interest to fisheries.
The banded houndshark is a species of houndshark in the family Triakidae, common in the northwestern Pacific Ocean from the southern Russian Far East to Taiwan. Found on or near the bottom, it favors shallow coastal habitats with sandy or vegetated bottoms, and also enters brackish water. This shark reaches 1.5 m (4.9 ft) in length. It has a short, rounded snout and mostly narrow fins; the pectoral fins are broad and triangular, and the trailing margin of the first dorsal fin is almost vertical. It is gray above and lighter below; younger sharks have darker saddles and dots, which fade with age.
The nursehound, also known as the large-spotted dogfish, greater spotted dogfish or bull huss, is a species of catshark, belonging to the family Scyliorhinidae, found in the northeastern Atlantic Ocean. It is generally found among rocks or algae at a depth of 20–60 m (66–197 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fins placed far back. It shares its range with the more common and closely related small-spotted catshark, which it resembles in appearance but can be distinguished from, in having larger spots and nasal skin flaps that do not extend to the mouth.
The lesser sand eel or sand lance is a species of fish in the sand lance family Ammodytidae. It is an elongated cylindrical fish which may be up to 20 centimetres (7.9 in) long.
The Wonderfish (Thaumatichthys) is a genus of deep-sea anglerfish in the family Thaumatichthyidae, with three known species. Its scientific name means "wonder-fish" in Greek; oceanographer Anton Bruun described these fishes as "altogether one of the oddest creatures in the teeming variety of the fish world." In contrast to other anglerfishes, the bioluminescent lure of Thaumatichthys is located inside its cavernous mouth. They are worldwide in distribution and are ambush predators living near the ocean floor.
The worm pearlfish is an eel-like fish in the family Carapidae.
Rhynchactis is a genus of deep-sea anglerfish in the family Gigantactinidae, containing three species found worldwide at depths greater than 400 m (1,300 ft). Adult female Rhynchactis reach a standard length (SL) of 11–13 cm (4.3–5.1 in) and have a dark-colored, streamlined body and a relatively small head bearing a very long illicium. Unlike almost all other deep-sea anglerfishes, the illicium bears no bioluminescent esca at the tip. The mouth is almost devoid of teeth, and the inside of both jaws are covered by numerous white glands that are unique to this genus.
Trypauchen vagina, commonly known as the burrowing goby, is a species of eel goby found in the Indo-Pacific region. It has an elongated body about 20 to 22 cm in length. It is reddish-pink in color and possesses distinctive pouches in the upper edges of its gill covers. It lives in burrows in the silty and muddy bottoms of its marine and brackish habitats. It has reduced eyes that are entirely covered with skin and the anterior portion of its head is protected by thick flesh. Both adaptations aid it in digging its burrows.
Brachysomophis cirrocheilos, also known as the stargazer snake eel, is a benthic marine fish belonging to the family Ophichthidae. The stargazer snake eel is a large fish which grows up to 159 cm (63 in) long.
Dysommina rugosa is an eel in the family Synaphobranchidae. It was described by Isaac Ginsburg in 1951. It is a marine, deep water-dwelling eel which is known from the western Atlantic and eastern central Pacific Ocean. It dwells at a depth range of 260–775 metres, and is found off the continental slope. Males can reach a maximum total length of 37 centimetres.
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