Halosaur
Encyclopedia
Halosaurs are eel
-shaped fish
es found only at great ocean depths. As the family Halosauridae, halosaurs are one of two families within the order Notacanthiformes
; the other being the deep-sea spiny eels. Halosaurs are thought to have a worldwide distribution, with some seventeen species in three genera represented. Only a handful of specimens have been observed alive, all via chance encounters with remotely operated submersibles
.
From the Greek
hals meaning "sea" and sauros meaning "lizard
", halosaurs look like living fossils from some throwback era. Their greatly elongated bodies end in a whip-like tail; their scales are large. There is one small dorsal fin close to the sharply pointed, mostly scaleless head. The tail fin is greatly reduced, with the anal fin being the largest fin. Their pecotral fins are slender and also greatly elongated. The mouth is somewhat large, with the lower jaw shorter than the upper jaw. The gas bladder
is absent.
The largest species, the 90 centimeter (3 feet) long abyssal halosaur
(Halosauropsis macrochir) is also one of the most deep-living fish, recorded at depths of 3,300 meters (11,000 feet). Halosaurs have developed certain adaptations to life at these extreme depths, where no light penetrates. Their lateral line
system is highly developed; this is a system of pores running the length of the fish's body, lending it a sort of "sixth sense" by detecting nearby vibrations. Some species are also known to hold their elongate pectorals erect and forward, possibly providing a further means of detection.
Halosaurs are benthic fish, spending their time cruising over or resting on the sea floor where temperatures may be just 2-4 degrees Celsius. They propel themselves with rhythmic undulations of the body, not unlike snake
s. Halosaurs are thought to prey mainly on benthic invertebrate
s, such as polychaete
worms, echinoderm
s and crustaceans such as copepod
s.
In life, most halosaurs are a grey to bluish black in colour. Like other notacanthiform fish, halosaurs are able to regenerate their tails easily if lost. This adaptation can be likened to certain terrestrial reptile
s such as the glass lizard
, which sacrifices its tail in order to evade predators.
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
-shaped fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es found only at great ocean depths. As the family Halosauridae, halosaurs are one of two families within the order Notacanthiformes
Notacanthiformes
Notacanthiformes is an order of deep-sea ray-finned fishes, consisting of the families Halosauridae and Notacanthidae The order is of relatively recent vintage; Fishes of the World lists it as a suborder Notacanthoidei of Albuliformes...
; the other being the deep-sea spiny eels. Halosaurs are thought to have a worldwide distribution, with some seventeen species in three genera represented. Only a handful of specimens have been observed alive, all via chance encounters with remotely operated submersibles
Rov
Rov is a Talmudic concept which means the majority.It is based on the passage in Exodus 23;2: "after the majority to wrest" , which in Rabbinic interpretation means, that you shall accept things as the majority....
.
From the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
hals meaning "sea" and sauros meaning "lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
", halosaurs look like living fossils from some throwback era. Their greatly elongated bodies end in a whip-like tail; their scales are large. There is one small dorsal fin close to the sharply pointed, mostly scaleless head. The tail fin is greatly reduced, with the anal fin being the largest fin. Their pecotral fins are slender and also greatly elongated. The mouth is somewhat large, with the lower jaw shorter than the upper jaw. The gas bladder
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
is absent.
The largest species, the 90 centimeter (3 feet) long abyssal halosaur
Abyssal halosaur
The Abyssal halosaur is a species of bottom-dwelling, deep-sea fish in the family Halosauridae that is found in all oceans at depths of 1100 to 3300 meters....
(Halosauropsis macrochir) is also one of the most deep-living fish, recorded at depths of 3,300 meters (11,000 feet). Halosaurs have developed certain adaptations to life at these extreme depths, where no light penetrates. Their lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
system is highly developed; this is a system of pores running the length of the fish's body, lending it a sort of "sixth sense" by detecting nearby vibrations. Some species are also known to hold their elongate pectorals erect and forward, possibly providing a further means of detection.
Halosaurs are benthic fish, spending their time cruising over or resting on the sea floor where temperatures may be just 2-4 degrees Celsius. They propel themselves with rhythmic undulations of the body, not unlike snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s. Halosaurs are thought to prey mainly on benthic invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s, such as polychaete
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worms, echinoderm
Echinoderm
Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....
s and crustaceans such as copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s.
In life, most halosaurs are a grey to bluish black in colour. Like other notacanthiform fish, halosaurs are able to regenerate their tails easily if lost. This adaptation can be likened to certain terrestrial reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s such as the glass lizard
Glass lizard
The glass lizards or glass snakes, genus Ophisaurus, are a group of reptiles that resemble snakes, but are actually lizards. Although most species have no legs, their head shape and the fact that they have movable eyelids and external ear openings identify them as lizards. A few species have very...
, which sacrifices its tail in order to evade predators.