Chimaera

Chimaeras[1] are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, rat fish, spookfish or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae or Siganidae, respectively.

At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks, though their last common ancestor with sharks lived nearly 400 million years ago.[2] Today, they are largely confined to deep water.[3]

Chimaeras
Temporal range: Early Devonian-Present[1]
Hydrolagus colliei
Hydrolagus colliei
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: Chimaeriformes
Obruchev, 1953
Families

Callorhinchidae
Chimaeridae
Rhinochimaeridae

Description and habits

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Chimaera egg case
Deep sea chimaera
Deep-sea chimaera photographed by the NOAAS Okeanos Explorer. Visible on its snout are tiny pores which lead to electroreceptor cells.

Chimaeras live in temperate ocean floors down to 2,600 m (8,500 ft) deep, with few occurring at depths shallower than 200 m (660 ft). Exceptions include the members of the genus Callorhinchus, the rabbit fish and the spotted ratfish, which locally or periodically can be found at relatively shallow depths. Consequently, these are also among the few species from the Chimaera order kept in public aquaria.[4] They have elongated, soft bodies, with a bulky head and a single gill-opening. They grow up to 150 cm (4.9 ft) in length, although this includes the lengthy tail found in some species. In many species, the snout is modified into an elongated sensory organ.[5]

Like other members of the class Chondrichthyes, chimaera skeletons are constructed of cartilage. Their skin is smooth and largely covered by placoid scales, and their color can range from black to brownish gray. For defense, most chimaeras have a venomous spine in front of the dorsal fin.

Chimaeras resemble sharks in some ways: they employ claspers for internal fertilization of females and they lay eggs with leathery cases. They also use electroreception to find their prey.[6] However, unlike sharks, male chimaeras also have retractable sexual appendages on the forehead (a type of tentaculum)[7] and in front of the pelvic fins.[5] The females lay eggs in spindle-shaped, leathery egg cases.[1]

They also differ from sharks in that their upper jaws are fused with their skulls and they have separate anal and urogenital openings. They lack sharks' many sharp and replaceable teeth, having instead just three pairs of large permanent grinding tooth plates. They also have gill covers or opercula like bony fishes.[5]

Classification

In some classifications, the chimaeras are included (as subclass Holocephali) in the class Chondrichthyes of cartilaginous fishes; in other systems, this distinction may be raised to the level of class. Chimaeras also have some characteristics of bony fishes.

A renewed effort to explore deep water and to undertake taxonomic analysis of specimens in museum collections led to a boom during the first decade of the 21st century in the number of new species identified.[2] They are 50 extant species in six genera and four families are described; an additional three genera (including the extinct genus Ischyodus) and two families are only known from fossils):

Phylogenetics

Tracing the evolution of these species has been problematic given the scarcity of good fossils. DNA sequences have become the preferred approach to understanding speciation.[8]

The order appears to have originated about 420 million years ago during the Silurian. The 39 extant species fall into three families—the Callorhinchids, Rhinochimaerids and Chimaerids with the callorhinchids being the most basal clade. The families appear to have diverged during the late Jurassic to early Cretaceous (170–120 mya).

Parasites

As other fish, chimaeras have a number of parasites. Chimaericola leptogaster (Chimaericolidae) is a monogenean parasite of the gills of Chimaera monstrosa; the species can attain 50 mm (2.0 in) in length.

See also

References

  1. ^ a b c Froese, Rainer, and Daniel Pauly, eds. (2014). "Chimaeriformes" in FishBase. November 2014 version.
  2. ^ a b "Ancient And Bizarre Fish Discovered: New Species Of Ghostshark From California And Baja California". ScienceDaily. September 23, 2009. Retrieved 2009-09-23.
  3. ^ Peterson, Roger Tory; Eschmeyer, William N.; Herald, Earl S. (1 September 1999). A Field Guide to Pacific Coast Fishes: North America. Houghton Mifflin Harcourt. p. 13. ISBN 0-618-00212-X. Retrieved 9 August 2015.
  4. ^ Tozer, Helen; Dagit, Dominique D. (2004). "Chapter 33: Husbandry of Spotted Ratfish, Hydrolagus colliei" (PDF). In Smith, Mark; Warmolts, Doug; Thoney, Dennis; Heuter, Robert (eds.). Elasmobranch Husbandry Manual: Captive Care of Sharks, Rays, and their Relatives. Ohio Biological Survey. pp. 487–491. ISBN 0-86727-152-3.
  5. ^ a b c Stevens, John; Last, Peter R. (1998). Paxton, John R.; Eschmeyer, William N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 69. ISBN 0-12-547665-5.
  6. ^ Bullock, T. H.; Hartline, R. H.; Kalmijn, A. J.; Laurent, P.; Murray, R. W.; Scheich, H.; Schwartz, E.; Szabo, T. (6 December 2012). Fessard, A. (ed.). Electroreceptors and Other Specialized Receptors in Lower Vertebrates. Springer Science & Business Media. p. 125. ISBN 978-3-642-65926-3.
  7. ^ Madrigal, Alexis (22 September 2009). "Freaky New Ghostshark ID'd Off California Coast". Wired. Retrieved 14 November 2018. ... Perhaps the most intriguing feature of the newly described species, Hydrolagus melanophasma, is a presumed sexual organ that extends from its forehead called a tentaculum. ...
  8. ^ Inoue, Jun G.; Miya, Masaki; Lam, Kevin; Tay, Boon-Hui; Danks, Janine A.; Bell, Justin; Walker, Terrence I.; Venkatesh, Byrappa (November 2010). "Evolutionary Origin and Phylogeny of the Modern Holocephalans (Chondrichthyes: Chimaeriformes): A Mitogenomic Perspective". Molecular Biology and Evolution. 27 (11): 2576–2586. doi:10.1093/molbev/msq147. Retrieved 14 November 2018.
Asteroid family

An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other.

Aurealis Award

The Aurealis Award for Excellence in Speculative Fiction is an annual literary award for Australian science fiction, fantasy and horror fiction. Only Australians are eligible for the award.

Callorhinchus

Callorhinchus, the plough-nose chimaeras or elephantfish, are the only living genus in the family Callorhinchidae (sometimes spelled Callorhynchidae). In addition, a few extinct genera only known from fossil remains are recognized. Callorhinchus are similar in form and habits to other chimaeras, but are distinguished by the presence of an elongated, flexible, fleshy snout, with a vague resemblance to a ploughshare. The snout is used to probe the sea bottom in search of the invertebrates and small fishes on which it preys. The remainder of the body is flat and compressed, often described as elongated. The mouth is just under this snout and the eyes are located high on top of the head. The usual color is black or brown, and, often a mixture between the two. Phylogenetically, they are the oldest group of living jawed Chondrichthyes. They possess the same cartilaginous skeleton seen in sharks but are considered holocephali to distinguish them from the shark and ray categorization. Because of this, they provide a useful research organism for studying the early development of the jawed characteristic. Among the Chondrichthyes genome, Callorhinchus has the smallest genome. Because of this, it has been proposed to be used for entire genome sequencing to represent the cartilaginous fish class. They are considered to resemble a cross between a shark and a ray or skate, but can be distinguished from sharks because they possess an operculum over their gill slits. Additionally, their skin is smooth, not covered in tough scales, characteristic of the shark. While the shark's jaw is loosely attached to the skull, the family Callorhinchidae differ in that their jaws are fused to their skulls. Many classify the Callorhinchidae as a chimeric species due to their shared characteristics of both the sharks and rays. They are found in muddy and sandy substrates of the ocean bottom, where they filter feed, with small shellfish making up the bulk of their diet. They have broad flat teeth that have adapted for this type of eating habit, two pair that reside in the upper jaw and one pair in the lower jaw. In addition to its utilization for feeding, the trunk of the Callorhinchus fish can sense movement and electric fields, allowing them to locate their prey. They possess large pectoral fins, believed to aid in moving swiftly through the water. They also have two dorsal fins spaced widely apart, which help identify the species in the open ocean.Plough-nose chimaeras are found only in the oceans of the Southern Hemisphere, and range from about 70 to 125 cm (2.30 to 4.10 ft) in total length.

Chimaera Publications

Chimaera Publications is a publisher based in Mount Waverley, Victoria, Australia. The company currently publishes the speculative fiction magazine Aurealis as well as running the Aurealis Awards.

Chimaeridae

The Chimaeridae, or shortnose chimaeras, are a family of cartilaginous fish.

They resemble other chimaeras in general form and habits, but have short, rounded snouts, without the modifications found in related families. Many species have long, tapering tails, giving them an alternative name of ratfish. Shortnose chimaeras have a venomous spine on their backs, which is sufficiently dangerous to injure humans.They are found in temperate and tropical marine waters worldwide. Most species are restricted to depths below 200 m (660 ft), but a few, notably the spotted ratfish and rabbit fish, can locally be found at relatively shallow depths. They range from 38 to 150 cm (1.25 to 4.92 ft) in maximum total length, depending on species.

Chimera

Chimera, chimaera, or chimaira may refer to:

Chimera (mythology), a monstrous creature with parts from multiple animals

Mount Chimaera, the region in Lycia that some believe was an inspiration for the myth

Chimera (genetics)

A genetic chimerism or chimera (/kaɪˈmɪərə/ ky-MEER-ə or /kɪˈmɪərə/ kə-MEER-ə, also chimaera (chimæra) is a single organism composed of cells with distinct genotypes. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood types, subtle variations in form (phenotype) and, if the zygotes were of differing sexes, then even the possession of both female and male sex organs (this is just one of many different phenomena that may result in intersexuality). Animal chimeras are produced by the merger of multiple fertilized eggs. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division. Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage.Another way that chimerism can occur in animals is by organ transplantation, giving one individual tissues that developed from a different genome. For example, transplantation of bone marrow often determines the recipient's ensuing blood type.

Chimera (mythology)

The Chimera ( or , also Chimaera (Chimæra); Greek: Χίμαιρα, Chímaira "she-goat") according to Greek mythology, was a monstrous fire-breathing hybrid creature of Lycia in Asia Minor, composed of the parts of more than one animal. It is usually depicted as a lion, with the head of a goat protruding from its back, and a tail that might end with a snake's head. It was one of the offspring of Typhon and Echidna and a sibling of such monsters as Cerberus and the Lernaean Hydra.

The term "chimera" has come to describe any mythical or fictional animal with parts taken from various animals, or to describe anything composed of very disparate parts, or perceived as wildly imaginative, implausible, or dazzling.

Dermotherium

Dermotherium is a genus of fossil mammals closely related to the living colugos, a small group of gliding mammals from Southeast Asia. Two species are recognized: D. major from the Late Eocene of Thailand, based on a single fragment of the lower jaw, and D. chimaera from the Late Oligocene of Thailand, known from three fragments of the lower jaw and two isolated upper molars. In addition, a single isolated upper molar from the Early Oligocene of Pakistan has been tentatively assigned to D. chimaera. All sites where fossils of Dermotherium have been found probably developed in forested environments and the fossil species probably were forest dwellers like living colugos, but whether they already had the gliding adaptations of the living species is unknown.

Some features of the teeth differentiate Dermotherium from both living colugo species, but other features are shared with only one of the two. The third lower incisor, lower canine, and third lower premolar at least are pectinate or comblike, bearing longitudinal rows of tines or cusps, an unusual feature of colugos (the first two lower incisors are unknown in Dermotherium). The fourth lower premolar instead resembles the lower molars. The front part of these teeth, the trigonid, is broader in D. chimaera than in D. major, which is known only from the second and third lower molars. The two species also differ in the configuration of the inner back corner of the lower molars. The upper molars are triangular teeth bearing a number of distinct small cusps, particularly on the second upper molar, and with wrinkled enamel.

Graft-chimaera

In horticulture, a graft-chimaera may arise in grafting at the point of contact between rootstock and scion and will have properties intermediate between those of its "parents". A graft-chimaera is not a true hybrid but a mixture of cells, each with the genotype of one of its "parents": it is a chimaera. Hence, the once widely used term "graft-hybrid" is not descriptive; it is now frowned upon.

Propagation is by cloning only. In practice graft-chimaeras are not noted for their stability and may easily revert to one of the "parents".

Jyu-Oh-Sei

Jyu-Oh-Sei (Japanese: 獣王星, Hepburn: Jū Ō Sei, lit. "Planet of the Beast King") is a Japanese manga series written and illustrated by Natsumi Itsuki. An 11-episode anime adaptation was animated by Bones and premiered on April 13, 2006 in Japan as part of Fuji TV's Noitamina programming block.

On May 2, 2009, the series made its North American television debut on the Funimation Channel.

Long-tailed ground roller

The long-tailed ground roller (Uratelornis chimaera) is a species of bird in the ground roller family Brachypteraciidae, placed in the monotypic genus Uratelornis. Endemic to arid spiny forests near the coast in southwestern Madagascar, this ground roller occurs at extremely low population densities throughout its habitat. This species requires shade and a deep layer of leaves on the ground, and it is absent from parts of the spiny forest lacking these features. It has no recognized subspecies, and its closest relative is the scaly ground roller. The long-tailed ground roller is the only ground roller to definitively display sexual dimorphism (differences in plumage or size between sexes). It is a medium-sized bird with a plump silhouette and a long tail. The upperparts are dark brown with black streaks while the underparts are light gray. The white throat is framed by black malar stripes and a black breastband, and a white stripe is present at the base of the bill. Sky-blue feathers are visible at the edge of the wings and the tail. Calls are rarely made outside the breeding season, though multiple courtship calls are made.

These ground rollers feed primarily on invertebrates, including ants, beetles, butterflies, and worms, which they find by searching through deep leaf litter or by remaining still and watching attentively. The ground roller primarily runs through its habitat on its strong legs, as its wings are relatively weak. It is a monogamous species, and it defends a territory during the breeding season of October to February. It digs a tunnel in the sand, at the end of which is a wider chamber where it makes its nest out of leaves and earthy pellets. Two to four eggs are laid. After the chicks fledge, the birds continue living in family groups until at least February before dispersing more widely across the scrubland.

This bird is classified as vulnerable by the IUCN and is threatened by habitat destruction. Since the arid, spiny forests in which it lives are not protected by the Malagasy government, it is losing habitat to slash-and-burn agriculture, charcoal collection, and logging. It is also hunted by the native peoples of Madagascar.

Mount Chimaera

Mount Chimaera was the name of a place in ancient Lycia, notable for constantly burning fires. It is thought to be the area called Yanartaş in Turkey, where methane and other gases emerge from the rock and burn. Some ancient sources considered it to be the origin of the myth of the monster called the Chimera, because of similarities described below.

Ctesias is the oldest traceable author to offer this euhemerizing theory. We know of this because of a citation by Pliny the Elder, who in his second book of Historia Naturalis identified the Chimera with the permanent gas vents in Mount Chimaera, in the country of the ancient Lycian city of Phaselis, which he described as being "on fire", adding that it "...indeed burned with a flame that does not die by day or night." Pliny was quoted by Photius and Agricola.

Strabo and Pliny are the only surviving ancient sources who would be expected to discuss a Lycian toponym, but the placename is also attested by Isidore of Seville and Servius, the commentator on the Aeneid. Strabo held the Chimaera to be a ravine on a different mountain in Lycia, placing it unhesitatingly in the vicinity of the Cragus Mountains, the southern part of the present Babadağ, some 75 km due west as the crow flies, and Isidore quotes writers on natural history (see below) that Mount Chimaera was on fire here, had lions and goats there, and was full of snakes over there. Servius goes so far as to arrange these with the lions on the peak of the mountain, pastures full of goats in the middle, and serpents all about the base, thus imitating Homer's description of the monster.

The site was identified by Sir Francis Beaufort in 1811, as the modern Turkish Yanar or Yanartaş, which was described by Thomas Abel Brimage Spratt in his Travels in Lycia, Milyas, and the Cibyratis, in company with the late Rev. E. T. Daniell. The discussion on the connection between the myth and the exact location of Mount Chimera was started by Albert Forbiger in 1844, and George Ewart Bean was of the opinion that the name was allochthonous and could have been transferred here from its original location further west, as cited by Strabo, owing to the presence of the same phenomenon and the fires.

Mycobacterium avium complex

Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium (No mention of M. chimera in ref) that are commonly grouped together because they infect humans together; this group, in turn, is part of the group of nontuberculous mycobacteria. These bacteria cause disease in humans called Mycobacterium avium-intracellulare infection or Mycobacterium avium complex infection. This group should not be confused with Mycobacterium tuberculosis complex.

Ornithoptera chimaera

Ornithoptera chimaera, the chimaera birdwing, is a birdwing butterfly of the family Papilionidae. It is found in mountain areas of New Guinea, 1000 meters above sea level.

The "chimaera" portion of both the scientific and vernacular name, is named after the Chimaera, Greek: Χίμαιρα, Khimaira, from χίμαρος, khimaros, a creature in Greek mythology, composed of parts of three animals.

Rabbit fish

Chimaera monstrosa, also known as the rabbit fish or rat fish, is a northeast Atlantic and Mediterranean species of fish in the Chimaeridae family.

Rhinochimaeridae

The Rhinochimaeridae, commonly known as long-nosed chimaeras, are a family of cartilaginous fish. They are similar in form and habits to other chimaeras, but have an exceptionally long conical or paddle-shaped snout. The snout has numerous sensory nerve endings, and is used to find food such as small fish. The first dorsal fin includes a mildly venomous spine, used in defense.Long-nosed chimaeras are found in temperate and tropical seas worldwide, from 200 to 2,000 m (660 to 6,560 ft) in depth. They range from 60 to 140 cm (2.0 to 4.6 ft) in maximum total length, depending on species.

TVR Chimaera

The TVR Chimaera is a two-seater convertible sports car manufactured by TVR between 1992 and 2003. The name was derived from Chimera, the monstrous creature of Greek mythology, which was made of the parts of multiple animals.

The car used the same backbone chassis as the Griffith and used the same derivatives of the Rover V8 engine.

The Chimaera was intended to be the long distance tourer of the range and as such was longer, more spacious and had slightly softer suspension than its sister car.

USS Chimaera (ARL-33)

USS Chimaera (ARL-33) was one of 39 Achelous-class landing craft repair ships built for the United States Navy during World War II. Named for the Chimaera (a mythological character, symbolic of the destructive forces of nature), she was the only U.S. Naval vessel to bear the name.

Originally planned as LST-1137, the ship was redesignated ARL-33 14 August 1944. Her design was a modification of the LST Mk.2. Other repair ships and tenders followed her precedent.

Extant cartilaginous fish orders
Elasmobranchii
Holocephali

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