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Hagfish Slime Predator Deterrence
Hagfish, of the class Myxini (also known as Hyperotreti) and order Myxiniformes , are eel-shaped, slime-producing marine fish (occasionally called slime eels). They are the only known living animals that have a skull but no vertebral column, although hagfish do have rudimentary vertebrae. Along with lampreys, hagfish are jawless; the two form the sister group to jawed vertebrates, and living hagfish remain similar to hagfish from around 300 million years ago. The classification of hagfish had been controversial. The issue was whether the hagfish was a degenerate type of vertebrate-fish that through evolution had lost its vertebrae (the original scheme) and was most closely related to lampreys, or whether hagfish represent a stage that precedes the evolution of the vertebral column (the alternative scheme) as is the case with lancelets. Recent DNA evidence has supported the original scheme. The original scheme groups hagfish and lampreys together as cyclostomata, cyclostomes ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eptatretus Hexatrema
''Eptatretus hexatrema'', the sixgill hagfish or snotslang, is a species of marine fish in the hagfish family (family Myxinidae) of order Myxiniformes. It is native to the South Atlantic Ocean and southwestern Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th .... Distribution Southeast Atlantic: known only from Walvis Bay, Namibia to Durban, South AfricaSmith, Margaret M, and Heemstra, P. (eds.) 2003. ''Smith's sea fishes''. South African Institute for Aquatic Biodiversity, Grahamstown. Struik publishers, Cape Town, 2003. Description Maximum recorded length 80.0 cm. Depth of body 15 times total length. Six gill openings. Colour slaty grey. Egg cases ovoid about 30mm long by 12mm wide with anchor filaments at each end. Eel shaped, with six barbels on the head a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zootaxa
''Zootaxa'' is a peer-reviewed scientific mega journal for animal taxonomists. It is published by Magnolia Press (Auckland, New Zealand). The journal was established by Zhi-Qiang Zhang in 2001 and new issues are published multiple times a week. From 2001 to 2020, more than 60,000 new species have been described in the journal accounting for around 25% of all new taxa indexed in The Zoological Record in the last few years. Print and online versions are available. Temporary suspension from JCR The journal exhibited high levels of self-citation and its journal impact factor of 2019 was suspended from ''Journal Citation Reports'' in 2020, a sanction which hit 34 journals in total. Biologist Ross Mounce noted that high levels of self-citation may be inevitable for a journal which publishes a large share of new species classification. Later that year this decision was reversed and it was admitted that levels of self-citation are appropriate considering the large proportion of papers f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myxine Kuoi
''Myxine'' is a genus of hagfish, from the Greek μυξῖνος (''myxinos'', "slimy"). In 2021, three new species of ''Myxine'' were described from the Galápagos including '' M. phantasma'', the only species of ''Myxine'' to not have melanin-based pigments. Species * ''Myxine affinis'' Günther, 1870 (Patagonian hagfish) * '' Myxine australis'' Jenyns, 1842 (southern hagfish) * ''Myxine capensis'' Regan, 1913 (Cape hagfish) * ''Myxine circifrons'' Garman, 1899 (whiteface hagfish) * ''Myxine debueni'' Wisner & C. B. McMillan, 1995 (Magellan hagfish) * ''Myxine fernholmi'' Wisner & C. B. McMillan, 1995 (Falkland Islands hagfish) * ''Myxine formosana'' H. K. Mok & C. H. Kuo, 2001 (Formosa hagfish) * ''Myxine garmani'' D. S. Jordan & Snyder, 1901 (Garman's hagfish) * ''Myxine glutinosa'' Linnaeus, 1758 (Atlantic hagfish) *''Myxine greggi'' * ''Myxine hubbsi'' Wisner & C. B. McMillan, 1995 (Hubbs' hagfish) * ''Myxine hubbsoides'' Wisner & C. B. McMillan, 1995 * '' Myx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eptatretus Goliath
''Eptatretus'' is a large genus of hagfish. Species There are currently 49 recognized species in this genus: * ''Eptatretus aceroi'' Polanco Fernández & Fernholm, 2014 (Acero's hagfish)Polanco Fernandez, A. & Fernholm, B. (2014): A New Species of Hagfish (Myxinidae: ''Eptatretus'') from the Colombian Caribbean. ''Copeia, 2014 (3): 530–533.'' * ''Eptatretus alastairi'' Mincarone & Fernholm, 2010 (Alastair's hagfish) * ''Eptatretus ancon'' H. K. Mok, Saavedra-Diaz & Acero P, 2001 * ''Eptatretus astrolabium'' Fernholm & Mincarone, 2010 (Astrolabe hagfish) * ''Eptatretus atami'' Dean, 1904 (Brown hagfish) * '' Eptatretus bischoffii'' A. F. Schneider, 1880 (Bischoff's hagfish) * ''Eptatretus bobwisneri'' Fernholm, Norén, S. O. Kullander, Quattrini, Zintzen, C. D. Roberts, H. K. Mok & C. H. Kuo, 2013 (Bob Wisner's hagfish)Fernholm, B., Norén, M., Kullander, S.O., Quattrini, A.M., Zintzen, V., Roberts, C.D., Mok, H.-K. & Kuo, C.-H. (2013): Hagfish phylogeny and tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craniata
A craniate is a member of the Craniata (sometimes called the Craniota), a proposed clade of chordate animals with a skull of hard bone or cartilage. Living representatives are the Myxini (hagfishes), Hyperoartia (including lampreys), and the much more numerous Gnathostomata (jawed vertebrates).Campbell & Reece 2005 p. 676 Formerly distinct from vertebrates by including hagfish, molecular and anatomical research in the 21st century has led to the reinclusion of hagfish as vertebrates, making living craniates synonymous with living vertebrates. The clade was conceived largely on the basis of the Hyperoartia (lampreys and kin) being more closely related to the Gnathostomata (jawed vertebrates) than the Myxini (hagfishes). This, combined with an apparent lack of vertebral elements within the Myxini, suggested that the Myxini were descended from a more ancient lineage than the vertebrates, and that the skull developed before the vertebral column. The clade was thus composed of the Myx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathostomes
Gnathostomata (; from Greek: (') "jaw" + (') "mouth") are the jawed vertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates, including humans. In addition to opposing jaws, living gnathostomes have true teeth (a characteristic which has subsequently been lost in some), paired appendages (pectoral and pelvic fins, arms, legs, wings, etc.), the elastomeric protein of elastin, and a horizontal semicircular canal of the inner ear, along with physiological and cellular anatomical characters such as the myelin sheaths of neurons, and an adaptive immune system that has the discrete lymphoid organs of spleen and thymus, and uses V(D)J recombination to create antigen recognition sites, rather than using genetic recombination in the variable lymphocyte receptor gene. It is now assumed that Gnathostomata evolved from ancestors that already possessed a pair of both pectoral and pelvic fins. Until recently these ancestors, kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrates
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnatha
Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct ( conodonts and ostracoderms) species. Among recent animals, cyclostomes are sister to all vertebrates with jaws, known as gnathostomes. Recent molecular data, both from rRNA and from mtDNA as well as embryological data, strongly supports the hypothesis that living agnathans, the cyclostomes, are monophyletic. The oldest fossil agnathans appeared in the Cambrian, and two groups still survive today: the lampreys and the hagfish, comprising about 120 species in total. Hagfish are considered members of the subphylum Vertebrata, because they secondarily lost vertebrae; before this event was inferred from molecular and developmental data, the group Craniata was created by Linnaeus (and is still sometimes used as a strictly morphological descriptor) to reference hagfish plus vertebrates. While a few scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclostomata
Cyclostomi, often referred to as Cyclostomata , is a group of vertebrates that comprises the living jawless fishes: the lampreys and hagfishes. Both groups have jawless mouths with horny epidermal structures that function as teeth called ceratodontes, and branchial arches that are internally positioned instead of external as in the related jawed fishes. The name Cyclostomi means "round mouths". It was named by Joan Crockford-Beattie. Possible external relationships This taxon is often included in the paraphyletic superclass Agnatha, which also includes several groups of extinct armored fishes called ostracoderms. Most fossil agnathans, such as galeaspids, thelodonts, and osteostracans, are more closely related to vertebrates with jaws (called gnathostomes) than to cyclostomes. Cyclostomes seem to have split off before the evolution of dentine and bone, which are present in many fossil agnathans, including conodonts. Biologists disagree on whether cyclostomes are a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancelets
The lancelets ( or ), also known as amphioxi (singular: amphioxus ), consist of some 30 to 35 species of "fish-like" benthic filter feeding chordates in the order Amphioxiformes. They are the modern representatives of the subphylum Cephalochordata. Lancelets closely resemble 530-million-year-old ''Pikaia'', fossils of which are known from the Burgess Shale. Zoologists are interested in them because they provide evolutionary insight into the origins of vertebrates. Lancelets contain many organs and organ systems that are closely related to those of modern fish, but in more primitive form. Therefore, they provide a number of examples of possible evolutionary exaptation. For example, the gill-slits of lancelets are used for feeding only, and not for respiration. The circulatory system carries food throughout their body, but does not have red blood cells or hemoglobin for transporting oxygen. Lancelet genomes hold clues about the early evolution of vertebrates: by comparing genes fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lampreys
Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin , which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. ''Lamprey'' is sometimes seen for the plural form. There are about 38 known extant species of lampreys and five known extinct species. Parasitic carnivorous species are the most well-known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys engage in this micropredatory lifestyle. Of the 18 carnivorous species, nine migrate from saltwater to freshwater to breed (some of them also have freshwater populations), and nine live exclusively in freshwater. All non-carnivorous forms are freshwater species. Adults of the non-carnivorou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
