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 Danio rerio — zebra danio
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Celestichthys |
The danionins are a group of small minnow-type fish belonging to the family Cyprinidae. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates The Actinopterygii (the plural form of Actinopterygius) comprise the class of the ray-finned fishes. The Cypriniformes are an order of ray-finned fish, including the Carps Minnows Loaches and relatives The family Cyprinidae, from the Ancient Greek κυπρῖνος ( kuprīnos "carp" consists of the Carps The Celestial Pearl Danio, Danio margaritatus - often referred to in the aquarium trade as galaxy rasbora or " Microrasbora sp Chela is a Genus closely related to Devario. The Danio genus comprises many of the species of Danionins familiar to aquarists Danionella is a Genus comprising the Danionin Species D mirifica and D The genus Devario comprise of some Danionins familiar to aquarists Esomus is a Genus comprising the Flying Barbs. they are closely related to the Danio genus and are distinctive for their extremely Inlecypris is a Genus closely related to Devario comprising two smallish barred fish from Lake Inle in Myanmar. Microrasbora is a Genus of small Fishes The Generic name means "small Rasbora" however these fish appear to be more closely related Paedocypris is an Indonesian Genus of Fish in the family Cyprinidae (which also includes Carps and Minnows Parachela is a Genus closely related to Chela and Devario. Sundadanio axelrodi is a Danionin in the family Cyprinidae, the only species in the genus Sundadanio. The family Cyprinidae, from the Ancient Greek κυπρῖνος ( kuprīnos "carp" consists of the Carps Members of this group are mostly in the genera Danio and Devario. The Danio genus comprises many of the species of Danionins familiar to aquarists The genus Devario comprise of some Danionins familiar to aquarists They are native to the fresh waters of southeast Asia. Freshwater is a word that refers to bodies of water such as Ponds lakes rivers and streams containing low concentrations of dissolved Salts and other Total dissolved Many species are brightly coloured and are available as aquarium fish worldwide. An aquarium (plural aquariums or aquaria) is a Vivarium consisting of at least one transparent side in which Water -dwelling Plants Danio tend to have horizontal stripes and long barbels, Devario tend to have vertical bars and short rudimentary barbels, if barbels are present at all. The Danio genus comprises many of the species of Danionins familiar to aquarists The genus Devario comprise of some Danionins familiar to aquarists All danionins are egg scatterers and breed in the rainy season in the wild. They are carnivores living on insects and small crustaceans in the wild.
Contents |
Taxonomy
The grouping of fish now deemed danionins has been the subject of constant research and speculation throughout the 20th Century. Nearly all the fish named within the Danio and Devario genus were originally placed in the Danio genus upon discovery. However, in the first part of the 20th Century Dr George S Myers split them into three Genera; Danio, Brachydanio and Daniops. The sole fish within Daniops, Daniops myersi has long ago been found to be a synonym of Devario laoensis, however the Brachydanio genus lasted for much longer, as it included most of the fish now classed as Danio, whereas Danio included most of the fish now classed as Devario. [1]
However Danio dangila and Danio feegradei both of which had most of the characteristics of the Brachydanios (with the exception that they were much larger than the Brachydanios) were placed within the Danios. (Due to this and other mis-placing both Danio and Brachydanio were found to be paraphyletic by Fang in 2003. [2]). In 1941 H. M. Smith attempted to unite all the Brachydanios and Danios into one genus on the basis of a fish from Thailand which was supposed to bridge the gap. He downgraded both Danio and Brachydanio into subgenera and erected a new subgenera of Allodanio with one member Allodanio ponticulus, however Myers later pointed out that ponticulus was actually a member of the Barilius genus. [1]
In a 1986 paper, Tyson Roberts noted that the danionin group was thought to include Parabarilius, Danio, Brachydanio and Danionella. The Danio genus comprises many of the species of Danionins familiar to aquarists Danionella is a Genus comprising the Danionin Species D mirifica and D In this scheme, danionins were distinguished from other cyprinids by the uniquely shared character of the danionin notch, a large and peculiarly shaped indentation in the medial margin of the mandibles; this feature is not noted in rasborins, esomins, bariliins, or chelins. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place However, all of these categories at that time were informal. Microrasbora was not considered to be a part of the danionins, nor even closely related to Danionella, a part of the danionins of that time. Microrasbora is a Genus of small Fishes The Generic name means "small Rasbora" however these fish appear to be more closely related [3]
In the late 1980s and 1990s doubts grew about the validity of Brachydanio, with species being referred to their original naming of Danio, and in a 2003 paper Fang Fang determined that the genus Danio, recognized up to that point, was paraphyletic. In Phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all Danio was restricted to the species known as the "D. dangila species group", which at the time comprised nine species including D. dangila, D. rerio, D. nigrofasciatus, and D. albolineatus, and the remaining Danio species were moved to Devario. Devario at this time included among many others D. malabaricus, D. kakhienensis, D. devario, D. chrysotaeniatus, D. maetaengensis, D. interruptus, and D. apogon.
The only Danios to have been consistently called Danio were D. dangila & D. feegradei. As D. dangila was the first discovered Danio (or type) the name Danio had to remain with dangila, which is why the vast majority of species were moved to Devario.
Also, in Fang's 2003 paper, the sister group to Devario was deemed to be a clade formed by Inlecypris and Chela and, more controverisally, Esomus was found to be the sister group of Danio. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor Inlecypris is a Genus closely related to Devario comprising two smallish barred fish from Lake Inle in Myanmar. Chela is a Genus closely related to Devario. Esomus is a Genus comprising the Flying Barbs. they are closely related to the Danio genus and are distinctive for their extremely Cladistics is the hierarchical classification of Species based on evolutionary ancestry The relationships of Sundadanio, Danionella, Microrasbora remained unresolved. Sundadanio axelrodi is a Danionin in the family Cyprinidae, the only species in the genus Sundadanio. Danionella is a Genus comprising the Danionin Species D mirifica and D Microrasbora is a Genus of small Fishes The Generic name means "small Rasbora" however these fish appear to be more closely related The danionin notch was found to not supported to be a danionin synapomorphy. In Evolutionary biology, a synapomorphy is a derived Character state shared by two or more terminal groups ( taxa included in a Cladistic analysis [2]
In 2007 in another paper by Tyson Roberts, Celestichthys margaritatus was described as a new species of Danioninae. The Celestial Pearl Danio, Danio margaritatus - often referred to in the aquarium trade as galaxy rasbora or " Microrasbora sp Apparently, it is most closely related to Microrasbora erythromicron; the other Microrasbora species differ significantly from Celestichthys. The genus is identified as a danionin due specializations of its lower jaw and its numerous anal fin rays. The Anatomy of Fish is primarily governed by the physical characteristics of Water, which is much denser than air holds a relatively small amount of dissolved Though it lacks a danionin notch, Celestichthys exhibits the "danionin mandibular knob", a bony process on the side of the mandible behind the danionin notch or where the notch should be; it is perhaps diagnostic of danionins. This knob is better developed in males than females. The author notes that fish of Rasborinae almost invariably have anal fins with three spines and five rays. Celestichthys has 3 anal fin spines and 8½-10½ anal fin rays. Also, rasborins have the generalized cyprinid principal caudal fin ray count of 10/9, while all Asian cyprinids with fewer than 10/9 principal caudal fin rays are all diminutive species of Danioninae, including Celestichthys, M. erythromicron, Danionella, and Paedocypris. [4]
In 2007, an analysis of the phylogenetic relationships of the recently described genus Paedocypris was published, placing it as the sister taxon to Sundadanio. Paedocypris is an Indonesian Genus of Fish in the family Cyprinidae (which also includes Carps and Minnows The clade formed by these two genera was found to be sister to a clade including many danionin genera as well as some rasborin genera such as Rasbora, Trigonostigma, and Boraras, making the danionin group paraphyletic without these rasborin genera based on these results. This paper considered the danionin genera to be within a larger Rasborinae. [5]
Also in 2007, another study by various authors analyzed the relationships of Danio. These authors considered Rasborinae to have priority over Danioninae, suggesting that they have the same meaning. Also, Danio was found to be the sister group of a clade including Chela, Microrasbora, Devario, and Inlecypris, rather than in a clade exclusively with either Devario or Esomus as in previous studies. This paper supported the close relationship of "Microrasbora" erythromicron to Danio species; however, this study did not include Celestichthys, which was noted by Tyson Roberts in his 2007 paper as being likely to include erythromicron but with further research needed. [6][4]
Tanichthys is often regarded as a danionin by aquarists and grouped as such in some older aquatic publications, however there is no scientific basis for this, a fact stated on numerous occasions by Brittan and others[1] . Tanichthys Lin, 1932, is a Genus of Freshwater Fish in the Carp family (family Cyprinidae It is more closely related to the Rasboras. A rasbora is member of a group of small minnow-type fish in the family Cyprinidae (carps The danionins can be classed as a subfamily Danioninae which is increasingly gaining credibility as a distinct subfamily from Rasboriniae within the Cyprinidae family. The family Cyprinidae, from the Ancient Greek κυπρῖνος ( kuprīnos "carp" consists of the Carps [7]However, in Nelson, 2006, Danioninae was listed as a synonym of Rasborinae. In Scientific nomenclature, synonyms are different Scientific names used for a single Taxon. [8] On the other hand, neither inter- nor intrarelationships among the "rasborins" have as yet been thoroughly analyzed. [2]
A number of the species have only been recently discovered, in remote inland areas of Laos and Myanmar and do not yet have scientific names. Laos (ˈlɑːoʊs or /ˈlaʊs/ officially the Lao People's Democratic Republic, is a Landlocked country in Southeast Asia, bordered by Burma Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. They are listed as Danio or Devario sp "xxxx" within the relevant genera and disambiguation pages, where details of the fish can be found by clicking on the hyperlink.
In the aquarium
They are generally active swimmers occupying the top half of a tank and will eat just about any type of aquarium food. They will not, however, generally eat plants or algae.
Although boisterous and liable to chase each other and other fish, they are good community fish and will not generally attack each other or other fish, although they occasionally nip fins, more by accident than design and will, like most fish, eat eggs and any fish small enough to fit into their mouths.
They are best kept in a tank long enough for their active swimming, preferably with a current from a power filter (or at least airstone) as they often live in fast flowing streams in the wild. Generally this also results in them being sub tropical with temperatures of 20 to 22 degrees Celsius (low seventies degrees Fahrenheit) often being fine, however they are good jumpers and a tight fitting lid is recommended. The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724
Common names given to danionin species
Since 2004 many new danionins have been discovered which do not yet have scientific names and many other species, previously known only to the scientific fraternity have become available in Aquarist Shops. This has predictably led to total confusion as to the naming of some fish, with some species having up to five different common names in use and some common names bein used for up to four different species. As a result all danionin common names known to be in use are listed on a separate page:
Danionin species scientific names
Individual Danionin species are listed within the relevant pages for each Genera, however many Danionin species have been changed into different genera over the last decades in some cases repeatedly, similarly some species have been synomymised with other species and in some cases later unsynonymised, all of which has caused a lot of confusion. As a result a separate page has been created which lists all danionin species and also lists defunct species which have since been synonymised or renamed.
External links
- Danios and Devarios. Danios and devarios website. Retrieved on October 01, 2005. Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar.
- Clarke, Matt (2005) - A fishkeeper's guide to danios and devarios.. Article on danionins at Practical Fishkeeping's website. Retrieved on October 01, 2005. Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar.
References
- ^ a b c Brittan, Martin Ralph. "Danios, A guide to the identification, care and breeding of fishes of the genera Danio and Brachydanio". T. F. H. Publications, 1958, ASIN: B0000CK5BH.
- ^ a b c Fang, Fang (2003). "Phylogenetic Analysis of the Asian Cyprinid Genus Danio (Teleostei, Cyprinidae)". Copeia (4): 714–728. Copeia is a quarterly published Periodical pertaining to ichthyological and herpetological subjects doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Roberts, Tyson R. (1986). "Danionella translucida, a new genus and species of cyprinid fish from Burma, one of the smallest living vertebrates". Environmental Biology of Fishes 16 (4): 231–241. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ a b Roberts, T. R. (2007). "The "Celestial pearl danio", a new genus and species of colourful minute cyprinid fish from Myanmar (Pisces: Cypriniformes)" (PDF). The Raffles Bulletin of Zoology 55 (1): 131–140.
- ^ Rüber, Lukas; Kottelat, Maurice; Tan, Heok Hui; Ng, Peter KL; Britz, Ralf (2007). "Evolution of miniaturization and the phylogenetic position of Paedocypris, comprising the world's smallest vertebrate". BMC Evolutionary Biology 7 (38): 1–10. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Mayden, Richard L. ; Tang, Kevin L. ; Conway, Kevin W. ; Freyhof, Jörg; Chamberlain, Sarah; Haskins, Miranda; Schneider, Leah; Sudkamp, Mitchell; Wood Robert M. ; Agnew, Mary; Bufalino, Angelo; Sulaiman, Zohrah; Miya, Masaki; Saitoh, Kenji; He, Shunping (2007). "Phylogenetic relationships of Danio within the order Cypriniformes: a framework for comparative and evolutionary studies of a model species". J. Exp. Zool. (Mol. Dev. Evol. ) 308B: 1–13.
- ^ Clarke, Matt. "A fishkeeper's guide to danios and devarios". Practical Fishkeeping (March 2005). Practical Fishkeeping (also known as PFK) is the United Kingdom 's best-selling Aquarium
- ^ Nelson, Joseph S. (2006). Fishes of the World. Fishes of the World by Joseph S Nelson is a standard reference for Fish Systematics. John Wiley & Sons, Inc. John Wiley & Sons Inc, also referred to as Wiley, is a global Publishing company that markets its products to professionals and consumers students and instructors ISBN 0-471-25031-7.
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