Aulopiformes
Encyclopedia
Aulopiformes is an order
of marine
ray-finned fish consisting of some 15 extant and several prehistoric families
with about 45 genera
and over 230 species
. The common names grinners, lizardfishes and allies or aulopiforms are sometimes used for this group. The scientific name means "Aulopus-shaped", from Aulopus (the type genus
) + the standard fish
order suffix
"-formes". It ultimately derives from Ancient Greek
aulós (αὐλός, "flute" or "pipe") + Latin
forma ("external form"), the former in reference to the elongated shape of many Aulopiformes.
They are grouped together because of common features in the structure of their gill arches. Indeed, many authors have considered them so distinct as to warrant separation in a monotypic
superorder of the Teleostei
, under the name Cyclosquamata. However, monotypic taxa are generally avoided by modern taxonomists if not necessary, and in this case a distinct superorder seems indeed unwarranted: together with the equally dubious superorder "Stenopterygii
", the grinners appear to be so closely related to some Protacanthopterygii
to be included in that superorder. In particular, this group might be the sister taxon of the Salmoniformes (salmon, trouts and relatives). As an alternative, the superorders are sometimes united as an unranked clade
named Euteleostei, but in that case the Protacanthopterygii would need to be split further to account for the phylogenetic uncertainty. This would result in a highly cumbersome and taxonomically redundant group of 2 very small and no less than 4 monotypic superorders.
are hermaphrodite
s, some with the ability to self-fertilise. Some are benthic, but most are pelagic. In general, aulopiform fish have a mixture of advanced and primitive characteristics relative to other teleost fish.
They have no or just a vestigial gas bladder
, a hypaxialis muscle that is unusually extended to forward at its upper end and attaches to the neurocranium below the spine
(perhaps to snap the upper part of the skull down when catching prey) and the position of the maxilla
ry bone. Their second pharyngobranchial is greatly elongated posterolaterally away from third pharyngobranchial, which lacks a cartilaginous condyle to articulate with the preceding, but is contacted by the elongated uncinate process
of the second epibranchial. Other features include the position of the pelvic fins far back on the body, the fused medial processes of pelvic girdle and the presence of an adipose fin (which is also typical for the Protacanthopterygii).
The larva
e of some Aulopiformes are extremely bizarre-looking, with elongated fins, and do not resemble the adult animals. They were not only described as distinct species
, but even separated as genera
and finally in a family
"Macristiidae" which was allied with various Protacanthopterygii
(sensu lato). But the initial assessment – which found "Macristium" to resemble the deepwater lizardfishes (Bathysauridae) in some details – was not far off the mark: "Macristium" are larvae of Bathysaurus, while the supposed other "macristiid" genus "Macristiella" are larvae of the deepsea tripodfish Bathytyphlops.
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
ray-finned fish consisting of some 15 extant and several prehistoric families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
with about 45 genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
and over 230 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. The common names grinners, lizardfishes and allies or aulopiforms are sometimes used for this group. The scientific name means "Aulopus-shaped", from Aulopus (the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
) + the standard 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...
order suffix
Suffix
In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns or adjectives, and verb endings, which form the conjugation of verbs...
"-formes". It ultimately derives from Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
aulós (αὐλός, "flute" or "pipe") + Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
forma ("external form"), the former in reference to the elongated shape of many Aulopiformes.
They are grouped together because of common features in the structure of their gill arches. Indeed, many authors have considered them so distinct as to warrant separation in a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
superorder of the Teleostei
Teleostei
Teleostei is one of three infraclasses in class Actinopterygii, the ray-finned fishes. This diverse group, which arose in the Triassic period, includes 20,000 extant species in about 40 orders; most living fishes are members of this group...
, under the name Cyclosquamata. However, monotypic taxa are generally avoided by modern taxonomists if not necessary, and in this case a distinct superorder seems indeed unwarranted: together with the equally dubious superorder "Stenopterygii
Stenopterygii
Stenopterygii are a superorder of ray-finned fish in the infraclass Teleostei. Their validity is somewhat doubtful, as the group was established to separate, out of a large group of closely related Teleostei, a mere two rather peculiarly autapomorphic orders at best...
", the grinners appear to be so closely related to some Protacanthopterygii
Protacanthopterygii
Protacanthopterygii is a ray-finned fish taxon ranked as a superorder of the infraclass Teleostei. They inhabit both marine and freshwater habitat...
to be included in that superorder. In particular, this group might be the sister taxon of the Salmoniformes (salmon, trouts and relatives). As an alternative, the superorders are sometimes united as an unranked clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
named Euteleostei, but in that case the Protacanthopterygii would need to be split further to account for the phylogenetic uncertainty. This would result in a highly cumbersome and taxonomically redundant group of 2 very small and no less than 4 monotypic superorders.
Description
Many of the aulopiforms are deep-sea fishes, and many speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are hermaphrodite
Hermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
s, some with the ability to self-fertilise. Some are benthic, but most are pelagic. In general, aulopiform fish have a mixture of advanced and primitive characteristics relative to other teleost fish.
They have no or just a vestigial 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...
, a hypaxialis muscle that is unusually extended to forward at its upper end and attaches to the neurocranium below the spine
Vertebral column
In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...
(perhaps to snap the upper part of the skull down when catching prey) and the position of the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
ry bone. Their second pharyngobranchial is greatly elongated posterolaterally away from third pharyngobranchial, which lacks a cartilaginous condyle to articulate with the preceding, but is contacted by the elongated uncinate process
Uncinate process
Uncinate process can refer to:* Uncinate process of ethmoid bone* Uncinate process of vertebra - a hook shaped process on the lateral borders of the superior surface of the vertebral bodies of the third to the seventh cervical vertebrae....
of the second epibranchial. Other features include the position of the pelvic fins far back on the body, the fused medial processes of pelvic girdle and the presence of an adipose fin (which is also typical for the Protacanthopterygii).
The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of some Aulopiformes are extremely bizarre-looking, with elongated fins, and do not resemble the adult animals. They were not only described as distinct species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, but even separated as genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
and finally in a family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
"Macristiidae" which was allied with various Protacanthopterygii
Protacanthopterygii
Protacanthopterygii is a ray-finned fish taxon ranked as a superorder of the infraclass Teleostei. They inhabit both marine and freshwater habitat...
(sensu lato). But the initial assessment – which found "Macristium" to resemble the deepwater lizardfishes (Bathysauridae) in some details – was not far off the mark: "Macristium" are larvae of Bathysaurus, while the supposed other "macristiid" genus "Macristiella" are larvae of the deepsea tripodfish Bathytyphlops.
Classification
- Suborder Alepisauroidei
- Family Alepisauridae – lancetfishes
- Family Anotopteridae – daggertooths (may belong in Paralepididae)
- Family Evermannelidae – sabertooth fishes
- Family Omosudidae – Hammerjaw (sometimes included in Alepisauridae)
- Family Paralepididae – barracudinas
- Family Scopelarchidae – pearleyes
- Suborder Chlorophthalmoidei
- Family Bathysauroididae – bathysauroidids
- Family Chlorophthalmidae – greeneyes
- Family IpnopidaeIpnopidaeIpnopidae is a family of fishes in the order Aulopiformes. They are small slender fishes, with maximum length ranging from about to about . They are found in temperate and tropical deep waters of the Atlantic, Indian and Pacific Oceans.A number of species, especially in the genus Bathypterois...
– deepsea tripodfishes (including Bathysauropsidae) - Family NotosudidaeNotosudidaeWaryfishes are deep-sea aulopiform fishes in the small family Notosudidae. They are thought to have a circumglobal distribution in sub-Arctic to subantarctic waters...
– waryfishes
- Suborder Enchodontoidei (including Halecoidei, Ichthyotringoidei, may belong in Alepisauroidei; fossilFossilFossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
)- Genus Nardorex (fossil, tentatively placed here)
- Genus Serrilepis (fossil, tentatively placed here)
- Genus Yabrudichthys (fossil, tentatively placed here)
- Family Apateopholidae (fossil)
- Family Cimolichthyidae (fossil)
- Family Dercetidae (fossil)
- Family Enchodontidae (fossil)
- Family Eurypholidae (fossil)
- Family Halecidae (fossil)
- Family Ichthyotringidae (fossil)
- Family Prionolepididae (fossil)
- Suborder Giganturoidei
- Family BathysauridaeBathysauridaeThe Bathysauridae are a small family of deep water aulopiform fish, related to the telescopefishes. There are just two species in the family, both belonging to the genus Bathysaurus. Commonly called deepwater lizardfishes or "deepsea lizardfishes", the latter name usually refers to the species B...
– deepwater lizardfishes - Family Giganturidae – telescopefishes
- Family Bathysauridae
- Suborder Synodontoidei
- Family AulopidaeAulopidaeThe Aulopidae are a small family of aulopiform fish, containing the single genus Aulopus. They are found in most tropical and subtropical oceans, being absent only in the eastern Pacific and commonly known as flagfins....
– flagfins - Family Paraulopidae – "cucumberfishes"
- Family PseudotrichonotidaePseudotrichonotidaeThe Pseudotrichonotidae are a small family of aulopiform fish, consisting of just two species in a single genus, Pseudotrichonotus....
– sandliving lizardfishes, sand-diving lizardfishes - Family SynodontidaeSynodontidaeThe Lizardfishes are a family, the Synodontidae, of aulopiform fish. They are found in tropical and subtropical marine waters throughout the world....
– typical lizardfishes
- Family Aulopidae