Lampriformes
Encyclopedia
Lampriformes is an order
of ray-finned fish. They are collectively called "lamprids" (which is more properly used for the Lampridae) or lampriforms, and unite such open-ocean
and partially deep-sea Teleostei
as the crestfish
es, oarfish
, opah
s and ribbonfish
es. A synonym for this order is Allotriognathi, while an often-seen but apparently incorrect spelling variant is Lampridiformes. They contain 7 extant families
which are generally small but highly distinct, and a mere 12 lampriforms genera
with some 20 species
altogether are recognized.
The scientific name literally means "Shaped (like the) bright (one)". But as "Lampr-", meaning bright, comes from Lampris the generic name for the Opah, then "opah-shaped" would be a more meaningful translation. In fact, most living lampriforms are actually ribbon-like and not very similar to the disc-shaped opahs in habitus
. They are, however, quite distinctly united by their anatomy
, and the family's phylogeny as well as the most ancient fossil
s of this order suggest that the original lampriform was indeed rather "opah-shaped". The scientific name is a combination of Lampris (the type genus
) + the standard fish
order suffix
"-formes". It ultimately derives from Ancient Greek
lamprós (λαμπρός, "bright") + Latin
forma ("external form"), the former in reference to brilliant coloration of opahs.
ic fishes are pelagic
feeders that stay well above the seafloor, and normally occur in waters 100–1000 meters deep. They are typically brightly coloured as adults, often with brilliant crimson
fin
s. Lampriforms have a highly variable body form, but they are generally laterallly compressed. Some are rounded in lateral view, while others are very elongate. The former are termed bathysomes – "deep-bodies", from Ancient Greek
bathýs (βᾶθύς) "deep" + sōma (σῶμα) "body" – and the latter taeniosomes – "ribbon-bodies", Greek tainía (ταινία) "ribbon". They vary greatly in size, too, ranging from less than 30 cm (11.8 in) in the sailfin moonfishes (Veliferidae) to Regalecus glesne, the longest of all living bony fishes, which may reach 17 m (55.8 ft) in length.
The lampriforms have 84-96 total vertebrae; an orbitosphenoid bone is present in some members of this order. Their premaxilla
completely excludes the maxilla
from the gape, but the jaw
s are highly protrusible nonetheless. The upper jaw's protrusion is achieved in a unique way: the maxilla, instead of being ligament
ously attached to the ethmoid and palatine
, slides in and out with the highly protractile premaxilla
. The pelvic fins have up to 17 rays and are placed rather far toward the front of the animal, but they can be missing entirely. The dorsal fin
is long, and tend to extend along most of the length of the body. Fin spines are absent in all. Some have a physoclistous gas bladder
, while others have none. They either have tiny scale
s or naked skin.
The order
Lampriformes is anatomically similar to some Acanthopterygii
at a first glance. But more detailed studies reveal that they are not as advanced, and many authors assign them to a basal position inside the advanced spiny-rayed Teleostei
clade
called Acanthomorpha
, as monotypic
superorder "Lampridiomorpha". Unlike their presumed relatives they lack fin spines, however, and other authors have considered them to form a lineage just outside the Acanthomorpha, and the sister taxon of the Myctophiformes
. Molecular
data also supports the view that the Lampriformes are close to the advanced Teleostei. But the data does not agree on their exact relationships, and the Myctophiformes are also inferred to be close to the Protacanthopterygii
, one of the core groups of moderately advanced teleosts. As modern taxonomy
tries to avoid a profusion of small taxa, and the delimitation of the Euteleostei (Protacanthopterygii
sensu stricto and their allies) versus Acanthopterygii remains uncertain, the systematics
and taxonomy of the Lampriformes among the teleosts are in need of further study.
The lampriforms diverged from other teleosts in the Cretaceous
, perhaps 80 Ma (million years ago) or slightly more, considering that the oldest known lampriforms, Nardovelifer
, dates from the late Campanian
epoch and is already clearly assignable to the present order. The basal lampriforms were bathysomes, while the taeniosome body shape is apomorphic and seems to have evolved only once. The order underwent its main radiation
in the Paleocene
period; the opah
-like Turkmenidae
were a family
of lampriforms thriving at that time, but going extinct around the start of the Neogene
, about 23 Ma. Other fossil
Lampridiformes are Bajaichthys
, Palaeocentrotus
and Veronavelifer
.
The order is occasionally divided in the Bathysomi and the Taeniosomi. The former are a paraphyletic assemblage, and thus effectively synonymous with the entire order, while the latter can be considered a valid suborder. Including fossil taxa, the classification of the Lampriformes in phylogenetic sequence, with the number of living genera
and species
, can thus be given as follows:
Basal and incertae sedis
Suborder Taeniosomi
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 ray-finned fish. They are collectively called "lamprids" (which is more properly used for the Lampridae) or lampriforms, and unite such open-ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
and partially deep-sea 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...
as the crestfish
Crestfish
Crestfishes are lampriform fishes in the family Lophotidae. They are elongate ribbon-like fishes, silver in color, found in deep tropical and subtropical waters worldwide...
es, oarfish
Oarfish
Oarfish are large, greatly elongated, pelagic Lampriform fishes comprising the small family Regalecidae. Found in all temperate to tropical oceans yet rarely seen, the oarfish family contains four species in two genera...
, opah
Opah
Opah are large, colorful, deep-bodied pelagic Lampriform fish comprising the small family Lampridae . There are only two living species in a single genus: Lampris...
s and ribbonfish
Ribbonfish
The ribbonfish are any lampriform in the family Trachipteridae. These pelagic fish are named for their slim, ribbon-like appearance. They are rarely seen alive as they typically live in deep waters ....
es. A synonym for this order is Allotriognathi, while an often-seen but apparently incorrect spelling variant is Lampridiformes. They contain 7 extant 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...
which are generally small but highly distinct, and a mere 12 lampriforms 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...
with some 20 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...
altogether are recognized.
The scientific name literally means "Shaped (like the) bright (one)". But as "Lampr-", meaning bright, comes from Lampris the generic name for the Opah, then "opah-shaped" would be a more meaningful translation. In fact, most living lampriforms are actually ribbon-like and not very similar to the disc-shaped opahs in habitus
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
. They are, however, quite distinctly united by their anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, and the family's phylogeny as well as the most ancient fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of this order suggest that the original lampriform was indeed rather "opah-shaped". The scientific name is a combination of Lampris (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...
lamprós (λαμπρός, "bright") + 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 brilliant coloration of opahs.
Description and ecology
These oceanOcean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
ic fishes are pelagic
Pelagic zone
Any water in a sea or lake that is not close to the bottom or near to the shore can be said to be in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means "open sea". The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes...
feeders that stay well above the seafloor, and normally occur in waters 100–1000 meters deep. They are typically brightly coloured as adults, often with brilliant crimson
Crimson
Crimson is a strong, bright, deep red color. It is originally the color of the dye produced from a scale insect, Kermes vermilio, but the name is now also used as a generic term for those slightly bluish-red colors that are between red and rose; besides crimson itself, these colors include...
fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
s. Lampriforms have a highly variable body form, but they are generally laterallly compressed. Some are rounded in lateral view, while others are very elongate. The former are termed bathysomes – "deep-bodies", 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...
bathýs (βᾶθύς) "deep" + sōma (σῶμα) "body" – and the latter taeniosomes – "ribbon-bodies", Greek tainía (ταινία) "ribbon". They vary greatly in size, too, ranging from less than 30 cm (11.8 in) in the sailfin moonfishes (Veliferidae) to Regalecus glesne, the longest of all living bony fishes, which may reach 17 m (55.8 ft) in length.
The lampriforms have 84-96 total vertebrae; an orbitosphenoid bone is present in some members of this order. Their premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
completely excludes 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...
from the gape, but the jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s are highly protrusible nonetheless. The upper jaw's protrusion is achieved in a unique way: the maxilla, instead of being ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
ously attached to the ethmoid and palatine
Palatine bone
The palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
, slides in and out with the highly protractile premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
. The pelvic fins have up to 17 rays and are placed rather far toward the front of the animal, but they can be missing entirely. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is long, and tend to extend along most of the length of the body. Fin spines are absent in all. Some have a physoclistous 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...
, while others have none. They either have tiny scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
s or naked skin.
Systematics and evolution
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...
Lampriformes is anatomically similar to some Acanthopterygii
Acanthopterygii
Acanthopterygii is a superorder of bony fishes in the class Actinopterygii. Members of this superorder are also known as the ray-finned fishes for the characteristic sharp, bony rays in their fins; however this name is also often given to the class Actinopterygii as a whole.Orders:* Order...
at a first glance. But more detailed studies reveal that they are not as advanced, and many authors assign them to a basal position inside the advanced spiny-rayed 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...
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...
called Acanthomorpha
Acanthomorpha
Acanthomorpha is an order of prehistoric fish that was described by Rosen in 1973. Fossils range from the Late Cretaceous to the Early Oligocene -28.4mya)...
, as 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 "Lampridiomorpha". Unlike their presumed relatives they lack fin spines, however, and other authors have considered them to form a lineage just outside the Acanthomorpha, and the sister taxon of the Myctophiformes
Myctophiformes
Myctophiformes is an order of ray-finned fish consisting of two families of deep-sea marine fish, most notably the highly abundant lanternfishes...
. Molecular
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...
data also supports the view that the Lampriformes are close to the advanced Teleostei. But the data does not agree on their exact relationships, and the Myctophiformes are also inferred to be close to the Protacanthopterygii
Protacanthopterygii
Protacanthopterygii is a ray-finned fish taxon ranked as a superorder of the infraclass Teleostei. They inhabit both marine and freshwater habitat...
, one of the core groups of moderately advanced teleosts. As modern taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
tries to avoid a profusion of small taxa, and the delimitation of the Euteleostei (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 stricto and their allies) versus Acanthopterygii remains uncertain, the systematics
Systematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
and taxonomy of the Lampriformes among the teleosts are in need of further study.
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, perhaps 80 Ma (million years ago) or slightly more, considering that the oldest known lampriforms, Nardovelifer
Nardovelifer
Nardovelifer altipinnis is the oldest known lamprid fish. It dates from the Campanian epoch of Nardò, Italy....
, dates from the late Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
epoch and is already clearly assignable to the present order. The basal lampriforms were bathysomes, while the taeniosome body shape is apomorphic and seems to have evolved only once. The order underwent its main radiation
Evolutionary radiation
An evolutionary radiation is an increase in taxonomic diversity or morphological disparity, due to adaptive change or the opening of ecospace. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment,...
in the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
period; the opah
Opah
Opah are large, colorful, deep-bodied pelagic Lampriform fish comprising the small family Lampridae . There are only two living species in a single genus: Lampris...
-like Turkmenidae
Turkmenidae
Turkmenidae is an extinct family of lamprids from the Paleogene of Turkmenistan. They were small, disk-shaped fish that bore a strong resemblance to their closest living relatives, the opahs....
were 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...
of lampriforms thriving at that time, but going extinct around the start of the Neogene
Neogene
The Neogene is a geologic period and system in the International Commission on Stratigraphy Geologic Timescale starting 23.03 ± 0.05 million years ago and ending 2.588 million years ago...
, about 23 Ma. Other fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
Lampridiformes are Bajaichthys
Bajaichthys
Bajaicthys elegans is an extinct Lutetian lamprid from the Monte Bolca Lagerstatten.- Anatomy and appearance :The holotype is four centimeters in length...
, Palaeocentrotus
Palaeocentrotus
Palaeocentrotus is an extinct genus of Lampridiformes.-External links:* at the Paleobiology Database...
and Veronavelifer
Veronavelifer
Veronavelifer sorbinii is an extinct sailfin moonfish from the Lutetian epoch of the Monte Bolca lagerstatten....
.
Classification
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 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...
, can thus be given as follows:
Basal and incertae sedis
Incertae sedis
, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
- Genus BajaichthysBajaichthysBajaicthys elegans is an extinct Lutetian lamprid from the Monte Bolca Lagerstatten.- Anatomy and appearance :The holotype is four centimeters in length...
(fossil) - Genus NardoveliferNardoveliferNardovelifer altipinnis is the oldest known lamprid fish. It dates from the Campanian epoch of Nardò, Italy....
(fossil) - Genus PalaeocentrotusPalaeocentrotusPalaeocentrotus is an extinct genus of Lampridiformes.-External links:* at the Paleobiology Database...
(fossil) - Family TurkmenidaeTurkmenidaeTurkmenidae is an extinct family of lamprids from the Paleogene of Turkmenistan. They were small, disk-shaped fish that bore a strong resemblance to their closest living relatives, the opahs....
(fossil) - Family VeliferidaeVeliferidaeSailfin moonfishes are a small family, Veliferidae, of lampriform fishes. They are found in the Indian and western Pacific Oceans.Unlike other lampriforms, they live in shallow, coastal waters, of less than depth, rather than in the deep ocean. They are also much smaller than most of their...
— sailfin moonfishes (2 genera, 2 species) - Family Lampridae — opahs (1 genus, 2 species)
Suborder Taeniosomi
- Family Stylephoridae — Tube-eye or Thread-tail (monotypicMonotypicIn 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...
) - Family Lophotidae — crestfishes (2 genera, 3 species)
- Family Radiicephalidae — Tapertail (monotypic)
- Family Trachipteridae — ribbonfishes (3 genera, 10 species)
- Family Regalecidae — oarfishes (2 genera, 4 species)