The Syngnathiformes are an order of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

es that includes the

trumpetfish The trumpetfishes are three species of highly specialized, tubularly-elongated marine fishes in the genus ''Aulostomus'', of the monogeneric family Aulostomidae. The trumpetfishes are members of the order Syngnathiformes, together with the sea ...

es and

seahorse A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine fish in the genus ''Hippocampus''. "Hippocampus" comes from the Ancient Greek (), itself from () meaning "horse" and () meaning "sea monster" or " ...

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

(2005)
Order Summary for Syngnathiformes
Version of 2005-FEB-15. Retrieved 19 Aug 2008. These fishes have elongated, narrow, bodies surrounded by a series of bony rings, and small, tubular mouths. The shape of their mouth—in at least syngnathids—allows for the ingestion of prey at close range via

suction Suction is the colloquial term to describe the air pressure differential between areas. Removing air from a space results in a pressure differential. Suction pressure is therefore limited by external air pressure. Even a perfect vacuum cannot ...

. Several groups of Syngnathiformes live among

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

and swim with their bodies aligned vertically, to blend in with the stems. The most defining characteristic of this order is their reverse sexual system. In this order, males conduct in specialized brooding and rearing of the embryos. The males house eggs in an osmoregulated pouch or adhere eggs to their tail until the eggs reach maturity. The name Syngnathiformes means "conjoined-jaws". It is derived from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''syn'' (συν, "together") + ''gnathos'' (γνάθος, "jaw"). The ending for fish orders "-formes" is derived from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

and indicates "of similar form".

Systematics and taxonomy

In some models, these fishes are placed as the

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Syngnathoidei of the order

Gasterosteiformes Gasterosteoidei is a suborder of ray-finned fishes that includes the sticklebacks and relatives, the 5th edition of '' Fishes of the World'' classifies this suborder within the order Scorpaeniformes. Systematics Gasterosteoidei is treated as ...

together with the

stickleback The sticklebacks are a family of ray-finned fishes, the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters. They were thought to be related to the pipefish and seahorses but are now thought to be more closel ...

s and their relatives. Better supported by the evidence now available is the traditional belief that they are better considered separate orders, and indeed among the

Acanthopterygii Acanthopterygii (meaning "spiny finned one") is a superorder of bony fishes in the class Actinopterygii. Members of this superorder are sometimes called ray-finned fishes for the characteristic sharp, bony rays in their fins; however this name ...

, they might not be particularly close relatives at all. In addition, the

Pegasidae The seamoths make up a family of fishes, the Pegasidae, within the order Syngnathiformes. They are named for Pegasus, a creature from Greek mythology. Seamoths are notable for their unusual appearance, including flattened bodies, the presence o ...

(dragonfishes and sea moths) are variously placed with the pipefish or the stickleback lineage. While the placement in Syngnathiformes seems to be correct for the latter, the former is possibly an actinopterygian order of its own. Following the convention of the major fish classification organizations (Fish Base, ITIS, Encyclopedia of Life), the Indostomidae are currently placed in the Gasterosteiformes. Morphological traits uniting the

flying gurnard The flying gurnard (''Dactylopterus volitans''), also known as the helmet gurnard, is a bottom-dwelling fish of tropical to warm temperate waters on both sides of the Atlantic. On the American side, it is found as far north as Massachusetts (ex ...

s (Dactylopteridae) and the Syngnathiformes have long been noted.Pietsch, T.W. (1978): Evolutionary relationships of the sea moths (Teleostei: Pegasidae) with a classification of gasterosteiform families. ''

Copeia ''Ichthyology & Herpetology'' (formerly ''Copeia'') is a quarterly peer-reviewed scientific journal covering research in ichthyology and herpetology that was originally named after Edward Drinker Cope, a prominent American researcher in these fiel ...

'' 1978(3): 517–529
JPEG abstract and first page text
/ref> Most authors, however, placed them with the

Scorpaeniformes The Scorpaeniformes are a diverse order of ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species, with over 1,320. They are ...

. However,

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

data quite consistently support the belief that the latter are

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

with the Gasterosteiformes ''sensu lato''. As it seems, flying gurnards are particularly close to

Aulostomidae The trumpetfishes are three species of highly specialized, tubularly-elongated marine fishes in the genus ''Aulostomus'', of the monogeneric family Aulostomidae. The trumpetfishes are members of the order Syngnathiformes, together with the seaho ...

and

Fistulariidae The cornetfishes or flutemouths are a small family, the Fistulariidae, of extremely elongated fishes in the order Syngnathiformes. The family consists of a single genus, ''Fistularia'', with four species, found worldwide in tropical and subtropic ...

, and probably should be included with these. The order as set out in the 5th Edition of Fishes of the World is classified as follows: * Order Syngnathiformes ** Suborder Syngnathoidei *** Superfamily

Pegasoidea The seamoths make up a family of fishes, the Pegasidae, within the order Syngnathiformes. They are named for Pegasus, a creature from Greek mythology. Seamoths are notable for their unusual appearance, including flattened bodies, the presence o ...

**** Family

(seamoths) *** Superfamily Syngnathoidea **** Family

Solenostomidae ''Solenostomus'', also known as the ghost pipefishes, false pipefishes or tubemouth fishes, is a genus of fishes in the order Syngnathiformes. ''Solenostomus'' is the only genus in the family Solenostomidae, and includes six currently recognized ...

(ghost pipefishes) **** Family

Syngnathidae The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons (''Phycodurus'' and ''Phyllopteryx''). The name is derived from grc, σύν (), meaning "together", and (), meaning "jaw". The fused jaw is one of the tra ...

(pipefishes and

s) ***** Subfamily

Syngnathinae Pipefishes or pipe-fishes (Syngnathinae) are a subfamily of small fishes, which, together with the seahorses and seadragons (''Phycodurus'' and ''Phyllopteryx''), form the family Syngnathidae. Description Pipefish look like straight-bodied seah ...

(

pipefishes Pipefishes or pipe-fishes (Syngnathinae) are a subfamily of small fishes, which, together with the seahorses and seadragons (''Phycodurus'' and ''Phyllopteryx''), form the family Syngnathidae. Description Pipefish look like straight-bodied seah ...

) ***** Subfamily

Hippocampinae The Hippocampinae are a subfamily of small marine fishes in the family Syngnathidae. Depending on the classification system used, it comprises either seahorses and pygmy pipehorses,Kuiter, R.H. (2000) "Seahorses, Pipefishes and their Relatives ...

(seahorses and pygmy pipehorses) ** Suborder

Aulostomoidei ''Aulostomoidei'' is a suborder of the order Syngnathiformes, which also contains groups such as the seahorses, pipefishes and dragonets. Classification There are two superfamilies within the Aulostomoidei and they are: * Superfamily Aulosto ...

*** Superfamily

Aulostomoidea ''Aulostomoidei'' is a superfamily of the order Syngnathiformes, which also contains groups such as the seahorses, pipefishes and dragonets. It is one of two superfamilies which make up the suborder Aulostomoidei within the Syngnathiformes. ...

**** Family

(

es) **** Family Fistularidae (

cornetfish The cornetfishes or flutemouths are a small family, the Fistulariidae, of extremely elongated fishes in the order Syngnathiformes. The family consists of a single genus, ''Fistularia'', with four species, found worldwide in tropical and subtropic ...

es) *** Superfamily

Centriscoidea Centriscoidea is a superfamily of the suborder Aulostomoidei, part of the order which includes the sea horses, piperfishes and dragonets, the Syngnathiformes. They are chareacterised by having the 5-6 anterior vertebrae being elongated and the ...

**** Family

Macroramphosidae Macroramphosidae, the snipefishes and bellowsfishes is a family of oviparous, marine fish which form part of the superfamily Centriscoidea, which is one of the two superfamilies in the suborder Aulostomoidei of the order Syngnathiformes, which inc ...

(snipefishes) **** Family

Centriscidae The Centriscidae are a family of fishes from the order Syngnathiformes which includes the snipefishes, shrimpfishes, and bellowfishes. A small family, consisting of only about a dozen marine species, they are of an unusual appearance, as reflecte ...

(shrimpfishes) **** Family

Dactylopteridae The flying gurnards are a family, Dactylopteridae, of marine fish notable for their greatly enlarged pectoral fins. As they cannot literally fly or glide in the air (like flying fish), an alternative name preferred by some authors is helmet gurna ...

(flying gurnards) Other authorities are of the view that without the inclusion of other taxa within Syngnathiformes then the order is

. This wider order consists of a "long snouted"

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

and a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

clade and this classification is: Abstract. * Order Syngnathiformes ** "long snouted clade" *** Suborder Syngnathoidei **** Family

(ghost pipefishes) **** Family

(pipefishes and seahorses) **** Family

(

es) **** Family Fistularidae (

es) **** Family

(shrimpfishes and snipefishes) ** "Benthic clade" *** Suborder

Callionymoidei Callionymoidei is a suborder of the Perciformes, the largest order of fish. The suborder includes the dragonet Dragonets are small, percomorph, marine fish of the diverse family Callionymidae (from the Greek ''kallis'', "beautiful" and ' ...

**** Family

Callionymidae Dragonets are small, percomorph, marine fish of the diverse family Callionymidae (from the Greek ''kallis'', "beautiful" and ', "name") found mainly in the tropical waters of the western Indo-Pacific. They are benthic organisms, spending most ...

(dragonets) **** Family

Draconettidae The Draconettidae, slope dragonets, are a small family (about 14 species) of fish in the order Perciformes. They are found in temperate to tropical waters of the Atlantic, Indian and western Pacific Oceans. They are closely related to, and appea ...

(slope dragonets) *** Suborder Mulloidei **** Family

Mullidae The goatfishes are perciform fish of the family Mullidae. The family is also sometimes referred to as the red mullets, which also refers more narrowly to the genus ''Mullus''. The family name and the English common name mullet derived from Lati ...

(goatfishes) *** Suborder Dactylopteroidei **** Family

(flying gurnards) **** Family

(seamoths) In their study Longo ''et al'' (2017) found that there were short distances between the groupings on the Syngnathiform

phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

and this supported a

hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...

that there had been a rapid but ancient

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

in the basal Syngnathiformes.

Fossil record

The earliest known syngnathiform is a species of Macroramphosidae, '' Gasteroramphosus zuppichini'' from the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

, which is similar in form to ''Marcroramphosus'' but which has some characters which are suggestive of a relation to

Gasterosteoidei Gasterosteoidei is a suborder of ray-finned fishes that includes the sticklebacks and relatives, the 5th edition of ''Fishes of the World'' classifies this suborder within the order Scorpaeniformes. Systematics Gasterosteoidei is treated as a ...

References

Integrated Taxonomic Information System The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...

(ITIS) (2004)
Syngnathoidei (TSN 166438)
Retrieved 2006-APR-08 * * Nelson, Joseph S. (2006): ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

''. John Wiley & Sons, Inc.

External links

* Skaphandrus.co
Syngnathiformes
{{Authority control Ray-finned fish orders