The Syngnathiformes are an

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

es that includes the leafy seadragons, sea moths, trumpetfishes and

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

s, among others.

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 generally elongate, narrow bodies surrounded by a series of bony rings, with small, tubular mouths. The shape of their mouth—at least, in syngnathids—allows for the ingestion of prey at close range via

suction Suction is the day-to-day term for the movement of gases or liquids along a pressure gradient with the implication that the movement occurs because the lower pressure pulls the gas or liquid. However, the forces acting in this case do not orig ...

. Many species of Syngnathiformes also employ strategic

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

(such as cryptic coloration and overall physical form) to hunt successfully and gain closer access to prey, as well as to protect themselves from larger predators. Several groups, for example, 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 ...

, not only swimming with their bodies aligned vertically (to blend in with the floating plant matter) but have also developed physical features that mimic the seaweed. The pygmy seahorses are among the smallest of all syngnathids, with most being so tiny—and mimicking the specific

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

they spend their lives on—that they were only recently described by scientists. The most defining characteristic of Syngnathiformes is their reproductive and sexual system, in which syngnathid males become "pregnant" and carry the embryonic fry. The males house the fertilized eggs in an osmo-regulated brood pouch, or (in some species) adhere them 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 classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''syn'' (συν, "together") + ''gnathos'' (γνάθος, "jaw"). The ending for

orders Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * H ...

, "-formes", is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

, and indicates "of similar form".

Fossil record

The earliest known syngnathiform is '' Gasteroramphosus'' from the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

(either

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

) of

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

, 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 ...

. However, most recent studies have reaffirmed it being a syngnathiform. The second oldest syngnathiform is the syngnathoid '' Eekaulostomus'' from the early

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

(

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretac ...

) of

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. Many fossil syngnathiform families are known from the

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

Systematics and taxonomy

In some models, these fishes are placed as the

suborder Order () 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 recognized ...

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 a ...

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 close ...

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 teleost, 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 th ...

, they might not be particularly close relatives at all. In addition, the Pegasidae (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 gurnards (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 fi ...

'' 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 (biology), order of Actinopterygii, 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 spec ...

. However,

DNA sequence A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nu ...

data quite consistently support the belief that the latter are

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

with the Gasterosteiformes ''sensu lato''. As it seems, flying gurnards are particularly close to Aulostomidae and Fistulariidae, 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 The Syngnathiformes are an order of ray-finned fishes that includes the leafy seadragons, sea moths, trumpetfishes and seahorses, among others.FishBase (2005)Order Summary for Syngnathiformes Version of 2005-FEB-15. Retrieved 19 Aug 2008. Th ...

*** Superfamily Pegasoidea **** Family Pegasidae (seamoths) *** Superfamily Syngnathoidea **** Family Solenostomidae (ghost pipefishes) **** Family Syngnathidae (pipefishes and

s) ***** Subfamily Syngnathinae (

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 (seahorses and pygmy pipehorses) ** Suborder Aulostomoidei *** Superfamily Aulostomoidea **** Family Aulostomidae ( trumpetfishes) **** Family Fistularidae ( cornetfishes) *** Superfamily Centriscoidea **** Family Macroramphosidae (snipefishes) **** Family Centriscidae (shrimpfishes) **** Family Dactylopteridae (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 In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

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 the Ancient Greek word (), meaning "the depths". ...

clade and this classification is: Abstract. * Order Syngnathiformes ** "long snouted clade" *** Suborder Syngnathoidei **** Family Solenostomidae (ghost pipefishes) **** Family Syngnathidae (pipefishes and seahorses) **** Family Aulostomidae ( trumpetfishes) **** Family Fistularidae ( cornetfishes) **** Family Centriscidae (shrimpfishes and snipefishes) ** "Benthic clade" *** Suborder Callionymoidei **** Family Callionymidae (dragonets) **** Family Draconettidae (slope dragonets) *** Suborder Mulloidei **** Family Mullidae (goatfishes) *** Suborder Dactylopteroidei **** Family Dactylopteridae (flying gurnards) **** Family Pegasidae (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 or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...

and this supported a

hypothesis A hypothesis (: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educated guess o ...

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 a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

in the basal Syngnathiformes. Syngnathiformes contains about 290 recognized extant species, depending which taxonomy is adopted. Of these, 252 are in the family Syngnathidae.

Fossil families

The following fossil families are known: * Family † Aulorhamphidae * Family † Paraeoliscidae * Suborder

** Family † Eekaulostomidae ** Superfamily Aulostomoidea *** Family † Fistularioididae *** Family † Parasynarcualidae *** Family † Urosphenidae ** Superfamily Syngnathoidea *** Family † Protosyngnathidae **Superfamily Centriscoidea *** Family † Gerpegezhidae * Suborder Dactylopteroidei ** Superfamily Pegasoidea *** Family † Rhamphosidae

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'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

''. John Wiley & Sons, Inc.

External links

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