Syngnathiformes

Taxobox
name = Syngnathiformes

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image_width = 200px
image_caption = Trumpetfish ("Aulostomus maculatus": Aulostomidae), head in natural pose
regnum = Animalia
phylum = Chordata
superclassis = Osteichthyes
classis = Actinopterygii
subclassis = Neopterygii
infraclassis = Teleostei
superordo = Acanthopterygii
ordo = Syngnathiformes
ordo_authority = Helfman, Collette & Facey, 1997
subdivision_ranks = Families
subdivision =
Aulostomidae
Centriscidae
Fistulariidae
Pegasidae (disputed)
Solenostomidae
Syngnathidae
and see text

Syngnathiformes is an order of ray-finned fishes that includes the pipefishes and seahorses.FishBase (2005)]

These fishes have elongate, narrow, bodies surrounded by a series of bony rings, and small, tubular mouths. Several groups live among seaweed and swim with the body aligned vertically, to blend in with the stems.

The name "Syngnathiformes" means "conjoined-jaws". It is derived from Ancient Greek "syn" ("συν", "together") + "gnathos" ("γνάθος", "jaw"). The ending for fish orders "-formes" is derived from Latin and indicates "of similar form".

Systematics and taxonomy

In some treatments, these fishes are placed as the suborder Syngnathoidei of the order Gasterosteiformes together with the sticklebacks and their relatives [E.g. Helfman "et al." (1997), ITIS (2004), Nelson (2006)] . Better supported by the evidence nowadays available is the traditional view [E.g. McAllister (1968)] that they are better considered separate orders, and indeed among the Acathopterygi they might be not particularly close relatives at allKawahara (2008)] .

In addition, the armoured stickleback (Indostomidae) and 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 probably still best considered an actinopterygian order of its own for the time being.

Morphological traits uniting the flying gurnards (Dactylopteridae) and the Syngnathiformes have long been noted [Pietsch (1978)] . Most authors however placed them with the Scorpaeniformes. However, DNA sequence data quite consistently supports the view that the latter are paraphyletic with the Gasterosteiformes "sensu lato". As it seems, flying gurnards are particularly close to Aulostomidae and Fistulariidae, and would have to be included with these.

A tentative list of the families in the phylogenetic sequence can be given as follows:
* Centriscidae – razorfishes, shrimpfishes and snipefishes (including Macroramphosidae)
* Pegasidae – dragonfishes and sea moths (tentatively placed here)
* Solenostomidae – false pipefishes, ghost pipefishes and tubemouth fishes
* Syngnathidae – seahorses and true pipefishes
* Aulostomidae – trumpetfishes
* Dactylopteridae – flying gurnards (tentatively placed here)
* Fistulariidae – cornetfishes

Footnotes

References

* (2005): [http://www.fishbase.org/Summary/OrdersSummary.cfm?order=Syngnathiformes Order Summary for Syngnathiformes] . Version of 2005-FEB-15. Retrieved 2008-AUG-19.
* (2004): [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=166438 Syngnathoidei (TSN 166438)] . Retrieved 2006-APR-08
* (2008): Interrelationships of the 11 gasterosteiform families (sticklebacks, pipefishes, and their relatives): A new perspective based on mitogenome sequences from 75 higher teleosts. "Mol. Phylogenet. Evol." 46(1): 224–236. doi|10.1016/j.ympev.2007.07.009 (HTML abstract)
* (1968): Evolution of branchiostegals and classification of teleostome fishes. "Bulletin of the Nattional Museum of Canada, Ottawa" 221: 1–239.
* (2006): "Fishes of the World". John Wiley & Sons, Inc. ISBN 0471250317
* (1978): Evolutionary relationships of the sea moths (Teleostei: Pegasidae) with a classification of gasterosteiform families. "Copeia" 1978(3): 517–529. [http://www.jstor.org/pss/1443620 JPEG abstract and first page text]