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The family Syngnathidae
with more than 230 species are part of the Gasterosteiformes. Their closest
relatives the Sticklebacks have only seven species and are concentrated
in the Europe and North America. Recent evidence suggests that the Syngnathidae
had their centre of origin in the Pacific about 40 million years ago.
From there they migrated until they occupied most oceans of the world.
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Fossil
seahorse:
Hippocampus ramulosus (Fossil), Age:
Lower Pliocene, Size:108 mm in length. Location: Marecchia
River Formation, Poggio Berni, Rimimini Province, Italy. |
Fossil pipefish |
The development and
diversification of the male brood pouch appears to be a driving force
in the evolution of different taxon. Some brood pouch types appear conservative;
the Pacific and Atlantic Syngnathus sp. pipefish are only distantly
related even though their brood pouch types are similar. However, other
structures such as raised dorsal fin bases, absence of caudal fins, and
prehensile tails have had many independent origins in the Syngnathids.
Therefore, current
evidence suggests that the Syngnathidae first evolved in the Pacific and
that some Syngnathids, mainly the Hippocampus sp. (seahorses) and
Syngnathid sp. (pipefish) then colonised the other oceans.
Southern Australian
species include the highest diversity of genera in the world. These include
the beautiful and unique Seadragons and many other genera. The Stigmatopora
sp. pipefish, which recent studies have shown to include new species,
appear to be of ancient lineage and of phylogenetic status equivalent
to the seahorses (Hippocampus sp.), Syngnathid and Doryrhampus
pipefish.
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The diagram
(left) shows the lineage of most Syngnathids. The species or genera
in red are found in southern Australia.
For more details on the unique Syngnathids of southern Australia
see World
Distribution of Syngnathids
; and for details of southern
Australian species see Southern
Australian Pipefish. The main phylogenetic theme of the
Southern Australian Pipefish table is a revision of the pipefish
genera Stigmatopora. Also reference is made to species in
the Vanacampus genera which probably also includes several
novel species.
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