Seahorses Seadragons Pipehorses and Pipefish

Kingdom:   Animalia

Phylum:  Chordata

Subphylum:  Vertebrata

Infraphylum:  Gnastostomata

Parvphylum:  Osteichthyes

Gigaclass:  Actinopterygii

Class:    Actinopteri

Subclass:    Teleostei

Order:  Syngnathiformes

Family:  Syngnathidae

Syngnathidae's are the Family that includes Seahorses, Pipefish, Pipehorses, and Seadragons. Melbourne is lucky to have all three of these. What makes them unique is that the males carry the eggs and are then responsible for ensuring their offspring are born.
“The hippocampus is found in the temporal lobe below the cerebral cortex. Although we often refer to it in the singular, there are actually two hippocampi—one in each cerebral hemisphere. The term hippocampus comes from the Greek word for seahorse, because when it is removed from the brain, the hippocampus vaguely resembles a seahorse.” (2) 
The major differences between the species, besides their physical appearance,
  1. DNA, obviously
  2. Where and how they hold the eggs.
  • Seahorses carry the eggs in a brood pouch.
  • Seadragons carry their eggs on their tales in cup like structures.
  • Pipefish can carry eggs on their tail past the anus while others carry it forward of the anus. Pipefish are separated even more by how they hold their eggs with different skin structures.
Reproduction of Syngnathidaes
Skinner, M 2018 Encyclopedia of Reproduction 2nd Edition. Fig. 4. Evolution of syngnathid fishes. Brood pouch types are shown with increasing complexity within the Urophori and Gastrophori. Modified from Wilson, A.B., Ahnesjö, I., Vincent, A.C., Meyer, A., 2003. The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (family Syngnathidae). Evolution 57, 1374–1386. dated 14.11.2021
In Port Phillip Bay we have two species of seahorses, (maybe 3) all in the (FAMILY: Syngnthidae SUBFAMILY: Hippocampinae) Genus: Hippocampus.
Port Phillip Bay has the Big bellied and Short headed Seahorses. There was a third believed to be extinct, however scientists got excited about a photo in 2019 that may have been a photo of the extinct species.
How do you tell the difference between seahorses?
Mostly by the coronet or the head. Different seahorses have different arrangements of filaments or appendages on their heads. Check out pictures of a big bellied sea horse and pictures a short headed seahorse.
Check the obvious differences.
Size:   Big bellied seahorses can grow to 30cm and the Short headed seahorse only grows to about 8cm at adult size.'
Colour:    Seahorses can change colour depending on habitat. but if you look at the pics attached the short headed seahorses have white dots on the body.
Hippocampus abdominalis
 Photo by Paul Sorensen. Taken at Blairgowrie Pier
 Bigbellied Seahorse Hippocampus abdominalis
 Photo by Paul Sorensen. Taken at Mornington Pier
Short Headed Seahorse
Hippocampus breviceps  (Peters, 1869)
Short Headed Seahorse  Hippocampus breviceps
Photo by Paul Sorensen. Taken at Blairgowrie Pier
 Short Headed Seahorse  Hippocampus breviceps
 Photo by Paul Sorensen. Taken at Blairgowrie Pier
Leafy Seadragon
Phycodurus eques   (Gunther, 1865)
Leafy Seadragon
Photo by Paul Sorensen. Taken at Rapid Bay 11.03.2020.
Weedy Seadragon

Phyllopteryx taeniolatus  (Lacepede, 1804)

Weedy Seadragon
Photo by Paul Sorensen. Taken at Flinders Pier
Ringback Pipefish
Stipecampus cristatus
Ringback Pipefish (Stipecampus cristatus, McCulloch & Waite, 1918)
Sydney Pygmy Pipehorse

Idiotropiscis lumnitzeri  (Kuiter, 2004)

Sydney Pygmy Pipehorse Idiotropiscis lumnitzeri	(Kuiter, 2004)