Enigmatic pygmies - our latest featured iSeahorse observation

By Kately Nikiforuk

For a miniscule fish, Pontoh’s pygmy seahorse, our species du jour, has caused disproportionately hefty levels of confusion. Thanks to iSeahorse user tantsusoo for a stunning and thought-provoking picture from Raja Amput, Indonesia!

Hippocampus pontohi , in Raja Ampat, Indonesia. Photo by tansusoo on iSeahorse

Hippocampus pontohi, in Raja Ampat, Indonesia. Photo by tansusoo on iSeahorse

So, what’s odd about this observation? Well, the taxonomy surrounding pygmy seahorses is still a tad fuzzy, which makes them hard to concretely identify. Originally, the photographer suggested that this individual was H. pontohi, but, a day later, wondered if perhaps it was a closely related, similar-looking species instead - Coleman’s pygmy seahorse, H. colemani. Project Seahorse wasn’t sure either, so we consulted with Dr. Richard Smith, our pygmy seahorse expert.

Dr. Smith’s verdict was Pontoh’s pygmy - thus far, Coleman’s pygmy has only been found at Lord Howe Island, a remote volcanic crater rim east of Australia, and tantsusoo’s observation was in Indonesia. However, that doesn’t necessarily mean Coleman’s don’t live elsewhere - considering how long it took to discover the mere existence of pygmy seahorses, it wouldn’t be overly surprising if they’re hiding in other habitats. That being said, Lord Howe Island is a hotspot for endemic species, so maybe Coleman’s truly is found nowhere else on earth.  

To complicate matters further, it is entirely possible that H. pontohi and H. colemani are actually the same species! If Pontoh’s and Coleman’s were clumped together, it wouldn’t be the first time for H. pontohi. Severn’s pygmies and Pontoh’s pygmies were once considered two species that were very similar, except that one was brown and the other was white. H. pontohi and H. severnsi were regarded as separate largely because these colour variants were not sex-based, and the two types weren’t seen together - both phenomena can be a tell-tale clue that speciation (formation of new and distinct species in the course of evolution) has taken place.

These days, what used to be H. severnsi is just a colour morph of H. pontohi, after their DNA was sequenced and they were found to be identical. Now, if only we could do that with Pontoh’s pygmy and Coleman’s pygmy! DNA sequencing is a handy forensic tool when solving species mysteries, but we simply don’t know enough yet to crack this particular case. There are currently no Coleman’s pygmy seahorse pictures on iSeahorse, and our pygmy seahorse expert, Dr. Richard Smith, is yet to even see one in the wild.

Dr. Smith is in Lord Howe in February though, so fins crossed that he’ll find some H. colemani! We’ll keep you posted!

Check out Dr. Richard Smith’s website:
http://oceanrealmimages.com/pygmy-seahorses/species/

Learn more about Pontoh’s pygmy seahorses:
https://www.iucnredlist.org/species/107261198/54909454

Learn more about Coleman’s pygmy seahorses:
https://www.iucnredlist.org/species/47728602/47736420