Project Seahorse recently published a revision of the seahorses, genus Hippocampus, in support of conservation and management of these vulnerable marine fishes:
Sara A. Lourie, Riley A. Pollom & Sarah J. Foster (2016) A global revision of the seahorses Hippocampus Rafinesque 1810 (Actinopterygii: Syngnathiformes): Taxonomy and biogeography with recommendations for further research. Zootaxa 4146 (1): 001–066.
Our global revision of 41 seahorse species was based on the best available morphological, genetic, and geographic information. The changes we have made will make a positive difference in seahorse conservation and management going forward by reducing confusion surrounding seahorse taxonomy. For example, all species can be told apart from nearest neighbours by their morphology alone – this is essential if seahorses are to be identified by fisheries agencies, Customs officers and citizen scientists, among others. We have also indicated standard common names for all valid species. The Catalogue of Fishes, which is considered by many to be the standard taxonomic reference for valid species of fish, has already been updated to reflect most of the taxonomic changes we propose in our revision.
In the coming months we will be working with the IUCN Red List of Threatened Species, The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), FishBase, and iNaturalist (which powers our citizen science initiative iSeahorse) to consider how best to incorporate the changes we have made. If adopted, however, our revision will have limited impact on the IUCN Red List, CITES or iSeahorse as they currently stand.
For more details on this go to the Seahorse, Pipefish and Stickleback Species Specialist Group website