Sodwana Pygmy Seahorse, Hippocampus nalu Short et al, 2020

Introduction

The Sodwana Pygmy Seahorse, Hippocampus nalu, is the first pygmy seahorse species to be found in African waters and the Indian Ocean.

The new Sodwana Pygmy Seahorse is tiny, growing to just over 2 cm (about the size of a grain of rice) and has a honey-brown colour overlaid with a white netted pattern and a reddish tail.

Hippocampus nalu was described by Australian Museum Research Associate, Graham Short. The scientific name of the Sodwana pygmy seahorse, Hippocampus nalu, means “here it is” in the local Xhosa and Zulu languages to highlight that the species was there all along until its discovery. The name also refers to the middle name of the person who discovered it and first brought the species to the attention of the researchers, Savannah Nalu Olivier .

Researchers first noticed this new species of pygmy seahorse on a sandy flat reef area at a popular scuba diving area within the iSimangaliso Wetland Park, a World Heritage site located along the north coast of KwaZulu Natal province South Africa. The individuals were found at 14m depth and were using their prehensile tails to loosely hang onto small clumps of short algal turf. These amazing seahorses were often observed being covered in sand or being swept from one location to another in sandy gullies.

Hippocampus nalu differs from the closely related “Japan pig seahorse” (Hippocampus japapigu), recently described by the same research team in 2018, and other pygmy seahorses in the shape of the large spines located directly behind the head. Whereas the large spines are flat-tipped in most pygmy seahorse species, H. nalu possesses unusual double pointed large spines, which were revealed using micro computed tomography (CT).

Hippocampus nalu represents the eighth member of the pygmy seahorse clade to be described from the Indo-Pacific, while being the first confirmed record from the African continent and the Indian Ocean. The first pygmy seahorse, Hippocampus bargibanti, was discovered in New Caledonia in 1969 and described by Australian Museum Fish Curator, Gilbert Whitley in 1970. Since then seven more pygmy seahorses have been discovered from including Hippocampus denise (2003) from Indonesia, Hippocampus colemani (2003) from Lord Howe Island, Hippocampus pontohi (2008), Hippocampus satomiae (2008) and Hippocampus walaenanus (2009) ; all discovered from Indonesia and Hippocampus japapigu (2018) discovered from Japan.

Reference:

Short, G., Claassen L, Smith, R., Brauwer, M., & Hamilton, H., Stat M., Harasti, D. 2020. Hippocampus nalu,​ a new species of pygmy seahorse from South Africa, and the first record of a pygmy seahorse from the Indian Ocean (Teleostei, Syngnathidae) ZooKeys. DOI: 10.3897/zookeys.934.50924.

Further information:

Caboz, J. 2020. Meet the Indian Ocean's first pygmy seahorse - which was discovered in KZN. Business Insider South Africa.

Gomon, M. F. 1997 See ref. at BHL A remarkable new pygmy seahorse (Syngnathidae: Hippocampus) from south-eastern Australia, with a redescription of H. bargibanti Whitley from New Caledonia. Memoirs of the Museum of Victoria v. 56 (no. 1): 245-253.

Gomon, M. F. and R. H. Kuiter 2009. Two new pygmy seahorses (Teleostei: Syngnathidae: Hippocampus) from the Indo-West Pacific. aqua, International Journal of Ichthyology v. 15 (no. 1): 37-44.

Ketchell, M. 2020. How an underwater photo led to the discovery of a tiny new seahorse species. The Conversation.

Kuiter, R. H. 2003. A new pygmy seahorse (Pisces: Syngnathidae: Hippocampus) from Lord Howe Island. Records of the Australian Museum v. 55: 113-116. . See ref. online

Lourie, S. A. and J. E. Randall 2003. A new pygmy seahorse, Hippocampus denise (Teleostei: Syngnathidae), from the Indo-Pacific. Zoological Studies v. 42 (no. 2): 284-291.

Lourie, S. A. and R. H. Kuiter 2008. Three new pygmy seahorse species from Indonesia (Teleostei: Syngnathidae: Hippocampus). Zootaxa No. 1963: 54-68.

Main, D. 2020. New pygmy seahorse discovered, first of its kind in Africa. National Geographic.

Short, G., Ri. Smith, H. Motomura, D. Harasti and H. Hamilton 2018 See ref. online Hippocampus japapigu, a new species of pygmy seahorse from Japan, with a redescription of H. pontohi (Teleostei, Syngnathidae). ZooKeys No. 779: 27-49.

University of Leeds. 2020. Meet Africa's first pygmy seahorse species. Phys Org.

Whitley, G.P. 1970. [Bargibant's sea-horse from New Caledonia] in Abstracts of Proceedings. Proceedings of the Linnean Society of New South Wales. 94(3) No.421:294.