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)

By

Short, Graham
Claassens, Louw
Smith, Richard
De Brauwer, Maarten
Hamilton, Healy
Stat, Michael
Harasti, David

Type

Article

Date of Publication

2020

Original Publication

ZooKeys

Volume

934

Pages

141--156

Subjects

Africa , COI , cryptobenthic , Ichthyology , marine fish , Morphology , Sodwana Bay , taxonomy

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/zookeys.934.50924

 

Abstract

A new species and the first confirmed record of a true pygmy seahorse from Africa, Hippocampus nalusp. nov., is herein described on the basis of two specimens, 18.9–22 mm SL, collected from flat sandy coral reef at 14–17 meters depth from Sodwana Bay, South Africa. The new taxon shares morphological synapomorphies with the previously described central Indo-Pacific pygmy seahorses, H. colemani, H. japapigu, H. pontohi, and H. satomiae, and H. waleananus, including diminutive size, twelve trunk rings, prominent cleithral ring and supracleithrum, spines on the fifth and twelfth superior and lateral trunk ridges, respectively, and prominent wing-like protrusions present on the first and/or second superior trunk rings posterior to the head. Hippocampus nalusp. nov. is primarily distinguished from its pygmy seahorse congeners by highly distinct spine morphology along the anterior segments of the superior trunk ridge. Comparative molecular analysis reveals that the new species demonstrates significant genetic divergence in the mitochondrial COI gene from the morphologically similar H. japapigu and H. pontohi (estimated uncorrected p-distances of 16.3% and 15.2%, respectively). Hippocampus nalusp. nov. represents the eighth member of the pygmy seahorse clade to be described from the Indo-Pacific, the first confirmed record from the African continent and the Indian Ocean, and an extension of more than 8000 km beyond the previously known range of pygmy seahorses from the Central and Western Indo-Pacific.