A new seahorse (Teleostei: Syngnathidae: Hippocampus) from south-western Australia

Abstract

A new species of syngnathid fish, Hippocampus paradoxus sp. nov., from mid-continental shelf waters of south-western Australia is described from the only known specimen. It can be distinguished from all congeners, including the very similar H. minotaur Gomon 1997, by the following features: the lack of a dorsal fin, a series of fleshy, fin-like lobes along the dorsal midline of the trunk and tail and an extremely robust cleithrum and prominent first nuchal plate. In addition to the traditional methods of syngnathid taxonomists, X-ray microtomography (CT scanning) was employed and demonstrated to be a valuable research tool for examining seahorse species that are problematic due to reduced ossification and small size. CT scanning is more capable of imaging poorly ossified and soft tissue regions than traditional radiography and provides a detailed three dimensional view of salient features.