''Leiognathus longispinis'', commonly known as the longspine- or Smithurst's ponyfish, is a fish of brackish and marine waters found in the Indian and western Pacific Oceans, from India through Malaysia and Indonesia south to northern Australia and east to the Philippines and Fiji It was described in 1835 by French Zoologist

Achille Valenciennes Achille Valenciennes (9 August 1794 – 13 April 1865) was a French zoology, zoologist. Valenciennes was born in Paris, and studied under Georges Cuvier. His study of parasitic worms in humans made an important contribution to the study of parasi ...

from a specimen caught off

Waigeo Waigeo is an island in the Southwest Papua province of eastern Indonesia. The island is also known as Amberi or Waigiu. It is the largest of the four main islands in the Raja Ampat Islands archipelago, between Halmahera and about to the nort ...

island in Irian Jaya in New Guinea. In 1886 Ramsay and Ogilby described what turned out to the same species from Hood Lagoon in Papua New Guinea, naming it ''Leiognathus smithursti''. In 2008, ichthyologists Prosanta Chakrabarty and John S. Sparks resurrected the genus ''Aurigequula'' and placed ''L. longispinis'' and '' L. fasciatus'' in it, on the basis of a horizontal row of yellow markings on their flanks and elongated second spine of the dorsal fin. However, a molecular study showed that the genus ''Leiognathus'' was nested within ''Aurigequula'', and hence the genera were merged once more. Fishbase places this species in ''Leiognathus'' while retaining the striped ponyfish (''Aurigequula fasciata)'' in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

''Aurigequula''. The longspine ponyfish reaches a total length of . It is distinguished by a long spine on both its dorsal and anal fin. Found to depths of around , the longspine ponyfish forages on the sea floor, generally in murky environs, consuming fish, crustaceans, arrow worms,

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

s, and shellfish such as bivalves, and gastropods. Like all members of the

ponyfish Leiognathidae, the ponyfishes, slipmouths or slimys / slimies, are a small family of fishes in the order Perciformes. They inhabit marine and brackish waters in the Indian and West Pacific Oceans. They can be used in the preparation of ''bagoo ...

family, the longspine ponyfish is bioluminescent. The ventral surface glows, which is thought to provide camouflage and confuse predators.

References

{{Taxonbar, from=Q5234639 Fish of the Pacific Ocean Fish of the Indian Ocean Fish of the Philippines Bioluminescent fish Fish described in 1835 longispinis