Smallspine turretfish

Lore & Background

The smallspine turretfish was first formally described as Triorus reipublicae in 1930 by Australian ichthyologist Gilbert Percy Whitley, with its type locality given as Moreton Bay in Queensland. Whitley based his description on Lactophrys reipublicae described by James Douglas Ogilby in 1913, which is a nomen nudum, plus additional material. Some authorities regard the taxon Tetrosomus concatenatus as a synonym of the Western Atlantic Lactophrys triqueter, and that Indo-Pacific specimens assigned to T. concatenatus are actually this species.

The genus name Tetrosomus combines tetra, meaning 'four', and somus, meaning 'body', referring to the quadrangular shape of the body. The specific name reipublicae means 'commonwealth', an allusion to the Commonwealth of Australia, a name invented by Ogilby for the Australian populations of L. concatenatus.

The smallspine turretfish is greenish to brown or pinkish, with juveniles marked by dark spots; as they grow, the numbers of blue spots and lines increase. It has two spines on the dorsal ridge, a carapace with a triangular cross-section, a small mouth, and a pointed snout. The dorsal fin is located further forward than the anal fin.

Reader's Guide

The smallspine turretfish is a member of the genus Tetrosomus within the family Ostraciidae, classified in the suborder Ostracioidea of the order Tetraodontiformes according to the 5th edition of Fishes of the World. Its significance lies in its distinctive morphology—a quadrangular body with a triangular carapace and two dorsal spines—and its wide Indo-Pacific distribution, from East Africa through Indonesia north to southern Japan and south to Australia. In Australia, it ranges from Albany to northeast of the Monte Bello Islands, Western Australia, and north Queensland as far south as Tathra, New South Wales, as well as in the Lord Howe Province in the Tasman Sea. The species inhabits inshore reefs and seagrass meadows. The taxonomic history includes a nomen nudum by Ogilby and ongoing uncertainty regarding the synonymy of Tetrosomus concatenatus, which some authorities consider a Western Atlantic species rather than an Indo-Pacific one. This species reaches a maximum total length of 30 cm.

Did You Know?

• Its specific name reipublicae means 'commonwealth', referring to the Commonwealth of Australia.
• Juveniles have dark spots that are replaced by increasing numbers of blue spots and lines as they grow.
• The species has two spines on the dorsal ridge and a carapace with a triangular cross-section.