A Pliocene boxfish (Tetraodontiformes, Ostraciidae) from New Zealand – a preview of future environmental change?

Abstract

ABSTRACT We report on an articulated fossil boxfish (Tetraodontiformes, Ostraciidae) recently recovered from the Pliocene of the North Island of New Zealand. The specimen was collected from the Tangahoe Formation, a mid-Pliocene (c. 3.0-3.4 Ma) shallow marine deposit, at Waihi Beach, South Taranaki. The fossil boxfish measures 10.7 cm in standard length, with an estimated total length of c. 13–14 cm (the caudal fin is not preserved). The fish is preserved in right lateral view, lying on its side, and has an intact body covering of fused hydroxyapatite plates that rigidly encase the fish, as is characteristic of boxfishes. The plates are hexagonal to subhexagonal in shape and largest close to the dorsal midline. Fossil boxfish have previously been recorded from Northern Hemisphere sites ranging in age from Palaeocene to Quaternary, but not from the Southern Hemisphere. Recent reports note that boxfishes and several other tropical Pacific fish species are now being seen off of northern New Zealand – the Pliocene boxfish from Taranaki, as well as an intriguing addition to New Zealand’s paleohistory, may also reflect how the ongoing impact of climate change will return New Zealand to a warmer marine ecosystem – similar to what prevailed during the Pliocene.