Paleontologists have discovered a trackway of seven moa footprints and an associated separate footprint at a riverbank outcrop of the Maniototo Conglomerate Formation in the Kyeburn River, South Island, New Zealand.
The footprints of the Emeidae moa found in the Kyeburn River, South Island, New Zealand; the associated Dinornithidae footprint can be seen between the first two footprints to the left. Image credit: Ian Griffin / Otago Museum.
The moa is an extinct order of giant, flightless birds (Dinornithiformes) comprising nine species that lived during the Late Quaternary epoch.
The species varied from the size of a large turkey (e.g. Euryapteryx curtus) up to the 3 m tall female giant moa (Dinornis spp.).
Some species showed high amounts of sexual dimorphism with females being considerably larger than the males.
Moa species appear to have been adapted to different habitats and diets, inhabiting a wide range of environments, including subalpine areas, forest, and open shrubland-grasslands.
They were important natural food source species to Māori until their extinction approximately 600 years ago.
The first known moa footprints were found near the mouth of the Tūranganui River in Tairawhiti Gisborne in 1866.
Since then, several other sporadic finds have been made across the North Island but moa footprints have only recently been found in the South Island.
These include the newly-described Kyeburn footprints as well as those found in Paeroa, south of Timaru, South Canterbury in 2022.
An artist’s impression of the moa which created the Kyeburn footprints. Image credit: Paulina Barry.
In their study, Tūhura Otago Museum paleontologist Kane Fleury and colleagues found that a trackway of seven Kyeburn footprints were left by a member of the moa family Emeidae, most likely of the genus Pachyornis.
The footprints were 4.6 cm deep, 27.2-30 cm wide and 26-29.4 cm in length.
The trackway maker had a mean mass of 84.61 kg and was traveling at a speed of 2.61 km/h.
To the researchers’ surprise, a 3D photogrammetry model of the fossil site later revealed the presence of a second moa.
This individual left a separate footprint around 44.8 cm wide and 28.5 cm long.
The bird was from the family Dinornithidae, most likely from the genus Dinornis with an estimated mass of 158 kg.
These footprints are the second-earliest fossil record of moa and, given the dimensions of the lone Dinornithidae print, moa had attained their legendary gigantic size by the Pliocene.
“Many moa remains or traces are extremely recent in geological terms — less than 10,000 years old,” Dr. Fleury said.
“However, the Kyeburn prints were buried 3.6 million years ago, so they offer a rare glimpse into a period of moa evolution that is not well understood, making them still more significant.”
The study was published in the Journal of the Royal Society of New Zealand.
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Kane Fleury et al. The moa footprints from the Pliocene – early Pleistocene of Kyeburn, Otago, New Zealand. Journal of the Royal Society of New Zealand, published online November 14, 2023; doi: 10.1080/03036758.2023.2264789
