A collaborative team of paleontologists from New Zealand and Australia has identified a new, extinct species of Shelduck from Holocene fossil bone deposits located in the Likov Chatham Islands.
The artistic reconstruction of rēkohu Shelduck (Tadnarekov) highlights the dark feathers typical of island-dwelling birds. Image credit: Sasha Votyakova/Te Papa.
The rēkohushelduck (Tadnarekov) is a newly described species that inhabited the Chatham Islands, a remote archipelago situated 785 km east of the New Zealand mainland.
“The archipelago comprises Chatham Island, Rangihautepit, Mangere, Tapua, and various smaller islands,” explained the researchers.
“These islands were completely submerged during the late Miocene and early Pliocene epochs.”
“Subsequent geological activities resulted in their re-emergence roughly three million years ago.”
According to the research team, the ancestors of the Rēkohu Shelduck reached the Chatham Islands around 390,000 years ago, during the late Pleistocene.
“While this may seem like a brief period, it’s long enough to influence species development,” Dr. Lawrence noted.
“At that time, the Rēkohu Shelduck exhibited shorter, more robust wings and longer leg bones, adaptations that impacted flight capability.”
“These evolutionary changes resulted from various factors, such as ample food availability, a lack of ground predators, and windy conditions, making flight less necessary.”
“If you don’t use them, you lose them; wings start to diminish,” remarked Dr. Pascare Lube from University of Otago.
“Flying is energy-efficient, so if it’s not essential, why expend the effort?”
“More robust leg bones support increased muscle mass and strength for takeoff, which is crucial when wings are small.”
The researchers utilized ancient DNA analysis and bone morphology to characterize the rēkohushelduck, a cousin of the Paradise Shelduck (Tadorna variegata) native to New Zealand.
Rēkohu Shelduck spent a majority of its time on the ground and became extinct prior to the 19th century.
“The discovery of rēkohushelduck bones in early Moriori Midden deposits indicates that hunting likely contributed to its extinction prior to European contact and the subsequent Māori settlements in the 19th century,” the scientists reported.
Their study was published in the July 2025 issue of The Linnaean Society’s Journal of Zoology.
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Nicholas J. Lawrence et al. 2025. Ancient DNA and morphometrics reveal a new species of Shelduck, an extinct island inhabitant from the Rēkohu Chatham Islands. The Linnaean Society’s Journal of Zoology 204 (3): ZLAF069; doi: 10.1093/zoolinnean/zlaf069
Source: www.sci.news
