Extinct New Zealand Raven was one species
Saturday 01 October 2016
R Paul Scofield, Kieren J Mitchell, Jamie R Wood, Vanesa L De Pietri, Scott Jarvie, Bastien Llamas, Alan Cooper (2016) The Origin and Phylogenetic Relationships of the New Zealand Ravens, Molecular Phylogenetics and Evolution.
Chatham Island Raven
A new DNA study of the extinct New Zealand Raven and Chatham Island Raven, published in Molecular Phylogenetics and Evolution (2016), has found that they formed a single species with one or two subspecies, and were not two species with two subspecies as previously thought.
According to authors Paul Scofield and Vanesa De Pietri (Canterbury Museum), Kieren Mitchell, Alan Cooper and Bastien Llamas (University of Adelaide), Jamie Wood (Landcare Research) and Scott Jarvie (University of Otago), the New Zealand Ravens were sister-taxa to a surviving clade comprising Australian Raven, Little Raven, and Forest Raven of Australia.
In the study – 'The Origin and Phylogenetic Relationships of the New Zealand Ravens' – they estimate that the divergence between the New Zealand Raven and Australian Raven clade occurred in the late Pliocene, about 2.6 million years ago, and that the divergence between the two New Zealand taxa probably occurred in the late Pleistocene, about 12,000 years ago, making their separation as species within New Zealand untenable.
They also conclude that the morphology of the skull suggests Chatham Island Raven was unique among the genus Corvus and suggest that it may have been an adaptation for a unique dietary specialisation: opportunistic scavenging at the vast sea lion rookeries that once lined the beaches of the North Island and eastern and southern South Islands and Chatham Islands.
Weighing up to one kilogram, New Zealand Raven was one of the largest songbird species in New Zealand before it became extinct at the time of human arrival. Like their Australian relatives, they were probably glossy black, omnivorous and aggressive. They had relatively long, slender legs, a long, broad pointed bill, and retained the power of flight.
See the media release here.
Image credit: Chatham Islands Raven. Corvus moriorum. From the series: Extinct Birds of New Zealand, 2004, Masterton, by Paul Martinson. Purchased 2006 © Te Papa CC BY-NC-ND licence. Te Papa (2006-0010-1/15)