The New Zealand Thrush: an extinct oriole

Area of Science:

• Avian Phylogenetics
• Molecular Evolution
• New Zealand Endemic Fauna

Background:

• The extinct New Zealand Thrush (Piopio) has uncertain phylogenetic placement, with past suggestions including thrushes, Australasian magpies, and bowerbirds based on morphology.
• Previous molecular studies offered weak support for a bowerbird affinity, necessitating further investigation into the Piopio's evolutionary relationships.

Purpose of the Study:

• To resolve the phylogenetic relationships of the extinct New Zealand Thrush (Piopio) using molecular data.
• To determine the Piopio's evolutionary affinities among passerine birds.

Main Methods:

• Analysis of sequence data from three nuclear introns.
• Bayesian phylogenetic analysis of concatenated genetic data.
• Divergence time estimation for the Oriolidae family.

Main Results:

• All three nuclear introns independently support an oriole (Oriolidae) affinity for the Piopio.
• Strong statistical support (posterior probability = 1.0) for the monophyly of typical orioles (Oriolus), figbirds (Sphecotheres), and the Piopio.
• Divergence time estimates suggest Piopio arrived in New Zealand via dispersal, not ancient vicariance.

Conclusions:

• This study provides the first molecular evidence for an oriole affinity of the Piopio.
• The Piopio's presence in New Zealand is attributed to trans-Tasman dispersal, occurring after the Oriolidae clade originated approximately 20 million years ago.