A possible early bowerbird from the Miocene of New Zealand

Aotearoa New Zealand is home to several endemic passerine bird lineages that likely dispersed from Australia between the Eocene and Miocene. Although the Australian pre-Pleistocene passerine fossil record is well-described, comparatively little is known about Miocene passerines from New Zealand. Here, we describe a distinctive tarsometatarsus attributable to a new passerine species, <i>Aeviperditus gracilis</i> gen. et sp. nov. from the Miocene locality St Bathans, New Zealand, which exhibits derived similarities with bowerbirds (Ptilonorhynchidae). This species, tentatively referred to total-group Ptilonorhynchidae, appears to represent a previously unknown passerine lineage for New Zealand and may drastically alter the prehistoric geographic distribution of bowerbirds, which are presently known from Australia and New Guinea. Trait-based similarity analysis shows the tarsometatarsus of <i>A. gracilis</i> is most comparable to the ‘avenue builder’ subclade of crown Ptilonorhynchidae. However, its diminutiveness and elongate proportions are unlike those of extant and fossil bowerbirds. <i>Aeviperditus gracilis</i> may represent a stem ptilonorhynchid, whereby similarities to extant bowerbirds are most likely plesiomorphic; however, additional, more complete fossils are required to clarify its phylogenetic position. Surviving endemic passerine lineages in New Zealand may represent the relicts of a once-diverse passerine avifauna, with the extinction of species like <i>A. gracilis</i> potentially associated with climatic cooling. ZooBank publication LSID urn:lsid:http://www.zoobank.org/zoobank.org:pub:2991625B-E79E-4DE7-BD8C-67685CC58693