Sheathbill-like birds (Charadriiformes: Chionoidea) from the Oligocene and Miocene of Australasia

The Chionoidea are a small, southern hemispheric shorebird clade that today includes the Magellanic Plover (Pluvianellidae) and two species of sheathbills (Chionidae). Here we describe the first fossil remains attributable to this group. The two newly described species, the early Miocene Neilus sansomae gen. et sp. nov. from New Zealand and the late Oligocene Chionoides australiensis gen. et sp. nov. from South Australia, are overall more similar to sheathbills, but the mosaic of characters shared with both Chionidae and Pluvianellidae preclude referral to either lineage. Attribution of fossils this age to these lineages also conflicts with divergence dates based on molecular data, as the split between the Magellanic Plover and sheathbills is hypothesised to be more recent. We therefore suggest that these Australasian, plover-size species represent the first record of stem-group taxa within Chionoidea. http://zoobank.org/urn:lsid:zoobank.org:pub:2A5A2FD1-C3B5-4BAB-88D8-5862FE9E797