landbird

In the previous post – a spinoff of a still earlier post about phorusrhacids – I discussed the South American landbird theory.

Archive 2006-11-01 Darren Naish 2006

Seriemas were without close relatives and were the most basal group within Neoaves (the neognath clade that excludes waterfowl and gamebirds), bustards [see adjacent image] were on their own and near the middle of the neoavian radiation, trumpeters, cranes and limpkins grouped with hoatzins in a clade that also included flamingos, tubenosed seabirds, divers and penguins, and rails and finfoots were members of a ‘higher landbird’ clade.

Archive 2006-11-01 Darren Naish 2006

Based – it has to be said – on just a handful of detailed morphological characters, combined with some inference based on biogeography and superficial similarity, the South American landbird group theory suggests the following: that there might be a hoatzin-cariamaen clade, probably persisting as relicts in South America but more widespread during the early Cenozoic.

Archive 2006-11-01 Darren Naish 2006

Olson (1985) supported the possible monophyly of the South American landbird group, writing ‘the seriemas and hoatzins appear to be part of an early radiation of primitive land birds, members of which have persisted in South America, perhaps as a result of its isolation’ (pp. 143-144).

Archive 2006-11-01 Darren Naish 2006

Finally, New World vultures (which have all their earliest fossil occurrences in the Old World) might be allies of the South American landbird group.

Archive 2006-11-01 Darren Naish 2006

As it happens, one of my favourite ‘alternative’ theories involves cariamaens: it is the South American landbird hypothesis.

Archive 2006-11-01 Darren Naish 2006

The fossil record indicates that St. Helena most likely supported at least four endemic landbird species (two flightless rails, a cuckoo, and a hoopoe) when the first human settlers arrived.

St. Helena scrub and woodlands 2008

The landbird fauna of the Seychelles is particularly unique.

Granitic Seychelles forests 2008

Like so many alternative theories, the South American landbird theory hinges on just a few characters that are swamped by a larger number of characters that convey a different signal.

Archive 2006-11-01 Darren Naish 2006

Finally, New World vultures (which have all their earliest fossil occurrences in the Old World) might be allies of the South American landbird group.

Giant hoatzins of doom Darren Naish 2006