Until humans arrived 750 twelvemonth ago , New Zealand was a paradise for raspberry . Facing almost no competition or predation from mammals some of them take a deep outlandish turn . The adzebill evolved such an rum dead body that , one C of years after it go extinct , bird watcher have struggled to work out how it live , and identify its nearest relatives . Dr Kieren Mitchellof Adelaide University has helped lick its family tree , but admits to being stumped on the first question . There is really nothing else like it that we know of today , so it ’s surd to make comparisons .
Mitchell is co - writer of a paper inDiversityshowing the adzebill ’s penny-pinching last relatives are Madagascan Bronx cheer barely thousandth of its weight . This opens up the question of how the adzebill ’s ancestors traveled between such distant property .
Prior to humans ( and companion rats ) get in in New Zealand , the islands were inhabited by wench as large as the moa , the largest of which weighed 250 kilogram ( 550 pound ) . By those standards , the adzebill , which weighed up to 19 kilograms ( 42 pounds ) , sounds small-scale , but it was probably the island ’s gravid predator . Todayonly sevenspecies of birds matter more .
Like the moa , and many surviving New Zealand birds , the adzebill was flightless . flight take a lot of energy , and when you do n’t have to deal with predatory mammal it wee-wee gumption to abandon it . However , this was no defenseless herbivore . Adzebills ' isotopes reveal them as predators , although their accurate diet is unknown . Mitchell told IFLScience their “ heavily reinforced legs and skull ” may have been used to smash up unresolved stinky logs to get at insects or minor lizards living inside .
As captain bookman Alexander Boast said in astatement , the adzebill “ had an enormous reinforce skull and snoot , almost like an axe , which is where they got their English name . ”
An artists ' impression of the nonextant south island adzebill , with a relatively normal penguin behind it . Paul Martinson
Using DNA press out from adzebill bone fragments and eggshells Boast and Mitchell have found they were closest to the Madagascan Grant Wood rails and flufftails , which exist both in Madagascar and on the African mainland . The last common ascendent appears to have populate around 40 million years ago .
Although Mitchell told IFLScience their ancestors could presumably fly , Madagascar to New Zealand is still an epic journey . With New Zealand ’s most famed bird , the kiwi being relate to Madagascar ’s mighty elephant birds , and related to species of teals living in both places , it seems there was a passageway between the two emplacement which many birds took . Rather than being via Australia , the authors think the connection was through Antarctica , which had forests around its coast until around 34 million years ago .
Mitchell explain to IFLScience that 30 - 40 million age ago when the journey took space Gondwana was long break up , and the continents positioned not too far from where they are now . migrant birds of many species patently flew from Madagascar to the Antarctic outskirt , and at some point later their descendants made the journey to New Zealand before losing the might of flight of steps . Unfortunately , evidence to confirm this hypothesis is likely bury under the Antarctic ice and therefore very hard to get at .
The first adzebills evolved from these migratory ancestor on New Zealand ’s South Island and apparently did so quickly since a fossil from 16 - 19 million years ago looks quite similar to more recent examples . They walked across to the North Island during a time period when the two were connected by a land span 1.5 - 2 million years ago . Once the connection was turn a loss , the populations depart to become two species , both of which pull through until concisely after human comer in the 13th century .
