Re: Baobab treee evolution and spread

On 5/15/2024 1:57 PM, Pro Plyd wrote:

 Since species rafting has been a topic
upon occasion... This isn't rafting per se
but does illustrate how something can
establish itself elsewhere thanks to ocean
currents.
 https://www.nytimes.com/2024/05/15/science/baobab-trees-evolution.html
 The Unusual Evolutionary Journey of the
Baobab Tree
New research shows the “upside-down trees”
originated in Madagascar and then caught a
ride on ocean currents to reach mainland
Africa and Australia.
...
For all the tales told about baobabs, though,
their origin story has remained a mystery.
 Scientists have debated for years how baobabs
wound up in the places where they grow. Eight
species exist around the world, and their
distribution, like the trees themselves, is
unusual: One species occurs across much of
mainland Africa, while six are in Madagascar.
The last is found faraway, in northwestern
Australia.
 Most researchers have hypothesized that the
trees originated on mainland Africa. But
findings published Wednesday in the journal
Nature tell a different story. Baobabs
instead most likely first evolved in
Madagascar, where they diversified into
different species. Two then embarked on
long-distance oceanic journeys to distant
continents.
...
  https://www.nature.com/articles/s41586-024-07447-4
The rise of baobab trees in Madagascar
 Abstract
The baobab trees (genus Adansonia) have
attracted tremendous attention because of
their striking shape and distinctive
relationships with fauna1. These
spectacular trees have also influenced
human culture, inspiring innumerable
arts, folklore and traditions. Here we
sequenced genomes of all eight extant
baobab species and argue that Madagascar
should be considered the centre of origin
for the extant lineages, a key issue in
their evolutionary history2,3. Integrated
genomic and ecological analyses revealed
the reticulate evolution of baobabs,
which eventually led to the species
diversity seen today. Past population
dynamics of Malagasy baobabs may have
been influenced by both interspecific
competition and the geological history of
the island, especially changes in local
sea levels. We propose that further
attention should be paid to the
conservation status of Malagasy baobabs,
especially of Adansonia suarezensis and
Adansonia grandidieri, and that
intensive monitoring of populations of
Adansonia za is required, given its
propensity for negatively impacting the
critically endangered Adansonia perrieri.
 

The AIG believes that the koala, kangaroos, and echidna made it back to Australia after the flood on massive rafts of floating vegetation that were part of the flood debris.  Baobabs were obviously a major constituent of those rafts so they found themselves upside down under.
Ron Okimoto