From
the robust boa constrictor to the venomous rattlesnake, all of the more
than 3,400 snake species that slither today may have descended from the
same prehistoric forest prowler, whose sinuous body had two small hind
legs with toes and ankles, researchers reported on Tuesday.
After
analyzing data gathered through fossils, genetic sequencing and
anatomical comparisons of 73 snake and lizard species, a team of
paleontologists from Yale University has constructed what it calls the
most comprehensive snake “family tree” to date. The findings provide an
answer to longstanding questions about when, where and how modern snakes
originated.
“Having
that tree as a backbone let us draw a ton of conclusions for what the
ancestral snake would have been like,” said Daniel J. Field, a doctoral
candidate in evolutionary biology and an author of the study. The team
concluded that the most recent common ancestor of all living snakes was
nocturnal, thrived 128.5 million years ago in the Southern Hemisphere
and devoured relatively large prey whole using its sharp, hooked teeth
as a hunting tool.
To
reach this conclusion, the team’s first step was to reconstruct the
snake’s family tree from tips to its trunk. To better understand when
certain characteristics — like the ability to constrict prey or hunt at
night — first appeared, the researchers used the genetic and
morphological data they collected to piece together how different groups
of living snakes are related to one another...Continue reading...
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