Evolution and dispersal of snakes across the Cretaceous-Paleogene mass
extinction

Abstract

Mass extinctions have repeatedly shaped global biodiversity. The
Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of
numerous vertebrate groups, and its aftermath saw the rapid
diversification of surviving mammals, birds, frogs, and teleost
fishes. However, the effects of the K-Pg extinction on the evolution
of snakes—a major clade of predators comprising over 3,700 living
species—remains poorly understood. Here, we combine an extensive
molecular dataset with phylogenetically and stratigraphically
constrained fossil calibrations to infer an evolutionary timescale for
Serpentes. We reveal a potential diversification among crown snakes
associated with the K-Pg mass extinction, led by the successful
colonisation of Asia by the major extant clade Afrophidia. Vertebral
morphometrics suggest increasing morphological specialisation among
marine snakes through the Paleogene. The dispersal patterns of snakes
following the K-Pg underscore the importance of this mass extinction
event in shaping Earth’s extant vertebrate faunas.

https://www.nature.com/articles/s41467-021-25136-y

This is a very technical paper, which seems to be lacking a summary,
making it difficult to get an overview.

On Wednesday, September 15, 2021 at 2:19:21 PM UTC-4, Pandora wrote:
> Evolution and dispersal of snakes across the Cretaceous-Paleogene mass
> extinction
>
> Abstract
>
> Mass extinctions have repeatedly shaped global biodiversity. The
> Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of
> numerous vertebrate groups, and its aftermath saw the rapid
> diversification of surviving mammals, birds, frogs, and teleost
> fishes. However, the effects of the K-Pg extinction on the evolution
> of snakes—a major clade of predators comprising over 3,700 living
> species—remains poorly understood. Here, we combine an extensive
> molecular dataset with phylogenetically and stratigraphically
> constrained fossil calibrations to infer an evolutionary timescale for
> Serpentes. We reveal a potential diversification among crown snakes
> associated with the K-Pg mass extinction, led by the successful
> colonisation of Asia by the major extant clade Afrophidia.

This seems to be contradicted by the following statement in the article:

"We recovered a strong signal for an Asian origin of the major clade Afrophidia (Fig. 3)"

This is a shame, because this is the only reference to dispersal in the abstract. Fortunately,
Fig. 3 is something to feast one's eyes on for about an hour, unless you are color blind.
I have excellent color vision, especially since my cataracts were removed,
and so I guess it will take me about an hour to figure out all the ins and outs of the
various "pie graphs" that show how each sizable clade was represented in the
continents and island groups, and in what proportion of species.

It was surprising to see how the Caribbean already had a lineage close to the
K-P boundary on the P side, which has persisted to the present. It is a bit
difficult to tell the lavender shade used for it from the slightly darker shade
for Europe. The latter shows Europe only acquiring snakes at the beginning
of the Neogene [= Miocene on up] and only a single European
lineage to have made it to the present. I wonder: does it have any poisonous snakes?

But the details that fascinate me the most are the ones having to do with
India and Sri Lanka, here treated as one. Most of the lineages had one India-Sri Lankan
represented close to the K-P boundary. This is remarkable: India and Sri Lanka
formed a small continent in the middle of the Indian ocean back then, far
from the other continents.

How did so many different lineages get there? Sad to say, the article only
mentions India once, and that once gives no clue. Sri Lanka never gets mentioned at all.

> Vertebral morphometrics suggest increasing morphological specialisation among
> marine snakes through the Paleogene. The dispersal patterns of snakes
> following the K-Pg underscore the importance of this mass extinction
> event in shaping Earth’s extant vertebrate faunas.

Obviously, there is much more than a mass extinction involved here.

>
> https://www.nature.com/articles/s41467-021-25136-y

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos

On Wed, 15 Sep 2021 20:19:19 +0200, Pandora <pandora@knoware.nl>
wrote:

>Evolution and dispersal of snakes across the Cretaceous-Paleogene mass
>extinction
>
>Abstract
>
>Mass extinctions have repeatedly shaped global biodiversity. The
>Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of
>numerous vertebrate groups, and its aftermath saw the rapid
>diversification of surviving mammals, birds, frogs, and teleost
>fishes. However, the effects of the K-Pg extinction on the evolution
>of snakes—a major clade of predators comprising over 3,700 living
>species—remains poorly understood. Here, we combine an extensive
>molecular dataset with phylogenetically and stratigraphically
>constrained fossil calibrations to infer an evolutionary timescale for
>Serpentes. We reveal a potential diversification among crown snakes
>associated with the K-Pg mass extinction, led by the successful
>colonisation of Asia by the major extant clade Afrophidia. Vertebral
>morphometrics suggest increasing morphological specialisation among
>marine snakes through the Paleogene. The dispersal patterns of snakes
>following the K-Pg underscore the importance of this mass extinction
>event in shaping Earth’s extant vertebrate faunas.
>
>https://www.nature.com/articles/s41467-021-25136-y

Related:

Rapid increase in snake dietary diversity and complexity following the
end-Cretaceous mass extinction.

Abstract

The Cenozoic marked a period of dramatic ecological opportunity in
Earth history due to the extinction of non-avian dinosaurs as well as
to long-term physiographic changes that created new biogeographic
theaters and new habitats. Snakes underwent massive ecological
diversification during this period, repeatedly evolving novel dietary
adaptations and prey preferences. The evolutionary tempo and mode of
these trophic ecological changes remain virtually unknown, especially
compared with co-radiating lineages of birds and mammals that are
simultaneously predators and prey of snakes. Here, we assemble a
dataset on snake diets (34,060 observations on the diets of 882
species) to investigate the history and dynamics of the
multidimensional trophic niche during the global radiation of snakes.
Our results show that per-lineage dietary niche breadths remained
remarkably constant even as snakes diversified to occupy disparate
outposts of dietary ecospace. Rapid increases in dietary diversity and
complexity occurred in the early Cenozoic, and the overall rate of
ecospace expansion has slowed through time, suggesting a potential
response to ecological opportunity in the wake of the end-Cretaceous
mass extinction. Explosive bursts of trophic innovation followed
colonization of the Nearctic and Neotropical realms by a group of
snakes that today comprises a majority of living snake diversity. Our
results indicate that repeated transformational shifts in dietary
ecology are important drivers of adaptive radiation in snakes and
provide a framework for analyzing and visualizing the evolution of
complex ecological phenotypes on phylogenetic trees.

Open access:
https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001414

On Fri, 15 Oct 2021 17:07:42 +0200, Pandora <pandora@knoware.nl>
wrote:

>On Wed, 15 Sep 2021 20:19:19 +0200, Pandora <pandora@knoware.nl>
>wrote:
>
>>Evolution and dispersal of snakes across the Cretaceous-Paleogene mass
>>extinction
>>
>>Abstract
>>
>>Mass extinctions have repeatedly shaped global biodiversity. The
>>Cretaceous-Paleogene (K-Pg) mass extinction caused the demise of
>>numerous vertebrate groups, and its aftermath saw the rapid
>>diversification of surviving mammals, birds, frogs, and teleost
>>fishes. However, the effects of the K-Pg extinction on the evolution
>>of snakes—a major clade of predators comprising over 3,700 living
>>species—remains poorly understood. Here, we combine an extensive
>>molecular dataset with phylogenetically and stratigraphically
>>constrained fossil calibrations to infer an evolutionary timescale for
>>Serpentes. We reveal a potential diversification among crown snakes
>>associated with the K-Pg mass extinction, led by the successful
>>colonisation of Asia by the major extant clade Afrophidia. Vertebral
>>morphometrics suggest increasing morphological specialisation among
>>marine snakes through the Paleogene. The dispersal patterns of snakes
>>following the K-Pg underscore the importance of this mass extinction
>>event in shaping Earth’s extant vertebrate faunas.
>>
>>https://www.nature.com/articles/s41467-021-25136-y
>
>Related:
>
>Rapid increase in snake dietary diversity and complexity following the
>end-Cretaceous mass extinction.
>
>Abstract
>
>The Cenozoic marked a period of dramatic ecological opportunity in
>Earth history due to the extinction of non-avian dinosaurs as well as
>to long-term physiographic changes that created new biogeographic
>theaters and new habitats. Snakes underwent massive ecological
>diversification during this period, repeatedly evolving novel dietary
>adaptations and prey preferences. The evolutionary tempo and mode of
>these trophic ecological changes remain virtually unknown, especially
>compared with co-radiating lineages of birds and mammals that are
>simultaneously predators and prey of snakes. Here, we assemble a
>dataset on snake diets (34,060 observations on the diets of 882
>species) to investigate the history and dynamics of the
>multidimensional trophic niche during the global radiation of snakes.
>Our results show that per-lineage dietary niche breadths remained
>remarkably constant even as snakes diversified to occupy disparate
>outposts of dietary ecospace. Rapid increases in dietary diversity and
>complexity occurred in the early Cenozoic, and the overall rate of
>ecospace expansion has slowed through time, suggesting a potential
>response to ecological opportunity in the wake of the end-Cretaceous
>mass extinction. Explosive bursts of trophic innovation followed
>colonization of the Nearctic and Neotropical realms by a group of
>snakes that today comprises a majority of living snake diversity. Our
>results indicate that repeated transformational shifts in dietary
>ecology are important drivers of adaptive radiation in snakes and
>provide a framework for analyzing and visualizing the evolution of
>complex ecological phenotypes on phylogenetic trees.
>
>Open access:
>https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001414

From the above:
****************************
With nearly as many species of snakes as there are mammals, however,
the Cenozoic might just as well be called the “Age of Snakes”
*****************************

Except there are no herbivorous snakes, demonstrating a certain lack
of imagination. Even lizards evolved a few plant munchers.

On Sat, 16 Oct 2021 13:12:21 -0400, jillery <69jpil69@gmail.com>
wrote:

>>Rapid increase in snake dietary diversity and complexity following the
>>end-Cretaceous mass extinction.
>>
>>Abstract
>>
>>The Cenozoic marked a period of dramatic ecological opportunity in
>>Earth history due to the extinction of non-avian dinosaurs as well as
>>to long-term physiographic changes that created new biogeographic
>>theaters and new habitats. Snakes underwent massive ecological
>>diversification during this period, repeatedly evolving novel dietary
>>adaptations and prey preferences. The evolutionary tempo and mode of
>>these trophic ecological changes remain virtually unknown, especially
>>compared with co-radiating lineages of birds and mammals that are
>>simultaneously predators and prey of snakes. Here, we assemble a
>>dataset on snake diets (34,060 observations on the diets of 882
>>species) to investigate the history and dynamics of the
>>multidimensional trophic niche during the global radiation of snakes.
>>Our results show that per-lineage dietary niche breadths remained
>>remarkably constant even as snakes diversified to occupy disparate
>>outposts of dietary ecospace. Rapid increases in dietary diversity and
>>complexity occurred in the early Cenozoic, and the overall rate of
>>ecospace expansion has slowed through time, suggesting a potential
>>response to ecological opportunity in the wake of the end-Cretaceous
>>mass extinction. Explosive bursts of trophic innovation followed
>>colonization of the Nearctic and Neotropical realms by a group of
>>snakes that today comprises a majority of living snake diversity. Our
>>results indicate that repeated transformational shifts in dietary
>>ecology are important drivers of adaptive radiation in snakes and
>>provide a framework for analyzing and visualizing the evolution of
>>complex ecological phenotypes on phylogenetic trees.
>>
>>Open access:
>>https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001414
>
>
>From the above:
>****************************
>With nearly as many species of snakes as there are mammals, however,
>the Cenozoic might just as well be called the “Age of Snakes”
>*****************************
>
>Except there are no herbivorous snakes, demonstrating a certain lack
>of imagination. Even lizards evolved a few plant munchers.

If the diversity (number of species) of land vertebrates is the
criterion for naming an era then the Cenozoic would still be the Age
of Dinosaurs.