Isotope data from amino acids indicate Darwin’s ground sloth was not
an herbivore.

Abstract

Fossil sloths are regarded as obligate herbivores for reasons
including peculiarities of their craniodental morphology and that all
living sloths feed exclusively on plants. We challenge this view based
on isotopic analyses of nitrogen of specific amino acids, which show
that Darwin’s ground sloth Mylodon darwinii was an opportunistic
omnivore. This direct evidence of omnivory in an ancient sloth
requires reevaluation of the ecological structure of South American
Cenozoic mammalian communities, as sloths represented a major
component of these ecosystems across the past 34 Myr. Furthermore, by
analyzing modern mammals with known diets, we provide a basis for
reliable interpretation of nitrogen isotopes of amino acids of
fossils. We argue that a widely used equation to determine trophic
position is unnecessary, and that the relative isotopic values of the
amino acids glutamate and phenylalanine alone permit reliable
reconstructions of trophic positions of extant and extinct mammals.

Open access:
https://www.nature.com/articles/s41598-021-97996-9

On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
> Isotope data from amino acids indicate Darwin’s ground sloth was not
> an herbivore.
>
> Abstract
>
> Fossil sloths are regarded as obligate herbivores for reasons
> including peculiarities of their craniodental morphology and that all
> living sloths feed exclusively on plants. We challenge this view based
> on isotopic analyses of nitrogen of specific amino acids, which show
> that Darwin’s ground sloth Mylodon darwinii was an opportunistic
> omnivore. This direct evidence of omnivory in an ancient sloth
> requires reevaluation of the ecological structure of South American
> Cenozoic mammalian communities, as sloths represented a major
> component of these ecosystems across the past 34 Myr. Furthermore, by
> analyzing modern mammals with known diets, we provide a basis for
> reliable interpretation of nitrogen isotopes of amino acids of
> fossils. We argue that a widely used equation to determine trophic
> position is unnecessary, and that the relative isotopic values of the
> amino acids glutamate and phenylalanine alone permit reliable
> reconstructions of trophic positions of extant and extinct mammals.
>
> Open access:
> https://www.nature.com/articles/s41598-021-97996-9
Very cool. So maybe marine sloths ate algae and animals.

On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
> On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
> > Isotope data from amino acids indicate Darwin’s ground sloth was not
> > an herbivore.
> >
> > Abstract
> >
> > Fossil sloths are regarded as obligate herbivores for reasons
> > including peculiarities of their craniodental morphology and that all
> > living sloths feed exclusively on plants. We challenge this view based
> > on isotopic analyses of nitrogen of specific amino acids, which show
> > that Darwin’s ground sloth Mylodon darwinii was an opportunistic
> > omnivore. This direct evidence of omnivory in an ancient sloth
> > requires reevaluation of the ecological structure of South American
> > Cenozoic mammalian communities, as sloths represented a major
> > component of these ecosystems across the past 34 Myr. Furthermore, by
> > analyzing modern mammals with known diets, we provide a basis for
> > reliable interpretation of nitrogen isotopes of amino acids of
> > fossils. We argue that a widely used equation to determine trophic
> > position is unnecessary, and that the relative isotopic values of the
> > amino acids glutamate and phenylalanine alone permit reliable
> > reconstructions of trophic positions of extant and extinct mammals.
> >
> > Open access:
> > https://www.nature.com/articles/s41598-021-97996-9
> Very cool. So maybe marine sloths ate algae and animals.

Marine sloths? I didn't know there was such a thing. I am enlightened.

On Friday, October 8, 2021 at 11:34:57 PM UTC-4, erik simpson wrote:
> On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
> > On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
> > > Isotope data from amino acids indicate Darwin’s ground sloth was not
> > > an herbivore.
> > >
> > > Abstract
> > >
> > > Fossil sloths are regarded as obligate herbivores for reasons
> > > including peculiarities of their craniodental morphology and that all
> > > living sloths feed exclusively on plants. We challenge this view based
> > > on isotopic analyses of nitrogen of specific amino acids, which show
> > > that Darwin’s ground sloth Mylodon darwinii was an opportunistic
> > > omnivore. This direct evidence of omnivory in an ancient sloth
> > > requires reevaluation of the ecological structure of South American
> > > Cenozoic mammalian communities, as sloths represented a major
> > > component of these ecosystems across the past 34 Myr. Furthermore, by
> > > analyzing modern mammals with known diets, we provide a basis for
> > > reliable interpretation of nitrogen isotopes of amino acids of
> > > fossils. We argue that a widely used equation to determine trophic
> > > position is unnecessary, and that the relative isotopic values of the
> > > amino acids glutamate and phenylalanine alone permit reliable
> > > reconstructions of trophic positions of extant and extinct mammals.
> > >
> > > Open access:
> > > https://www.nature.com/articles/s41598-021-97996-9
> > Very cool. So maybe marine sloths ate algae and animals.
> Marine sloths? I didn't know there was such a thing. I am enlightened.

Great. Now see my bizarre comment about kansaignathus sogdiana and please enlighten me. Its important.

On 10/8/21 8:34 PM, erik simpson wrote:
> On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
>> On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
>>> Isotope data from amino acids indicate Darwin’s ground sloth was not
>>> an herbivore.
>>>
>>> Abstract
>>>
>>> Fossil sloths are regarded as obligate herbivores for reasons
>>> including peculiarities of their craniodental morphology and that all
>>> living sloths feed exclusively on plants. We challenge this view based
>>> on isotopic analyses of nitrogen of specific amino acids, which show
>>> that Darwin’s ground sloth Mylodon darwinii was an opportunistic
>>> omnivore. This direct evidence of omnivory in an ancient sloth
>>> requires reevaluation of the ecological structure of South American
>>> Cenozoic mammalian communities, as sloths represented a major
>>> component of these ecosystems across the past 34 Myr. Furthermore, by
>>> analyzing modern mammals with known diets, we provide a basis for
>>> reliable interpretation of nitrogen isotopes of amino acids of
>>> fossils. We argue that a widely used equation to determine trophic
>>> position is unnecessary, and that the relative isotopic values of the
>>> amino acids glutamate and phenylalanine alone permit reliable
>>> reconstructions of trophic positions of extant and extinct mammals.
>>>
>>> Open access:
>>> https://www.nature.com/articles/s41598-021-97996-9
>> Very cool. So maybe marine sloths ate algae and animals.
>
> Marine sloths? I didn't know there was such a thing. I am enlightened.
>
Semper fi.

On Friday, October 8, 2021 at 9:05:51 PM UTC-7, John Harshman wrote:
> On 10/8/21 8:34 PM, erik simpson wrote:
> > On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
> >> On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
> >>> Isotope data from amino acids indicate Darwin’s ground sloth was not
> >>> an herbivore.
> >>>
> >>> Abstract
> >>>
> >>> Fossil sloths are regarded as obligate herbivores for reasons
> >>> including peculiarities of their craniodental morphology and that all
> >>> living sloths feed exclusively on plants. We challenge this view based
> >>> on isotopic analyses of nitrogen of specific amino acids, which show
> >>> that Darwin’s ground sloth Mylodon darwinii was an opportunistic
> >>> omnivore. This direct evidence of omnivory in an ancient sloth
> >>> requires reevaluation of the ecological structure of South American
> >>> Cenozoic mammalian communities, as sloths represented a major
> >>> component of these ecosystems across the past 34 Myr. Furthermore, by
> >>> analyzing modern mammals with known diets, we provide a basis for
> >>> reliable interpretation of nitrogen isotopes of amino acids of
> >>> fossils. We argue that a widely used equation to determine trophic
> >>> position is unnecessary, and that the relative isotopic values of the
> >>> amino acids glutamate and phenylalanine alone permit reliable
> >>> reconstructions of trophic positions of extant and extinct mammals.
> >>>
> >>> Open access:
> >>> https://www.nature.com/articles/s41598-021-97996-9
> >> Very cool. So maybe marine sloths ate algae and animals.
> >
> > Marine sloths? I didn't know there was such a thing. I am enlightened.
> >
> Semper fi.
Oorah!

On Fri, 8 Oct 2021 20:34:56 -0700 (PDT), erik simpson
<eastside.erik@gmail.com> wrote:

>On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
>> On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
>> > Isotope data from amino acids indicate Darwin’s ground sloth was not
>> > an herbivore.
>> >
>> > Abstract
>> >
>> > Fossil sloths are regarded as obligate herbivores for reasons
>> > including peculiarities of their craniodental morphology and that all
>> > living sloths feed exclusively on plants. We challenge this view based
>> > on isotopic analyses of nitrogen of specific amino acids, which show
>> > that Darwin’s ground sloth Mylodon darwinii was an opportunistic
>> > omnivore. This direct evidence of omnivory in an ancient sloth
>> > requires reevaluation of the ecological structure of South American
>> > Cenozoic mammalian communities, as sloths represented a major
>> > component of these ecosystems across the past 34 Myr. Furthermore, by
>> > analyzing modern mammals with known diets, we provide a basis for
>> > reliable interpretation of nitrogen isotopes of amino acids of
>> > fossils. We argue that a widely used equation to determine trophic
>> > position is unnecessary, and that the relative isotopic values of the
>> > amino acids glutamate and phenylalanine alone permit reliable
>> > reconstructions of trophic positions of extant and extinct mammals.
>> >
>> > Open access:
>> > https://www.nature.com/articles/s41598-021-97996-9
>> Very cool. So maybe marine sloths ate algae and animals.
>
>Marine sloths? I didn't know there was such a thing. I am enlightened.

There used to be in the Miocene and Pliocene:

https://en.wikipedia.org/wiki/Thalassocnus

On Saturday, October 9, 2021 at 6:26:31 AM UTC-4, Pandora wrote:
> On Fri, 8 Oct 2021 20:34:56 -0700 (PDT), erik simpson
> <eastsi...@gmail.com> wrote:
>
> >On Friday, October 8, 2021 at 8:06:05 PM UTC-7, daud....@gmail.com wrote:
> >> On Friday, October 8, 2021 at 2:29:50 PM UTC-4, Pandora wrote:
> >> > Isotope data from amino acids indicate Darwin’s ground sloth was not
> >> > an herbivore.
> >> >
> >> > Abstract
> >> >
> >> > Fossil sloths are regarded as obligate herbivores for reasons
> >> > including peculiarities of their craniodental morphology and that all
> >> > living sloths feed exclusively on plants. We challenge this view based
> >> > on isotopic analyses of nitrogen of specific amino acids, which show
> >> > that Darwin’s ground sloth Mylodon darwinii was an opportunistic
> >> > omnivore. This direct evidence of omnivory in an ancient sloth
> >> > requires reevaluation of the ecological structure of South American
> >> > Cenozoic mammalian communities, as sloths represented a major
> >> > component of these ecosystems across the past 34 Myr. Furthermore, by
> >> > analyzing modern mammals with known diets, we provide a basis for
> >> > reliable interpretation of nitrogen isotopes of amino acids of
> >> > fossils. We argue that a widely used equation to determine trophic
> >> > position is unnecessary, and that the relative isotopic values of the
> >> > amino acids glutamate and phenylalanine alone permit reliable
> >> > reconstructions of trophic positions of extant and extinct mammals.
> >> >
> >> > Open access:
> >> > https://www.nature.com/articles/s41598-021-97996-9
> >> Very cool. So maybe marine sloths ate algae and animals.
> >
> >Marine sloths? I didn't know there was such a thing. I am enlightened.
> There used to be in the Miocene and Pliocene:
>
> https://en.wikipedia.org/wiki/Thalassocnus

Swim faster than walking quadrupedally or climbing
https://www.youtube.com/watch?v=Z22yFkyfYaE

Good video on sloth diversification
https://www.youtube.com/watch?v=pt9tBtQoAHo