[dinosaur] Early amniote hypothesis: Parareptilia are diapsids, Varanopidae not synapsids

--000000000000077b02059a61b502
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: Quoted-printable

Ben [email protected]=0D=0A=0D=0AA new paper:=0D=0A=0D=0A=
=0D=0ADavid P. Ford & Roger B. J. Benson (2019)=0D=0AThe phylogeny of early=
 amniotes and the affinities of Parareptilia and=0D=0AVaranopidae.=0D=0ANat=
ure Ecology & Evolution 4: 57-65=0D=0Adoi:10.1038/s41559-019-1047-3=0D=0Aht=
tps://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.nature.com_article=
s_s41559-2D019-2D1047-2D3&d=3DDwIBaQ&c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p=
7CSfnc_gI&r=3DRy_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=3DqbG4sstjTx9Ck=
Wkgvm1Vq6CEMU1l5uMZuATCbSjWyik&s=3Dg98K0DDQmSpCNNc63VTJ8rk5B5kEZogGJW6pjgXl=
ISM&e=3D =0D=0A=0D=0A=0D=0AAmniotes include mammals, reptiles and birds, re=
presenting 75% of extant=0D=0Avertebrate species on land. They originated a=
round 318 million years ago in=0D=0Athe early Late Carboniferous and their =
early fossil record is central to=0D=0Aunderstanding the expansion of verte=
brates in terrestrial ecosystems. We=0D=0Apresent a phylogenetic hypothesis=
 that challenges the widely accepted=0D=0Aconsensus about early amniote evo=
lution, based on parsimony analysis and=0D=0ABayesian inference of a new mo=
rphological dataset. We find a reduced=0D=0Amembership of the mammalian ste=
m lineage, which excludes varanopids. This=0D=0Aimplies that evolutionary t=
urnover of the mammalian stem lineage during the=0D=0AEarly-Middle Permian =
transition (273 million years ago) was more abrupt=0D=0Athan has previously=
 been recognized. We also find that Parareptilia are=0D=0Anested within Dia=
psida. This suggests that temporal fenestration, a key=0D=0Astructural inno=
vation with important functional implications, evolved fewer=0D=0Atimes tha=
n generally thought, but showed highly variable morphology among=0D=0Aearly=
 reptiles after its initial origin. Our phylogeny also addresses=0D=0Acontr=
oversies over the affinities of mesosaurids, the earliest known=0D=0Aaquati=
c amniotes, which we recover as early diverging parareptiles.=0D=0A=0D=0A=
=3D=3D=3D=3D=3D=0D=0A=

--000000000000077b02059a61b502
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: Quoted-printable

<div dir=3D"ltr"><div><br></div>Ben Creisler<div><a href=3D"mailto:bcreisle=
[email protected]">[email protected]</a></div><div><br></div><div>A new paper:<=
br><div><br></div><div><br></div><div>David P. Ford &amp; Roger B. J. Benso=
n (2019)<br>The phylogeny of early amniotes and the affinities of Pararepti=
lia and Varanopidae.<br>Nature Ecology &amp; Evolution 4: 57-65 <br>doi:10.=
1038/s41559-019-1047-3<br><a href=3D"https://urldefense.proofpoint.com/v2/u=
rl?u=3Dhttps-3A__www.nature.com_articles_s41559-2D019-2D1047-2D3&amp;d=3DDw=
MFaQ&amp;c=3DclK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&amp;r=3DRy_mO4IFaU=
mGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&amp;m=3DqbG4sstjTx9CkWkgvm1Vq6CEMU1l5uMZu=
ATCbSjWyik&amp;s=3Dg98K0DDQmSpCNNc63VTJ8rk5B5kEZogGJW6pjgXlISM&amp;e=3D">ht=
tps://www.nature.com/articles/s41559-019-1047-3</a></div><div><br><br>Amnio=
tes include mammals, reptiles and birds, representing 75% of extant vertebr=
ate species on land. They originated around 318 million years ago in the ea=
rly Late Carboniferous and their early fossil record is central to understa=
nding the expansion of vertebrates in terrestrial ecosystems. We present a =
phylogenetic hypothesis that challenges the widely accepted consensus about=
 early amniote evolution, based on parsimony analysis and Bayesian inferenc=
e of a new morphological dataset. We find a reduced membership of the mamma=
lian stem lineage, which excludes varanopids. This implies that evolutionar=
y turnover of the mammalian stem lineage during the Early-Middle Permian tr=
ansition (273 million years ago) was more abrupt than has previously been r=
ecognized. We also find that Parareptilia are nested within Diapsida. This =
suggests that temporal fenestration, a key structural innovation with impor=
tant functional implications, evolved fewer times than generally thought, b=
ut showed highly variable morphology among early reptiles after its initial=
 origin. Our phylogeny also addresses controversies over the affinities of =
mesosaurids, the earliest known aquatic amniotes, which we recover as early=
 diverging parareptiles.<br><br>=3D=3D=3D=3D=3D<br></div></div></div>=0A=

--000000000000077b02059a61b502--