[dinosaur] Squamate brains + end-Permian extinction + track plastotypes + more

Ben Creisler
[email protected]


Some recent non-dino papers that may be of interest:

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Free pdf:

Nathan S. Upham, Jacob A. Esselstyn & Walter Jetz (2019)
Ecological causes of speciation and species richness in the mammal tree of
life
bioRxiv 504803 (preprint)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1101_504803&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=oC9a1IEn1o6oLz-EtG4SGU7LR8VpalCFC-tpwdZnHNA&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.biorxiv.org_content_10.1101_504803v3&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=JyQd-dYcyWAe8yAD95fkM6H9451jzC2PQNgn_I1fITk&e= 

Biodiversity is distributed unevenly from the poles to the equator, and
among branches of the tree of life, yet how those patterns are related is
unclear. We investigated global speciation-rate variation across crown
Mammalia using a novel time-scaled phylogeny (N=5,911 species, ~70% with
DNA), finding that trait- and latitude-associated speciation has caused
uneven species richness among groups. We identify 24 branch-specific shifts
in net diversification rates linked to ecological traits. Using time-slices
to define clades, we show that speciation rates are a stronger predictor of
clade richness than age. Mammals that are low dispersal or diurnal
diversify the fastest, indicating roles for geographic and ecological
speciation, respectively. Speciation is slower in tropical than
extra-tropical lineages, consistent with evidence that longer tropical
species durations underpin the latitudinal diversity gradient. These
findings juxtapose modes of lineage diversification that are alternatively
turnover-based, and thus non-adaptive, or persistence-based as associated
with resource adaptations.

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Free pdf:

Simone Macrì, Yoland Savriama, Imran Khan & Nicolas Di-Poï  (2019)
Comparative analysis of squamate brains unveils multi-level variation in
cerebellar architecture associated with locomotor specialization.
Nature Communications 10, Article number: 5560
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1038_s41467-2D019-2D13405-2Dw&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=BC25C7U7oDN9-N9iTd2Bhe_PQ44fHA4zSAJoyQzxa14&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41467-2D019-2D13405&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=psTe5iYiDCArGpxQVgUoW8YNqx-ccX7TllRvDDTlZOA&e= 

Free pdf:
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41467-2D019-2D13405-2Dw.pdf&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=QgUkaL1RnEEPa8oSky6ijTjtmhMTcjrEG2bfPWqmeTg&e= 



Ecomorphological studies evaluating the impact of environmental and
biological factors on the brain have so far focused on morphology or size
measurements, and the ecological relevance of potential multi-level
variations in brain architecture remains unclear in vertebrates. Here, we
exploit the extraordinary ecomorphological diversity of squamates to assess
brain phenotypic diversification with respect to locomotor specialization,
by integrating single-cell distribution and transcriptomic data along with
geometric morphometric, phylogenetic, and volumetric analysis of
high-definition 3D models. We reveal significant changes in cerebellar
shape and size as well as alternative spatial layouts of cortical neurons
and dynamic gene expression that all correlate with locomotor behaviours.
These findings show that locomotor mode is a strong predictor of cerebellar
structure and pattern, suggesting that major behavioural transitions in
squamates are evolutionarily correlated with mosaic brain changes.
Furthermore, our study amplifies the concept of ‘cerebrotype’, initially
proposed for vertebrate brain proportions, towards additional shape
characters.


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Gerald Soslau (2019)
The role of the red blood cell and platelet in the evolution of mammalian
and avian endothermy.
Journal of Experimental Zoology -B: Molecular and Developmental Evolution
(advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1002_jez.b.22922&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=jhV37EN2V7RViQ8B7SbK9a2-0iZFU-MMfhGVw7UXOUU&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__onlinelibrary.wiley.com_doi_10.1002_jez.b.22922&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=-hvYC40NfQKHx9TIrhf7i9AAXPlFT12ryEnrgsGfy4k&e= 


This review presents evidence to support the hypothesis that the reduced O2
during the Permian/Triassic period was the impetus for the evolutionary
selection of endothermic animals. The evolution of smaller red blood cells
with greater surface areas along with increased: capillary density,
capillary surface area, hematocrits, blood pressure, blood flow rates, and
shear rates were critical for efficient gas exchange in endothermy. The
evolution of the four‐chambered mammalian/avian heart allowed for low
pulmonary and high systemic blood pressure. It is proposed that
hypoxia‐induced angiogenesis led to increased vascularization in
endothermic animals. The increased blood pressure, flow rates, and shear
forces likely required changes in hemostatic mechanisms that were met in
mammals by the evolution of anucleate platelets. The evolution of mammals
and birds occurred in a parallel fashion with further genetic changes to
anucleate RBCs/platelets occurring in mammals. Although it is possible that
the evolution of endothermy in birds and mammals occurred as two
independent events, it is more likely that a common ancestor developed
genetic mutations that laid down the road map for parallel alterations of
their cardiovascular system in response to environmental pressures. Model
systems to support the proposed changes from ectotherm to endotherm were
developed from published data. The evolutionary development of endothermy
occurred over millions of years with a continuum of genetic alterations
that involved skeletal, soft tissue, cardiovascular macrochanges along with
numerous molecular alterations. Genetic signals and potential regulators
for the evolutionary changes of endothermic blood cells from their
bipotential stem cells are also proposed.

============

Free pdf:

Stephen M. Jones, Murray Hoggett, Sarah E. Greene & Tom Dunkley Jones
 (2019)
Large Igneous Province thermogenic greenhouse gas flux could have initiated
Paleocene-Eocene Thermal Maximum climate change.
Nature Communications  10, Article number: 5547
doi:  https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1038_s41467-2D019-2D12957-2D1&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=RXm5521SMZ5FOIkntRSQ-vBNNtuham8pF1J20JbiB8U&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41467-2D019-2D12957-2D1&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=VylclESMy88UDbQkqKhP7XQYbH_0psYYf20TaeN2cPQ&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41467-2D019-2D12957-2D1.pdf&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=sYohhLUVKm0CLBwnZZBtLABlxvO2h2u-5qKstmhNNDk&e= 

Large Igneous Provinces (LIPs) are associated with the largest climate
perturbations in Earth’s history. The North Atlantic Igneous Province
(NAIP) and Paleocene-Eocene Thermal Maximum (PETM) constitute an exemplar
of this association. As yet we have no means to reconstruct the pacing of
LIP greenhouse gas emissions for comparison with climate records at
millennial resolution. Here, we calculate carbon-based greenhouse gas
fluxes associated with the NAIP at sub-millennial resolution by linking
measurements of the mantle convection process that generated NAIP magma
with observations of the individual geological structures that controlled
gas emissions in a Monte Carlo framework. These simulations predict peak
emissions flux of 0.2–0.5 PgC yr–1 and show that the NAIP could have
initiated PETM climate change. This is the first predictive model of carbon
emissions flux from any proposed PETM carbon source that is directly
constrained by observations of the geological structures that controlled
the emissions.

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Jennifer Botha, Adam K. Huttenlocker, Roger M.H. Smith, Rose Prevec, Pia
Viglietti & Sean P. Modesto (2019)
New geochemical and palaeontological data from the Permian-Triassic
boundary in the South African Karoo Basin test the synchronicity of
terrestrial and marine extinctions.
Palaeogeography, Palaeoclimatology, Palaeoecology 109467 (advance online
publication)
https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.palaeo.2019.109467&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=_1nYqnmPu7o68WzlxiIdecsG7xLJL22IAx-4ZsWXJD4&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_abs_pii_S003101821930728X&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=cNXuP4ZPdJARWk_MGvruk8wbULf-vdBIukSnrmjivaY&e= 


Highlights

A new site containing a complete sequence through the terrestrial PTB
A new radiometric date for the terrestrial end-Permian extinction
Data suggests that the marine and terrestrial extinctions were synchronous.
The current placement of the PTB in the Karoo Basin of South Africa is
retained.

Abstract

The end-Permian mass extinction (EPME) is widely recognised as the largest
mass extinction in Phanerozoic history. In marine strata the main
extinction event is well constrained, and has been radiometrically-dated to
an interval of some 60 kyr, approximately 251.9 million years ago. However,
the age and duration of the EPME in the terrestrial realm, as well as its
possible synchronicity with that of the marine realm, is debated. Here, we
shed light on issues pertaining to the identification and position of the
terrestrial EPME in southern Africa. Using recently collected
sedimentological (facies sequences), palaeontological (biostratigraphic
ranges), geochemical (stable isotope analyses) and detrital zircon
(ID-TIMS) data from a new site in the Xhariep District of the South African
Karoo Basin, we demonstrate that the Permian-Triassic boundary sequence
containing evidence for phased tetrapod extinctions is time equivalent with
the marine extinction. We conclude that the terrestrial EPME recorded in
the Karoo may be regarded as essentially synchronous with the EPME
currently defined in the marine realm, and was likely the result of the
same volcanically-induced atmospheric disturbances. This study describes
the first single, vertical succession of vertebrate and plant fossils that
span the terrestrial Permian-Triassic boundary that are also
well-constrained both by relative (stable isotopes) and absolute (detrital
zircon geochronology) dating methods.

====

Free pdf:

Vivi Vajda, Stephen McLoughlin, Chris Mays, Tracy D. Frank, Christopher R.
Fielding, Allen Tevyaw, Veiko Lehsten, Malcolm Bocking & Robert S. Nicolle
(2019)
End-Permian (252 Mya) deforestation, wildfires and flooding--An ancient
biotic crisis with lessons for the present;
Earth and Planetary Science Letters 529: 115875
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.epsl.2019.115875&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=4j6Fu-TKy5yTcZktDOYgU3Y60NPE2x74sPfhwkwdB_I&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S0012821X19305679&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=gxx9LtlSqbBXm-1HXQ9FcQO_zPuSxDxKm2s5vhqP6Nw&e= 

Highlights

End-Permian extinction event (EPE) analyzed in a high-palaeolatitude
continental setting.
Glossopteris peat-forming forests collapsed abruptly at the EPE.
Immediate post-EPE deposits rich in charcoal and fungi signify disaster
interval.
Algae-rich mudstones indicate water-table rise and ponding following EPE.
Recovery of vascular plants evident <2 m above level of the EPE.

Abstract

Current large-scale deforestation poses a threat to ecosystems globally,
and imposes substantial and prolonged changes on the hydrological and
carbon cycles. The tropical forests of the Amazon and Indonesia are
currently undergoing deforestation with catastrophic ecological
consequences but widespread deforestation events have occurred several
times in Earth's history and these provide lessons for the future. The
end-Permian mass-extinction event (EPE; ~252 Ma) provides a global,
deep-time analogue for modern deforestation and diversity loss. We
undertook centimeter-resolution palynological, sedimentological, carbon
stable-isotope and paleobotanical investigations of strata spanning the
end-Permian event at the Frazer Beach and Snapper Point localities, in the
Sydney Basin, Australia. We show that the typical Permian temperate,
coal-forming, forest communities disappeared abruptly, followed by the
accumulation of a 1-m-thick mudstone poor in organic matter that, in
effect, represents a 'dead zone' hosting degraded wood fragments, charcoal
and fungal spores. This signals a catastrophic scenario of vegetation
die-off and extinction in southern high-latitude terrestrial settings. Lake
systems, expressed by laterally extensive but generally less than a
few-metres-thick laminated siltstones, generally lacking bioturbation,
hosting assemblages of algal cysts and freshwater acritarchs, developed
soon after the vegetation die-off. The first traces of vascular plant
recovery occur ~1.6 m above the extinction horizon. Based on analogies with
modern deforestation, we propose that the global fungal and acritarch
events of the Permo-Triassic transition resulted directly from inundation
of basinal areas following water-table rise as a response to the abrupt
disappearance of complex vegetation from the landscape. The Corg values
reveal a significant excursion toward low isotopic values, down to -31‰  (a
shift of ~4‰), across the end-Permian event. The magnitude of the shift at
that time records a combination of changes in the global carbon cycle that
were enhanced by the local increase in microbial activity, possibly also
involving cyanobacterial proliferation. We envisage that elevated levels of
organic and mineral nutrients delivered from inundated dead forests,
enhanced weathering and erosion of extra-basinal areas, together with local
contributions of volcanic ash, led to eutrophication and increased salinity
of basinal lacustrine–lagoonal environments. We propose that the change in
acritarch communities recorded globally in nearshore marine settings across
the end-Permian event is to a great extent a consequence of the influx of
freshwater algae and nutrients from the continents. Although this event
coincides with the Siberian trap volcanic activity, we note that
felsic–intermediate volcanism was extensively developed along the
convergent Panthalassan margin of Pangea at that time and might also have
contributed to environmental perturbations at the close of the Permian.

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Spencer G. Lucas & Jerald D. Harris (2019)
The "Plastotype Problem" in Ichnological Taxonomy
Ichnos (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1080_10420940.2019.1688802&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=tNDGydTf6fdAtSKG04dqe6wUmGc6nXKMCMURLtV_aP8&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.tandfonline.com_doi_full_10.1080_10420940.2019.1688802&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=Kns6b1YZD1PmGCGBvT1cEYLrBDiyDqkiu5B7I2gaFvE&s=DUzqsK0Xzqf_8To6y1xK2n-QBdiuvnlOg-rm6TaDfz0&e= 


When naming ichnotaxa based on uncollectable trace fossils, the holotype is
the actual ichnofossil in the outcrop, though some ichnologists identify
the holotype as a replica (cast) held in a museum collection, and refer to
it as a "plastotype," although not all such replicas are made from plaster.
Nevertheless, through its Code, the International Commission on Zoological
Nomenclature (ICZN) makes it clear that an artificial, human-made replica
(plaster cast or otherwise) is not eligible to be the holotype of an
ichnotaxon. This directive is potentially destabilizing to much
ichnological taxonomy, which is based on holotypes left in the field that
have disappeared or will disappear. One possible solution for ichnologists
will be to petition the ICZN to recognize that artificial, human-made
replicas of ichnofossils can serve as name-bearing types. These may best be
called "axiotypes" (from the Greek axios, meaning "of equal value").

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