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Extreme seasonality in central Permian Pangea + small tetrapod directional hearing + more non-dino papers



Ben Creisler
bcreisler@gmail.com

A number recent (and not so recent) non-dino refs that may be of
interest (some are open access):

Cindy V. Looy, Stephanie L. Ranks, Dan S. Chaney, Sophie Sanchez,
Sébastien Steyer, Roger M.H. Smith, Christian A. Sidor, Timothy S.
Myers, Oumarou Ide & Neil J. Tabor (2016)
Biological and physical evidence for extreme seasonality in central
Permian Pangea.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi:10.1016/j.palaeo.2016.02.016
http: // www.sciencedirect.com/science/article/pii/S0031018216000900

Highlights

Biological and physical evidence supports extreme climate in central
Permian Pangea
Paleosols and sedimentology indicate aridity with periodic high water
availability
Carbon isotopes suggest soil productivity and evapotranspiration were very low
Pareiasaur bones shows evidence of active metabolism and distinct growth marks
The macroflora includes a 25 m long petrified log and voltzian conifer fossils

Abstract

Climate models indicate increased desertification in the continental
interior of Pangea during the Permian, which would have affected the
composition of the flora and fauna. We present a multi-proxy
paleoenvironmental reconstruction of a terrestrial ecosystem in
central Pangea of Lopingian age. The reconstruction is based on
biological and physical data from the Moradi Formation, located in the
Tim Mersoi Basin, northern Niger. Paleosols and sedimentological
evidence indicate that the prevailing climate was semi-arid to very
arid with marked intervals of high water availability. Carbon stable
isotope data from organic matter and paleosols suggest that both the
soil productivity and actual evapotranspiration were very low,
corresponding to arid conditions. Histological analysis of pareiasaur
bones shows evidence of active metabolism and reveals distinct growth
marks. These interruptions of bone formation are indicative of growth
rhythms, and are considered as markers for contrasting seasonality or
episodic climate events. The macrofossil floras have low diversity and
represent gymnosperm-dominated woodlands. Most notable are ovuliferous
dwarf shoots of voltzian conifers, and a 25-m long tree trunk with
irregularly positioned branch scars. The combined biological and
physical evidence suggests that the Moradi Formation was deposited
under a generally arid climate with recurring periods of water
abundance, allowing for a well-established ground water-dependent
ecosystem. With respect to its environment, this system is comparable
with modern ecosystems such as the southern African Namib Desert and
the Lake Eyre Basin in Australia, which are discussed as modern
analogues.

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Kimberly V. Lau, Kate Maher, Demir Altiner, Brian M. Kelley, Lee R.
Kump, Daniel J. Lehrmann, Juan Carlos Silva-Tamayo, Karrie L. Weaver,
Meiyi Yu, and Jonathan L. Payne
Marine anoxia and delayed Earth system recovery after the end-Permian
extinction.
Proceedings of the National Academy of Sciences (advance online publication)
doi:10.1073/pnas.1515080113
http: // www.pnas.org/content/early/2016/02/09/1515080113
http: // www.pnas.org/content/early/2016/02/09/1515080113.full.pdf

Significance

The end-Permian mass extinction not only decimated taxonomic diversity
but also disrupted the functioning of global ecosystems and the
stability of biogeochemical cycles. Explaining the 5-million-year
delay between the mass extinction and Earth system recovery remains a
fundamental challenge in both the Earth and biological sciences. We
use coupled records of uranium concentrations and isotopic
compositions to constrain global marine redox conditions across the
end-Permian extinction horizon and through the subsequent 17 million
years of Earth system recovery. Our finding that the trajectory of
biological and biogeochemical recovery corresponds to variations in an
ocean characterized by extensive, shallow marine anoxia provides, to
our knowledge, the first unified explanation for these observations.

Abstract

Delayed Earth system recovery following the end-Permian mass
extinction is often attributed to severe ocean anoxia. However, the
extent and duration of Early Triassic anoxia remains poorly
constrained. Here we use paired records of uranium concentrations
([U]) and 238U/235U isotopic compositions (δ238U) of Upper
Permian−Upper Triassic marine limestones from China and Turkey to
quantify variations in global seafloor redox conditions. We observe
abrupt decreases in [U] and δ238U across the end-Permian extinction
horizon, from ∼3 ppm and −0.15‰ to ∼0.3 ppm and −0.77‰, followed by a
gradual return to preextinction values over the subsequent 5 million
years. These trends imply a factor of 100 increase in the extent of
seafloor anoxia and suggest the presence of a shallow oxygen minimum
zone (OMZ) that inhibited the recovery of benthic animal diversity and
marine ecosystem function. We hypothesize that in the Early Triassic
oceans—characterized by prolonged shallow anoxia that may have
impinged onto continental shelves—global biogeochemical cycles and
marine ecosystem structure became more sensitive to variation in the
position of the OMZ. Under this hypothesis, the Middle Triassic
decline in bottom water anoxia, stabilization of biogeochemical
cycles, and diversification of marine animals together reflect the
development of a deeper and less extensive OMZ, which regulated Earth
system recovery following the end-Permian catastrophe.


News:

https://urldefense.proofpoint.com/v2/url?u=http-3A__phys.org_news_2016-2D02-2Doxygen-2Dstarved-2Doceans-2Dheld-2Dlife-2Drecovery.html&d=CwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=x82f3Wlkwtmbr1z8IAt9jA&m=J2mUDtsH1d8v52CRp7MV0g7JemanfcNYJ8aunMQEjIU&s=HzyXGMCA0GJB1y6QFWWoIERSYZxdgaLJJH_lZY5Ns0k&e=
 

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Silvia N. Césari & Carina Colombi (2016)
Palynology of the late Triassic ischigualasto formation, Argentina:
Paleoecological and paleogeographic implications.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi:10.1016/j.palaeo.2016.02.023
http: // www.sciencedirect.com/science/article/pii/S0031018216000973?np=y

Highlights

Palynological samples from the Late Triassic Ischigualasto Formation
are described.
Assemblages include species characteristic of the Onslow and Tethyan areas.
A uniform floral belt was extended to westernmost Gondwana during the Carnian.

Abstract

In this study we describe and compare the palynological assemblages
from the Carnian Ischigualasto Formation of westernmost Gondwana to
those of eastern Gondwana, which have been referred to the Onslow and
Ipswich phytogeographic provinces. The palynofloras studied contain
many taxa common to both regions, as well as several species that are
widely recorded in European Carnian successions and less frequently
recovered in the Carnian of the Southern Hemisphere. For the first
time in Argentinean assemblages, we recognize Anapiculatisporites
spiniger, Cadargasporites granulatus, Cycadopites stonei,
Ellipsovelatisporites plicatus, Enzonalasporites vigens, Ovalipollis
pseudoalatus, O. ovalis, Patinasporites densus, Quadraeculina
anellaeformis, Samaropollenites speciosus, Staurosaccites quadrifidus,
“Rimaesporites” aquilonalis, Vallasporites ignacii and Zonalasporites
cinctus. The new evidence extends the distribution of the Onslow
palynoflora to include Carnian associations formerly assigned to the
Ipswich Province. The affinities of Argentinean palynofloras seem to
indicate the existence of a similar flora extending from the northern
Australian margin (West Timor), through the western Tethys coasts, to
westernmost Gondwana during the Carnian. Moreover, the new data
reinforce the close relationship between some diagnostic species and
humid environmental conditions.

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Federico Fanti , Gabriele Larocca Conte, Luana Angelicola & Andrea Cau (2016)
Why so many dipnoans? A multidisciplinary approach on the Lower
Cretaceous lungfish record from Tunisia.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi:10.1016/j.palaeo.2016.02.024
http: / /www.sciencedirect.com/science/article/pii/S0031018216000985

Highlights

We describe lungfish material from the Albian of Tunisia
Material is referable to five lineages provides new insights in the
taxonomic diversity.
Taphonomic factors explain unexpectedly high taxonomic diversity

Abstract

The Lower Cretaceous record of vertebrates from Africa is problematic
as the majority of fossil localities lack adequate stratigraphic and
paleoecological data when compared with coeval Laurasian deposits.
Thereby, our comprehension of paleocommunities and paleobiogeographic
patterns may be affected by the lack of multidisciplinary approach.
Among taxonomically and paleoecological significant clades, lungfishes
(Sarcopterygii, Dipnoi) are commonly found in the Cretaceous fresh
water, brackish and marginal-marine deposits of Gondwana, although
identifiable elements are limited to isolated tooth plates. We provide
the first taxonomic identification of dipnoans from the Ain el Guettar
Formation of southern Tunisia (Oum ed Diab Member, Albian).
Identification of tooth plates based on morphological parameters and
phylogenetic analyses indicate the co-occurrence in a discrete
stratigraphic unit of at least five lineages referable to
Equinoxiodus, Neoceratodus, Asiatoceratodus and/or Ferganoceratodus,
Ceratodus, and Lavocatodus. This unusually high diversity is
unparalleled in the fossil record and is also challenged by an
actualistic comparison with extant taxa. We suggest that a series of
taphonomic factors significantly inflated observed lungfish diversity
in the estuarine and marginal-marine deposits of the Oum ed Diab
Member. Therefore, we recognize the fossil fauna as representative of
a larger, inland paleo-hydrographic system. This study confirms the
paleoecological scenario resulted from the analyses on terrestrial
reptiles from the Oum ed Diab Member.

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


Cretaceous mosquito (free pdf)


Art Borkent & David A. Grimaldi (2016)
The Cretaceous Fossil Burmaculex antiquus Confirmed as the Earliest
Known Lineage of Mosquitoes (Diptera: Culicidae)
Zootaxa   4079(4): 457-466
DOI: http: // dx.doi.org/10.11646/zootaxa.4079.4.5
http: // www.mapress.com/j/zt/article/view/zootaxa.4079.4.5

A second female of mid-Cretaceous Burmaculex antiquus Borkent &
Grimaldi, preserved in 99 myo Burmese amber, and the oldest known
member of the Culicidae, is described in detail. Although generally
opaque and distorted, some character states are added or refined. The
discovery of well-developed scales on the legs shows that this feature
must now be considered a synapomorphy of both the fossil and all
extant members of the family. Previously described synapomorphies and
further interpretation here confirm the phylogenetic position of this
fossil as the sister group to extant and all known fossil Culicidae.
It is placed in the new subfamily Burmaculicinae.

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Directional hearing in small tetrapods


Open Access

Matthew J. Mason  (2016)
Internally coupled ears in living mammals.
Biological Cybernetics (advance online publication)
DOI: 10.1007/s00422-015-0675-1
http: // link.springer.com/article/10.1007/s00422-015-0675-1


It is generally held that the right and left middle ears of mammals
are acoustically isolated from each other, such that mammals must rely
on neural computation to derive sound localisation cues. There are,
however, some unusual species in which the middle ear cavities
intercommunicate, in which case each ear might be able to act as a
pressure-difference receiver. This could improve sound localisation at
lower frequencies. The platypus Ornithorhynchus is apparently unique
among mammals in that its tympanic cavities are widely open to the
pharynx, a morphology resembling that of some non-mammalian tetrapods.
The right and left middle ear cavities of certain talpid and golden
moles are connected through air passages within the basicranium; one
experimental study on Talpa has shown that the middle ears are indeed
acoustically coupled by these means. Having a basisphenoid component
to the middle ear cavity walls could be an important prerequisite for
the development of this form of interaural communication. Little is
known about the hearing abilities of platypus, talpid and golden
moles, but their audition may well be limited to relatively low
frequencies. If so, these mammals could, in principle, benefit from
the sound localisation cues available to them through internally
coupled ears. Whether or not they actually do remains to be
established experimentally.

==

A. P. Vedurmudi, J. Goulet, J. Christensen-Dalsgaard, B. A. Young, R.
Williams, and J. L. van Hemmen (2016)
How Internally Coupled Ears Generate Temporal and Amplitude Cues for
Sound Localization.
Physical Review Letters  116: 028101
DOI: 10.1103/PhysRevLett.116.028101
http: // journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.028101


In internally coupled ears, displacement of one eardrum creates
pressure waves that propagate through air-filled passages in the skull
and cause displacement of the opposing eardrum, and conversely. By
modeling the membrane, passages, and propagating pressure waves, we
show that internally coupled ears generate unique amplitude and
temporal cues for sound localization. The magnitudes of both these
cues are directionally dependent. The tympanic fundamental frequency
segregates a low-frequency regime with constant time-difference
magnification from a high-frequency domain with considerable amplitude
magnification.

News:

https://urldefense.proofpoint.com/v2/url?u=http-3A__phys.org_news_2016-2D02-2Dinternally-2Dcoupled-2Dears-2Denable-2Danimals.html&d=CwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=x82f3Wlkwtmbr1z8IAt9jA&m=J2mUDtsH1d8v52CRp7MV0g7JemanfcNYJ8aunMQEjIU&s=BWgbGVo_hqAppvjSqRo-Az6MLI4KWTGxo9Yf1Lufr68&e=
 

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