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Maniraptoran fossils from Bauru, Brazil (free pdf) + Chinese fossils (free pdfs) + more



Ben Creisler
bcreisler@gmail.com

A number of recent papers not yet mentioned on the DML:


Rafael Delcourt & Orlando Nelson Grillo (2014)
On maniraptoran material (Dinosauria: Theropoda) from Vale do Rio do
Peixe Formation, Bauru Group, Brazil.
Revista Brasileira de Paleontologia 17(3):307-316
doi: 10.4072/rbp.2014.3.03
http://www.sbpbrasil.org/assets/uploads/files/rbp17-3/03_Delcourt%20%26%20Grillo_pg307a316.pdf

Non-avian theropod remains are scarce in Brazil and few specimens were
referred to Maniraptora. Remains of a non-avian theropod dinosaur (DGM
930-R) from Vale do Rio do Peixe Formation, Bauru Group, found near
the Santo Anastácio municipality, São Paulo State are described. DGM
930-R is represented by two partial caudal vertebra centra, a partial
diaphysis of the right femur with marked lines of arrested development
(indicatives of a habitat with marked seasonality), a partial dorsal
rib and other rib fragments, a partial bone that possibly represents
the proximal portion of the ischium, and some unidentifi able
elements. DGM 930-R is referred as a Maniraptoran incertae sedis,
possibly related to Deinonychosauria because of the box-like anterior
vertebral centrum with quadrangular-shaped posterior articulation. The
circumference of the femur of DGM 930-R suggests it was a medium-sized
dinosaur (about 3 m long) that shared the same geographic space with
other theropods (megaraptorans, abelisauroids, and
carcharodontosaurids) and  esoeucrocodylians.


===


National Science Review Special Issue: Fossils in China

http://nsr.oxfordjournals.org/content/current

Articles with free pdfs include:

Hai-Lu You (2014)
A tale of a ‘middle’ tail.
National Science Review  1 (4): 487
doi:10.1093/nsr/nwu056
http://nsr.oxfordjournals.org/content/1/4/487.extract
http://nsr.oxfordjournals.org/content/1/4/487.full.pdf+html

Zhongornis refers to a ‘middle’ or ‘intermediate’ bird because its
tail was claimed to be transitional between primitive birds with a
long bony tail (such as Archaeopteryx and Jeholornis) and those with a
short tail ending in a fused tip called the pygostyle (such as
Confuciusornis). This finding is significant, as it appeared to fill a
‘gap’ at a critical stage in the early evolution of birds.

***
Jin Meng (2014)
Mesozoic mammals of China: implications for phylogeny and early
evolution of mammals.
National Science Review (December 2014) 1 (4): 521-542
doi:10.1093/nsr/nwu070
http://nsr.oxfordjournals.org/content/1/4/521.abstract

All Mesozoic mammaliaforms reported from China are briefly documented
herein. These forms can be divided into at least five major
assemblages: Lufeng, Yanliao (Daohugou), Jehol, Fuxin and Bayan
Mandahu, ranging from the Early Jurassic to the Late Cretaceous
periods. Although the temporal and geographic distributions of these
mammaliaforms are not dense, the records do reveal a pattern that is
generally consistent with patterns that have been recognized globally.
The initial stage of mammalian evolution was represented by stem
mammaliaforms or primitive ‘triconodonts’ from the Lufeng. This was
followed by the Middle-Late Jurassic Yanliao episode that showed a
high diversity and disparity of mammaliaforms in which terrestrial,
swimming, arboreal and gliding species were present. The disparity, at
least in molar morphology and types of locomotion, decreased but the
diversity persisted into the Cretaceous, a period that was dominated
by eutriconodontans, multituberculates and trechnotherians. The superb
specimens from nearly all major groups of Mesozoic mammals in China
provided a great amount of information that contributed to our
understanding on some major issues in phylogeny and the early
evolution of mammals, such as divergences of mammals and the evolution
of the mammalian middle ear. A hypothesis on the transformation of the
allotherian tooth pattern is proposed as an example to illustrate the
potential for future studies of mammalian evolution.

***
Zhonghe Zhou (2014)
The Jehol Biota, an Early Cretaceous terrestrial Lagerstätte: new
discoveries and implications.
National Science Review 1 (4): 543-559
doi:10.1093/nsr/nwu055
http://nsr.oxfordjournals.org/content/1/4/543.abstract
http://nsr.oxfordjournals.org/content/1/4/521.full.pdf+html

The study of the Early Cretaceous terrestrial Jehol Biota, which
provides a rare window for reconstruction of a Lower Cretaceous
terrestrial ecosystem, is reviewed with a focus on some of the latest
progress. A newly proposed definition of the biota based on
paleoecology and taphonomy is accepted. Although the Jehol fossils are
mainly preserved in two types of sedimentary rocks, there are various
types of preservation with a complex mechanism that remains to be
understood. New discoveries of significant taxa from the Jehol Biota,
with an updated introduction of its diversity, confirm that the Jehol
Biota represents one of the most diversified biotas of the Mesozoic.
The evolutionary significance of major biological groups (e.g.
dinosaurs, birds, mammals, pterosaurs, insects, and plants) is
discussed mainly in the light of recent discoveries, and some of the
most remarkable aspects of the biota are highlighted. The global and
local geological, paleogeographic, and paleoenvironmental background
of the Jehol Biota have contributed to the unique composition,
evolution, and preservation of the biota, demonstrating widespread
faunal exchanges between Asia and other continents caused by the
presence of the Eurasia–North American continental mass and its link
to South America, and confirming northeastern China as the origin and
diversification center for a variety of Cretaceous biological groups.
Although some progress has been made on the reconstruction of the
paleotemperature at the time of the Jehol Biota, much more work is
needed to confirm a possible link between the remarkable diversity of
the biota and the cold intervals during the Early Cretaceous. Finally,
future directions for the study of the Jehol Biota are proposed that
highlight the great potential of more comprehensive and
multidisciplinary studies to further our understanding of the
biological and geological implications of the Jehol Lagerstätte.

***
Shu-zhong Shen and Samuel A. Bowring (2014)
The end-Permian mass extinction: a still unexplained catastrophe.
National Science Review 1 (4): 492-495
doi:10.1093/nsr/nwu047
http://nsr.oxfordjournals.org/content/1/4/492.extract
http://nsr.oxfordjournals.org/content/1/4/492.full.pdf+html

The end-Permian mass extinction is widely regarded as the largest mass
extinction in the past 542 million years with loss of about 95% of
marine species and 75% of terrestrial species. There has been much
focus and speculation on what could have caused such a catastrophe.
Despite decades of study, the cause or causes remain mysterious.
Numerous scenarios have been proposed, including asteroid impact,
Siberian flood basalt volcanism, marine anoxia and euxinia, sea-level
change, thermogenic methane release and biogenic methane release due
to explosive growth of a methanogenic microbe.

==========

Jeremías R. A. Taborda, Andrew B. Heckert & Julia B. Desojo (2015)
Intraspecific variation in Aetosauroides scagliai Casamiquela
(Archosauria: Aetosauria) from the Upper Triassic of Argentina and
Brazil: an example of sexual dimorphism?
Ameghiniana (advance online publication)
Preprint doi: 10.5710/AMGH.05.01.2015.2824
http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/1044


Aetosaurs are a group of quadrupedal, armoured pseudosuchian
archosaurs from the Upper Triassic. They are characterized by dorsal
and ventral carapaces, and appendicular osteoderms, all of them
ornamented. Aetosaurs have been proposed as index fossils based in
large part on the distinctiveness of some osteoderms; therefore, it is
important to understand the intraspecific variation of these elements
in the clade. In the present contribution, we describe three types of
ornamentation on the medial area of paramedian osteoderms in the
dorsal armour of Aetosauroides scagliai: the “radial pattern” consists
of radial grooves and ridges, with small pits inside the grooves; the
“anastomosing pattern” is composed of anastomosing crests and
proportionately larger, more irregular pits; and an “intermediate” or
“transitional pattern” between the “radial” and “anastomosing
patterns”. The articulated dorsal armour preserved in specimens PVL
2059 and PVL 2073 possess all three patterns of ornamentation, but
they differ in the position of each throughout the carapace. Recent
studies of histological thin-sections in osteoderms of A. scagliai
show the absence of remodeling of osteoderm tissues, allowing the
estimation of age by counting LAGs (lines of arrested growth). PVL
2073 is slightly longer (~10% longer centra) but also ontogenetically
younger (5 LAGs) than PVL 2059 (10 LAGs; slightly wider osteoderms).
Combining this information and comparing it with that of living
crocodiles (where the male specimens are typically relatively larger
than the females of the same age), we conclude that the intraspecific
variation observed in A. scagliai is compatible with the hypothesis of
sexual dimorphism. These results show the need to explore the sources
of intraspecific variation in aetosaurs.



======

In Japanese with free pdf

KUBO Tai (2014)
A biogeographical analysis of the Early Cretaceous dinosaurs including
dinosaurs from Fukui, Japan using Tree Reconciliation analysis.
Memoirs of the Fukui Prefectural Dinosaur Museum 13:1–7.
http://www.dinosaur.pref.fukui.jp/archive/memoir/memoir013-001.pdf

Taxon cladogram of Early Cretaceous dinosaurs that include all three
species of dinosaurs found from Fukui prefecture, Japan, was manually
constructed by combining three taxon cladograms and a dinosaur
supertree of Lloyd et al. (2008). This cladogram was biogeographically
analyzed using Tree Reconciliation analysis. Dinosaur taxa were
assigned to eight biogeographical areas:Japan,
(China+Mongolia),(Thailand+Laos), Africa, Europe, North America, South
America and Australia. The result showed the dinosaur fauna of Fukui
is closely related to those of China+Mongolia) and North America.
However, in the resultant area cladogram (Thailand+Laos) was closely
related to Australia, South America, and Africa, which is incongruent
with the accepted paleogeography of the Early Cretaceous. Areas that
belong to Laurasia except (Thailand+Laos) formed a clade and Africa is
the sister group of this clade. Other areas of Gondwana were placed in
the basal position of the area cladogram. These topologies matches
with the accepted paleogeography of the Early Cretaceous. However, the
resultant area cladogram failed the randomization test of a software
Treemap, because the number of vicariance event was not statistically
high. For the future work of dinosaur biogeography, an algorithm that
can compare taxa of different ages without limitation in the number of
analyzed taxa is warranted.

======

Michael Holz (2015)
Mesozoic paleogeography and paleoclimates – a discussion of the
diverse greenhouse and hothouse conditions of an alien world.
Journal of South American Earth Sciences (advance online publication)
doi:10.1016/j.jsames.2015.01.001
http://www.sciencedirect.com/science/article/pii/S0895981115000024


Highlights
An abridged but updated overview of the Mesozoic is shown.
Mesozoic paleoclimatic variations included from mini-ice ages to
hothouse conditions.
Dinosaur occurrences from Brazilian continental basins are briefly
characterized.
The entire data set as discussed in the text is summarized in a chart.

Abstract
The Mesozoic was the time of the break-up of Pangaea, with profound
consequences not only for the paleocontinental configuration, but also
for paleoclimates and for the evolution of life. Cool greenhouse
conditions alternated with warm greenhouse and even hothouse
conditions, with global average temperatures around 6 to 9°C warmer
than the present ones. There are only sparse and controversial
evidence for polar ice; meanwhile, extensive evaporitic and desertic
deposits are well described. Global sea levels were mainly high, and
the content of atmospheric O2 was varying between 15 and 25%. These
conditions make the Mesozoic Earth an alien world compared to
present-day conditions. Degassing from volcanism linked to the rifting
process of Pangaea and methane emissions from reptilian biotas were
climate-controlling factors because they enhanced atmospheric CO2
concentrations up to 16 times compared to present-day levels. The
continental break-up modified paleopositions and shoreline
configurations of the landmasses, generating huge epicontinental seas
and altering profoundly the oceanic circulation. The Mesozoic was also
a time of important impact events as probable triggers for “impact
winters”; and for the Era at least nine huge (diameter > 20km) impact
structures are known. This paper presents an abridged but updated
overview of the Mesozoic paleogeographic and paleoclimatic variations,
characterizing each period and sub-period in terms of paleoclimatic
state and main tectonic and climatic events, and provides a brief
geologic, stratigraphic, paleoclimatic and taphonomic characterization
of dinosaur occurrences as recorded in the Brazilian continental
basins.