[dinosaur] Baurusuchids as apex predators + Yabeinosaurus with skin, last meal + Neurankylus + early tetrapodomorph biogeograph

Ben Creisler
[email protected]

Some recent non-dino papers:

Free pdf:

Felipe C. Montefeltro, Stephan Lautenschlager, Pedro L. Godoy,  Gabriel S.
Ferreira & Richard J. Butler (2019)
A unique predator in a unique ecosystem: modelling the apex predator from
the Late Cretaceous crocodyliform-dominated fauna in Brazil.
bioRxiv 843334 (preprint)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1101_843334&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=s1eiOCsOXgNLVpm-c8Kmaudec2B_pRU-cJMOH77FHp8&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.biorxiv.org_content_10.1101_843334v1&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=Q-RMZj8jON0Ab3wwhJQUYWI3oVIdIotaBo1nO4mSBK0&e= 


Theropod dinosaurs were relatively scarce in the Late Cretaceous ecosystems
of southeast Brazil. Instead, the abundant hypercarnivore crocodyliforms
known as baurusuchids were probably playing the ecological role as apex
predators. Baurusuchids exhibited a series of morphological adaptations
associated to this ecological role, but quantitative biomechanical
assessments to support this were lacking to date. Here, we employ a
biomechanical modelling approach, using finite element analysis (FEA) on
skull and mandible models of a baurusuchid specimen, allowing us to
characterise the craniomandibular apparatus of baurusuchids, as well as to
test the hypothesis that their functional morphology allowed them to
outcompete other carnivores, such as theropods. Our results demonstrate,
for the first time, the ecological role of this group as specialised apex
predators in the continental Late Cretaceous ecosystems of South America.
With a with a relatively weak bite force (~600 N), baurusuchids preying
strategies probably relied on other morphological specializations, such as
ziphodont dentition and strong cervical musculature. Consistently,
comparative assessments of the stress distribution and magnitude of scaled
models of other predators (the theropod Allosaurus fragilis and the living
crocodylian Alligator mississippiensis) show discrepant responses to
loadings under the same functional scenarios, further suggesting
considerably distinct predatory behaviors for these animals. The unique
selective pressures from the arid to semi-arid Late Cretaceous
palaeoecosystems of southeast Brazil, which were dominated by
crocodyliforms, possibly drove the emergence and evolution of such
exclusive set of biomechanical features seen in baurusuchids, which had not
been previously reported for any other predatory taxon.

====

Lida Xing, Kechung Niu, Rod S. Taylor & Susan E.Evans (2019)
Integumentary remains and abdominal contents in the Early Cretaceous
Chinese lizard, Yabeinosaurus (Squamata), demonstrate colour banding and a
diet including crayfish.
Cretaceous Research 104320 (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.cretres.2019.104320&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=UdMHO7ktWC_slK2nks_e9SThL3axygHjQolOqevy1cc&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S0195667119303283&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=gPj1OptXHxJAFW733Mq_RwMVdL2Wq1wm4ypdUvJWVgY&e= 

Highlights

A new specimen of Yabeinosaurus robustus is the largest complete example on
record.
Abdominal contents show that this individual had fed on a large crayfish.
Integumentary traces indicate the lizard’s body was strikingly banded in
life.

Abstract

The Early Cretaceous lizard Yabeinosaurus is well-represented in the Jehol
Biota of northeast China, with specimens yielding information on
ontogenetic development, reproductive strategy, and diet, as well as
skeletal morphology. However, a large, well-preserved, new specimen of
Yabeinosaurus robustus from the Lamadong locality, Liaoning, provides
further insights into the morphology and biology of this species.
Integumentary traces demonstrate that, in life, Y. robustus was coloured
with well-defined light and dark banding through both the body and the
tail. The integumentary traces also confirm that Yabeinosaurus was covered
with thin, non-overlapping osteoderms, each of which seems to have
underlain only part of a scale. Previous specimens have contained fish
remains, suggesting that Yabeinosaurus foraged in, or close, to the water.
The new specimen supports that hypothesis as it contains the remains of a
large crayfish, identified as belonging to the species Palaeocambarus
licenti Taylor et al. 1999. Body parts of the crayfish provide an estimated
original total length of 120-140 mm.

===

Giulio Panascí, David J. Varricchio & Ren Hirayama (2019)
New occurrence of Neurankylus sp. (Testudines: Paracryptodiria: Baenidae)
in the Upper Cretaceous Frontier Formation of south western Montana (USA).
Cretaceous Research 104318 (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.cretres.2019.104318&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=0iEh3nTP4U-jPGFaHdLWJhx_xomkML3TsmbvK_DXf8w&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S0195667119302162&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=B_Yod_W2vEdwNls7laHhq5FrBbtH3pZX-V-Hems7tkw&e= 


An incomplete specimen assigned to the genus Neurankylus sp. was collected
from Coniacian deposits of the Frontier Formation of Montana (USA). The
material consists of anterior plastron, a costal plate and neural plate
fragment, and several undetermined skeletal elements. The identification is
based on the relatively large size of the specimens, scute elements joining
along the mid-line of the plastron with the intergulars reaching the
humerals, and complete fusion of the sutures. The specimen represents the
first baenid turtle reported from non-marine Frontier Formation deposits
and is particularly relevant for understanding stratigraphical and
paleogeographical distribution of the Family Baenide. This will have
important implications for phylogenetic studies and paleoenvironmental
interpretation of non-marine Frontier Formation deposits of south-western
Montana.

===

Jacob D. Gardner, Kevin Surya & Chris L. Organ (2019)
Early tetrapodomorph biogeography: Controlling for fossil record bias in
macroevolutionary analyses.
Comptes Rendus Palevol (advance online publication)
Early tetrapodomorph biogeography: Controlling for fossil record bias in
macroevolutionary analyses
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.crpv.2019.10.008&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=CfKZKqq3ibQHviDBk9lUk1g3cpx2Wp05MVNFj9ibMNY&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_abs_pii_S1631068319301861&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=-VI-nYsglYCHuOVDHgHjm1HNHNOdV28rRDs_RxxLspg&s=FIqdc_fPiDxBwrdP8YdUHQLCvjXZ7koSMP0gOrKueWk&e= 


The fossil record provides direct empirical data for understanding
macroevolutionary patterns and processes. Inherent biases in the fossil
record are well known to confound analyses of this data. Sampling bias
proxies have been used as covariates in regression models to test for such
biases. Proxies, such as formation count, are associated with
paleobiodiversity, but are insufficient for explaining species dispersal
owing to a lack of geographic context. Here, we develop a sampling bias
proxy that incorporates geographic information and test it with a case
study on early tetrapodomorph biogeography. We use recently-developed
Bayesian phylogeographic models and a new supertree of early
tetrapodomorphs to estimate dispersal rates and ancestral habitat
locations. We find strong evidence that geographic sampling bias explains
supposed radiations in dispersal rate (potential adaptive radiations). Our
study highlights the necessity of accounting for geographic sampling bias
in macroevolutionary and phylogenetic analyses and provides an approach to
test for its effect.