[dinosaur] Neusticemys cranial fossils + Varanus lungs unidirectional airflow + more

Ben Creisler
[email protected]

Some recent non-dino papers:


P. González Ruiz, M. S. de la Fuente  and M.S. Fernández (2019)
New cranial fossils of the Jurassic turtle Neusticemys neuquina and
phylogenetic relationships of the only thalassochelydian known from the
eastern Pacific.
Journal of Paleontology (advance online publication)
DOI: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1017_jpa.2019.74&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=r9EU81MI0g9ZsFTQxz-6kbJ6BZlATFgoy-KMG08oKXU&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.cambridge.org_core_journals_journal-2Dof-2Dpaleontology_article_new-2Dcranial-2Dfossils-2Dof-2Dthe-2Djurassic-2Dturtle-2Dneusticemys-2Dneuquina-2Dand-2Dphylogenetic-2Drelationships-2Dof-2Dthe-2Donly-2Dthalassochelydian-2Dknown-2Dfrom-2Dthe-2Deastern-2Dpacific_DB63A515ACD55CC60A87C12E6E724E78&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=ok-JlvPjpE39OXkWwsYc8rX0jtxVNORCYYvUTfFqyzo&e= 


Neusticemys neuquina (Fernández and de la Fuente, 1988) is a turtle from
the Upper Jurassic of the Neuquén Basin, Patagonia, Argentina. Here we
describe in detail a new skull, lower jaw, and a vertebra, utilizing both
traditional anatomical description and computed tomography (CT). New
diagnostic cranial characters of Neusticemys neuquina are: a round
depression on the ventral surface of the basisphenoid, a relatively larger
oval foramen nervi trigemini, and reduced and steepened triturating
surfaces on both the maxilla and dentary. The new morphological information
presented in this study was included in a phylogenetic analysis, the
primary result of which was recovery of Neusticemys neuquina within
Thalassochelydia. Characters recognized as synapomorphies of this clade
include: (1) anterolateral recess of the anterior surface of the quadrate
positioned lateral to the processus trochlearis oticum, (2) presence of a
fossa on the supraoccipital-opisthotic-exoccipital contact area, (3)
foramina anterius caroticus cerebralis located close together but
independently perforating the basisphenoid, and (4) the presence of the
splenial in the mandible. Two contrasting dispersal scenarios could explain
how this species of Thalassochelydia can be found outside of Europe. The
presence of Neusticemys neuquina in the Neuquén Basin could be the
consequence of an early dispersion event, for which we lack intermediate
forms, or it could be the result of a later event once the clade was
already established in Europe.

==

Robert L. Cieri  & C.G. Farmer (2019)
Computational fluid dynamics reveals a unique net unidirectional pulmonary
pattern of airflow in savannah monitor lizards (Varanus exanthematicus).
The Anatomical Record (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1002_ar.24293&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=ZIqWTELCaFLMv3raFsi8bBFEwhY_d0NpQc7p3yCoY-w&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__anatomypubs.onlinelibrary.wiley.com_doi_10.1002_ar.24293&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=ZzdkA104y_4Mc9DsJVEcEl2iphvtGaHP2UbFt5JK5jY&e= 


This report models pulmonary airflow in the savannah monitor (Varanus
exanthematicus) using computational fluid dynamics simulations, which are
based on computed tomography data. Simulations were validated by
visualizing the flow of aerosolized lipids in excised lungs with good but
not perfect agreement. The lung of this lizard has numerous successive
bronchi branching off a long intrapulmonary bronchus, which are
interconnected by intercameral perforations. Unidirectional flow has been
documented in the lateral secondary bronchi of the savannah monitor, but
patterns of airflow in the rest of the lung remain unknown, hindering our
understanding of the evolution of pulmonary patterns of airflow in
tetrapods. These results indicate the lung contains a unique net
unidirectional flow, where the overall flow scheme is similar during
expiration and late inspiration, but dissimilar during early inspiration.
Air is transported net caudad through the intrapulmonary bronchus and net
craniad through secondary bronchi, much like the pattern of flow in birds.
The simulations show that many chambers feature flow in multiple directions
during parts of the respiratory cycle, but some regions also show robust
unidirectional airflow. Air moves craniad through secondary bronchi and
between adjacent secondary bronchi through intercameral perforations. The
first secondary bronchus, the hilar‐cranial bronchus, contains tidal flow
that may improve ventilation of the central and dorsal lung parenchyma.
These results expand our understanding of flow patterns in varanid lungs
and suggest lungs with net unidirectional flow as an evolutionary pathway
between tidal flow and complete unidirectional flow in multicameral lungs.

===

Juan M. Jannello, Ignacio A. Cerda & Marcelo S. de la Fuente (2019)
The relationship between bone shell microanatomy and palaeoecology in
Testudinata from South America.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online
publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.palaeo.2019.109412&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=E8QhRJBMMUzTWG0RFZSK_az6sC4TfUeVP3zpUW-gL3A&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_abs_pii_S0031018219304791&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=7x1I3WWraj8AWwlKiktpK9e0_hEVzrQcgTVKn5WAsQg&s=xX-ytFBSftZbk_MTSH30r1F94JtfF-yrDL7kN1-xvv4&e= 

Highlights

A comprehensive qualitative and quantitative description of shell
microanatomy of Testudinata is presented.
Data do not support a correlation between costal bone shell microstructure
and habitats.
Paleoecological inferences based on bone microstructure must be taken very
cautiously.

Abstract

Extant turtles exhibit a range of ecological adaptations to terrestrial and
pelagic marine habitats. Bone shell microanatomy, and specifically,
qualitative and quantitative approaches to shell bone porosity, have been
used to infer palaeoecology and habitat. However, such inferences are
hindered by the lack of a comprehensive sampling of testudine taxa and, in
some instances, of long bones of vertebrates other than turtles. In this
paper, we carry out an osteohistological analysis of Testudinata shell
bones, including 31 different taxa, both extant and extinct, of known
habitats. Costal and peripheral elements of published species and new data
presented here are statistically analysed. Although, in some cases, values
are congruent with those expected for a particular habitat (e.g.
Hydromedusa casamayorensis), this is not true for all taxa examined.
Moreover, microanatomical features of several taxa (e.g. Chelonia mydas)
are inconsistent with habitat data. Results indicate that, although the
microanatomical structure of the shell is related to habitat, this is not
the only influence and indeed, in several cases, not the most important
factor.


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