[dinosaur] Rhinochelys neurovascular anatomy + Miocene fossils of Lacerta + CT scan (free pdfs)

Ben Creisler
[email protected]


Some recent non-dino papers with free pdfs:


Free pdf:

Serjoscha W. Evers,  James M. Neenan,  Gabriel S. Ferreira,  Ingmar
Werneburg,  Paul M. Barrett &  Roger B. J. Benson (2019)
Neurovascular anatomy of the protostegid turtle Rhinochelys pulchriceps and
comparisons of membranous and endosseous labyrinth shape in an extant
turtle.
Zoological Journal of the Linnean Society, zlz063
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1093_zoolinnean_zlz063&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=H2eg1hNLHSEwIhZHTtZSIgPa6Cih4h0UhlyeAzEHPOI&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__academic.oup.com_zoolinnean_advance-2Darticle_doi_10.1093_zoolinnean_zlz063_5552592-3Fsearchresult-3D1&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=WbyqN1WatzC3MzzVfak4adGiiWKRDhoQugs0hXKoZEQ&e= 

Chelonioid turtles are the only surviving group of reptiles that
secondarily evolved marine lifestyles during the Mesozoic Early chelonioid
evolution is documented by fossils of their stem group, such as
protostegids, which yield insights into the evolution of marine adaptation.
Neuroanatomical features are commonly used to infer palaeoecology owing to
the functional adaptation of the senses of an organism to its environment.
We investigated the neuroanatomy and carotid circulation of the early Late
Cretaceous protostegid Rhinochelys pulchriceps based on micro-computed
tomography data. We show that the trigeminal foramen of turtles is not
homologous to that of other reptiles. The endosseous labyrinth of R.
pulchriceps has thick semicircular canals and a high aspect ratio.
Comparisons among turtles and other reptiles show that the endosseous
labyrinth aspect ratio is not a reliable predictor of the degree of aquatic
adaptation, contradicting previous hypotheses. We provide the first models
of neuroanatomical soft tissues of an extant turtle. Turtle brain
morphology is not reflected by the brain cavity, and the endosseous
labyrinth provides an incomplete reflection of membranous semicircular duct
morphology. Membranous labyrinth geometry is conserved across gnathostomes,
which allows approximate reconstruction of the total membranous labyrinth
morphology from the endosseous labyrinth despite their poor reflection of
duct morphology.

===

Free pdf:

Muofhe Tshibalanganda,  Anton du Plessis,  Stephan G. Le Roux, Wendy L.
Taylor, Roger M. H. Smith & Claire Browning  (2019)
Systematic experiments to quantitatively assess image quality for CT scans
of a Karoo tetrapod fossil.
Palaeontologia Africana 54: 1-13
URI: https://urldefense.proofpoint.com/v2/url?u=https-3A__hdl.handle.net_10539_27891&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=kIFKNDYTw-gftidB3bg7Q8MUAZmngDPWAQpHV36NYt8&e= 
https://urldefense.proofpoint.com/v2/url?u=http-3A__wiredspace.wits.ac.za_handle_10539_27891&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=F-moKAjvCF9eQYrBjx8euExSfMfoZdl71Nw7K6wkMlE&e= 


Over the past decade non-destructive, three-dimensional visualization and
analysis of fossils using X-ray tomography has greatly  advanced
palaeontological studies worldwide. Micro-computed tomography (microCT) is
now accepted as best practice in  palaeontological studies to augment the
anatomical description of newly discovered fossils. Despite advances in
laboratory microCT  hardware, software and skills of users, there is a lack
of clear methodologies for scanning and analysing fossils. Here we report
on a  systematic and detailed study of the quantitative effects of the
variation of different microCT scanning parameters on the image quality  of
an unprepared fossilized Karoo tetrapod skull and parts of the postcrania.
Results indicate that voltage variations do not increase the  contrast for
the bone as one would expect, and the best image quality solution is found
using high frame averaging and high X-ray flux  (current). Although this
study was limited to one specimen, the results may find a practical use for
future studies involving similar  fossils.

===========


Free pdf:

Andrej Čerňanský & Elena V. Syromyatnikova (2019)
The first Miocene fossils of Lacerta cf. trilineata (Squamata, Lacertidae)
with a comparative study of the main cranial osteological differences in
green lizards and their relatives.
PLoS ONE 14(8): e0216191.
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1371_journal.pone.0216191&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=CEpdAluokxIjLKg4Z30YQfDfps_jhNcfzZA8WlxYk_w&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__journals.plos.org_plosone_article-3Fid-3D10.1371_journal.pone.0216191&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XF1tapqo9YGImV4kNcrvxGQatS4awp-GvDjN2-NKn4g&s=cGS1kXo_mSCXtUMPpWz5b4zYBgThnh4uVTvscBEya5Q&e= 


We here describe the first fossil remains of a green lizard of the Lacerta
group from the late Miocene (MN 13) of the Solnechnodolsk locality in
southern European Russia. This region of Europe is crucial for our
understanding of the paleobiogeography and evolution of these middle-sized
lizards. Although this clade has a broad geographical distribution across
the continent today, its presence in the fossil record has only rarely been
reported. In contrast to that, the material described here is abundant,
consists of a premaxilla, maxillae, frontals, parietals, jugals, quadrate,
pterygoids, dentaries and vertebrae. The comparison of these elements to
all extant green lizard species shows that these fossils are
indistinguishable from Lacerta trilineata. Thus, they form the first
potential evidence of the occurrence of this species in the Miocene. This
may be also used as a potential calibration point for further studies.
Together with other lizard fossils, Solnechnodolsk shows an interesting
combination of survivors and the dawn of modern species. This locality
provides important evidence for the transition of an archaic Miocene world
to the modern diversity of lizards in Europe. In addition, this article
represents a contribution to the knowledge of the comparative osteological
anatomy of the selected cranial elements in lacertids. This study gives
special emphasis to the green lizards, but new data are also presented for
related taxa, e.g., Timon lepidus, Podarcis muralis or Zootoca vivipara.
Although the green lizards include several cryptic species for which
determination based on isolated osteological material would be expected to
be difficult, our comparisons show several important morphological
differences, although a high degree of variability is present.


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