Journal of Anatomy,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Aug. 21, 2024
Abstract
The
current
study
examines
the
growth
pattern
and
lifestyle
habits
of
freshwater
snapping
turtles
Chelydra
Macrochelys
based
on
limb
bone
histology.
Femora,
humeri,
tibiae
25
individuals
selected
from
a
range
ontogenetic
stages
were
assessed
to
determine
inter‐element
intraskeletal
histological
variation.
Osteohistological
assessment
multiple
elements
is
consistent
with
overall
moderate
rates
as
revealed
by
dominance
parallel‐fibered
bone.
However,
was
cyclical
shown
deposition
lines
arrested
growths
in
compacta.
It
appears
that
tissue
C.
serpentina
more
variable
through
ontogeny
intermittent
higher
rates.
M
.
temminckii
grow
slowly
than
C
possessing
compact
thick
cortices
accordance
their
larger
size.
Overall,
vascularization
decreases
humeri
femora
being
well‐vascularized
both
species.
Contrarily,
epipodials
are
poorly
vascularized,
though
simple
longitudinal
radial
canals
present,
suggesting
differences
patterns
when
compared
associated
diaphyseal
sections.
found
be
least
remodeled
bones
therefore
better
suited
for
skeletochronology
turtles.
Intra‐elementally,
preserved
cortical
vascularity
ventrally,
suggestive
faster
relative
growth.
We
hypothesize
differential
may
relate
functional
constraints,
where
forelimbs
operational
swimming
while
hindlimbs
provide
stability.
Journal of Anatomy,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 19, 2025
Abstract
Troodontidae
is
a
family
of
small‐bodied
theropods
known
predominantly
from
Asia
but
are
comparatively
scarce
in
North
America.
In
the
Dinosaur
Park
Formation
(DPF)
Alberta,
Canada,
they
isolated
material,
precluding
taxonomic
and
ontogenetic
precision
for
this
clade.
Previously
never
sampled
histologically
within
DPF,
here
we
attempt
to
fill
gaps
our
knowledge
about
life
histories
clade
formation
by
surveying
metatarsals,
which
among
most
abundant
identifiable
troodontid
elements
DPF.
We
11
metatarsals
(three
metatarsal
IIs,
three
IIIs
five
IVs)
varying
sizes
included
pathological
individuals
describe
microanatomy
both
healthy
determine
status
each
element
graph
their
pattern
growth.
Osteohistology
reveals
that
grew
remodelled
asymmetrically
cortex,
ceasing
growth
remodelling
primarily
along
articular
surfaces
entheses.
Pathological
ranged
displaying
features
response
localised
stress
(chronic
callus
avulsion/chip
fracture)
extreme
modification
trauma
inflammation
at
distal
joint.
Only
latter
appeared
be
related
overall
growth,
suggesting
condition
either
developed
early
stunted
or
another
underlying
cause
was
responsible
resulting
observed.
Overall,
tracking
specimens
there
least
two
trajectories
DPF
differentiated
timing
major
spurts
plateaus.
Whether
represents
sexual
dimorphism,
diversity,
form
variation
warrants
further
investigation.
Journal of Anatomy,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 22, 2025
Abstract
Plesiosauria
is
a
clade
of
marine
reptiles
that
thrived
from
the
Late
Triassic
to
end
Cretaceous.
Among
plesiosaurs,
elasmosaurids
are
particularly
notable
for
their
diverse
body
sizes.
Small‐sized
specimens
Kawanectes
lafquenianum
exhibit
fully
closed
neuro‐central
sutures
indicating
skeletal
maturity.
To
independently
assess
whether
they
indeed
small‐bodied
adults,
we
analysed
paleohistology
long
bones
three
differently
sized
recovered
La
Colonia
Formation,
Chubut
Province,
Argentina.
The
microanatomy
revealed
differences
in
architectural
organization
hindlimbs
and
forelimbs,
with
humerus
being
highly
remodelled
as
compared
femur.
Extensive
secondary
reconstruction
propodials
ribs
suggests
high
rate
calcium
mobilization,
perhaps
related
biomechanical
stresses.
Despite
extensive
all
studied,
primary
bone
tissue
comprising
parallel‐fibred
lamellar
was
identified
at
outermost
cortex,
along
an
external
fundamental
system
propodial
one
specimens.
Overall
osteohistology
features
indicate
adult
stage
specimens,
although
it
appears
our
sample
represents
individuals
different
levels
Lines
arrested
growth
were
also
registered,
giving
minimum
age
11
14
years
MPEF‐PV
1155
11545,
respectively.
These
results
indicated
K.
elasmosaurid
(3.8
m–4.2
m
length).
Additionally,
microstructure
postcranial
elements
reflects
interelemental
variability.
Further
research
involving
additional
needed
explore
other
palaeobiological
aspects
,
such
dynamics,
sexual
dimorphisms,
locomotion,
among
others.
Historical Biology,
Journal Year:
2022,
Volume and Issue:
35(3), P. 303 - 314
Published: Feb. 26, 2022
Aetosaurs
were
a
group
of
armoured
pseudosuchians,
recorded
in
most
the
Upper
Triassic
continental
deposits
worldwide.
Several
osteohistological
contributions
aetosaurs
focused
on
their
osteoderms,
but
rarely
appendicular
bones.
Here,
we
analyse
microstructure
humerus,
femur
and
tibia
Aetosauroides
scagliai
(specimens
PVL
2073
[holotype]
2052).
These
exhibit
cortical
bone
formed
by
highly
vascularised
fibrolamellar
present
inner
portion
cortex,
mixed
with
scarce
parallel-fibred
bone.
Also,
they
show
outermost
cortex.
A
general
growth
pattern
that
includes
first
rapid
stage
followed
slow
is
reported.
Nevertheless,
rate
presence
embedded
layers
recognise
more
variation
within
Aetosauria.
The
value
bones
osteoderms
as
age
estimators
variable,
being
useful
early
stages,
late
stages
are
better
(based
particular
osteoderms).
Through
morphological
(neurocentral
sutures)
histological
(EFS
absent)
information,
holotype
(PVL
2073)
was
recovered
between
juvenile
subadult
stages.
Using
statistical
model
combines
microanatomical
data,
terrestrial
lifestyle
inferred
for
Aetosauroides,
which
concur
previous
analyses.
Journal of Anatomy,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 23, 2025
Abstract
Notosuchia
were
a
successful
lineage
of
Crocodyliformes
that
achieved
remarkable
diversity
during
the
Cretaceous
Gondwana,
particularly
in
South
America.
Although
paleohistology
has
expanded
our
knowledge
paleobiology
notosuchians,
several
clades
this
remain
poorly
understood
aspect.
Here
we
help
to
address
gap
by
conducting
first
histological
analysis
appendicular
bones
peirosaurid.
To
increase
about
growth
dynamics
and
examine
intraeskeletal
interspecific
variation,
analyze
microstructure
tibia,
fibula,
phalanx,
fragment
ornamented
element
(possible
osteoderm
or
skull
bone)
possible
long
bone
an
individual
assigned
Peirosauridae
indet.
(MAU‐Pv‐437).
The
peirosaurid
studied
here
appears
have
reached
sexual
but
not
somatic
maturity
minimum
age
inferred
from
results
lower
estimated
than
osteoderms
previous
study
on
same
individual.
cortical
MAU‐Pv
437
is
formed
vascularized
parallel
fibered
bone/lamellar
which
indicates
experienced
moderate
rate.
This
different
what
been
observed
for
other
notosuchians
specimens,
suggesting
lack
uniform
pattern
clade.
Scientific Reports,
Journal Year:
2022,
Volume and Issue:
12(1)
Published: Oct. 15, 2022
Abstract
Intraspecific
variation
in
growth
trajectories
provides
a
fundamental
source
of
upon
which
natural
selection
acts.
Recent
work
hints
that
early
dinosaurs
possessed
elevated
levels
such
compared
to
other
archosaurs,
but
comprehensive
data
uniting
body
size,
bone
histology,
and
morphological
from
stratigraphically
constrained
dinosaur
population
are
needed
test
this
hypothesis.
The
Triassic
theropod
Coelophysis
bauri
,
known
bonebed
preserving
single
coeval
individuals,
an
exceptional
system
assess
whether
highly
variable
patterns
were
present
near
the
origin
Dinosauria.
Twenty-four
histologically
sampled
individuals
less
than
year
at
least
four
years
old
confirm
right-skewed
age
distribution
assemblage.
Poor
correlations
among
age,
maturity
strongly
support
presence
unique,
relative
archosaurs
their
living
kin.
Journal of Anatomy,
Journal Year:
2023,
Volume and Issue:
243(6), P. 893 - 909
Published: July 31, 2023
"Rauisuchia"
is
a
non-monophyletic
group
of
quadrupedal
and
carnivorous
pseudosuchians
that
inhabited
the
entire
world
during
Middle-Upper
Triassic
period
(Anisian/Ladinian-Rhaetian).
In
South
America,
"rauisuchians"
reached
largest
sizes
among
continental
carnivores.
Despite
their
important
ecological
role,
some
aspects
palaeobiology
have
been
poorly
examined.
Here,
we
study
appendicular
bones,
dorsal
ribs
osteoderms
two
genera,
Argentinean
Fasolasuchus
tenax
(PVL
3850,
holotype)
Brazilian
Prestosuchus
chiniquensis
(SNSB-BSPG
AS
XXV)
respectively.
The
femur
F.
formed
by
laminar
fibrolamellar
bone,
which
composed
non-fully
monorefringent
woven-fibred
matrix
primary
osteons;
rib
has
Haversian
bone
composition
with
an
external
fundamental
system
recorded
osteoderm
well-organised
parallel-fibred
bone.
femur,
humerus
fibula
P.
are
mostly
strongly
arranged
vascularisation.
minimal
ages
obtained
correspond
to
9
years
for
(based
on
maximum
number
growth
marks
in
osteoderm)
4
(obtained
from
highest
count
humerus).
attained
somatic
skeletal
maturity,
while
was
near
reaching
sexual
but
it
somatically
immature.
overall
rapid
rate
high
uniform
vascularisation
seems
imply
these
features
common
most
"rauisuchians",
except
chiniquensis.
Communications Biology,
Journal Year:
2022,
Volume and Issue:
5(1)
Published: Nov. 28, 2022
Patterns
of
growth
throughout
the
lifetime
an
animal
reflect
critical
life
history
traits
such
as
reproductive
timing,
physiology,
and
ecological
interactions.
The
ancestral
pattern
for
tetrapods
has
traditionally
been
described
slow-to-moderately
paced,
akin
to
modern
amphibians,
with
fast
high
metabolic
rates
considered
a
specialized
physiological
trait
amniotes.
Here,
we
present
bone
histology
from
ontogenetic
series
Early
Carboniferous
stem
tetrapod
Whatcheeria
deltae,
document
evidence
fibrolamellar
bone-primary
tissue
associated
growth.
Our
data
indicate
that
juveniles
grew
rapidly
reached
skeletal
maturity
quickly,
allowing
them
occupy
large-bodied
predator
niche
in
their
paleoenvironment.
This
strategy
contrasts
those
other
indicates
diversity
patterns
existed
at
origins
diversification.
Importantly,
marks
unexpectedly
early
occurrence
Tetrapoda,
both
temporally
phylogenetically.
These
findings
reveal
elevated
juvenile
is
not
limited
amniotes,
but
deep
clade
may
have
played
previously
unrecognized
role
invasion
land.
Journal of Systematic Palaeontology,
Journal Year:
2024,
Volume and Issue:
22(1)
Published: July 9, 2024
A
new
iguanodontian
dinosaur,
Comptonatus
chasei
gen.
et
sp.
nov.,
is
described
from
the
Lower
Cretaceous
Wessex
Formation
of
Isle
Wight.
These
strata
provide
an
important
record
a
critical
time
in
development
diversity.
The
specimen,
which
here
for
first
time,
was
found
and
excavated
2013
represents
most
complete
skeleton
discovered
Wealden
Group
century.
taxon
diagnosed
by
several
autapomorphies
neurocranium,
teeth,
coracoid
other
parts
body,
together
with
unique
suite
characters.
include
dentary
straight
ventral
border,
markedly
expanded
prepubic
blade.
features
set
it
apart
sympatric
Mantellisaurus
atherfieldensis,
Brighstoneus
simmondsi
Iguanodon
cf.
bernissartensis,
increasing
known
diversity
this
clade
Barremian–early
Aptian
England.
http://zoobank.org/urn:lsid:zoobank.org:pub:2F3125A5-BDEF-4835-8829-92104752A86F
Biological Journal of the Linnean Society,
Journal Year:
2022,
Volume and Issue:
136(1), P. 41 - 58
Published: Feb. 15, 2022
Abstract
Dwarfed
insular
mammals
are
of
significant
interest
to
evolutionary
biology
because
their
morphological
and
physiological
adaptations
triggered
by
variables
inherent
geographical
isolation.
One
life
history
trait
that
is
expected
be
modified
in
relation
body
size
reduction
extended
longevity
facilitated
ecological
parameters
such
as
predator
competitor
release
fluctuating
resource
availability.
However,
systematic
examination
extreme
cases
dwarfism
difficult
largely
represented
fossils
extinct
species.
We
studied
seven
rib
fragments
the
extraordinary
endemic
Pleistocene
dwarf
deer
Candiacervus
(size
2)
test
whether
its
bone
matrix
shows
evidence
for
extensive
remodelling
typically
seen
large
long-living
mammals.
found
all
ribs
had
well-remodelled
Haversian
bone,
implying
several
generations
resorption
re-deposition
processes.
Osteon
density
was
high
relative
small
cross-section
size,
with
examples
porosity
similar
elderly
animals.
report
first
combined
micro-morphological
micro-morphometric
record
histology,
agreeing
previous
literature
discussing
ruminants.
Further
experimental
validation
osteon
extant
will
confirm
dwarfed
indeed
lived
longer
than
mass.
The Anatomical Record,
Journal Year:
2023,
Volume and Issue:
307(4), P. 1254 - 1270
Published: Nov. 8, 2023
Abstract
Maximum
individual
body
size
in
pseudosuchian
archosaurs
is
not
well
constrained
the
fossil
record,
but
it
may
be
influenced
by
a
variety
of
factors
including
basal
metabolic
rate,
evolutionary
relationships,
and
environmental
conditions.
Body
varies
among
Aetosauria
which
estimated
total
length
ranges
between
1
m
(e.g.,
Coahomasuchus
kahleorum
)
5
Desmatosuchus
spurensis
).
A
new,
very
large
specimen
aetosaurian
Typothorax
coccinarum
from
Petrified
Forest
National
Park
northeastern
Arizona
nearly
twice
all
other
known
specimens
largest
aetosaur
currently
worldwide.
The
lacks
co‐ossified
neurocentral
sutures
trunk
vertebrae
suggest
that
had
yet
reached
skeletal
maturity,
smaller
T.
exhibit
partially
or
fully
same
region.
If
correlates
with
maturity
aetosaurs,
this
discrepancy
warns
timing
suture
co‐ossification
aetosaurs
reliable
indicator
ontogenetic
stage.
Osteohistological
observations
rib
demonstrate
although
PEFO
42506
shows
size,
did
deposit
an
external
fundamental
system
despite
depositing
as
many
19
growth
lines,
further
indicating
maturity.
Thus,
at
least
within
Aetosauria,
correlate,
whereas
can
incongruent
comparison.
Furthermore,
indicates
non‐desmatosuchin
could
sizes
suggests
some
have
experienced
indeterminate
growth.