A fast start: Evidence of rapid growth in Trialestes romeri, an early Crocodylomorpha from the Upper Triassic continental beds of Argentina based on osteohistological analyses
Journal of Anatomy,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 31, 2025
The
palaeobiology
aspects
of
early
Crocodylomorpha
during
their
origin
in
the
Triassic
are
poorly
known,
despite
occupying
an
important
palaeoecological
role
continental
environments.
In
this
study,
we
report
microstructural
features
appendicular
bones
two
specimens
Trialestes
romeri,
a
non-Crocodyliformes
from
Upper
NW
Argentina.
Our
goals
to
infer
life
history
(i.e.
age
estimation
and
maturity
events),
inter-elemental
variation
growth
dynamics
within
phylogenetic
framework.
samples
include
humerus
ulna
holotype
(PVL
2561)
femur
referred
specimen
3889).
All
elements
mostly
composed
by
fibrolamellar
complex
with
variable
distribution
parallel-fibred
bone
cortex.
Furthermore,
they
possess
uniform
homogeneous
vascularisation,
formed
mainly
laminar
pattern.
PVL
2561
records
lines
arrested
(LAGs)
no
cyclical
marks
were
registered
ulna.
Meanwhile,
3889
exhibit
single
LAG.
Hence,
slight
disparate
is
reported
both
individuals.
absence
external
fundamental
system
(EFS)
homogenous
matrix
vascularisation
suggest
that
did
not
attain
sexual
somatic
maturity.
Overall,
histological
T.
romeri
indicate
rapid
rate
just
like
other
crocodylomorphs
(Terrestrisuchus,
Saltoposuchus),
whereas
others
rather
moderate
(Crocodylomorpha
indet.
BP/1/8484
specimen)
or
slower
(Hesperosuchus)
rate.
These
findings
reveal
rates
widely
present
among
occurrence
evolutionary
might
it
plesiomorphic
condition.
Язык: Английский
A review of the non‐semiaquatic adaptations of extinct crocodylomorphs throughout their fossil record
The Anatomical Record,
Год журнала:
2024,
Номер
308(2), С. 266 - 314
Опубликована: Ноя. 25, 2024
Abstract
Crocodylomorphs
constitute
a
clade
of
archosaurs
that
have
thrived
since
the
Mesozoic
until
today
and
survived
numerous
major
biological
crises.
Contrary
to
historic
belief,
their
semiaquatic
extant
representatives
(crocodylians)
are
not
living
fossils,
and,
during
evolutionary
history,
crocodylomorphs
evolved
live
in
variety
environments.
This
review
aims
summarize
non‐semiaquatic
adaptations
(i.e.,
either
terrestrial
or
fully
aquatic)
different
groups
from
periods,
highlighting
how
exactly
those
lifestyles
inferred
for
animals,
with
regard
geographic
temporal
distribution
phylogenetic
relationships.
The
ancestral
condition
Crocodylomorpha
seems
been
lifestyle,
linked
several
morphological
such
as
an
altirostral
skull,
long
limbs
allowing
erect
posture
specialized
dentition
diets
based
on
land.
However,
some
members
this
clade,
thalattosuchians
dyrosaurids
display
opposite,
aquatic
interestingly
same
type
observations.
Finally,
new
techniques
inferring
paleobiology
extinct
animals
put
forward
last
decade,
appearing
complementary
approach
traditional
descriptions
comparisons.
Such
is
case
paleoneuroanatomical
(CT
scan
data),
histological,
geochemical
studies.
Язык: Английский
Evolution of growth strategy in alligators and caimans informed by osteohistology of the late Eocene early‐diverging alligatoroid crocodylian Diplocynodon hantoniensis
Journal of Anatomy,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 9, 2025
Among
living
crocodylians,
alligatoroids
exhibit
a
wide
range
of
body
sizes
and
biogeographic
distribution
that
spans
tropical-to-subtropical
climates.
The
fossil
record
alligatoroids,
however,
reveals
even
greater
diversity,
including
multiple
examples
gigantism
broader
extends
into
polar
latitudes.
Osteohistological
studies
on
extant
show
alligators
caimans
both
seasonal
growth,
with
roughly
comparable
growth
rates.
However,
diverged
from
one
another
over
60
million
years
ago;
the
dearth
extinct
makes
it
unclear
if
shared
condition
in
taxa
reflects
convergent
responses
to
rapid
climatic
changes
recent
past
or
represents
ancestral
alligatoroids.
Additionally,
sample
are
often
limited
two
individuals,
especially
obscuring
any
intraspecific
variation
present.
To
address
this
uncertainty,
we
conducted
largest
monospecific
osteohistological
study
an
crocodylian
date,
based
nine
femora,
providing
unique
insight
early-diverging
alligatoroid
Diplocynodon
hantoniensis
late
Eocene
UK.
bone
microanatomy
D.
shows
moderate
compactness,
well-defined
medullary
cavity,
features
generally
consistent
those
Samples
vary
greatly
along
continuum
degree
remodelling
vascularity,
highlighting
importance
evaluating
limitations
basing
histological
assessments
singleton
samples.
Ontogenetic
assessment
indicates
our
captures
skeletally
immature
mature
approximately
corresponding
femoral
size,
but
notable
exceptions
possibly
driven
by
sexual
dimorphism.
Body
size
estimates
for
(1.2-3.4
m)
fall
within
typical
American
(Alligator
mississippiensis).
Reconstruction
cyclical
marks
similar
overall
rate
between
A.
mississippiensis.
As
more
generally,
is
determinate,
seasonally-controlled
growth.
Femoral
circumference
scales
positively
length
hantoniensis,
demonstrating
allometry
This
differs
some
other
crocodylians
(e.g.
Crocodylus
niloticus
johnstoni)
suggests
conservation
allometric
relationships
in-depth
look
early
diverging
seasonality
rates
present
members
were
established
near
base
clade.
Furthermore,
highlights
larger
samples
singular
species
order
capture
potential
when
making
clade-wide
interpretations.
Язык: Английский
The osteohistology of Orthosuchus stormbergi using synchrotron radiation microcomputed tomography
Journal of Anatomy,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 27, 2024
Abstract
Orthosuchus
stormbergi
was
a
small‐bodied
crocodyliform,
representative
of
diverse
assemblage
Early
Jurassic,
early
branching
crocodylomorph
taxa
from
the
upper
Elliot
Formation
South
Africa.
The
life
history
these
remains
poorly
understood,
with
only
sparse
investigations
into
their
osteohistology,
yet
species
like
have
potential
to
inform
about
macroevolution
growth
strategies
on
stem
leading
crown
crocodilians.
In
order
elucidate
patterns
,
we
used
propagation
phase
contrast
X‐ray
synchrotron
micro‐computed
tomography
virtually
image
osteohistology
postcrania
two
specimens,
including
multiple
elements
type
(SAM‐PK‐K409),
and
femur
referred
specimen
(BP/1/4242).
total,
scanned
nine
mid‐diaphyseal
sections
humerus,
radius,
ulna,
radiale,
femur,
tibia,
fibula,
rib.
We
then
compared
our
results
osteohistological
published
literature.
Our
show
that
most
predominant
bone
tissue
in
is
lamellar,
few
patches
woven
parallel‐fibred
bone.
contains
four
five
lines
arrested
hindlimb
present
outer
circumferential
lamellae,
whereas
six
seven.
Both
specimens
grew
at
similar
rates,
reaching
adult
skeletal
body
size
year
or
five.
sectioned
bones,
notably
radius
are
comparatively
thick
walled
compact.
virtual
one
first
for
an
broad
sample
makes
key
anchor
point
understanding
plesiomorphic
traits
clade.
Язык: Английский