Taxonomic Status of Nanotyrannus lancensis (Dinosauria: Tyrannosauroidea)—A Distinct Taxon of Small-Bodied Tyrannosaur
Fossil Studies,
Год журнала:
2024,
Номер
2(1), С. 1 - 65
Опубликована: Янв. 3, 2024
Tyrannosaurs
are
among
the
most
intensively
studied
and
best-known
dinosaurs.
Despite
this,
their
relationships
systematics
highly
controversial.
An
ongoing
debate
concerns
validity
of
Nanotyrannus
lancensis,
interpreted
either
as
a
distinct
genus
small-bodied
tyrannosaur
or
juvenile
Tyrannosaurus
rex.
We
examine
multiple
lines
evidence
show
that
strongly
supports
recognition
species
for
following
reasons:
1.
High
diversity
tyrannosaurs
predatory
dinosaurs
idea
tyrannosaurids
inhabited
late
Maastrichtian
Laramidia;
2.
lacks
characters
supporting
referral
to
Tyrannosaurinae
but
differs
from
T.
rex
in
>150
morphological
characters,
while
intermediate
forms
combining
features
unknown;
3.
Histology
shows
specimens
showing
(i)
skeletal
fusions,
(ii)
mature
skull
bone
textures,
(iii)
slow
growth
rates
relative
rex,
(iv)
decelerating
final
years
life,
(v)
curves
predicting
adult
masses
~1500
kg
less,
these
animals
subadults
young
adults,
not
Tyrannosaurus;
4.
series
other
tyrannosaurids,
including
Tarbosaurus
Gorgosaurus,
do
changes
proposed
Nanotyrannus–Tyrannosaurus
series,
deriving
requires
several
inconsistent
with
known
patterns
dinosaur
development;
5.
Juvenile
exist,
diagnostic
6.
Phylogenetic
analysis
suggests
may
lie
outside
Tyrannosauridae.
Tyrannosaur
before
K-Pg
extinction
is
higher
than
previously
appreciated.
The
challenges
inherent
diagnosing
based
on
fossils
mean
paleontologists
be
systematically
underestimating
ancient
ecosystems.
Язык: Английский
A giant tyrannosaur from the Campanian–Maastrichtian of southern North America and the evolution of tyrannosaurid gigantism
Scientific Reports,
Год журнала:
2024,
Номер
14(1)
Опубликована: Янв. 11, 2024
Abstract
Tyrannosaurid
dinosaurs
dominated
as
predators
in
the
Late
Cretaceous
of
Laurasia,
culminating
evolution
giant
Tyrannosaurus
rex
,
both
last
and
largest
tyrannosaurid.
Where
when
Tyrannosaurini
(
T.
kin)
originated
remains
unclear.
Competing
hypotheses
place
tyrannosaurin
origins
Asia,
or
western
North
America
(Laramidia).
We
report
a
new
tyrannosaurin,
mcraeensis
from
Campanian–Maastrichtian
Hall
Lake
Formation
New
Mexico,
based
on
fossil
previously
referred
to
.
predates
by
~
6–7
million
years,
yet
rivaled
it
size.
Phylogenetic
analysis
recovers
sister
suggests
southern
Laramidia.
Evolution
tyrannosaurs
America,
alongside
ceratopsians,
hadrosaurs,
titanosaurs
large-bodied
evolved
at
low
latitudes
America.
Язык: Английский
Multiple lines of evidence support anagenesis in Daspletosaurus and cladogenesis in derived tyrannosaurines
Cretaceous Research,
Год журнала:
2025,
Номер
unknown, С. 106080 - 106080
Опубликована: Янв. 1, 2025
Язык: Английский
Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U–Pb geochronology
Canadian Journal of Earth Sciences,
Год журнала:
2023,
Номер
60(12), С. 1627 - 1646
Опубликована: Июль 5, 2023
The
100
m
thick
stratigraphic
section
exposed
at
Dinosaur
Provincial
Park
(DPP;
southern
Alberta)
contains
bentonites
that
have
been
used
for
more
than
30
years
to
date
DPP’s
rocks
and
fossils
using
the
K–Ar
decay
scheme.
Limited
reproducibility
among
different
vintages
of
40
Ar/
39
Ar
ages
inhibited
development
a
high-resolution
chronostratigraphy.
Here,
we
employ
further
test
recently
completed
U–Pb
geochronology
associated
age-stratigraphy
model
update
temporal
constraints
on
Park’s
bentonites,
formational
contacts,
other
markers.
In
turn,
document
rock
accumulation
rates
calibrate
durations
informal
megaherbivore
dinosaur
assemblage
zones
biozones.
Weighted
mean
206
Pb/
238
U
from
five
range
76.718
±
0.020
74.289
0.014
Ma
(2σ
internal
uncertainties)
through
an
interval
88.75
m,
indicating
duration
∼2.43
Myr
overall
rate
3.65
0.04
cm/ka.
An
increase
in
above
Oldman–Dinosaur
contact
conforms
regionally
expressed
pattern
increased
accommodation
∼76.3
across
Alberta
Montana.
Palynological
biozone
data
suggest
condensed
section/hiatus
uppermost
portion
Oldman
Formation.
exhibit
∼700–600
kyr
are
significantly
shorter
those
overlying
Horseshoe
Canyon
A
decreased
turnovers
last
eight
million
Mesozoic
western
Canada
may
be
explained
by
withdrawal
Western
Interior
Seaway
expansion
ecologically
homogenous
lowlands
its
wake.
Язык: Английский
Lokiceratops rangiformis gen. et sp. nov. (Ceratopsidae: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals rapid regional radiations and extreme endemism within centrosaurine dinosaurs
PeerJ,
Год журнала:
2024,
Номер
12, С. e17224 - e17224
Опубликована: Июнь 20, 2024
The
Late
Cretaceous
of
western
North
America
supported
diverse
dinosaur
assemblages,
though
understanding
patterns
diversity,
evolution,
and
extinction
has
been
historically
limited
by
unequal
geographic
temporal
sampling.
In
particular,
the
existence
extent
faunal
endemism
along
eastern
coastal
plain
Laramidia
continues
to
generate
debate,
finer
scale
regional
remain
elusive.
Here,
we
report
a
new
centrosaurine
ceratopsid,
Lokiceratops
rangiformis,
from
lower
portion
McClelland
Ferry
Member
Judith
River
Formation
in
Kennedy
Coulee
region
Canada-USA
border.
Dinosaurs
same
small
region,
nearby,
stratigraphically
equivalent
horizons
Oldman
Canada,
reveal
unprecedented
ceratopsid
richness,
with
four
sympatric
taxa
one
chasmosaurine
taxon.
Phylogenetic
results
show
that
Lokiceratops,
together
Albertaceratops
Medusaceratops,
was
part
clade
restricted
northern
approximately
78
million
years
ago.
This
group,
Albertaceratopsini,
multiple
clades
undergo
geographically
radiations,
Nasutuceratopsini
south
Centrosaurini
Pachyrostra
north.
High
centrosaurs
is
associated
with,
may
have
driven
by,
high
speciation
rates
competition
between
dinosaurs
limiting
their
range.
turn
sexual
selection
or
latitudinally
uneven
climatic
floral
gradients.
seen
centrosaurines
other
implies
diversity
underestimated
contrasts
large
ranges
most
extant
mammalian
megafauna.
Язык: Английский
A New Tyrant Dinosaur from the Late Campanian of Mexico Reveals a Tribe of Southern Tyrannosaurs
Fossil Studies,
Год журнала:
2024,
Номер
2(4), С. 245 - 272
Опубликована: Сен. 25, 2024
The
end
of
the
Cretaceous
saw
Western
Interior
Seaway
divide
North
America
into
two
land
masses,
Laramidia
in
west
and
Appalachia
east.
Laramidian
dinosaurs
inhabited
a
narrow
strip
extending
from
Mexico
to
Alaska.
Within
this
geographically
restricted
area,
evolved
high
diversity
endemism,
with
distinct
species
north
south.
Here,
we
report
new
tyrannosaurid
Late
Campanian-aged
Cerro
del
Pueblo
Formation
Coahuila,
Mexico,
which
is
part
tribe
tyrannosaurs
originating
southern
Laramidia.
Phylogenetic
analysis
recovers
tyrannosaur
as
clade
including
Labocania
anomala
La
Bocana
Roja
Baja
California
Norte,
Bistahieversor
sealeyi
Kirtland
New
Teratophoneus
curriei
Kaiparowits
Utah,
Dynamoterror
dynastes
Menefee
Mexico.
Distinct
frontal
morphology
younger
age
(~72.5–73
Ma
versus
>75.8
for
L.
anomala)
support
recognition
Labocania,
aguillonae.
dominated
at
time
when
was
by
daspletosaurins
albertosaurines.
endemism
seen
tyrannosaurids
remarkable,
given
that
modern
apex
predators
have
large
geographic
ranges
hints
carnivorous
has
been
underestimated.
Язык: Английский
Anagenesis and the tyrant pedigree: A response to “Re-analysis of a dataset refutes claims of anagenesis within Tyrannosaurus-line tyrannosaurines (Theropoda, Tyrannosauridae)”
Cretaceous Research,
Год журнала:
2024,
Номер
163, С. 105957 - 105957
Опубликована: Июнь 29, 2024
Taxonomic
diversity
in
the
derived
tyrannosaurine
Daspletosaurus
has
been
hypothesized
to
represent
a
variety
of
evolutionary
patterns
by
different
authors.
The
recent
description
D.
wilsoni,
third
species
this
genus,
was
proposed
support
paraphyly
and
participation
its
within
single
anagenetic
lineage
terminating
at
base
clade
formed
Tyrannosaurus
other
gigantic
tyrannosaurines
(Tarbosaurus,
Zhuchengtyrannus).
However,
reanalysis
including
additional
data
challenged
interpretation,
instead
recovering
as
monophyletic
sister
group
closest
relatives,
characterized
several
cladogenetic
events.
Here
we
show
that
incorporating
further
correcting
erroneous
interpretations
relevant
anatomical
features
overturns
result.
Using
novel
phylogenetic
analysis
specimens,
recover
paraphyletic
Daspletosaurus,
with
genus
forming
successive
taxa
Tyrannosaurus-line
tyrannosaurines.
This
result
facilitates
an
interpretation
currently
recognized
representing
lineage,
agreement
stratigraphic
distribution
specimens
qualitative
range
morphological
variation
observable
wilsoni.
Язык: Английский