Page 10 - Asylv_molars_Pmax_revised_2014_01

10

A
latitudinal
trend
in
molar
shape
was
previously
described
in
the
European
wood
mouse
(Renaud

and
Michaux
2007).
It
was
confirmed
here
on
the
total
mainland
data
set
(multivariate
regression
of

FCs
vs.
latitude:
N
=
413,
P
<
0.0001).
The
latitudinal
trend
in
molar
shape
was
parallel
to
all

documented
Pmax.
Although
discrete,
it
corresponds
to
a
similar
trend
ranging
from
broad
to
slender

molars
(Fig.
2B).

Allometric
variations

Significant
molar
size
variations
were
documented
across
geographic
groups.
Trends
in
molar
size

may
contribute
to
the
pattern
in
molar
shape
if
both
are
coupled
by
allometric
mechanisms.
Overall,

intra-­‐population
allometry
was
very
limited,
being
non-­‐significant
in
three
out
of
five
populations

(Lantabat:
P
=
0.461;
Tarquinia:
P
=
0.206;
Porquerolles:
P
=
0.085).
The
two
significant
intra-­‐
population
allometric
relationships
(Mimizan:
P
=
0.013;
Tourch:
P
<
0.001)
were
not
robustly

estimated,
not
related
together
and
not
related
to
Pmax
(Table
5;
Fig.
4).

The
inter-­‐population
allometric
direction
was
estimated
on
mainland,
based
on
group
means
and
on

all
specimens,
both
providing
robust
and
similar
estimates
of
the
allometric
direction
(Table
5).
These

directions
were
not
related
to
Pmax,
and
were
not
or
only
weakly
related
to
intra-­‐group
allometry

(Table
5).
Overall,
this
suggests
a
limited
role
of
allometry
in
molar
shape
differences.

Pmax
and
insular
divergence

Neighboring
mainland
localities
were
considered
as
reference
for
evaluating
the
importance
of

insular
divergence.
All
islands
documented
by
a
single
specimen
were
not
further
investigated.

Porquerolles
emerged
as
well
differentiated
among
the
Hyères
islands
while
Port-­‐Cros
was
not
(FR-­‐SE

vs.
Port-­‐Cros:

PMANOVA
=
0.100;
vs.
Porquerolles:
P
<
0.001).
Ibiza
was
not
differentiated
from

mainland
Spain
(vs.
SP-­‐E:
P
=
0.080).
Among
islands
related
to
the
Italian
clade,
Corsica
was
weakly

differentiated
while
Sardinia
was
clearly
divergent
(IT-­‐CW
vs.
Corsica:
P
=
0.031;
vs.
Sardinia:
P
<

0.001).
Among
Atlantic
French
islands,
Oléron
and
Ré
were
significantly
divergent
(FR-­‐W
vs.
Oléron:
P

<
0.001;
vs.
Ré:
P
<
0.001).
Noirmoutier
molars
were
not
significantly
differentiated
from
the

continent
(P
=
0.310).
Finally,
Sicily
constitutes
a
peculiar
case
of
an
old
endemic
lineage,
related
to

the
Italian
clade
from
which
it
significantly
differ
in
molar
shape
(vs.
IT:
P
=
0.010).

For
the
insular
populations
showing
a
significant
divergence,
the
direction
of
differentiation
was

compared
to
Pmax
(Table
6;
Fig.
4).
In
all
cases
except
Sardinia,
the
insular
divergence
followed
the