Bulletin of The British Ornithologists' Club 1995 115:75-87
40028842

A new species of Puffinus shearwater from the western Indian Ocean

H.
Shirihai
et
al.
79
Bull.
B.O.C.
1995
115(2)
Relationships
and
recognition
(see
also
Appendix).
Atrodorsalis
differs
markedly
from
the
North
Atlantic
race
baroli
of
Little
Shearwater
(also
Australasian
races:
nominate
assimilis
and
tunneyi)
in
being
larger
with
relatively
longer
and
more
slender
bill,
dorsally
blacker
and
lacking
prominent
white
extensions
over
the
eye
(most
noticeable
in
baroli).
It
more
closely
resembles
the
large
races
of
Little
including
elegans
(widespread
in
Southern
Oceans),
haurakiensis
(islets
off
east
coast
of
North
Island,
New
Zealand),
and
kermadecensis
(Kermadec
group),
but
differs
in
having
a
proportionally
longer,
more
slender
bill
and
in
lacking
extensive
pale
feather
tips
and/or
darker
subterminal
markings
to
its
predominantly
black
(rather
than
greyish-black)
upperparts.
These
larger
races
of
assimilis
also
show
a
diffuse,
whitish
or
pale
area
around
the
eye
and
ear-coverts
and
lack
the
distinctive
black-hooded
appearance
typically
shown
by
atrodorsalis.
All
the
above
mentioned
races
of
assimilis
(as
well
as
race
myrtae,
Rapa
Is.)
have
diagnostically
white
instead
of
dusky-grey
undersides
to
their
remiges
(at
least
on
much
of
the
inner
webs)
and
usually
show
more
pronounced
white-tipped
greater
coverts.
Atrodorsalis
also
differs
from
the
controversial
boydi
of
Cape
Verde
Is.,
which
different
authorities
refer
to
P.
assimilis
(Cramp
&
Simmons
1977)
or
to
P.
Iherminieri
(Murphy
1927,
Jouanin
&
Mougin
1979).
Although
boydi
shares
similarly
coloured
greyish-blue
legs/feet
and
dusky-grey
remiges,
it
differs
from
atrodorsalis
in
having
mainly
dull
brown
undertail
coverts
(instead
of
white),
slightly
more
blackish-brown
upperparts,
paler
or
whitish
mottling
around
the
eye
and
upper
ear-coverts,
and
partially
white
lores
(nearer
assimilis),
as
well
as
smaller
size,
and
a
shorter
bill
like
most
small/medium-sized
races
of
Little
Shearwater
(see
below).
Proportionally,
atrodorsalis
resembles
some
races
of
Audubon's
rather
than
Little
by
its
longer-billed
appearance,
and
longer
and
more
pointed
wings/tail,
but
it
differs
from
nicolae,
the
most
widely
distributed
race
of
Aubudon's
in
the
Indian
Ocean,
in
lacking
the
brown
upperparts,
brown
undertail
coverts
and
prominent
pectoral
patches
as
well
as
in
its
slightly
larger
size
(see
Appendix);
nicolae
also
has
a
broader
bill
with
strongly
developed
nasal
tubes
and
maxillary
unguis,
and
flesh-pink
legs.
With
bailloni
(Mascarene
Is.),
atrodorsalis
shares
white
undertail
covers,
but
otherwise
differs
as
described
above
for
nicolae.
Furthermore,
atrodorsalis
is
distinctly
different
from
all
races
of
Audubon's
found
in
the
Western
Atlantic
(nominate
Iherminieri,
loyemilleri)
and
Pacific
(bannermani,
dichrous,
polynesiae
,
gunax,
heinrothi,
subalaris),
in
lacking
their
distinctly
browner
upperparts,
variably
brown
undertail
covers,
longer
and
stronger
bill,
flesh-pink
legs,
and
more
variegated
underwing
coverts
(more
widely
framed
by
brown,
with
varying
amount
of
brownish-grey
on
underwing
coverts
and
axillaries).
The
single
known
individual
of
the
recently
described
temptator,
from
Moheli,
Comoro
Islands
(Louette
&
Herremans
1985),
which
we
have
not
examined,
differs
strikingly
in
its
more
obvious
dusky
underwing
and
appears
similar
to
other
Audubon's
races.
All
other
allied
forms
of
smallish/medium-sized
shearwaters,
including
Persian
Shearwater
P.
(I.)
persicus
(sometimes
considered