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Five taxa of fossil birds comprising at least 17 individuals have been discovered in a Cenomanian (early Late Cretaceous) nearshore marine deposit along the Carrot River, near the Pasquia Hills of Saskatchewan, Canada. More than a hundred fossils, all from a single locality, constitute the oldest and most diverse avifauna from the Cretaceous of North America. Four species represent the earliest known North American Ornithurae, two of them new species of the baptornithid Pasquiaornis, n. gen. (Hesperornithiformes), and the other two referred to the ichthyornithid Ichthyornis (Ichthyornithiformes). Pasquiaornis is more primitive than Baptornis, and its humérus and femur show resemblances to those of flying birds. A presumed enantiornithine is also present.
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Early Late Cretaceous birds from Saskatchewan,
Canada: the oldest diverse avifauna known from North
America
Tim T. Tokaryk
a
, Stephen L. Cumbaa
b
& John E. Storer
c
a
Eastend Fossil Research Station, Box 460, Eastend, Saskatchewan, Canada, S0N 0T0
b
Paleobiology, Canadian Museum of Nature, P.O. Box 3443, Station “D”, Ottawa, Ontario,
Canada, K1P 6P4
c
Royal Saskatchewan Museum, 2340 Albert Street, Regina, Saskatchewan, Canada, S4P 3V7
Published online: 24 Aug 2010.
To cite this article: Tim T. Tokaryk , Stephen L. Cumbaa & John E. Storer (1997) Early Late Cretaceous birds from
Saskatchewan, Canada: the oldest diverse avifauna known from North America, Journal of Vertebrate Paleontology, 17:1,
172-176
To link to this article: http://dx.doi.org/10.1080/02724634.1997.10010961
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Journal of Vertebrate Paleontology 17(1):172
-176
. March 1997
© 1997 by the Society of Vertebrate Paleontology
EARLY
LATE
CRETACEOUS
BIRDS
FROM
SASKATCHEWAN, CANADA:
THE
OLDEST
DIVERSE
AVIFAUNA
KNOWN
FROM
NORTH
AMERICA
TIM
T.
TOKARYKJ,
STEPHEN
L.
CUMBAN
,
and
JOHN
E. STORER3
'Eastend
Fossil
Research
Station.
Box
460.
Eastend,
Saskatchewan
,
Canada
SON
OTO
;
-Paleobiology,
Canadian
Museum
of
Nature. P.O.
Box
3443, Station "
D"
, Ottawa, Ontario,
Canada
KIP
6P4;
3Royal
Saskatchewan
Museum,
2340
Albert
Street, Regina.
Saskatchewan
,
Canada
S4P
3V7
ABSTRACT-Five
taxa of fossil birds comprising at least 17 individuals have been discovered in a Cenomanian (early
Late Cretaceous) nearshore marine deposit along the Carrot River.
near
the Pasquia Hills of Saskatchewan.
Canada
.
More
than a hundred fossils. all from a single locality. constitute the oldest and most diverse avifauna from the
Cretaceous of North America.
Four
species represent the earliest known North American Ornithurae, two of them new
species
of
the baptornithid Pasquiaornis, n. gen. (Hesperornithiformes). and the other two referred to the ichthyornithid
lchthyornis (Ichthyornithiformes). Pasquiaornis is more primitive than Baptornis, and its humerus and femur show
resemblances to those
of
flying birds. A presumed enantiornithine is also present.
INTRODUCTION
The
richest previously reported North
American
Cretaceous
avifauna is from the Niobrara
Chalk
of
Kansas (Stewart, 1990).
and
assemblages
from
New
Jersey also contain
abundant
bird
remains
(Olson
and
Parris. 1987).
Other
Cretaceous birds
have
been described from scattered localities representing
diverse
biostratigraphic zones.
The
Ornithurae (usage
of
Martin
, 1983)
are the
best
documented
group. and include the loon-like Hes-
perornithiformes
(Hesperomis, Baptornis, and their relatives).
the tern-like Ichthyornithiformes
(lchthyornis) and
modem
birds;
Cretaceous
Ornithurae
are
best
known
from the Niobrara
Chalk
of
Kansas (Coniacian to
lower
Campanian)
.
Older
re-
cords
are
sparse and pre-Turonian Ornithurae
have
not been
reported in
North
America.
This
preliminary description
of
some
of
the material
extends
the record
back
significantly, into
the
Cenomanian
of
western
Canada
.
Dickson
Hardie
of
Arborfield,
Saskatchewan
, has for
many
years collected fossils from a locality
near
his farmhouse along
the Carrot
River
,
near
the
Pasquia
Hills (Fig . 1).
Hardie's
site
(SMNH
locality
63E03-000l)
was excavated in 1992
and
1993
by the Royal
Saskatchewan
Museum.
Regina. and the
Canadian
Museum
of
Nature,
Ottawa
. In it a discontinuous
bone
breccia
underlies a 3 to 5
cm
bentonite
layer
.
Sediment
samples
taken
above
and
below
the
bone
layer
contain diverse pollen, dino-
flagellates, and
Foraminifera
typical
of
the late
Cenomanian
. D.
Jarzen
(pers. cornm.),
Canadian
Museum
of
Nature. identified
36 taxa
of
dinoflagellates, 65 taxa
of
fern spores. bryophytes,
and
gymnosperm
and
angiosperm
pollen.
Several
diagnostic
taxa are
Cenomanian
marker
species. D.
McNeil
, Geological
Survey
of
Canada,
Calgary,
Alberta
, identified the Foraminifera
and
concluded
that the
abundance
of
Verneuilinoides perplexus
indicates
placement
in the
Belle
Fourche
Member. Ashville For-
mation
(pers.
comm
.: see
also
Cumbaa
et al., 1992;
Cumbaa
and Tokaryk, 1993).
Bloch
et aI. (1993)
have
recently re-as-
signed the Ashville
Formation
to the Belle
Fourche
Formation
.
Unfortunately, no articulated fossils are found at this site.
The
vertebrate fauna includes sharks. bony fishes, plesiosaurs, a
turtle, three vertebrae
of
an ornithopod dinosaur, and the birds
reported here.
The
fossils
were
probably deposited in shallow
water
less than 6 m
deep
,
near
the eastern
shore
of
the Western
Interior
Seaway
(Cumbaa
et aI., 1992;
Cumbaa
and Tokaryk,
1993),
which
divided
North
America
into eastern and western
sub-continents
during
much
of
the last 30 million years
of
the
Cretaceous
Period. We
know
little
about
the northern portions
of
this
seaway
. In 1994, larger samples
of
bone
breccia
were
discovered approximately 100 km northeast
of
the Pasquia Hills
site and
contain
many
more
bird fossils
of
similar nature.
This
site was revisited in 1995 with extraordinary results.
When
this
material is prepared, a full description
of
all the elements from
both sites will be given.
Institutional
Abbreviations-FHSM
,
Fort
Hays State
Mu-
seum
,
Hays
, Kansas;
KU
, University
of
Kansas, Lawrence,
Kansas;
SMNH.
Royal
Saskatchewan
Museum
, Regina. Sas-
katchewan (formerly the
Saskatchewan
Museum
of
Natural
History).
SYSTEMATIC
PALEONTOLOGY
Class
AVES
Order
HESPERORNITHIFORMES
Furbringer
, 1888
Family
BAPTORNITHIDAE
American
Ornithologist's Union. 1910
Genus
PASQUIAORNIS,
gen.
nov
.
Etymology-Pasquia,
reference to the
Pasquia
Hills region;
ornis, bird.
Diagnosis-Differs
from
the only
other
member
of
the fam-
ily.
Baptornis, in: the trochanteric ridge
of
the femur is
closer
to the shaft; proximal
end
relatively less
expanded
laterome-
dially; the intercotylar
prominence
of
the tarsometatarsus is an-
terior,
overhanging
the shaft, and; trochlea for digit 2 posterior
and
close
to the base
of
trochlea for digit 3.
Discussion-Though
none
of
the specimens in this genus is
articulated, sorting by size
and
morphology
of
femora, tarso-
metatarsi, and tentatively the humeri
suggest
two taxonomic
units.
Femora
of
Parahesperornis (e.g.,
KU2287)
and Hesper-
ornis
(Marsh
, 1880) are
more
robust and
expanded
at their ar-
ticulating
ends
, with distinctive intermuscular lines. Tarsomet-
atarsi
of
these
same
two
groups
are
unlike those
of
Baptornis
and Pasquiaornis in that the
4th
trochlea is
wider
distally than
the 3rd.
PASQ
UIAORNI
S
HARDlEI
, gen . et sp. nov.
(Fig
.2A-C)
Etymology-hardiei
,
after
Dickson Hardie
of
Arborfield,
Saskatchewan,
who
donated his collection
from
the type local-
ity,
which
included
some
of
the bird
specimens
.
Holotype-BMNH
P20n
.117, left tarsometatarsus.
Paratype-SMNH
P20n
.60, right femur.
Referred
Specimens-SMNH
P2409.1, proximal
end
of
172
Downloaded by [University of Regina] at 09:17 24 September 2013
TOKARYK
ET
AL.-CRETA
CEO
US
BIRDS
FROM
SASKATCHEWAN
173
500 m
II"du",
B.rJ
o
r-----
,
,
,
,
,
,
IrJl
I~u
'u"
" ,
, ,
I '
I "
I ,
, "
C
rro
t * ' ,
, ,
Riv r I "
I ,
I I
I I
I I
I I
, I
I I
: . :
- _ °
Winn
peg I
, -
----
.
,
,
,
I
,
....
_---
Reg na
,..-
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
........
.........
'
'-
0-
'
-0
AlbrnJl
~
,
,
\
\
I
\
\
\
\
\ .
,'Calg ry
I
,..,
,
,
,
,
I
,
,
I
\
,
,
I
,
-_
...
,
----
8
~:.tb..,
(/, .
'.-1
0
.,
,
,
,
,
,
--'
FIGURE
I.
Area
and locality (inset)
of
the
Carrot
River
site
SMNH
locality 63E03-0001.
right femur;
SMNH
P2077.62. shaft and distal end
of
right fe-
mur;
SMNH
P2409.9, proximal end and shaft
of
left tarso-
metatarsus;
SMNH
P2409
.49, trochlea for digits 2 and 4;
SMNH
P2077.IIO,
SMNH
P2409.11,
SMNH
P2487.7, proxi-
mal ends and shafts
of
right tarsometatarsi.
Tentatively
Referred
Specimens-SMNH
P2487.3, shaft
and distal end
of
right humerus;
SMNH
P2077.125, distal end
of
a ?juvenile left tarsometatarsus.
Diagnosis-Internal
cotyle
of
the tarsometatarsi deflected to-
ward shaft; neck
of
3rd trochlea higher anteriorly than 4th ; fe-
mur
small (Table 1), distal rim
of
head perpendicular to shaft.
PASQUlAOR
NlS TA
NKEl,
sp. nov.
(Fig
.2D-F)
Etymology-tankei,
after Darren Tanke
of
Drumheller, AB,
the first author's first teacher
of
paleontology and good friend.
Holotype-SMNH
P2077.63, left tarsometatarsus missing
3rd trochlea and distal end
of
2nd trochlea.
Paratype-SMNH
P2077.108, left femur.
Referred
Specimens-SMNH
P2077.120, left quadrate;
SMNH
P2077.113, partial left coracoid;
SMNH
P2077.123,
P2077
.124
,
P2077
.127,
partial
pelvic
elements;
SMNH
P2409.3, shaft and distal end
of
left femur;
SMNH
P2077.109,
left femur;
SMNH
P2487.2, right femur;
SMNH
P2077.107,
shaft and distal end
of
left femur;
SMNH
2467 .3, distal end
of
left femur;
SMNH
P2077.116, shaft and distal end
of
left femur;
SMNH
P2467.2, shaft and distal end
of
right femur;
SMNH
P2077.IO, distal end
of
right femur;
SMNH
P2487.8, proximal
end and shaft
of
left tibiotarsus;
SMNH
P2077.120, shaft and
distal end
of
right tibiotarsus;
SMNH
P2077.119, proximal end
and shaft
of
right tarsometatarsus;
SMNH
P2077.79, shaft and
distal end
of
right tarsometatarsus;
SMNH
P2409
.2, proximal
end
of
left tarsometatarsus;
SMNH
P2077.118, proximal end
of
left tarsometatarsus;
SMNH
P2077.72, proximal end
of
right
tarsometatarsus.
Tentatively
Referred
Specimens-SMNH
P2467.8, shaft
and distal end
of
left humerus;
SMNH
P2487.4, shaft and distal
end
of
right humerus.
Diagnosis-Internal
cotyla
of
the tarsometatarsi nearly an-
terior-posterior, neck
of
4th trochlea higher anteriorly than 3rd;
femur large (Table 1), distal rim
of
head slanted toward shaft.
DISCUSSION
OF
THE
SKELETON
OF
PASQUIAORNIS
Humerus-The
humeri, which we tentatively assign to this
genus, deserve special attention and are not considered ich-
thyornithiform for two reasons: 1) humeri
of
Ichthyornis from
the Turonian are generally smaller than in later members
of
this
genus (Fox , 1984; Lucas et al., 1982), whereas the specimens
from the Pasquia Hills are comparatively large; 2) the distal
ends are angular, whereas in
Pasquiaornis lateral expansion
of
the distal end is more gradual.
In
P. tankei, the ectepicondylar prominence is a low ridge,
parallel to the shaft and extending farther than the external con-
dyle .
P. hardiei has a less well-defined external condyle and
ectepicondylar prominence. Again, if confirmed,
Pasquiaornis
appears to retain characteristics
of
its possible flying ancestors
that are not seen in any other hesperornithiforms.
Femur-Absence
of
intermuscular lines on the femur is an-
other primitive character among hesperornithiforms.
Pasquiaor-
nis
possessed less strength in the hind legs than later hesperor-
nithiforms, and may not have been capable
of
as powerful aque-
ous and subaqueous propulsion.
P. hardiei, the smaller
of
the
two species, has the shortest length
of
femur
(-26%
less than
P. tankei and
-46
% less than Baptornis advenus). P. tankei is
-14%
smaller than B. advenus. Ichthyornithiforms and hespe-
rornithiforms are abundant in the Pasquia Hills, and evolution-
ary divergence must have occurred considerably earlier.
Tarsometatarsus-In
P. hardiei, the tarsometatarsus is
-37
% smaller than in P. tankei, and - 36% that
of
B. advenus.
P. tankei
is slightly larger than B. advenus.
The
tarsometatarsus
Downloaded by [University of Regina] at 09:17 24 September 2013
174
JOURNAL
OF
VERTEBRATE
PALEONTOLOGY, VOL.
17
, NO
.1,
1997
FIGURE
2.
A-C
Pasquia
om
is hardiei, gen . et sp. nov.
(A)
P20n.60,
right
femur
(paratype), posterior view
(maximum
length 47.5 mm, about
X1.4). (B)
P20n
.117, left tarsometatarsus (holotype), anterior view
(maximum
length 54.0 mm , about X1.38).
(C)
P2487.3, shaft and distal
end
of
right humerus,
palmar
view
(maximum
length 30.5 mm, about X1.84).
D-F
, P. tankei, sp. nov. (D) P2077.108, left
femur
(paratype), posterior
view
(maximum
length 64.5 mm, about X 1.05).
(E)
P20n
.63, left tarsometatarsus (holotype), anterior view
(maximum
length 85.6 mm , about
XO.81).
(F)
P2487.4
, shaft and distal end
of
right
humeru
s,
palmar
view
(maximum
length 41.5 mm , about X1.63). All above specimens
were
coated with
ammonium
chloride.
(G)
Ichth
yomi
s sp. A,
P20n.67
, partial left coracoid, dorsal view
(maximum
length
40.0
mm, about X 1.69).
(H)
Ichthy
omis
sp. B.,
P20n
.lll,
partial right
cor
acoid, dorsal view
(maximum
length 14.8 rnm, about X2.9). 1-J,
SEM
photogr
aphs
of
Enan-
tiornithine?,
P20n
.66,
outer
metatarsal.
(I)
dor
sal view
(maximum
length 12.6 mrn, about X6.4).
(J)
dorso-distal view
(maximum
length
of
distal
end 2.9 mm,
about
X13.1).
of
Pasquiaornis was also compared with the "Enaliornis-like"
specimen from the Lincoln Limestone
Member
, Greenhorn For-
mation (Cenomanian)
of
Kansas
(FHSM
VP 6318 ; Martin,
1983), which differs in the presence
of
proximal foramina, more
sharply defined external cotyla, and reduction
of
the intercotylar
prominence.
Pasquiaornis cannot be closely related to the
Greenhorn taxon.
Quadrate-The
quadrate
of
Pasquiaornis is apneumatic, and
has a fossa near the angled base
of
the orbital process as in
other hesperornithiforms (Witmer, 1990).
We have yet to compare the Saskatchewan material with that
of
the Albian Enaliornis from England. Martin and Tate (1976)
suggested close relationships between
Enaliornis and hesperor-
nithiforms, but a recent study
of
the brain case
of
Enaliornis
"places
a caveat on the hypothesis" (Elzanowski et al., 1991:
105).
Downloaded by [University of Regina] at 09:17 24 September 2013
TOKARYK
ET
AL.-CRETACEOUS
BIRDS
FROM
SASKATCHEWAN
175
TABLE
I.
Measurements
of
the femora and tarsometatarsi
of
Pasquiaornis gen. nov. and Baptornis (Martin and Tate, 1976). Asterisk denotes
estimate;
TMT
= tarsometatarsus.
Pasquiaornis tankei
F
E
M
U
R
T
M
T
Length
Diameter
of
head
Diameter
of
distal articulation
Antero-posterior
diameter
of
mid-shaft
Transverse
diameter
of
mid-shaft
Diameter
of
proximal end
Length
Proximal antero-posterior
diameter
Proximal width
Distal width
Tip
of
trochlea 2 to distal end
Pasquiaornis hardiei
P2077.60 P2077.117 P2077.108
47.5 64.5
7.3 8.5
16.5 21.8
8.8
11.3
6.3 10.2
14.8 10.5
54.0
6.1
9.5
7.4
P2077.63
85.6
13.0
16.0
15.0*
Baptornis
advenus
KU2290
75.0
11.7
26.0
12.5
11.0
28.0
84*
13.5
18.0
16.0
12.0
Order
ICHTIIYORNITHIFORMES
Family
ICHTHYORNITHIDAE
Genus
!CHTHYORN
IS
Discussio
n-
Two species
of
!chthyornis, hereafter assigned
to species A and species B,
occur
in the Pasquia Hills avifauna.
We have not attempted to revise
lchthyornis, the sole North
American genus
of
Ichthyorniformes, even though current tax-
onomy is unsatisfactory (Olson, 1985; Parris and Echols, 1982).
The material assigned to Ichthyornithiformes from Russia and
adjacent regions (Nessov, 1992) is too fragmentary for
com
-
parison.
The
Pasquia Hills records are several million years
older than the earliest previously known
!chthyornis, from the
Turonian
of
Alberta and New Mexico (Fox, 1984; Lucas et al.,
1982).
Both species are referred to
!chthyornis on the basis
of
the
coracoid scap
ular
facet nearly parallel to the sternal end
of
the
glenoid facet (Marsh, 1880) and are quite unlike hesperornithi-
forms (see Martin and Tate, 1976: fig. 9c). A partial radius,
SMNH
P2077.71, is assigned to this genus without further spe-
cific designation.
!CHTHYORNIS
species A
(Fig
.2G)
Referred
Speci
me
ns-SMNH
P2077.67,
P2077
.112,
P2487.5, partial left coracoids;
SMNH
P2077.II,
partial right
coracoid.
Comment-The
less robust
of
the two species, with a round
scapular facet . All three specimens are close in size
of
glenoid
facet and diameter
of
dorsoventral triosseal canal (Table 2).
!CHTHYORNIS
species B
(Fig. 2H)
Referred
Speci
men-SMNH
P2077.111, partial right cora-
coid.
TABLE
2.
Measurements
of
lchthyornis coracoids from
Pasquia
Hills
Saskatchewan.
Asterisk
denotes estimate.
lchthy-
lchthyornis
species A ornis
species B
P2077.67 P2077.112
P2077.11 P2077.111
Length
of
glenoid facet
6.5
6.5* 6.7 7.0
Width
of
glenoid facet
3.5 3.3 3.1 3.9
Maximum
diameter
of
scapular facet 3.0 3.4 2.9 3.5
Dorso-ventral
diameter
of
triosseal cannal
7.2
7.2
7.2
8.7
Com
ment-Robust
element (Table 2), with angular scapular
facet .
Infraclass
ENANTIORNITHES?
(Fig. 21,
J)
Referred
Specimen
-SMNH
n077
.66, a probable outer
metatarsal.
Discussion- A
member
of
the infraclass Enantiornithes may
be represented by a hollow, asymmetrical shaft with a distal
articulating surface. Examination
of
the fish debris from the site
shows no similarity to this specimen, and we are led to rule
this group out as a possibility.
One
side
of
the shaft is blunt
laterally, suggesting the articular surface
of
the third metatarsal.
Only the very primitive
Archaeopteryx. and Sinornis and the
Enantiornithes have distally unfused metatarsals (Martin, 1983;
Sereno, et al., 1992).
Walker (1981) erected the avian subclass Enantiornithes
based on several skeletons from Argentina, probably Maastrich-
tian in age. Martin (1983) suggested that this group should be
regarded as an infraclass
under
the subclass Sauria. Reexami-
nation and new discoveries, reported by Chiappe (1992) have
explored
some
of
the interrelationships
of
several enantiorni-
thines and suggest that this avian group was a more significant
element in the faunas
of
the Late Cretaceous than had been
realized. In regard to the Pasquia Hills assemblage, however,
we can state only that a bird, not referable to the Ornithurae,
possibly an enantiornithine,
was
part
of
the avifauna.
If
this is
confirmed with
other
discoveries, it would supplement the
group's earlier Cretaceous fossil record and would place it un-
questionably in an Ornithurae-dominated fauna, a combination
never before recorded.
OTHER
AVIAN
ELEMENTS
Unidentified avian elements in the Pasquia Hills fauna in-
clude four fused vertebrae
of
the synsacrum, the proximal end
of
a right carpometacarpus, several coracoids, as well as
many
broken, hollow bones that can not be associated with other taxa.
Three pelvic elements are known and based on the size
of
the
acetabulum, may belong to
Pasquiaornis.
DISCUSSION
The
Pasquia Hills assemblage, composed
of
four, probably
five species, is the oldest, diverse avian fauna known from a
single North American locality. Based on single elements from
within each species, there appear to be at least nine individuals
of
Pasquiaornis tankei, three
of
P. hardiei, three
of
lchthyornis
species A, and one
of
lchthyornis species B.
None
of
these
species is
known
from other avifaunas.
The
new baptornithid
Downloaded by [University of Regina] at 09:17 24 September 2013
176
JOURNAL
OF
VERTEBRATE
PALEONTOLOGY, VOL. 17,
NO.1,
1997
Pasquiaornis sheds new light on the early evolution
of
hespe-
rornithiforms; it retained some features characteristic
of
flying
birds, and was probably a
weaker
diver than later members
of
the group.
It is also interesting to note that the rates
of
evolution for
Ichthyorniformes and Hesperornithiformes may have been dif-
ferent if one looks at the available, accepted, avian record dur-
ing the Late Cretaceous. Ichthyornithiformes may have been in
relative stasis for most
of
the Late Cretaceous, as indicated by
the singularity
of
genera (and possibly species) within that
group; the evolutionary pace
of
Hesperornithiformes may have
been
quicker as indicated by the number
of
genera (and pos-
sibly species). Thus, the Hesperornithiformes may be especially
sensitive to shoreline fluctuation as caused by documented
transgressive and regressive cycles in the Western Interior Sea-
way. A possible enantiornithine may extend that group's North
American temporal range significantly.
In total, 16 or 17 avians were deposited at this site in the
Pasquia Hills. It will be interesting to see if the faunal com-
ponent
of
the new site 100 krn northeast will remain the same
and
if
further clarification
can
be made on some
of
the tenta-
tively assigned specimens.
ACKNOWLEDGMENTS
Our
thanks to Mr. Dickson Hardie, whose effort in obtaining
the original collection is greatly appreciated. Photographic ser-
vices were provided by the University
of
Saskatchewan, Sas-
katoon, and Flying Pigment Design Studio, Pinawa, Manitoba.
Indirect financial support was provided by Nature Saskatche-
wan. Rick Day (Canadian
Museum
of
Nature, Ottawa) prepared
some
of
the above specimens and was a major contributor to
the collecting efforts. Richard Zakrzewski (Fort Hays State Uni-
versity, Hays) kindly lent the first author the Greenhorn For-
mation
"Enaliornis-like" specimen. Luis Chiappe (American
Museum
of
Natural History,
New
York) and Larry D. Martin
(University
of
Kansas, Lawrence) reviewed this manuscript in
its various stages
of
development. Special appreciation is di-
rected to Larry Martin who opened his collections, home, and
thoughts to the first author.
Our
families provided precious per-
sonal support.
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... Pasquiaornis was originally assigned to the Baptornithidae [46]. However, subsequent phylogenetic analysis failed to Pasquiaornis was erected to unite two species of small hesperornithiforms from the marine Belle Fourche Formation (Cenomanian) of Canada [47]. Pasquiaornis was originally assigned to the Baptornithidae [47]. ...
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... In order to examine stratigraphic ranges of vertebrate taxa, specimens were grouped by genus and arranged by lithostratigraphic member along with additional taxonomic and stratigraphic information according to the host museum's records. Taxa were classified using the most up-to-date information (Aotsuka and Sato, 2016;Bice and Shimada, 2016;Cumbaa et al., 2010;Jiménez-Huidobro and Caldwell, 2019;Konishi and Caldwell, 2011;Otero, 2016;Tokaryk et al., 1997), and those with taxonomic uncertainty were identified to the lowest possible level. Taxa with stratigraphic uncertainty were appointed to a probable member based on locality, preservation, and rock matrix properties. ...
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Full-text available
The braincase of the Early Cretaceous bird Enaliornis is indicative of a primitive avian brain with a relatively large medulla oblongata, a small cerebellum, small cerebral hemispheres broadly separated from the labyrinth, and a strong basilordotic bend of the whole brain, the latter being characteristic of an airencephalic skull. The reduction of the dorsal pneumatic recess, the large size of the auricular fossa, and possibly the lack of interfoliar ridges on the roof of the cerebellar fossa suggest diving habits and thus support the association of the braincases with the type tarsometatarsus of Enaliornis. The braincase of Enaliornis is most similar to those of Hesperornis, Phaethon, Diomedeidae and Fregata. Most of the similarities to these taxa are primitive for birds.
Article
Full-text available
Several characters of the tarsometatarsus of the Cretaceous enantiornithine birds are discussed, with emphasis on the genus Avisaurus, which was considered a non-avian theropod taxon by its authors. Two synapomorphies (metatarsal IV reduced with respect to metatarsals II and III; well-developed knob on the anterior face of metatarsal II) relate Avisaurus to the remaining enantiornithine tarsometatarsi types and support reference of this taxon within the Enantiornithes. Three other synapomorphies (laterally compressed, J-shaped metatarsal I; anterior surface of the mid-shaft of metatarsal III strongly convex transversely; strong posterior projection of the internal rim of trochlea on metatarsal III) shared by Avisaurus and a Late Cretaceous enantiornithine from northwestern Patagonia further support its avian affinities. Avisaurus and the family Avisauridae are assigned to the avian subclass Enantiornithes.
Chapter
First published in 1983 to celebrate the centennial of the American Ornithologists' Union, Perspectives in Ornithology collects together a series of essays and commentaries by leading authorities about especially active areas of research on the biology of birds. Readers will find in this collection a useful overview of many major concepts and controversies in ornithology.