PDF (Lo-Res) - Smithsonian Institution Libraries

A New Species of Graculavus from the
Cretaceous of Wyoming (Aves: Neornithes)
ABSTRACT
A new species of Graculavus from the Lance Formation, Wyoming,
extends the range of the genus from the Atlantic paleocoastline
to the near-shore of the Cretaceous inland sea. The type and
referred species were nearly contemporaneous in the late Maastrichtian.
The new species was a very large flying bird with the
proximal end of the humems in the size range of the largest modem
gulls or geese. The systematic and biogeographic significance
of Graculavus-like birds is discussed.
Introduction
Graculavus velox Marsh, 1872, was described as a cormorant,
but since then it has been diagnosed as a shorebird
(Shufeldt, 1915) and characterized as "transitional," referring
to intermediacy between charadriiforms and gruiforms (Olson,
1985:171). The genus has been monotypic since Olson and
Parris (1987) synonymized G. pumilus Marsh, 1872, with Telmatomis
priscus Marsh, 1870. The changing taxonomic treatments
reflect the difficulty of identifying isolated fragments of
unknown birds.
The discovery of a very large new species of Graculavus
provides an opportunity to review the significance of this genus
of early neomithine birds. The two known species of Graculavus
are approximately contemporaneous representatives of
widely separated, near-shore environments in the Late Cretaceous.
Both species are known only from the proximal end of
the humems, which, interestingly, is very similar to that of the
early anseriform Presbyornis. Because the phylogenetic position
of the Anseriformes remains a key problem in avian taxonomy
(Ericson, 1996), the resemblance of Graculavus to both
Presbyornis and the Charadriiformes takes on systematic interest.
This paper describes the new species and provides a brief
Sylvia Hope
Sylvia Hope, Department of Ornithology and Mammalogy, California
Academy of Sciences, Golden Gate Park, San Francisco, California
94118, United States.
261
perspective on the characters and biogeography of Graculavuslike
birds.
METHODS
CHARACTER ANALYSIS.—Polarity of osteologie characters
was judged from comparison of a broad selection of neomithine
birds with other Ornithurae and with Enantiornithes
(Hope, unpublished data). Because uncertainties surround the
basal phylogeny of Neornithes, the definition and phylogenetic
diagnosis of higher groupings within it is uncertain. Principal
comparisons herein are to "waterbirds" as defined below. Characters
cited for waterbirds occur in most of them, and some
characters occur elsewhere among Neornithes as isolated instances
but not as a concerted complex. At the genus and species
levels, diagnosis of fragments by synapomorphy is rarely
possible, so identification at these levels is based on a unique
combination of attributes.
NAMES.—Higher taxon names are used in the sense of Wetmore
(1960), except that these names are used herein in the
node-based sense (de Queiroz and Gauthier, 1992) to include
fossil forms sharing a most recent common ancestor with the
extant crown taxon. The name "Ciconiiformes" is avoided because
of gross disparity in usage, both historical and recent.
English vernacular names are used for groups of birds with
equivocal systematic status. Such names do not necessarily imply
monophyly and are as follows: "waterbirds," refers to all
"seabirds," "shorebirds," and the Anseriformes; "seabirds" refers
to the Procellariiformes, Pelecaniformes, penguins, loons,
and grebes; "shorebirds" refers to the Charadriiformes, ibises
and flamingos, storks, and herons.
ACKNOWLEDGMENTS.—For the opportunity to collect in the
field and to describe this and other specimens, I thank Malcolm
C. McKenna, American Museum of Natural History, New
York (AMNH). Charlotte Holton (AMNH) arranged the loan
of fossil material. Storrs L. Olson, National Museum of Natural
History, Smithsonian Institution, Washington, D.C, gave access
to Hornerstown specimens and other fossil material in his
care. David C. Parris and William B. Gallagher, New Jersey