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246 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
study, it has been possible to include first-hand observations
only for presbyomithids collected in the New World.
Presbyornithidae
Presbyornis pervetus Wetmore: CM 11360 (holotype),
11358, 11359, 11360a, 12032, 12033, 12035-12038; UCMP
119394-119401, 126173-126257; USNM 492550^192552;
UW 20593-20600, 20651-20653, 20655-20666.
Telmabates antiquus Howard: AMNH 3170 (holotype),
3166-3187,3225-3227.
Phoenicopteridae
Juncitarsus gracillimus Olson and Feduccia: USNM
244318 (holotype), 244319-244322, 244324-244338
(paratypes).
Juncitarsus cf. merkeli Peters: Buffalo Museum E 25106
(cast in USNM), referred to this taxon by Peters (1987). Only
the published description was available of the German holotype
of J. merkeli Peters (1987).
Previously unrecognized specimens of Juncitarsus from
Eocene deposits in Wyoming were discovered in the collections
of the National Museum of Natural History and the
American Museum of Natural History and are described herein.
Both were allocated to the genus Juncitarsus through comparisons
with the type material of J. gracillimus. Although they
are too large to be conspecific with J. gracillimus, they agree
well in size with J. merkeli. Most skeletal elements present in
the new specimens have already been described (forming the
foundation for their allocation to Juncitarsus). A few previously
unknown, or poorly described elements do occur among the
new material.
Genus Juncitarsus Olson and Feduccia, 1980
Juncitarsus cf. merkeli Peters, 1987
REFERRED MATERIAL.—USNM 468466, apparently associated
material consisting of symphyseal part of furcula, parts of
costal region and manubrium of sternum, anterior part of left
scapula, complete right coracoid, sternal part of left coracoid,
caput of right humems, proximal half of left humems, distal
end of right radius, distal end of right carpometacarpus, right
phalanx 1 of digit II, right phalanx 2 of digit II, complete right
femur, complete left femur, lateral condyle of right tibiotarsus,
distal end of right tarsometatarsus, and four pedal phalanges.
Collected in Wyoming, Uinta County, Wildcat Butte, section 1,
T. 17 N, R. 113 W, 1 mile south of Church Butte, "very low exposures,"
on 2 August 1959 by CL. Gazin.
A second lot of material consists of the following: part of
manubrial region of sternum, AMNH 16232; anterior part of
left scapula, AMNH 6046; distal end of right ulna, AMNH
5956; proximal end of right radius, AMNH 6025; part of proximal
end of left carpometacarpus, AMNH 6028; proximal half of
right femur, AMNH 16231; part of proximal end of left femur,
AMNH 6007; distal ends of right and left femoras, AMNH
5998; and part of shaft of tarsometatarsus, AMNH 7730.
AMNH 5956-7730 were collected in 1906 by Walter Granger
in Wyoming, Sweetwater County, Washakie Basin, 100 ft
above the brown sandstone north of Haystack Mountain. They
were found in the Washakie Formation, which is of Bridgerian
age. AMNH 16231-16232 were collected at an unknown date
in Wyoming, Sweetwater County, Washakie Basin, north of
Haystack Mountain.
DISTRIBUTION.—Early to middle Eocene in Wyoming and
Germany.
DIAGNOSIS.—The collections are referred to the genus Juncitarsus
based on the skeletal characteristics described in
"Comparative Osteology," below. The specimens are tentatively
referred to Juncitarsus merkeli Peters, 1987, based on their
overall similarity in size to this species, being markedly larger
than Juncitarsus gracillimus. Very few measurements can be
directly compared, however. The middle trochlea of tarsometatarsus
USNM 468466 is 4.4 mm wide (3.9 mm in Juncitarsus
gracillimus), and the inner trochlea is 6.9 mm deep (6.3 mm in
J. gracillimus).
REMARKS.—The two collections may consist of remains
from a single individual each. The two finds from Wyoming
described herein, together with the Buffalo Museum specimen,
referred to J. merkeli by Peters (1987), corroborate the intercontinental
distribution of Juncitarsus. The Buffalo Museum
specimen from the early Eocene Green River Formation of
Wyoming shows that Juncitarsus and Presbyornis did overlap
in time and space, although the latter seems not to have persisted
into the middle Eocene, when Juncitarsus became more
abundant.
Comparative Osteology
The characteristics described herein are only those that show
no overlap between Juncitarsus and the Presbyornithidae;
however, only a very few specimens exist for comparing Juncitarsus
with the abundant material of the Presbyornithidae. Although
the morphological range in the Presbyornithidae is unlikely
to change dramatically with the addition of more
specimens, the situation could change for Juncitarsus, and with
more material, additional aspects of its morphology may overlap
with the Presbyornithidae.
The most obvious difference between Presbyornis and Juncitarsus
is the typical desmognathous, duck-like head of the
former, in contrast to the schizognathous skull as shown in the
holotype of Juncitarsus merkeli (Olson and Feduccia, 1980;
Peters, 1987). The cranium of Juncitarsus gracillimus is almost
unknown. Despite the striking differences in cranial morphology,
the two taxa are very similar postcranially in several respects.
Although many of these similarities may be due to symplesiomorphy,
i.e., the retention of primitive morphologies, it
can be fairly assumed they also bear witness to a common ancestor
not too far removed in time. The Presbyornithidae have
been demonstrated to have an anseriform affinity (Ericson,
1997), whereas Juncitarsus is thought to have its closest living