A new species of Plesiocathartes (Aves: ?Leptosomidae) from
the Middle Eocene of Messel, Germany
GERALD MAYR
Forschungsinstitut Senckenberg, Sektion fur Ornithologic, Senckenberganlage 25, D-60325 Frankfurt a.M., Germany;
gmayr@sng.uni-frankfurt.de
A new species of the genus I'Icsiocatlmrtcs Gaillard 1908 is described from the middle Eocene of Messel (Germany).
Plesiocathartes It die ri sp. nov. is represented by two articulated skeletons and is the most substantial record of the
genus, previously only known from a few isolated bones. In addition, a distal end of a tarsometatarsus ofPlesiocathartes
sp. is described from the lower Eocene London Clay of England. The new specimens clearly demonstrate that
Plesiocathartes is no early European representative of the Cathartidae (New World vultures) as assumed by earlier
authors. Instead, both in terms of derived characters and in overall morphology, Plesiocathartes kcllcri most closely
corresponds to the Leptosomidae (Cuckoo-rollers), which today only occur in the Madagascan region. Accord-
ingly, the genus Plesiocathartes is tentatively assigned to the Leptosomidae. If this classification is correct, it would
be the first Tertiary fossil record of the Leptosomidae, and indicate that the extant distribution of this family is
relic tual.
PaleoBios 22(1): 10-20, May 15, 2002
© 2002 University of California Museum of Paleontology
INTRODUCTION
The avian genus Plesiocathartes wax described by Gaillard
( 1908) on the basis of a single incomplete tarsometatarsus
from the middle Eocene to upper Oligoccne fissure fillings
of the Quercy, France. Gaillard considered Plesiocathartes
europaeus, the only species of the genus described previ-
ously, to be an early Tertiary European representative of the
New World vultures (Cathartidae), and this classification
was adopted by subsequent authors (e.g., Cracraft and Rich
1972, Mourer-Chauvire 1982, Emslie 1988). However, re-
cently Mourer-Chauvire (2000) reported a second, more
completely preserved tarsometatarsus of P. europaeus that
docs not support assignment of this species to the Cathar-
tidae; she regarded its systematic affinities to be uncertain.
Mayr (2000a, in press) identified isolated bones of a new,
but as yet unnamed, species of Plesiocathartes from the
Middle Eocene fossil site of Geiscltal, Germany (Fig. 1A-
E). He suggested a possible relationship of Plesiocathartes
to cuckoo-rollers (Leptosomidae) which today include the
single species Lcptosomus discolor and occur in the
Madagascan region only.
A distal end of a tarsometatarsus from the early Miocene
ot Spain was described as ? Plesiocathartes jjaillardi by
Crusafont and Villalta (1955). This specimen cannot be lo-
cated (Sanchez Marco 1996), but based on the illustration
and description in Crusafont and Villalta (1955), it prob-
ably was referred incorrectly to the genus Plesiocathartes.
The specimen differs markedly from /'. europaeus in its pro-
portionally more mediolaterally compressed distal end, the
much narrower incisurac intertrochleares, and the longer
trochlcac metatarsorum. In this study, two articulated skel-
etons of a new species of Plesiocathartes are described from
the middle Eocene of Messel, Germany. In addition, a well
preserved distal end of a tarsometatarsus of Plesiocathartes
was identified among the fossil bird material from the lower
Eocene London Clay of England. The Messel and London
Clay specimens are the earliest records of the genus Plesio-
cathartes^ exceeding P. europaeus by—depending on the ex-
act age of the Quercy specimens (Legendre and Leveque
1997)—at least 10 million years. The fossiliferous deposits
of Messel originated about 49 million years ago in a deep
crater lake that was surrounded by dense paratropical for-
ests (see Schaal and Ziegler 1988 for general information
on the site). Birds are fairly abundant at this locality, and a
survey of the Messel avifauna was given by Mayr (2000b).
Although the lower Eocene Ix>ndon Clay sites are some-
what older and were deposited in a near-shore marine envi-
ronment, the fossil avifauna has a very similar composition
to that of Messel (e.g., Mayr 1998a, Mayr and Daniels 1998,
2001).
MAFERIALS AND METHODS
The measurements reported below represent the maxi-
mum length of the bone along its longitudinal axis. Re-
garding the claws, the distance between the tip of the
tuberculum extensorium and the apex phalangis was mea-
sured. Anatomical terminology follows Baumel and Winner
(1993) and Vanden Berge and Zweers (1993), if not other-
wise indicated.
Institutional abbreviations: BMNH—the Natural History
Museum, London; GMH—Geiseltalmuseum, Halle, Ger-
many; HLMD—Hessisches Landesmuscum, Darmstadt,
Germany; SMF—Forschungsinstitut Senckenberg, Frankfurt
am Main, Germany.
SYSTEMATIC PALEONTOLOGY
Class: Aves
Order: incertae sedis
Family: ? I .kptosom i dak
Genus: Pi.i-siocathartes Gaillard 1908
11
PALEOBIOS, VOL. 22, NUMBER 1, APRIL 2002
Fig. 1. Isolated bones of Plesiocathartes sp. A-K. GMH 559, from the middle Kocene of the Geiseltal, Germany. A. Left tibiotarsus
in caudal view. B. Left tibiotarsus in cranial view. C. right tarsometatarsus in plantar view. D. right tarsometatarsus in dorsal view.
E. right tarsometatarsus in distal view. F-H. HMNII A 6178, from the lower Eocene London Clay of Warden Point, Sheppcy Is
land, England. F. Distal end of left tarsometatarsus in plantar view. G. Distal end of left larsometatarsus in dorsal view. H. Distal
end of left tarsometatarsus in distal view. Scale bars - 5 mm; same scale for A-D and F-H.
The genus Plesiocathartes \s characterized by the follow-
ing putatively derived features of the tarsometatarsus (which
is the onlv bone known from /'. curopaeus, the tvpc species
of the genus): (1) shaft compressed in dorso-plantar direc-
tion, middle part with rectangular cross section, distal end
with plane dorsal surface, and cristae mediales et laterales
distinct (usually the shaft is less compressed in dorsoplantar
direction and has a more trapezoidal cross-section, which is
here considered to be the plesiomorphic condition in
neornithine birds); (2) fossa metatarsi I sharply defined,
but very small (in presumably basal neornithine birds, e.g.,
the palaeognathous Tinamidac anil the Galloansercs, this
fossa is larger, which probably is the plesiomorphic condi-
tion); (3) trochleae metatarsorum, especially those for the
second and third toe, very small and arranged on a weakly
curved line if the bone is viewed from its distal end (in
presumably basal neornithine birtls the trochleae
metatarsorum are much larger and those for the second and
fourth toe are turned more in plantar direction, which is the
primitive condition).
The tibiotarsus of the Messel species of Plesiocathartes
further corresponds to that of the above mentioned Geiseltal
MAYR-NEW SPECIES OF PLESIOCATHARTES
12
specimen in that the trochlea cartilaginis tibialis is very short
in proximo distal direction, which also is a derived feature
within ncornithine birds (sec below). The tibiotarsus of P.
europaeus is unknown.
Plesiocathartes kelleri sp. nov.
Figs. 2-8
Holotype—SMF-MF. 3639, an articulated skeleton on a
slab, lacking the left leg. Fig. 2.
Differential Diagnosis— Plesiocathartes kelleri s\i. nov. is
smaller than P. europaeus and the yet unnamed Geiseltal
species. The distal width of the tarsometatarsiis is about 5.9
mm vs. about 7.8 mm in P. europaeus (according to Gaillard
1908); the length of the bone is about 26.2 mm, vs. 40.8 in
the Geiseltal species and about 30-32 mm in P. europaeus
(estimated total length). The tarsometatarsiis of Plesio-
cathartes kelleri sp. nov. further is slightly less stout than
that of P. europaeus.
Type locality—Messel near Darmstadt (Hcsscn, Ger-
many)
Type horizon—lower middle Eocene (Legendre and
Leveque 1997).
Measurements of the holotype (maximum length in
mm)—Skull, -56.7; coracoid, -22.5 (left), -22 (right); right
humerus, 49.8; ulna, -58 (left), -57 (right); right
carpometacarpus, -28.8; right femur, -29; right tibiotarsus,
-46.2; right tarsometatarsiis, -26.2; right pedal phalanges,
II, -7; 111,7.1; 112,7.2; 113,4.3; III1, -5; III2, -6; III3,
6.7; IV1, 5.5; IV2, -4.7; IV3, 4.7; IV4, 6.6; IV5, 4.1.
Referred specimen—IILMD Be 162, a complete, articu-
lated skeleton on a slab. Fig. 3.
Measurements of the referred specimen (maximum
length in mm)-Skull, -57.3; humerus, -51.8 (left), 48.7
(right); ulna, 60.5 (left), 60.3 (right); carpometacarpus, 30.6
(left), 30.7 (right); left femur, -30.3; left tibiotarsus, 51.0;
left tarsometatarsiis, 28.2; pedal phalanges, 11, 7.2; III, 7.6;
112, 7.3; 113, 4.8; III1, -8; 1112, 7.9; III3, 7.2; III4, 5.8;
IV1, 5.0; IV2, 5.0; IV3, 4.0; IV4, 5.0; IV5, 5.1.
Etymology- The species has been named after Mr.
Manfred Keller, who found and prepared the holotype, and
who kindly donated it to Forschungsinstitut Senckenberg.
Description and comparison—Skull. I'he robust beak
measures slightly more than half of the entire skull; the cul-
men is moderately curved. The beak appears to be some-
what deeper than in Lcptosomus, but this impression might
in part be a result of the compression of the fossil specimen.
The narial openings reach distally to about the middle of
the beak (SMF-ME 3639); they appear to have been larger
than in Lcptosomus, although their exact shape cannot be
discerned clearly. The pars symphysialis of the mandible is
fairly long, measuring about 1/4 of the entire length of the
clement; fenestrae mandibulae are not visible. The ossa
praefrontalia are similar in shape and relative size to those of
Lcptosomus. Elongated processus postorbitales, one of the
most characteristic skull features of the I.eptosomidae, can-
not be discerned. Whether this is a result of the poor pies
ervation of the skulls of the two known skeletons of P. kelleri,
or whether these processes indeed were absent in this spe-
cies needs to be shown by future, better preserved speci-
mens.
Trachea: Ossified tracheal rings are preserved in speci-
men HLMD Be 162.
Vertebrae. About 19 presacral vertebrae can be counted
in the holotype, which is in concordance with the number
of presacral vertebrae in the majority of extant birds. The
cervical vertebrae are rather short and appear to have had
shallow lacunae intcrzygapophysiales.
Coracoid: The coracoid has similar proportions to that
of Lcptosomus. Unfortunately, in both specimens much of
the cxtrcmitas omalis is hidden by other overlying bones
and few features can be discerned. The processus
procoracoideus is well-developed and larger than in
Lcptosomus (Fig. 4); it bears a distinct articular facet for the
scapula. The processus acrocoracoideus is short, and the
whole cxtrcmitas omalis resembles that of extant Cuculidae
(in which, however, the processus procoracoideus is more
slender). As in Lcptosomus, the extremitas stemalis protrudes
medially. The shape of the processus lateralis cannot be dis-
cerned.
Furcula: Details of the furcula are visible only in the ho-
lotype. In having a straight end, the extremitas omalis has
an unusual shape (Fig. 4). In he holotype of P. kelleri, t he-
left scapus claviculae is visibk next to the left coracoid al-
though its width cannot be discerned. In Lcptosomus dis-
color, the extremitas omalis is more rounded and the scapi
clavicularum are very wide; the whole furcula of /,. discolor
is somewhat similar to that of owls (Strigifbrmes).
Scapula: The scapula is fairly straight and bears a short
acromion.
Sternum: As can be seen in the holotype, the sternum is
small with short processus craniolaterales. As in Lcptosomus,
a well-developed spina externa seems to be absent. The cau-
dal margin of the bone bears four small incisions of similar
size, whereas in /,. discolor the incisurae mediales are much
deeper than the almost completely reduced incisurae laterales.
Humerus: The humerus (Figs. 2, 3, 5) is long and the
shaft strongly flexed in its midsection (visible in the holo-
type). With regard to the latter feature and in overall pro-
portions, the bone closely resembles the humerus of
Lcptosomus (Fig. 5A). It mainly differs in the proportionally-
shorter crista deltopcctoralis which in Plesiocathartes kelleri
is of similar size to the crista deltopcctoralis of, for example,
Falco spp. (Falconiformes). The proximal end of the bone is
comparatively small, and the caput humeri is oriented ob-
liquely to the longitudinal axis of the shaft, as in Lcptosomus.
The tuberculum dorsale is indistinct. Except for the absence
of a distinct processus supracondylars dorsalis, details of
the distal end of the bone cannot be discerned.
Ulna: The ulna exceeds the humerus in length and is the
longest limb element. This feature distinguishes Plesio-
13
PALEOMOS, VOL. 22, NUMBER 1, APRIL 2002
f     <f'    '
Fig. 2. Pksiocatbartcs kelkri sp. nov., holoiypc (SM1-MK 3639). Coated with ammonium chloride, scale bar    20 mm.
AM7K-NKW SPECIES OF PLESIOCATHARTES
14
I
Fig. 3. Plesiocathartes kelkri sp. now, referred specimen (HI.MD Be 162). Coated with ammonium chloride, scale bar = 10 mm.
15
PALEOBIOS, VOL. 22, NUMBER /, APRIL 2002
Fig. 4. Plcsiocatliartcs kclkri sp. now, holotype (SMF-MF.
3639), shoulder girdle. The arrows point ro the processus
procoracoideus of the coracoid. Abbreviations: lc—extremitas
sternalis of left coracoid; leo—left extremitas umalis of furcula;
Is—left scapula; re—extremitas sternalis of right coracoid; reo—
right extremitas omalis of furcula; rs—right scapula. Coated
with ammonium chloride, scale bar = 5 mm.
cathartes kclkri from a number of avian taxa, as, for ex-
ample, in the Cuculidae (cuckoos) and Musophagidae
(turacos) in which the ulna is shorter or about as long as
the humerus. Since a short ulna occurs in the palaeognathous
Tinamidae and most Galloanseres—the latter are considered
by most recent authors (e.g., Sibley and Ahlquist 1990) to
be the sister taxon of all other Neomithes (but see also
Ericson et al. 2001)—this feature is here considered to be
plesiomorphic within neornithinc birds. Phylogenetically
relevant details of the proximal and distal ends of the bone
unfortunately cannot be discerned in either specimen. The
papillae remigales are weakly developed.
Carpometacarpus. The carpometacarpus is elongated and
slender, and, as far as it can be observed, it closely resembles
the corresponding bone of Leptosomus disco/or (Fig. 5C).
The os metacarpalc minus runs parallel to the os metacarpale
majus, the processus extensorius is protruding and of simi-
lar shape to that of Leptosomus. In neither specimen, how-
ever, can it be discerned whether the os metacarpale minus
protrudes farther distally than the os metacarpale majus, as
in Leptosomus.
Pelvir. Details of the pelvis are not visible in either speci-
men.
Femur. The femur is similar to that of Leptosomus in its
proportions. As in the latter, and contrary to most other
birds, the caput femoris is not globular, but proximodistally
narrow. This feature is here considered to be a putative
synapomorphy of Plcsiocathartcs and Leptosomus (see be-
low). The trochanter femoris is only weakly developed.
Tibiotarsus. The distal end of the tibiotarsus corresponds
to that of Leptosomus (Fig. 5D) in that the trochlea
cartilaginis tibialis is very short in proximo-distal direction
(visible on the holotype). This feature is absent in most
other neornithinc birds including the Cathartidae (big. 5F),
and it is here considered to be another putative
synapomorphy of Plesiocatbartes and Leptosomus (see be-
low). Although the tibiotarsus is unknown from
Plesiocatbartes curopaeus, it is preserved in the associated
remains of the yet unnamed species from the Geiseltal ( Figs.
1A-B).
Tarsometatarsus. The tarsometatarsus (Fig. 6) is about
as long as the carpometacarpus. It also closely resembles
the corresponding bone of Leptosomus in overall morphol-
ogy. In both specimens, the hypotarsus is hidden by the
overlying distal end of the tibiotarsus. The shaft is com-
pressed in dorso-plantar direction, has an equal width over
most of its length, and a rectangular cross-section in its
middle part. It appears to have been slightly narrower than
the tarsometatarsus of 7'. europaeus. The crista mediano
plantaris extends only over 1/5 of the entire length of the
bone, cristae plantares mediales et laterales are present (Fig.
6). The distal end of the bone is poorly preserved in the
holotype. In the referred specimen III.Ml") Be 162, how-
ever, it is in an uncrushed condition and enough details are
visible to reveal that it exhibits the same morphology as the
three dimensionally preserved distal tarsometatarsus of the
London Clay specimen of Plesiocatbartes sp., which is de-
scribed below. The foramen vasculare distale is small (III .M1)
Me 162, left side). The trochlea metatarsi II is small, as is
the fossa metatarsi I, which is located on the medial margin
of the shaft (HLMD Be 162).
Toes: All toes have the usual number and proportions of
pedal phalanges. The third toe exceeds the others in length,
but it is slightly shorter than the tarsometatarsus. The hal-
lux is of similar relative length to that of extant Leptosomidae.
The claws are of average size and moderately curved. The
processus articularis tarsometatarsalis of the os meiatarsale
I is short.
Feathering: The wing feathering is well preserved in speci-
men HLMD Be 162 (Fig. 7). The longest primary mea-
sures about 110 mm, the secondaries have a length of about
94 mm. A single tail feather is preserved, which measures
about 85 mm. In contrast to the tail feathers of extant
Leptosomidae, it exhibits a distinct barring (Fig. 8; barred
MAYR-NEW SPECIES OF PLESIOCATHARTI-S
16
E
Fig. 5. Selected skeletal elements of Plesiocathartcs (?Leptosomidae), Leptosomus discolor (heptosonudae), and Sarcoramphus papa
(Cathartidae). A. /,. discolor, right humerus in caudal view. B. /'. kellerisp. nov., right humerus in caudal view. C. Leptosomusdis-
color, lelt carpometacarpus in dorsal view. D. /. discolor, distal end of left tibiotarsus in caudal view, showing the proximo distally
short trochlea cartilaginis tibialis. E. S. papa, distal end of left tibiotarsus in caudal view. F. Plesiocathartcs sp. (BMNII A 6178),
distal end of left tarsometatarsus in plantar view. G. Plesiocathartcs sp. (BMNH A 6178), distal end of left tarsometatarsus in distal
view. H. /.. discolor, distal end of left tarsometatarsus in distal view, the arrow points to the enlarged wing-like flange on the tro-
chlea metatarsi IV. Scale bars = 10 mm; same scale for A-C, D-E, and F-II.
tail leathers are also known from other Mcsscl birds, e.g.,
Mayr 1998b).
Plesiocathartcs sp.
Referred Specimen-BMNH A 6178, distal end of left
tarsometatarsus from the lower Eocene London Clay (strati-
graphic division D-E) of Warden Point, Sheppev Island,
England, collected by M. Collinson in 1978, Figs. IF-H.
Measurements (in mm)—Length as preserved, 10.0; dis-
tal width across trochleae, 6.2; width of trochlea metatarsi
III, 2.2.
Description and comparison—This species is similar in
size to Plesiocathartcs kellerisp. nov., and, thus, also slightly
smaller than /'. cnropaais which it otherwise closely resembles
in morphology. The fossa metatarsi I is very small and lo-
cated on the medial margin of the shaft. The trochlea meta-
tarsi III also is small and, contrary to that of leptosomus, it
is wider in dorsoplantar than in mediolateral direction. The
trochlea metatarsi II reaches slightly farther distally than
the trochlea metatarsi IV. It is somewhat smaller than in
extant Leptosomidae and accordingly the incisura
intertrochlearis medialis is wider. L. discolor has a semi-zy-
godactyl foot, i.e., it is able to spread the fourth toe later-
ally, and thus the trochlea metatarsi IV bears a distinct
wing-like flange (Fig. 511). I'his flange is only weakly devel-
oped in BMNH A 6178, as in the other species of
Plesiocathartcs (Fig. 5). A marked sulcus ("outer extensor
groove" of Howard 1929) passes into the foramen vasculare
distale (Fig. 1G). As in L. discolor, a foramen interosseus
distalis is present. I'his foramen which is probably
plesiomorphic within neornithine birds, and which is not to
be confused with the foramen vasculare distale, is absent in
17
PALEOBIOS, VOL 22, NUMBER 1, APRIL 2002
Fig. 6. Pksiocathartes kellerisp. nov., feet. A. Holotype (SMF-MK 3639), right foot. B. Referred specimen (HI.MD Be 162), left
foot. C. Referred specimen (HI.MD Be 162), right foot. The toes are numbered, coated with ammonium chloride, scale bar = 10
mm.
most of the more derived ("higher7
landbirds.
Olson 1985)
DISCUSSION
The species of the genus Pksiocathartes arc much smaller
than any of the extant New World vultures and, as shown
by the specimens of the new species from Mcssel, Pksio-
cathartes lacked a hooked, raptorial beak. Assignment of
the fossil genus to the Cathartidac has not been convinc-
ingly established with derived characters. Cracraft and Rich
(1972: 275) listed a "deep anterior metatarsal groove [=
sulcus cxtensoriusj and the relative position of the trochlcae."
However, the first feature occurs in many other ncornithinc
birds and the latter is poorly defined. The tarsometatarsus
of Pksiocathartes more closely resembles that of the Lcpto-
somidac with which it was not compared by earlier authors.
The skeletons of Pksiocathartes kelleri sp. nov. further
agree in the following three derived ostcological features
with the Leptosomidae: (1) humerus distinctly bent in its
mid-section, if the bone is viewed from its cranial or caudal
side (this feature occurs in only a few other taxa, e.g.,
falconiform birds of the genus Eako, and it is absent in basal
ncornithinc birds, e.g., the palaeognathous Tinamidae and
the Galloanscres); (2) caput femoris proximodistally nar-
row (in basal ncornithinc birds and in the Cathartidac the
caput femoris is globular); (3) distal end of tibiotarsus with
proximodistally short condyles and a proximodistally short
trochlea cartilaginis tibialis, width across the condyles greater
than height of trochlea cartilaginis tibialis (this feature un-
questionably is derived within extant birds and only found
in few other taxa, such as parrots, Psittaciformes, and diur-
nal raptors, Falconiformes; in most other taxa, including
the Cathartidac, the height of the trochlea cartilaginis tibi-
alis is greater than the width across the condyles, see Figs.
5D-E).
In addition, the tarsometatarsus of the Geiseltal species
of Pksiocathartes exhibits two distinct furrows on the
hypotarsus (Fig. 1C), most likely for the tendons of muscu-
lus flexor hallucis longus and m. flexor digitorum longus.
The hypotarsus of Leptosomus is perforated by two probably
homologous canals, whereas in basal ncornithinc birds there
is cither no or just a single canal or furrow; the hypotarsus
of the Cathartidac is block-like and lacks furrows or canals.
Hither the complete absence of furrows and canals or the
presence of a single furrow is here considered to be the
primitive condition within ncornithinc birds.
MATR-NEW SPECIES OF PLESIOCATHARTES
IS
Fig. 7. Plcsiocathartcs kellcri sp. nov., referred specimen
(HLMD Be 162). Scale bar = 10 mm.
Although only the above listed derived characters shared
by Plcsiocathartcs'and Lcptosomusarc observable in the known
specimens, it has to be emphasized that the fossil genus is
very similar to extant cuckoo-rollers in overall morphology
of most skeletal elements, and is clearly distinguished from
all other fossil or extant taxa of which the skeleton is suffi-
ciently known. For example, extant turacos (Musophagidac)
and the superficially similar rcuculiform early Eocene family
Foratidae described by Olson (1992) differ from Plcsio-
cathartcs in the shape of the beak, the much shorter and
stouter ulna which does not exceed the humerus in length,
the shorter carpometacarpus, the more elongated tarsometa-
tarsus, and the different proportions of the pedal phalan-
ges-
Plcsiocathartcs kellcri mainly differs from Lcptosomus dis-
color in the proportionally somewhat shorter wing. Whereas
the hindlimb elements of the two species are about the same
size, the humerus, ulna, and carpometacarpus of P. kellcri
measure only about 3/4 of the length of the corresponding
bones of extant Leptosomidae. As can be deduced from the
absence of a distinct wing-like flange on the trochlea for the
fourth toe (Fig. 511), P. kellcri lacks semi-zygodactyl feet
Fig. 8. Plesiocathartes kellcri sp. nov. (HLMD Me 162), tail
feather. Note the distinct barring which is absent in extant
Ixptosomidae. Scale bar = 10 mm.
which, in accordance with Cracraft (1971: 745), are here
considered to be an autapomorphic feature of extant
Leptosomidae.
Cuckoo-rollers are generally classified in the Coraciiformes
and are considered to be closely related to typical rollers
(Coraciidae) and ground-rollers (Brachypteraciidae) (e.g.,
Maurer and Raikow 1981, Sibley and Ahlquist 1990,
Goodman 2001). However, a cladistic phylogenetic analysis
of coraciiform birds based on morphological characters did
not support monophyly of cuckoo-rollers and rollers, but
instead showed the Leptosomidae to be basal to a clade
including rollers, upupiform and alcediniform birds (Mayr
1998c, Fig. 9). Monophyly of leptosomidae, Coraciidae,
and Brachypteraciidae was also questioned by Herremanns
and Louette (1992), who considered the phylogenetic posi-
tion of the Leptosomidae "not too far from the Cucu-
liformcs." Tertiary fossil specimens of the Leptosomidae have
not yet been described, but rollers are known since the early
Eocene (Mayr and Mourer-Chauvire 2000; contrary to the
19
PALEOBIOS, VOL. 22, NUMBER 1, APRIL 2002
I
I
11	|	m 2
-si	I	3 fl> o to
1	1	li x: Q.
5<	m	a 3
statement in Kirchman et al. 2001, however, these do not
belong to the Brachypteraciidae, but to an extinct family).
In summary, available evidence more convincingly sup-
ports a tentative assignment of Pksiocathartcs to the Lepto-
somidae than any alternative classification (l*ig. 9). Although
extant Leptosomidae arc endemic to the Madagascan re-
gion, there is agreement that "Leptosomus evidently origi-
nated from an early invasion of Madagascar, well before that
which gave rise to the ground rollers" (Burton 1984: 426,
see also Cracraft 1971: 745). Thus, the presence of stem
group representatives of the Leptosomidae in the early Ter-
tiary of Europe might not be completely unexpected.
ACKNOWLEDGMENTS
I thank M. Keller (Frankfurt am Main) for donating the
holotype of Pksiocathartcs kellcri to the Forschungsinstitut
Senckenberg, and E. Brahm (SMF), S. Chapman and A.
Milner (BMNH), and N. Micklich (HLMD) for the loan
of fossil specimens. I am further indebted to C. Mourer-
Chauvire (Universite (Maude Bernard, Lyon) for informa-
tion on the Quercy specimens of P. eitropacus and to A.
Mancgold (Freic Universitat Berlin) for supplementary in-
formation concerning the osteology of Leptosomus discolor.
S. Trankncr (SMF) took the photographs. I also thank K.
Campbell (Los Angeles Natural History Museum) and an
anonymous reviewer for comments on the manuscript.
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