An early Cretaceous pellet.
- SourceAvailable from: Jingmai Kathleen O'Connor[show abstract] [hide abstract]
ABSTRACT: Preserved indicators of diet are extremely rare in the fossil record; even more so is unequivocal direct evidence for predator-prey relationships. Here, we report on a unique specimen of the small nonavian theropod Microraptor gui from the Early Cretaceous Jehol biota, China, which has the remains of an adult enantiornithine bird preserved in its abdomen, most likely not scavenged, but captured and consumed by the dinosaur. We provide direct evidence for the dietary preferences of Microraptor and a nonavian dinosaur feeding on a bird. Further, because Jehol enantiornithines were distinctly arboreal, in contrast to their cursorial ornithurine counterparts, this fossil suggests that Microraptor hunted in trees thereby supporting inferences that this taxon was also an arborealist, and provides further support for the arboreality of basal dromaeosaurids.Proceedings of the National Academy of Sciences 11/2011; 108(49):19662-5. · 9.74 Impact Factor
Article: The birds from Las Hoyas.[show abstract] [hide abstract]
ABSTRACT: Information on the first steps of the avian evolutionary history has dramatically increased during the last few years. The fossil record provides a general view of the morphological changes of the avian flight apparatus from nonvolant ancestors (non-avian theropod dinosaurs) to the first derived fliers of the Early Cretaceous. The Las Hoyas bird record includes three genera: Iberomesornis, Concornis and Eoalulavis. This fossil material has yielded information about the early avian evolutionary history. These Early Cretaceous birds (some 120 Myr old) had a wingbeat cycle and breathing devices similar to those of extant birds. The function of the rectricial fan was also similar. In the evolutionary transition from cursorial ancestors to derived fliers it is possible to verify a trend to increase lift. Primitive wing aspect ratio morphotypes were elliptical ones, other derived morphotypes appeared, for example, in the Neornithes (extant birds). Some primitive fliers, like the Las Hoyas genus Eoalulavis, had an alula (feathers attached to the first digit of the hand) similar to that of present day birds, indicating braking and manoeuvring skills similar to those of their extant relatives. Primitive avian life habits are poorly understood. Some evidence from the Las Hoyas bird record indicates that Early Cretaceous birds were present in the trophic chains.Science Progress 02/2002; 85(Pt 2):113-30.
- American Museum Novitates 12/2007; · 1.69 Impact Factor
anaesthetic and paralytic drugs to minimize
discomfort and pain in the mice can be
obtained from M.L.W.) We found no signifi-
cant differences in other pulmonary func-
tions (pulmonary compliance or resistance).
Increased lung permeability enhances access
by a toxin to the lung interstitium and pul-
monary circulation, correlating with the
extent of pathological lung injury.
We measured the distribution in particle
sizes to which the mice were exposed by
using a Berner low-pressure impactor, and
recorded differences in mass and concentra-
tion of certain elements. Mass and size distri-
butions for particles produced by coal/MSS
ash mixtures and by coal ash on its own are
quite similar, although the coal ash generates
a slightly greater fraction of nanometre-
sized particles. We conclude that the
increased toxicity of the MSS/coal is not due
to a difference in the size of the particles it
produces on combustion.
Instead, the toxic effects seem to be asso-
ciated with the presence of zinc in the parti-
cles. Combustion of MSS together with coal
increases the concentration of zinc in the
resulting airborne particulate matter in the
respirable-size particles (diameters between
0.3 and 2.5 ?m) from 2 to 14 wt% and in
ultrafine particles (diameter smaller than 0.1
?m) from 4 to 11 wt%. MSS also produces
10 wt% cobalt in the utrafines. Selenium,
arsenic, lead and vanadium were present in
similar amounts in particles from MSS/coal
and from coal, whereas more iron was found
in particles from coal burned alone. We
therefore believe that zinc is the culprit metal
that causes an increase in a measurable pre-
cursor for lung damage, a conclusion that is
supported by other measurements5of lung
inflammation after intratracheal injection.
The replacement of coal by MSS in power
stations is being considered as one option to
help meet the requirements of the Kyoto
Protocol and to replace landfill disposal of
MSS. Our results, indicating that the toxicity
to mice of inhaling particles from coal/MSS
co-combustion is greater than from coal
alone, suggest that the environmental
advantages may be tempered by the risk to
Art Fernandez*, Sheldon B. Davis*,
Jost O. L. Wendt*, Roberta Cenni†,
R. Scott Young‡, Mark L. Witten‡
*Department of Chemical and Environmental
Engineering, University of Arizona, Tucson,
Arizona 85721, USA
†Institut für Verfahrenstechnik und
Dampfkesselwesen, Universität Stuttgart,
D-70569 Stuttgart, Germany
‡Lung Injury Laboratory, Department of Pediatrics,
Arizona Health Sciences Center, Tucson,
Arizona 85721, USA
1. Dockery, D. W. et al. N. Engl. J. Med. 329, 1753–1759 (1993).
2. Lighty, J. S., Veranth, J. M. & Sarofim, A. F. J. Air Waste Manag.
Assoc. 50, 1565–1618 (2000).
3. Cenni, R., Frandsen, F., Gerhardt, T., Spliethoff, H. &
Hein, K. R. G. Waste Manag. 18, 433–444 (1998).
4. Fernandez, A., Wendt, J. O. L., Cenni, R., Young, R. S. &
Witten, M. L. J. Air Waste Manag. Assoc. (submitted).
5. Adamson, I. Y. R., Prieditis, H., Hedgecock, C. & Vincent, R.
Toxicol. Appl. Pharmacol. 166, 111–119 (2000).
An Early Cretaceous
show signs of having been digested. To our
knowledge, this rare finding of an Early
Cretaceous fossil of an apparently regurgi-
tated pellet provides the first evidence that
Mesozoic birds were prey animals.
The new fossil assemblage contains four
juvenile birds in an area smaller than 23
cm2(Fig. 1a,b). The two largest individuals
(1 and 2; shown in dark and light grey,
respectively, in Fig. 1) differ from one
another in their tail morphology. In bird 2,
the first seven caudal vertebrae are followed
by a large pygostyle; in bird 1, the tail is
composed of at least 12 free caudal verte-
brae (Fig. 1c). The femur of bird 1 is 5–10%
longer than that of bird 2, whereas the tar-
e have discovered a mass of fossil
bones from four juvenile birds at
Las Hoyas in Cuenca, Spain, which
NATURE | VOL 409 | 22 FEBRUARY 2001 | www.nature.com
Particulate emission from
ide emissions from traditionally coal-fired
power plants, as well as to overcome
sewage-disposal problems. Here we investi-
gate the effects of inhaling particles emitted
from the combustion of this mixture and
find that these cause significantly more lung
damage in mice than do particles from coal
alone, probably because of their zinc con-
tent. Our findings indicate that the use of
dried municipal sewage sludge as a ‘green’
(CO2-neutral) replacement fuel should be
considered with caution.
Airborne particulate matter is associated
with acute respiratory distress in humans1.
Suggested causes2of the lung damage caused
by these particles include their composition
— for example, they may contain soluble
transition metals such as copper, iron, vana-
dium, nickel or zinc — their acidity, and
their ultrafine size (some particles are less
than 0.1 ?m in diameter). These properties
are all features of airborne particulate matter
resulting from the co-combustion of pulver-
ized coal and biomass, including dried
municipal sewage sludge (MSS).
Combustion of pulverized coal (from the
University of Stuttgart) and of MSS/coal
mixtures was performed in a semi-
industrial-scale, 500-kW downfired pulver-
ized-fuel combustor3. MSS had been
processed (Swiss ‘Combi’ process) to pro-
duce 2–4-mm pellets, which were then pul-
verized and mixed (20% thermal, 50% mass
load) with coal. Sampled particulate matter
was resuspended and diluted4to a sufficiently
low concentration to allow the effects caused
by different particle properties to be assessed
on exposed mice. Mice were exposed for only
1 hour each day for 24 consecutive days to a
low dose of 1,000 ?g m–3and to a high dose
of 3,000 ?g m–3(the atmospheric dose of par-
ticulate matter less than 10 ?m in diameter
currently allowed by the United States Envi-
ronmental Protection Agency is 150 ?g m–3
averaged over 24 hours).
Figure 1 indicates that co-combustion of
MSS/coal ash produces airborne particulate
matter that has a significant effect on lung
permeability in mice, increasing with
dosage, which is greater than the effect of
either air on its own or a high dose of parti-
cles produced by burning only coal ash,
which appears to be relatively benign. Cell
counts in broncho-alveolar lavage fluid in
our mice decreased after exposure to partic-
ulate matter from MSS/coal, compared to
ambient air and coal ash alone, which again
appears relatively benign (Fig. 1). (Details of
measurement techniques and the use of
ixing dried human sewage sludge
with pulverized coal is being evalu-
ated as a way to reduce carbon diox-
Figure 1 Effect of inhaled particulates on lung permeability (top)
and broncho-alveolar lavage fluid cell counts (bottom). Thirty-two
specific, pathogen-free mice (strain C57BL/6) were randomly
divided into four groups (weight, 25.0?4.3 g; n?8), housed at
8 per cage under a 12-h light/12-h dark cycle at the Arizona
Health Science Center animal facility (approved by the American
Association for the Accreditation of Laboratory Animal Care, to
ensure proper treatment of animals), and fed a standard chow
diet and tap water. Results were analysed 24–30 h after the final
exposure to airborne particulate matter (see text). Cells were
counted from the first 3 of 6 lavages (1 ml sterile isotonic saline)
of the lungs. In the top bar graph, the asterisk symbol indicates
statistical significance compared with exposure to particles from
the coal/sewage ash of P?0.0001; in the bottom graph, the
asterisk and hash indicate statistical significance compared with
exposure to coal/sewage ash particles of P?0.0005 and
P?0.0001, respectively. Error bars indicate ?s.d. Bars: 1, con-
trols; 2, values corresponding to coal-ash exposure dose of
~3,000 ?g m–3; 3 and 4, values for coal/sewage-ash exposures
of ~1,000 ?g m–3and ~3,000 ?g m–3, respectively.
1 2 3 4
(×104 cells per ml)
Permeability K value
(% clearance min–1)
© 2001 Macmillan Magazines Ltd
sometatarsus of bird 1 is less than 85% the
length of that of bird 2. The smaller individ-
uals (birds 3 and 4) are comparable in size
and have similar anatomical traits. The four
individuals show a comparable degree of
ossification. Morphological and size data
suggest that at least three different species
are present in the fossil.
This aggregation is peculiar to the Las
Hoyas site1,2, which has yielded more than
200 terrestrial vertebrate specimens that
were usually isolated, fully articulated and
complete. Results from oxygen and carbon
isotope analysis of the Las Hoyas lacustrine
limestones are in the range typical for sedi-
ments deposited in a still body of water3.
Under these conditions, it would be unlike-
ly that the four immature birds of this bone
assemblage perished far apart and were
then buried together in such a small area.
There are two more parsimonious expla-
nations. The individuals could have been
living in a nest that was washed into the
lake, or their association could have resulted
from predation as individuals and regurgi-
tation by the predator combined into a pel-
let. The first of these two non-random
explanations assumes nest parasitism,
because the four individuals probably
belong to three different bird species. Such
a behaviour is unknown for any basal bird
and cannot be confidently inferred from
our knowledge of their closest relatives.
The idea that the fossil is a result of pre-
dation is supported by the corroded aspect
of some articular ends, surface pitting and
NATURE | VOL 409 | 22 FEBRUARY 2001 | www.nature.com
edge rounding of many of the bones (Fig.
1d), which look like digested bones from
modern birds4(Fig. 1e) and mammals5.
These features differ from those expected
from any other type of biological or geologi-
cal erosion6,7. The surface of bones from
juvenile birds is also porous during peri-
osteal formation, but this form of pitting is
more fibrous and can be distinguished from
that seen in digested bones (Fig. 1f).
Comparison with digested prey from
extant predators indicates that the digestion
of the Las Hoyas bone assemblage was
extensive, although not as thorough as prey
eaten by crocodiles8. The nearly intact
anatomical connections of the bones con-
trast with the small size of bone fragments
in dinosaur coprolites9. Impressions of com-
plete feathers surrounding the assemblage of
bones (Fig. 1a) resemble the feathers often
seen enveloping modern pellets. These
observations, together with the apparent
absence of faecal ground mass, indicate that
this multispecific aggregation of immature
bird bones is a regurgitated pellet.
Identifying the predator responsible for
this pellet is a problem. On the basis of the
existing (and expected) fossil record from
Las Hoyas, likely candidates could be large
fish, early mammals, lizards, crocodiles
(goniopholids), pterosaurs and dinosaurs
(including birds), although some can be
confidently excluded. Fishes and mammals
regurgitate loose masses of bones, and the
lizards and birds found at Las Hoyas are of
comparable size to the pellet structure
reported here. Goniopholids, close relatives
of modern crocodiles, would probably have
regurgitated more completely digested
bones. The most likely predators to have
produced the pellet are small, non-avian,
theropod dinosaurs or pterosaurs that
hunted different prey, swallowed them
whole and then regurgitated the indigestible
remains, much as owls do today.
José L. Sanz*, Luis M. Chiappe†,
Francisco Ortega*, Begoña Sánchez-
Chillón‡, Francisco J. Poyato-Ariza*,
Bernardino P. Pérez-Moreno*
*Unidad de Paleontología, Departamento de
Biología, Universidad Autónoma de Madrid,
28049 Cantoblanco, Madrid, Spain
†Natural History Museum of Los Angeles County,
900 Exposition Boulevard, Los Angeles,
California 90007, USA
‡Museo Nacional de Ciencias Naturales,
José Gutiérrez Abascal 2, 28006 Madrid, Spain
1. Pérez-Moreno, B. P. et al. Nature 370, 363–367 (1994).
2. Sanz, J. L., Fregenal-Martínez, M. A., Meléndez, N. & Ortega, F.
in Palaeobiology II (eds Briggs, D. E. G. & Crowther, P. R.)
(Blackwell Scientific, Oxford, in the press).
3. Poyato-Ariza, F. J., Talbot, M. R., Fregenal-Martínez, M. A.,
Meléndez, N. & Wenz, S. Palaeogeogr. Palaeoclimatol. Palaeoecol.
144, 65–84 (1998).
4. Bochenski, Z. M. et al. J. Archaeol. Sci. 25, 425–433 (1998).
5. Andrews, P. Owls, Caves and Fossils (Natural History Museum
Publications, London, 1990).
Figure 1 Fossil pellet from the Lower Cretaceous of Las Hoyas (Cuenca, Spain). a, Bird assemblage from Las Hoyas (specimen LH
11386, Museo de las Ciencias de Castilla-La Mancha, Cuenca, found by a local collector, D. A. Diaz Romeral) showing feather impres-
sions (arrow). b, Acid preparation of the specimen LH 11386. c, Camera lucida drawing of the bird assemblage from Las Hoyas. The
most complete individual (bird 1; dark grey) shows preservation of almost the entire vertebral column in articulation and multiple portions
of the appendicular skeleton in varying degrees of articulation. The second individual (bird 2; light grey) is identifiable from sections of its
pelvis, sacral and caudal series, and hindlimbs. The remaining two individuals (birds 3 and 4; black) are significantly smaller than the first
two. These specimens can be identified by only their hindlimb elements; at least three small metatarsi are present in the assemblage.
Individuals 1 and 2 are of roughly the same size but significantly larger than individuals 3 and 4. For example, the tarsometatarsi of indi-
viduals 3 and 4 are about 60% and 50% shorter than those of individuals 1 and 2, respectively. d, Scanning electron micrograph (SEM)
of specimen LH 11386 revealing surface damage (pitting and edge rounding) by digestion. Scale bar, 71.4 ?m. e, SEM of a modern
avian bone digested by a jackal (courtesy of P. Andrews). Crocodiles produce very extreme digestion grades8,10, higher than jackals and
other canids5. Scale bar, 71.4 ?m. f, SEM of an undigested modern juvenile bird bone (P. Andrews), showing absence of rounding and
the characteristic porous and fibrous surface of juveniles. The specimen shown in f is larger than that in d or e and the magnification is
reduced (scale bar, 667 ?m) so that structural features can be compared.
© 2001 Macmillan Magazines Ltd