Dr. Zhe-Xi Luo

Genetics
K. Arndt
T.-L. Ashman
G. Campbell
D. Chapman
G. Hatfull
J. Hildebrand
L. Jacobson
S. Kalisz
J. Martens
V. Oke
W. Saunders
B. Stronach
S. Tonsor
R. Wood

Microbiology
G. Hatfull
R. Hendrix
J. Lawrence
V. Oke
J. Pipas
M. Popa
I. Campbell
R.L. Duda
S. Godfrey

Molecular Biology
K. Arndt
J. Franzen
P. Grabowski
G. Hatfull
R. Hendrix
L. Jen-Jacobson
J. Martens
C. Peebles
J. Pipas
J. Rosenberg
A. Schwacha
C. Walsh

Plant Biology
T.-L. Ashman
W. Carson
S. Kalisz
V. Oke
C. Partanen
S. Tonsor
B. Traw

Science Education
A. Bledsoe
K. Curto
L. Daniels
S. Godfrey
N. Kaufmann
C. LaFave
J. Newman
E. Polinko
M. Popa
L. Roberts
T. Seiflein
R. Sherwin
A. Slinskey Legg

Structural Biology
M. Grabe
J. Hempel
R. Hendrix
L. Jen-Jacobson
J. Rosenberg
A. VanDemark

Former Faculty

Photo of Dr.
Luo

Phylogeny and Evolutionary Morphology of Mammals

Adjunct Professor

Dr. Luo received his Ph.D. in 1989 with William A. Clemens at the University of California at Berkeley, performed his postdoctoral studies with Alfred W. Crompton at Harvard University, and joined the Department in 1996.

Currently, Dr. Luo is co-sponsoring graduate students in his laboratory. Dr. Luo is not accepting undergraduate researchers, and does not sponsor students in other laboratories.

Professional Interests - Publications - Contact Information - Lab Personnel

Professional Interests of Zhe-Xi Luo

Evolution of hearing specializations in whales - The spectacular evolutionary radiation of whales (cetaceans) can be attributed, at least in part, to their specialization in underwater hearing. Because underwater environment can greatly limit vision and olfaction, whales have to rely on hearing (ears) for communication, navigation, and feeding. Whales have two phylogenetic groups: toothed whales (odontocetes) and baleen whales (mysticetes), each having a different specialization for underwater hearing.

Toothed whales have echolocation (ultrasonic sonar). High frequency clicking sound is beamed out to the aquatic environment from the forehead, and then its echoed sound is received by the mandible. Sensitivity to high (ultrasonic) frequencies are crucial for auditory perception of toothed whales of their environment. By contrast, the baleen whales can hear very low frequency (infrasonic) sounds but have no echolocation. This enables the baleen whales to communicate over long distance, as the low-frequency sound has better propagation and wider scatter underwater.

With these hearing specializations, numerous structures are specialized in the ears of whales. These ear structures are usually preserved in many fossil whales, providing an extensive fossil record from which to elucidate the pattern of their evolution. The ear structures of fossil whales will bestudied by using the techniques of serial grinding and computer graphic reconstruction that have a good potential to shed light on the ear anatomy. The objectives of this study are to explore the morphological features of the ear can be used for inferring relationships of cetaceans, and to establish the phylogenetic evolution of the ear structures, both for high-frequency hearing in toothed whale, and for the low frequency hearing in baleen whales.

Dr. Luo excavates dinosaur bones in China

Origins of mammals -Skull structures underwent fundamental changes through the transition of mammals from their phylogenetic relatives known as cynodonts, or Radvanced mammal-like reptiles. The derived mammalian skull features are correlated to many remarkable adaptations that are absent in non-mammal vertebrates: a more powerful and efficient mastication for feeding, a more sophisticated ear structure for a more sensitive hearing, and the diphyodont tooth replacement that is correlated with a unique pattern of the mammalian life history -- the altricial birth and the dependency of the young on parental mammary glands.

The phylogenetic evolution of these derived mammalian skull structures can be established by the comparative study of the skull structures in the earliest fossil mammals and their cynodont relatives. New fossil specimens, most of which are from the Mesozoic, are examined by using serial sectioning, graphic reconstruction, and computerized tomography. New morphological information of intricate skull structures of the transitional taxa would make it possible to test the phylogenetic hypotheses of non-mammalian cynodonts and early mammals and to elucidate the pattern of evolution of the skull structures crucial for biological adaptations of mammals.

Publication Archive
29 Citations
21 Abstracts
0 PDFs

Recent Publications of Zhe-Xi Luo

Li, G., and Z.X. Luo (2006) A Cretaceous symmetrodont therian with some monotreme-like postcranial features. Nature 439:195-200

Ji, Q., Z.X. Luo, C.X. Yuan, and A.R. Tabrum (2006) A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals. Science 311:1123-1127

Martin, T., and Z.X. Luo (2005) Paleontology. Homoplasy in the mammalian ear. Science 307:861-862

Luo, Z.X., and J.R. Wible (2005) A Late Jurassic digging mammal and early mammalian diversification. Science 308:103-107

Dooley, A.C., N.C. Fraser, and Z.-X. Luo (2004) The earliest known member of the rorqual-gray whale clade (Mammalia, Xetacea). J. Vertebr. Paleontol. 24:453-463

You, H.L., Z.X. Luo, N.H. Shubin, L.M. Witmer, Z.L. Tang, and F. Tang (2003) The earliest-known duck-billed dinosaur from deposits of late Early Cretaceous age in northwest China and hadrosaur evolution. Cretaceous Res. 24:347-355

Shapiro, M.D., H.L. You, N.H. Shubin, Z.X. Luo, and J.P. Downs (2003) A large ornithomimid pes from the lower cretaceous of the Mazongshan Area, northern Gansu Province, People's Republic of China. J. Vertebr. Paleontol. 23:695-698

You, H.L., F. Tang, and Z.X. Luo (2003) A new basal Titanosaur (Dinosauria : Sauropoda) from the early cretaceous of China. Acta Geol. Sin-engl 77:424-429

Luo, Z.-X., Q. Ji, J.R. Wible, and C.-X. Yuan (2003) An Early Cretaceous Tribosphenic mammal and metatherian evolution. Science 302:1934-1940

Kielan-Jaworowska, Z., R.L. Cifelli, and Z.-X. Luo (2002) Dentition and relationships of the Jurassic mammal Shuotherium. Acta Palaeontol. Pol. 47:479-486

Luo, Z.-X., Z. Kielan-Jaworowska, and R.L. Cifelli (2002) In quest for a phylogeny of Mesozoic mammals. Acta Palaeontol. Pol. 47:1-78

Ji, Q., Z.-X. Luo, C.-X. Yuan, J.R. Wible, J.-P. Zhang, and J.A. Georgi (2002) The ealiest known eutherian mammal. Nature 416:816-822

Luo, Z.-X., Z. Lielan-Jaworowska, and R.L. Cifelli (2001) In quest for a phylogeny of Mesozoic mammals. Acta Palaeontol. Pol. 47:1-78

Luo, Z-X., A.W. Crompton, and A.L. Sun (2001) A new mammaliaform from the Early Jurassic of China and evolution of mammalian characteristics. Science 292:1535-1540

Tang, F., Z.-X. Luo, Z.H. Zhou, H.L. You, J.A. Georgi, Z.L. Tang, and X.Z. Wang (2001) Biostratigraphy and palaeoenvironment of the dinosaur-bearing sediments in Lower Cretaceous of Mazongshan area, Gansu Province, China . Cretaceous Res. 22:115-129

Luo, Z.-X., R.C. Cifelli, and Z. Kielan-Jaworowska (2001) Dual evolution of tribosphenic mammals. Nature 409:53-57

Luo, Z.-X. (2000) Evolution - In search of the whales' sisters. Nature 404:235

How to Contact Zhe-Xi Luo

US Mail
Carnegie Museum of Natural History
Section of Vertebrate Paleontology

4400 Forbes Avenue
Pittsburgh, PA 15213-4048

Phone, FAX, Internet
Office : (412) 622-6578
Lab :
FAX : (412) 622-8837
Email : luoz@carnegiemnh.org
Web :

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