|
While the Stony Brook Vertebrate Fossil Preparation Lab prepares fossils from many areas in the world (green dots  ), three
major initiatives (red stars  ) are responsible for the majority of the work undertaken.
(click on map to view area of detail larger) |
STONY BROOK PROJECT
LEADERS: Dr. David Krause and
Dr. Catherine Forster
The face of the Earth changed greatly during the Late Jurassic and Cretaceous. It is
during this interval that the southern supercontinent Gondwana fragmented into
isolated landmasses, with dramatic consequences for the associated terrestrial and
freshwater vertebrate fauna. Reconstructions of the timing and sequence of this
fragmentation are based almost entirely on geophysical evidence and remain poorly
tested paleontologically. When, how, and from where the ancestors of the extant
vertebrates of Madagascar arrived on the island remain among the most intriguing
questions of natural history.
The Mahajanga Basin Project was initiated in 1993 and is conducted jointly by
paleontologists from Stony Brook University and the University of Antananarivo
in Madagascar. Discoveries in the Mahajanga Basin of northwestern Madagascar
have uncovered some of the most complete and scientifically significant specimens
of Late Cretaceous vertebrate animals in the world, including specimens of fishes,
frogs, turtles, lizards, snakes, crocodyliforms, dinosaurs, birds, and mammals.
Research on these discoveries has provided important information on the anatomy
and relationships of many animals, documentation of the geological structure and
history of the basin, key insights into the biogeographic origins of vertebrate
faunas on the island, and crucial new implications for the plate tectonic history
of Gondwana during the Mesozoic Era.
Field work has been funded by the National
Science Foundation and the National
Geographic Society.
(click on map to view area of detail larger) |
Stony Brook Project Leader, Dr. Alan H. Turner
Much work has been done on the subject of the extinction of
the dinosaurs 65
million years ago. But rather than focus on the demise of
these animals,
relatively little work has concentrated on their origins.
Where did they come
from? How did they diversify? Why were they more successful
than some of
their early contemporaries? When did dinosaurs first get
big? We know that
dinosaurs originated in the Late Triassic Period some 230 to
200 million years
ago. Their origins marked a replacement of faunas previously
dominated by a
variety of basal archosaur lineages such a aetosaurs and
“rauisuchians”. Until
recently the only evidence of dinosaur precursors was from
the Middle Triassic
Chañares Formation of Argentina. The recently discovered
Hayden Quarry near
Ghost Ranch New Mexico is providing a window into the early
evolution of
dinosaurs and their immediate precursors.
The Hayden Quarry contains the remains of many different
Late Triassic
vertebrates, from fish to dinosaurs. Animals found include
the large aquatic
metoposaurid amphibians, crocodile-like phytosaurs, armored
aetosaurs,
bipedal early crocodylomorph relatives, and dinosaurs. What
is most exciting
about the locality is that it contains a variety of true
dinosaurs, as well as their
closest relatives. Thus, we have preserved in the Hayden
Quarry the transition
from dinosaur precursors to true dinosaurs. By understanding
how these
species fit in the family tree, we can understand the timing
of the
diversification of the first dinosaurs and their relatives.
When we compare the
Hayden Quarry to other nearby localities with dinosaurs (for
example, the
Coelophysis Quarry), we can understand how long or fast it
took for dinosaurs
to go from being just another group to dominating the
landscape.
Located at Ghost Ranch, New Mexico, the area is better known
as the
inspiration for many of Georgia O'Keeffe's paintings. The
quarry is found within
rocks called the Chinle Formation, which was deposited as
river sediments
between 220 to 205 million years ago during the Late
Triassic Period. The
quarry is probably between 210 and 215 million years old.
For the past four
summers, a team of researchers from Stony Brook University,
the University of
California Museum of Paleontology, the American Museum of
Natural History,
The Field Museum of Natural History, and the University of
Utah has worked
this new locality and preliminary descriptive and
phylogenetic work in currently
underway. Stay tuned!
Fieldwork has been funded by the National Geographic Society
(click on map to view area of detail larger) |
STONY BROOK PROJECT LEADER: Dr.
Maureen O'Leary
The Cretaceous-Tertiary boundary (65 million years ago) represents one of the
five largest mass extinction events in Earth history. This extinction event
marks a transition point when dinosaurs (other than birds)
became extinct and modern orders of mammals first appeared. Identifying
geological sections from various continents to which vertebrate fossils
can be tied is very important for understanding which species of vertebrates
went extinct and which survived this extinction event. Mali is one of several
countries in the modern Sahara desert that has exposures of rock formations
left by shallow seaways that existed before and which survived.
Current research focuses on understanding vertebrate evolution across the
Cretaceous-Tertiary boundary in southern West Africa. Finding the remains of
species that lived within and along this ancient seaway, including the extinct
relatives of modern-day mammals, is of continued interest for
Dr. O'Leary and her team.
Explorations of rocks from the Taoudenit and Iullemeden Basins in Mali
began in 1999, and have resulted in the discovery of dinosaurs,
fossil forests, invertebrates, fishes, turtles, and crocodiles. Dr. O'Leary
and other researchers from the Unites States work in collaboration with the Centre
Nationale de la Recherche Scientifique et Technologique in the Republic of Mali.
Field work has been funded by the Saurus Institute, the Cranbrook Institute of
Science, the L. S. B.
Leakey Foundation, and the National Geographic Society.
(click on map to view area of detail larger) |
STONY BROOK PROJECT LEADERS: Doug Boyer, Dr. David Krause
In the ten million years following the extinction of dinosaurs, during the
Paleocene epoch (ca. 65-55 mya), mammals underwent a major adaptive radiation
and became dominant land animals. A large-scale turnover in mammalian faunas,
among the most significant during the Early Cenozoic, occurred from the middle
Paleocene to the late Paleocene. Despite the fact that almost one-half of the
known orders of Cenozoic mammals arose in the Paleocene, less is known about
composition and diversity of mammalian faunas during this time than any of
the later epochs.
The eastern Crazy Mountains Basin of south-central
Montana contains the best-known sequence of middle-to-late Paleocene
localities for fossil mammals in the world. Researchers
from Stony Brook University, the University of Michigan, and elsewhere
have conducted periodic field expeditions to the Crazy Mountains Basin for decades. Much of
the large collection previously amassed by Stony Brook University field
crews in the 1980s remains to be described and
employed in analyses to test hypotheses of faunal and climatic change.
Additionally, a freshwater limestone locality known for its remarkable
preservation of small mammal skeletons was relocated in 2002, promising
to yield new material otherwise unavailable from the Paleocene of North America.
Field work has been funded by the National Science Foundation and
the Geological Society of America.
Stony Brook University
Department of Anatomical Sciences
HSC T8 031
Stony Brook, NY 11794
(631) 444-3171
e-mail inquiries: jgroenke@notes.cc.sunysb.edu
|
