Geoscience Reference
In-Depth Information
ing sun. The first moments of excitement came on March 10 when
Rodolfo and some of our fossil hunters found a few bones of a meat-
eating dinosaur, which, although fragmentary, documented the pres-
ence of a colossal predator, much larger than the twentv-foot-long
Aucasaurus.
One of the fossils represented the end of a hipbone
called the pubic boot. The similarity in shape and size of this fragment
to those of the older
Giganotosaurus,
one of the largest carnivorous
dinosaurs ever discovered, suggested that a relative of this fearsome
creature had survived to roam Auca Mahuevo's river plains. Since
Rodolfo had originally studied and described the colossal
Giganoto-
saurus,
the glimpse of another such beast waiting to be discovered at
Auca Mahuevo fueled him and his team with a burst of determined
excitement throughout the next several weeks.
That day of prospecting also led to a second important discovery:
another flat area exposing large numbers of egg clutches. This surface
was somewhat smaller than that of the flats at egg layer 3, but it was
a stratigraphically higher part of our uppermost layer of eggs, egg layer
4. We knew that this would allow us to map the distribution of egg
clutches in egg layer 4 without having to remove huge amounts of
overburden, as well as to compare the distribution of eggs in layers 3
and 4. It was yet another day for celebration. Back at camp, our
cook, Omar, welcomed us with cold drinks and snacks that were fol-
lowed by a sumptuous
asado.
Equally exciting discoveries were made in the following days. On
March 12 two partial skeletons of titanosaur sauropods were spotted.
As we mentioned earlier, we had found skeletons of these beasts in
1997 near Doiia Dora's
puesto,
but this time, the bones were in
exactly the same rock layers as the eggs of egg layer 4. Andrea Arcucci,
an Argentine paleontologist from the Universidad de San Luis in cen-
tral Argentina, found one. Andrea is a specialist on South American
Triassic reptiles and a seasoned field person. Chatty and humorous,
Andrea was highly missed when she left a week before the end of the
expedition. Years of strolling across the reddish badlands of Triassic
rocks in Argentina had given Andrea a keen eye for discovering fossils.
This time, her eyes had spotted a few bone fragments weathering
down the slope of a small hill. David Loope sighted the other skeleton
on one of his forays in search of geological clues that could shed more
light on the ancient climatic conditions.
