PSAT Reading Practice Test 20

Questions 1-10 refer to the following information.

Spinosaurus Passage

At long last, paleontologists have solved a century-
old mystery, piecing together information discovered
by scientists from different times and places.
The mystery began when, in 1911, German
05paleontologist Ernst Stromer discovered the first evi-
dence of dinosaurs having lived in Egypt. Stromer,
who expected to encounter fossils of early mammals,
instead found bones that dated back to the Creta-
ceous period, some 97 to 112 million years prior.
10His finding consisted of three large bones, which
he preserved and transported back to Germany for
examination. After careful consideration, he
announced that he had discovered a new genus of
sauropod, or a large, four-legged herbivore with
15a long neck. He called the genus Aegyptosaurus,
which is Greek for Egyptian lizard. One of these
Aegyptosaurs, he claimed, was the Spinosaurus.
Tragically, the fossils that supported his claim were
destroyed during a raid on Munich by the Royal Air
20Force during World War II. The scientific world was
left with Stromer's notes and sketches, but no hard
evidence that the Spinosaurus ever existed.
It was not until 2008, when a cardboard box of
bones was delivered to paleontologist Nizar Ibrahim
25by a nomad in Morocco's Sahara desert, that a clue to
solving the mystery was revealed. Intrigued, Ibrahim
took the bones to a university in Casablanca for
further study. One specific bone struck him as in-
teresting, as it contained a red line coursing through
30it. The following year, Ibrahim and his colleagues at
Italy's Milan Natural History Museum were look-
ing at bones that resembled the ones delivered the
year before. An important clue was hidden in the
cross-section they were examining, as it contained
35the same red line Ibrahim had seen in Morocco.
Against all odds, the Italians were studying bones
that belonged to the very same skeleton as the bones
Ibrahim received in the desert. Together, these bones
make up the partial skeleton of the very first Spino-
40saurus that humans have been able to discover since
Stromer's fossils were destroyed.
Ibrahim and his colleagues published a study
describing the features of the dinosaur, which point
to the Spinosaurus being the first known swimming
45dinosaur. At 36 feet long, this particular Spinosaurus
had long front legs and short back legs, each with a
paddle-shaped foot and claws that suggest a carnivo-
rous diet. These features made the dinosaur a deft
swimmer and excellent hunter, able to prey on large
50river fish.
Scientists also discovered several aquatic adapta-
tions that made the Spinosaurus unique compared
to dinosaurs that lived on land but ate fish. Similar
to a crocodile, the Spinosaurus had a long snout,
55with nostrils positioned so that the dinosaur could
breathe while part of its head was submerged in wa-
ter. Unlike predatory land dinosaurs, the Spinosaur-
us had powerful front legs. The weight of these legs
would have made walking upright like a Tyranno-
60saurus Rex impossible, but in water, their strong legs
gave the Spinosaurus the power it needed to swim
quickly and hunt fiercely. Most notable, though, was
the discovery of the Spinosaurus's massive sail. Made
up of dorsal spines, the sail was mostly meant for
65display and did not serve a purpose of its own.
Ibrahim and his fellow researchers used both
modern digital modeling programs and Stromer's
basic sketches to create and mount a life-size replica
of the Spinosaurus skeleton. The sketches gave them
70a starting point, and by arranging and rearranging
the excavated fossils they had in their possession,
they were able to use technology to piece together
hypothetical bone structures until the mystery of
this semiaquatic dinosaur finally emerged from the
75murky depths of the past.