New_Scientist_3_08_2019

3 August 2019 | New Scientist | 47

group called noasaurs, and stands out by

having feet that balanced the dinosaur’s weight

on a single toe of each foot, which seem to

match strange tracks found nearby. But similar

tracks are also seen in older Jurassic rocks –

indicating that another one-toed dinosaur is

still awaiting discovery in those older strata.

So where can we look to find all these

missing species? There is still a great deal

of dinosaur-bearing rock that has yet to be

searched even once, much less dug into for

detail. “Some of the future hotspots for

dinosaur palaeontology are in south-eastern

and central Asia, much of Africa, and some

northern countries of South America,” says

Zanno. Remote, difficult-to-work sites could

yield important finds, too. “The Arctic and

Antarctic have huge potential for new dinosaur

discoveries,” says Evans. The Cretaceous strata

of Africa is also little-explored compared with

that in other parts of the world, he says, and

could yield important finds. That is still a lot

of ground to cover.

Some time periods are hazy in the

palaeontological imagination. “Targeting

poorly known time periods, like the Middle

Jurassic, is critical,” says Forster. This was the

time period during which dinosaurs truly

became globally dominant and increased the

range of sizes they were capable of reaching.

The novelty of these finds will undoubtedly

continue to make headlines. But there is

more to this than raw numbers. “Dinosaurs,

or any fossils, are part of our collective past,”

says Forster. Finding new species is the first

step in visualising and understanding

evolution and extinction. As Forster says,

“dinosaurs and ourselves are all part of the

same ever-changing system”. ❚

Riley Black, who previously wrote

under the name of Brian Switek,

is author of Skeleton Keys, and

My Beloved Brontosaurus

145 125 105 85 65

CRETACEOUS PERIOD PALAEOCENE PERIOD

150 mya

115 mya

Deinonychus

Fruitadens

Hesperornithoides

70 mya

Acheroraptor

66 mya

Huge asteroid collides

with Earth, wiping out

non-avian dinosaurs

1.8 metres

140 mya 68 mya

Tyrannosaurus rex

Triceratops

90 mya

Vespersaurus

96 mya

Moros intrepidus

Bajadasaurus

Evans at the University of Toronto, Canada.

But they are out there. “Over the past two

decades, many of the new dinosaur species

being recognised from classic localities like

Dinosaur Provincial Park in Alberta and in

the Hell Creek Formation of the western US

are on the small end of the dinosaur size range,

below the size of an average person,” he says.

“We are just scratching the surface in

terms of dinosaur diversity,” says Evans. “The

potential to fill in our knowledge of dinosaur

diversity on the small end of their size range

is huge.” This includes unusual forms of

dinosaurs as well as species similar to those

we have already found. In June this year, for

instance, Max Langer at the University of São

Paulo in Brazil, and his colleagues, described

an unusual dinosaur they named Vespersaurus

paranaensis in the Cretaceous rock of southern

Brazil. The dinosaur belonged to an enigmatic

Over the past 40 years,

palaeontologists have

spent a great deal of time

investigating the last of the

dinosaurs. It is only more

recently that they have

begun to get acquainted

with some of the first.

From discoveries in

the 1990s, such as the

metre-long Eoraptor

lunensis found in

Argentina, it seemed like

the earliest dinosaurs

emerged about 228 million

years ago in the middle

of the Triassic period. But

fieldwork in eastern Africa

has taken the dinosaur

record back even further,

dramatically altering our

image of what the first

dinosaurs were like.

In 2013, researchers

described Nyasasaurus

parringtoni from a

245-million-year-old

partial skeleton unearthed

in Tanzania. The skeleton

is too fragmented to tell

if it is definitively one of

the first dinosaurs, but

along with more complete

remains of related animals

called silesaurs, it gives

us clues about what the

first ones were like.

Instead of being

rapacious carnivores that

tore their way onto the

evolutionary scene, the

earliest dinosaurs seem

to have been lanky, German

shepherd-sized animals

that probably ate plants

as well as insects. They

were comparatively meek

creatures that lived in

a world dominated by

relatives of crocodiles.

Along with many other

forms of reptiles, dinosaurs

sprung up in the wake

of Earth’s worst mass

extinction 252 million

years ago. But they didn’t

dominate from the start.

Most were small and on

the ecological sidelines

until another mass

extinction 200 million

years ago removed most of

their reptilian competitors.

THE FIRST DINOSAUR

When alive, this

dinosaur glided

on bat-like wings

SUN ZIFA/SIPA USA/PA IMAGES