Microfossil Diatom Art
Bamyaniceras orientale Sone, Leman & Ehiro, 2001
Permian ammonoid species from Bera South, Pahang
A species name is in binomial form,
that is, Genus + species (e.g. Homo sapiens).
And it must be in Italic (otherwise be underlined).
Palaeontology,
but first Taxonomy (hierarchy = ranking)
Highest
Kingdom
(Animalia, Plantae, Fungi, Protista, Prokaryota in UK school)
Phylum
Class
Order
Family
Genus Binomial - Homo sapiens
species
Common system in Biology (and Palaeontology), that is,
regardless of extant or fossil species.
This is the way to memorize and never to
forget the taxonomic ranks.
Highest
Ken (or Karen)
Please
Come
Over
For
Great
Sxx
I’m serious. This is the way I learnt in my BSc Biology
class, and then we will never forget this.
FOSSIL CLASSIFICATION
(TAXONOMY)
•
•
•
•
•
•
•
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Primates
FAMILY: Hominidae
GENUS: Homo
SPECIES: Homo sapiens
SIG2006: Basic Paleontology
Superphylum / Phylum ARTHROPODA
Phanerozoic Time Scale
Since 545 Ma
Conventionally, the time
divisions/boundaries are
based on fossil records (ie.
biostratigraphy).
A DATE of each boundary
is determined based on
radiometric dating.
7
Ediacaran fauna
650 – 545 Ma
Cambrian
Explosion
8
Cambrian Monsters & Cambrian Explosion
Sea without fish!
But with sponges
Typical Cambrian
marine biota
9
9
Anomalocaris
Rajah Brooke's birdwing - Trogonoptera brookiana
Wing venation - Not random, but perfectly regular.
Malaysian tarantula in Bukit Kiara – Note this is not an insect.
ARTHROPODS – 90% of all terrestrial animal diversities today
MORE ARTHROPODS
Ordo/Sil. - Present
Ordo - Permian
In a market
Mating
Underside
Ostracods
Occur in most aquatic environments
Chitinous or calcium carbonate skeletons
• Cambrian – recent
• microscopic Crustacea with two valves
composed of calcite
• valves are bean-shaped
• valves do not show growth lines
(crustacea moult during growth - ecdysis)
• valves are of sand grain size
• Important palaeoclimate indicators
Arthropod monster - Arthropleura
Taman Negara in 2005
The picture can't be displayed.
I was definitely big.
Arthropleura – the Carboniferous Giant
2.6 metre-long relative of centipedes or millipedes, native to the
Late Carboniferous (340-280 Ma) of what is now
northeastern North America and Scotland. It is the largest known
land invertebrate of all time, and would have had few predators.
Their definitely
exact diet is big.
not known, but they may have likely been
I was
predators.
Reconstruction and estimated body size,
based on trace fossils.
The genus Meganeura – King in Carboniferous air
70 cm wide
Jaekelopterus rhenaniae
I was big too.
Pterygotus Group
(Sea scorpion)
For this scorpion species
measured an incredible 2.5
m (8 ft) from tip to tail and
weighed 180 kg. Its claw
alone was a formidable
46cm.
Fortunately for man, it
lived long before even the
first dinosaur walked the
Earth at between 460 Ma
and 255 Ma years ago
(Silurian-Permian).
From Germany.
WHY TRILOBITES? Tri-lobes (longitudinally) & 3 x 3
Glabella
Cephalon (head)
Trilobites – general evolutionary trends
Cephalon
glab
ella
Glabella
Cephalon (whole head)
Thorax (body) – trend towards reduction in the
number of thoracic segments. Segments widened and
straightened
Pygidium (tail) – increase in size. sometimes as
large as the cephalon
# Glabella – early form completely segmented, later,
furrows reduced and bulged towards the anterior end
of the glabella
Trend in time
Furrows in glabella
Facial sutures
TRILOBITE PYGIDIA (tails)
[a pygidium (sing.)]
fused segmentation
Pygidium’s proportion to
a cephalon
• Micropygous (pygidium
smaller)
• Isopygous (about equal)
• Macropygous (pygidium
larger)
DIVERSITY OF TRILOBITES
Boedaspis ensifer WHITTINGTON & BOHLIN 1960
Age: Lower Ordovician
Locality: St.Petersburg region, Russia
Stalked eye –
infaunal trilobite
Sphaerocoryphe cranium (Kutorga 1854)
Age: Middle Ordovician
Size: 1,7" (4,3 cm)
Locality: Wolhow river, St.Petersburg region, Russia
Many more weirdoes
First trilobites - Cambrian
 Early Cambrian forms with
many thoracic segments and
small pygidium – typically
micropygous
 May have no fused segments
– i.e. still segmented
 Eyes attached to glabella
 No Precambrian trilobite yet
known.
Post-Cambrian trilobites
 Greater morphological
diversity
 Reduction in thoracic
segments, but
 Increase in pygidial segments
 Asaphid typical of Ordovician
 In some, pygidium larger than
cephalon – Macropygous
 Broad frontal lobe
 Large holochroal eyes
 Exoskeleton with terraced
ridges for sensing pressure
changes
Post-Cambrian trilobites
 Harpetids had snowshoe-shaped,
pitted fringe.
 Uncertain whether used for sensory
purposes or respiration ??
 Last harpetids in Late Devonian,
Canning Basin, WA
Functions?
 Sensory pits
 Filter chamber for food
gathering
 Anti-predation by
increasing head size
 “Alleviating hydrostatic
device”
I’m a fly.
Please look at my eyes.
Holochroal eyes
holochroal
 Compound eyes where lens in contact
with each other and very small
 May be many hundreds, even
thousands in a single eye.
• Most trilobites had holochroal eyes.
In both eye types, a lens made from a single crystal of calcite
schizochroal
Schizochroal eyes
 Phacopid trilobites had these eyes
 Large lenses separated from each
other.
 Fewer lenses than in holochroal eyes
Eye variation
• Strong evolutionary selection for sight
• In this asaphid, eyes on stalks as trilobite
may have burrowed in sediment (infaunal)
- Just like “a periscope of a submarine”.
• This is found in the Ordovician of Estonia.
Blind trilobites
• Blindness evolved in many different
lineages. That is, this was physioenvironmental rather than genetical.
• Probably because they lived in deep water
or lived to be infaunal – dark worlds.
• This trilobite Thoracocare (left) was small
and had only two thoracic segments.
I am short.
Agnostids, tiny forms. Typical
isopygous blind trilobites in the
Cambro-Ordovician. This group
is often found in deep-water
sediments.
Burrowing trilobites
• Some trilobites effaced
(was hiding infaunal)
• This means they are
smooth and lost details
of trilobation (No lateral
trilobed partition)
• Suggested that these
forms lived in burrows
in sediment.
• They may be blind, too.
Swimming trilobites
• Forms with broad
thoracic axis and
narrow pleurae
swimmers.
• Wide geographical
distribution – because
of the mobility.
Often with large eyes
looking in all directions
Trilobite enrollment
 Thracic segments are not fused,
so the thorax is flexible and this
enables the animals to roll up.
 Many trilobites rolled up into a
ball.
 For protection or during times
of environmental stress.
 Evolved structures under front
of cephalon and tip of pygidium
 The pygidium may tuck up and
lock into the cephalon with a
teeth & socket structure.
ECDYSIS in Trilobites
(as many other arthropods do,
e.g. crabs, prawns)
How many actual bodies are here?
GROWTH STAGES IN TRILOBITES (Ontogeny)
Five of several growth stages of the single trilobite species.
Q: Is it easy to identify these indivicuals to be the same
species if they are from different horizons/localities?
ADDING NEW SEGMENTS – Trilobite ontogeny
Trilobite growing tricks
TRILOBITE history in the Palaeozoic
1. Already very common in the
Cambrian.
2. Up to the Devonian, trilobites can
locally be good biostratigraphic
tools (ie, age-indicative).
3. Only a few groups
survived/occurred after
Devonian.
4. Became extinct at the end of the
Permian.
The picture can't be displayed.
ARTHROPODS THRU TIME
(numbers of genera in each superclass
(or subphylum otherwise)
Remarkable expansion in the
Hexapoda (Insecta)
e.g. Bees & butterflies –
coincides with evolution of
flowering plants
(angiosperms) since the
Cretaceous
insects
Trilobites gone
The linked image cannot be displayed. The file may have been moved, renamed, or deleted. Verify that the link points to the correct file and location.
The Iapetus ocean (betw. 600–400 Ma) &
palaeobiogeography
- Different types of faunas on both sides of the
suture (closed ocean).
Trilobites could not swim across such a major
ocean!
(graptolites neither)
Position of the continents after the Caledonian
orogeny (Devonian to Permian times).
Differences in fossil faunas on both sides of
the red line (the Iapetus Suture) are evidence
for the existence of an ocean between the two
sides in the time before the continents were
joined in the supercontinent Pangea. (Wiki)
An Early Ordovician
marrellomorph
arthropod, probably
belonging to the
genus Furca from
Fezouata, Morrocco
A survivor of
Burgess-shale-type
animals…
Thank you.