Classification of Recent Mammals to ordinal level

1

• Classification of Recent Mammals to ordinal level
• Class MAMMALIA
• Subclass - PROTOTHERIA
• Order - Monotremata - echidnas and
  platypus 5 species
• Subclass - THERIA
• Infraclass Metatheria (Marsupials)
• Order Didelphimorphia - opossums 87 species
• Order Paucituberculata - rat oppossums 6 species
  
• Order Microbiotheria - Monito del Monte, Ilaca 1
  species
• Order Dasyuromorphia - extinct Tasmanian wolf,
  numbat, dasyures etc. 71 spp.
• Order Peramelemorphia - bandicoots 21 species
• Order Notoryctemorphia - marsupial "mole" 2
  species
• Order Diprotodontia - koala, wombats, kangaroos
  possums 143 species
• Infraclass Eutheria (Placentalia)
• Order Pholidota - pangolins 7 species
• Order Afrosoricida tenrecs golden moles 51
  species
• Order Macroscelidea - elephant shrews 15 species
  
• Order Tubulidentata - Aardvark 1 species

2
Some common misconceptions Mammals are
modern Mammals are most advanced Mammals
are dominant
3
Geological timescale

First hominids Diversification of modern
mammals Extinction of dinosaurs Earliest
mammals earliest dinosaurs Earliest
therapsids Earliest pelycosaurs Earliest
amniotes Earliest amhpibians Jawed
fish Earliest vertebrates
4
Cladistics (Phylogenetic Systematics) An
objective method of determining evolutionary
relationships of organisms (phylogeny), based on
comparative analysis of characters
(morphological, genetic, behavioral, etc).
Basic terminology Phenetics study of
evolutionary relationships based on overall
similarity Cladistics study of evolutionary
relationships based on derived similarity Charact
er (or trait) any discrete feature or attribute
that exhibits variation Character state
expression of a particular character (e.g.,
presence, absence) In group group of organisms
being studied Out group related group outside
that being studied (used as a point of reference
to determine character polarity) Character
polarity direction of evolutionary change in a
character Primitive character (plesiomorphy)
character state is primitive or generalized
(shared by both the ingroup and
outgroup) Derived character (apomorphy)
character state is advanced or specialized
(differs from the outgroup) Synapomorphy
(shared derived trait) derived trait shared by
2 or more groups Cladogram -- a graphical
representation of evolutionary relationships Mono
phyletic group (clade, or natural group) a
group of sharing a common ancestor. Represents
a complete evolutionary lineage. Polyphyletic
-- group with more than one ancestor an
artificial group. Paraphyletic -- group that
does not contain all descendants of a common
ancestor an incomplete group Node branching
point on a cladogram Sister groups groups on
either side of a node (i.e., closest relatives)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
AMNIOTE RELATIONSHIPS
.
Synapsida
9
AMNIOTE RELATIONSHIPS
10
Pelycosaur cladogram
11
Ancestral amniote skull types
12
Amniote skulls
13
(No Transcript)
14
Synapsid evolution
15
Synapsid evolution
Mammals
16
Pelycosaurs primitive
mammal-like reptiles
17
CLASS PELYCOSAURIA Ophiacodonts mid
Pennsylvanian early Permian
Varanopseids Permian Caseids Permian
Edaphosaurs late Pennsylvanian early Permian
Sphenacodonts late Pennsylvanian mid
Permian
18
(No Transcript)
19
Varanops
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Dimetrodon
24
(No Transcript)
25
Pelycosauria - Sphenacodontidae
Haptodus -- probable therapsid ancestor
26
Therapsids advanced
mammal-like reptiles
27
Pelycosaur Therapsid transition
Phthinosuchia
Haptodus
28
CLASS THERAPSIDA Tetraceratops early Permian,
N. Amer. Phthinosuchus late Permian,
Asia Dincephalia late Permian, Asia, S
Africa Anomodontia Dicynodonts late Permian
- mid Triassic world-wide to early
Cretaceous? -- Australia Theriodontia
Gorgonopsians late Permian, S. Africa, Asia
Tritylodonts late Triassic mid Jurassic
Eurasia, S Africa, N S America
Therocephalians late Permian early Triassic
Asia, Africa, Antarctica Cynodonts
late Permian early Jurassic Africa,
Antarctica, Asia, Europe, N S America

29
Therapsid cladogram
30
Therapsid evolution
CYNOGNATHUS
SPHENACODONT PELYCOSAUR ANCESTOR
31
THERAPSIDA Tetraceratops -- earliest
Therapsid
32
THERAPSIDA Phthinosuchus
33
THERAPSIDA Dinocephalia
Titanophoneus
34
THERAPSIDA Dinocephalia
Estemmenosuchus
35
THERAPSIDA Dicynodontia
Emydops
Diictodon
Kannemeyeria
36
THERAPSIDA Dicynodontia Early Cretaceous --
Australia ?
37
THERAPSIDA Tritylodontia
Tritylodon
Kayentatherium
38
THERAPSIDA Gorgonopsia
Lycaenops
39
THERAPSIDA Therocephalia
Pristerognathus
40
THERAPSIDA Cynodontia
Thrinaxodon
41
THERAPSIDA Cynodontia
Cynognathus
42
(No Transcript)