Class Sarcopterygii - the lobe finned fishes
Helfman et al. 1997
Class Sarcopterygii
• Four major groups
• Coelacanthimorpha-coelacanths (two
species)
• Dipnoi-lungfishes (six species)
• Osteolepimorpha (extinct)
• Tetrapoda (all non-fish vertebrates)
O
st
eo
le
pi
m
or
ph
a
Te
tr
ap
od
a
C
oe
la
ca
nt
hi
m
D
or
ip
ph
no
a
i
Class Sarcopterygii
Lobed fins
1
Class Sarcopterygii
• Lobe fins
• Bony leg-like supports, external to
body
Pectoral fin
Pelvic fin
O
st
eo
le
pi
m
or
ph
a
Te
tr
ap
od
a
C
oe
la
ca
nt
hi
m
D
or
ip
ph
no
a
i
Class Sarcopterygii
Lungs
Lobed fins
Order Coelacanthiformes
• Fossil record extends from M. Devonian
(370 Ma) to Cretaceous (65Ma)
2
Order Coelacanthiformes
Marjorie Courtenay-Latimer
Order Coelacanthiformes
• Smith describes the coelacanth,
Latimeria chalumnae, discovered in 1939,
a true living fossil
3
Bony plates
0n
eth
Te a t e s
pl
ha
rd
Diphycercal
tail
4
Order Coelacanthiformes
• “New” populaiton discovered at
Sulawesi, Indonesia 1997
5
Order Coelacanthiformes
• “New” populaiton discovered at
Sulawesi, Indonesia 1997
• DNA analyses indicate divergence from
L. chalumnae at 5.0-11.0 Ma
• Described as a new species L.
menadoensis
Order Coelacanthiformes
Order Coelacanthiformes
• Thin bony layer encases vertebral and
fin spines
6
Order Coelacanthiformes
• Thin bony layer encases vertebral and
fin spines
• Unossified notochord, vertebrae are not
fully developed
Order Coelacanthiformes
• Fleshy, lobed pectoral, pelvic, anal and
second dorsal fin
Order Coelacanthiformes
• Symmetric three-lobed tail
• Distal end has an epicaudal lobe
7
Order Coelacanthiformes
• Oil filled gas (swim)-bladder
Order Coelacanthiformes
• Oil filled gas (swim)-bladder
• Craniovetebral joint
• Increase gape
Order Coelacanthiformes
• Oil filled gas (swim)-bladder
• Craniovetebral joint
• Increase gape
8
Coelacanth Biology
• Lives along rocky shelves in deep (150 to 300 m)
waters
• Lurking predator, feeds on molluscs, fishes, and
cephalopods
• Stands on head while swimming, uses paired fins as
paddles
• Internal fertilization, ovoviviparous
O
st
eo
le
pi
m
or
ph
a
Te
tr
ap
od
a
C
oe
la
ca
nt
hi
m
D
or
ip
ph
no
a
i
Class Sarcopterygii
9
Dipnoi - the lungfishes
• Platelike teeth, crushing and grinding
Dipnoi
• Platelike teeth, crushing and grinding
• Oldest Fossils from the Lower Devonian
Dipnoi
• Platelike teeth, crushing and grinding
• Oldest Fossils from the Lower Devonian
• Fossils on all seven continents- even
Antarctica!
10
Dipnoi
• Platelike teeth, crushing and grinding
• Oldest Fossils from the Lower Devonian
• Fossils on all seven continents-yes,
even Antarctica!
• Extant species found only in S. America,
Africa, and Australia
Dipnoi
• Two extant orders, three families, six
species
• Order Ceratodontiformes - Australia
• Family Ceratodontidae
• Neoceratodus forsteri
Dipnoi
• Two extant orders, three families, six
species
• Order Lepidosireniformes
• Family Lepidosireneidae - S.
America
• Lepidosiren paradoxa
11
Dipnoi
• Two extant orders, three families, six
species
• Order Lepidosireniformes
• Family Protoperidae - Africa
• Protopterus (four species)
Dipnoi
Order Ceratodontiformes
• Pectoral and pelvic fins flipper-like
12
Order Ceratodontiformes
• Pectoral and pelvic fins flipper-like
• Scales large
Order Ceratodontiformes
• Pectoral and pelvic fins flipper-like
• Scales large
• Air-bladder unpaired
Order Ceratodontiformes
• Pectoral and pelvic fins flipper-like
• Scales large
• Air-bladder unpaired
• Larvae without external gills
13
Order Ceratodontiformes
• Pectoral and pelvic fins flipper-like
• Scales large
• Air-bladder unpaired
• Larvae without external gills
• Adults do not estivate
Order Ceratodontiformes
• Neoceatodus forsteri
• Southeast Queensland, Australia
• Facultative air-breather, rely on gills
Order Ceratodontiformes
• Neoceatodus forsteri
• can reach a very large size
14
Order Lepidosireniformes
• Pectoral and pelvic fins filamentous,
without rays
Order Lepidosireniformes
• Pectoral and pelvic fins filamentous,
without rays
• Scales small
Order Lepidosireniformes
• Pectoral and pelvic fins filamentous,
without rays
• Scales small
• Air-bladder paired
15
Order Lepidosireniformes
• Pectoral and pelvic fins filamentous,
without rays
• Scales small
• Air-bladder paired
• Larvae with external gills
Order Lepidosireniformes
• Pectoral and pelvic fins filamentous,
without rays
• Scales small
• Air-bladder paired
• Larvae with external gills
• Adults estivate in dry season
Order Lepidosireniformes
16
Order Lepidosireniformes
Order Lepidosireniformes
• Estivation, 7 to 8 months, in lab four
years!
• Air-breathe
• Lower heart rate
• Retain urea and other metabolites
• Metabolize body proteins, lose weight
Order Lepidosireniformes
Reproduction
• Protopteridae (central and southern
Africa)
• Males construct burrow-shaped nest
• Eggs guarded by male, eggs fanned with
tail
17
Order Lepidosireniformes
Reproduction
• Lepidosireneidae (Amazon and Parana
Rivers of S. America
• Males construct burrow-shaped nest
• Eggs guarded by male
• Males develop vascularized filaments in
pelvic fin-oxygenate water in burrow
Order Lepidosireniformes
Biology
• Family Lepidosireneidae
• Adults with reduced gills, obligate airbreathers
•Feed on fish
• Biology is not well known
Order Lepidosireniformes
• Family Lepidosireneidae
• Lepidosiren paradoxa
18
Order Lepidosireniformes
Biology
•Family Protopteridae
• Four species
• Adults diurnal (active during the day)
• Feed mainly on mollusks
• Adults, obligate air-breathers
Order Lepidosireniformes
• Family Protopteridae
• Protopterus
Dipnoi Phylogeny and Biogeography
• Distribution thought to reflect Gondwana
connections of southern continents
19