CT Scanning of museum specimens: a case study of

CT Scanning of museum specimens: a case study of

CT Scanning of museum specimens:
a case study of
diversity from the inside out
Amy McCune
Ecology and Evolutionary Biology
Cornell University
and
Cornell University Museum of Vertebrates
Evolutionary morphology and
phylogenetics have long focused on:
Computed Tomography (CT) is being used
increasingly for evolutionary morphology!
CU81425
A charciform fish,
Hoplias, collected
~1940s
but the extent and size of datasets present challenges
to museum curators unlike any dissection ever did!
Today talk about a case study of
anatomy using CT
Are gas bladders modified lungs?
What is a gas bladder?
buoyancy, hearing
sb
Zebrafish (Danio)
b
Chitala chitala
Functions: buoyancy, respiration, hearing, sound production
Orthodoxy: gas bladder is a modified
lung
(but some controversy)
relatively little
modification
1. duct and lungs rotate dorsally
2. paired lung reduced to single
of Osteichthyes
(from Romer 1974 The Vertebrate Body
after B.Dean 1895. Living and Fossil Fishes)
One source of controversy is the phylogentic
distribution of the pulmonary artery supply
PA PA PA PA PA PA ?
PA
Is the bowfin
pulmonary artery
(PA) convergent
or homologous?
3-D study of the arterial supply in rayfinned fishes & lungfish
Injected barium into dorsal aorta of euthanized fish
Imaged with micro-CT (spatial res 50-100 microns)
Analyzed with Microview and Osirix.
Sarah Longo
Mark
Riccio
Using micro-CT to show what some AOs actually look like…
AO =air-filled organ, a collective
term for lungs & gas bladders
Sturgeon (A. transmontanous)
pd
Gar (L. platyrhynchus)
lungs of bichir
dorsal view
(Polypterus ornatipinnis)
lungs
gut
lateral view
ventral view
African lungfish (Protopterus dolloi )
lung
• Duct connects ventrally
gut
• Lung largely dorsal
• Very long (98% coelom)
• Vesicular internally
Micro-CTs of injected fish
lungfish
sturgeon
gar
Polypterus
Pulmonary arteries branch off the
4th efferent branchial artery
anterior
anterior
anterior
PA
dorsal view
amphibian
lateral view
lateral view
African lungfish
bowfin
s
d
c
lp
rp
vlp
c
III
IV co
d
Comparative study of arterial vasculature
i
c’
d
African lungfish
Protopterus
I
II
III
Polypterus
Lepisosteus
IV
lp
d
rp
Polyodon
Amia
Polypterus
I
II
III
I
IV
II
A
II
II
II
III
I IV
II
III
III lp
IVIVco
vlp
d
lp
Polyodon
Amia
Polypterus
III lp
IV
vlp
c
s
rp
sc
d
d
da’
d
da’
d
Lepisosteus
Acipenser
Acipenser
I I
Polyodon
Polyodon
Amia
Amia
bowfin
Polypterus
Lepisosteus
olyodon
Polyodon
mia
Amia
da’
bichir
Protopterus
Lepisosteus
Acipenser
Acipenser
II II
III III
IV IVcoco
dd
IV’
IV’
IVIV
cc
II
I IIII
II IIIIII
III IVIV
IV
ss
dd
d
da’
da’
paddlefish
da’
Protopterus
Protopterussturgeon
Protopterus
Protopterus
IV’
IV
c
II
IIII
e e
s
c c
A
s
IV’rp
IVs
rp
c c
c
Amia
Lepisosteus
P
Amia
Lepisosteus
P
II
IIII
III
IIIIV
IV
lp
dd
i i
c’ c’
s
rp
c s
da’
gar
From Longo, Riccio, and McCune 2013
Sturgeon and paddlefish have small
arteries which branch off the 4th branchial
efferent arteries
Are these vestigial pulmonary arteries?
Longo, Riccio & McCune 2013
Bowfin PAs are homologous not convergent
PAs are synapomorphy of Osteichthyes
sturgeon
paddlefish
pa
Polypterus
tetrapods
lungfish
coelacanth
shark
Bony vertebrates
bowfin
Ray-finned Fleshy-finned
teleosts
gar
Ancestral states with R, using Max. Parsimony Reconstruction in APE package (Paradis 2004).
One project generated:
~12 jars
and
100.43 GB of CT data
(49,966 items)
of associated data
Acknowledgements
Collaborators:
Sara Longo (undergraduate thesis, Mark Riccio)
For help obtaining specimens:
Jan Hoover and Steven George, U.S. Army Engineer Research and Development
Center, Waterways Experiment Station
• Carl Rathjee, NY State D.E.C. Constantia Fish Hatchery
• Glenn Northcutt, Scripps Institute of Oceanography
• Charles Dardia, John Friel, Cornell Museum of Vertebrates.
Amia: dorsal AO is long (~70% coelom),
bilobed, and vesicular internally.
Endoscopy !
Swim bladder morphology is also diverse:
Chitala chitala
Soft tissue has been used some,
but not extensively
Adult Bowfin gas bladder