1. Character Acquisition Through
Geological Time
Graeme T. Lloyd

2. Tempo through time
Darwin Simpson Westoll
1859 1944 1949

3. Lungfish tempo
Westoll
“A balanced rate summing up total morphological
change…would be of the greatest value for the study of 1949
evolution” - Simpson 1953

4. Questions
• Was Westoll right about lungfish
evolution?
• Do other ‘living fossils’ show the same
pattern?
• Do other taxa show a different pattern?
• Are these results methodological artefacts
or peculiarities of the fossil record?

5. Problems with Westoll’s method
• Only well known taxa can be included
(Knoll et al. 1984)
• Error bars required (constrain
interpretation)
• Ancestor artificial (Schopf 1984)
• Reversals ignored (Derstler 1982)
• Assumes stratigraphically ordered
ancestor-descendant sequence

6. Lungfish again
(Lloyd in prep.)

7. Actinistians
Latimera chalumnae
(Cloutier 1991)

8. Sphenodontids
(Lloyd in prep.)
Paleoloricates
(Cherns 2004)
Sphenodon punctatus
Neopilina galatheae
Linguloids Xiphosurans
(Cusack et al. 1999) (Moore et al. in prep.)
Lingula Limulus polyphemus
anatina

9. Hipparionines
(Alroy 1995)

10. Temnopleurids Asteropygines
(Jeffrey and Emlet 2003) (Lieberman and Kloc 1997)
Artiodactyls Reptiles
(Gentry and Hooker 1988) (Rieppel and deBraga 1996)

11. Crocodilians
(Gatesy et al. 2004)
Alligator mississippiensis
Gavialis lewisi Crocodylus niloticus

12. Echinoids
(Littlewood and Smith 1995)
Tripneustes
Spatangus Heliocidaris

13. Common pattern
=
Common explanation

14. Character distribution
r2 = 0.98853131

15. Character distribution
Source Taxon R-squared Pearson
Alroy 1995 Hipparionines 0.99 0.99
Cherns 2004 Paleoloricates 0.98 0.99
Cloutier 1991 Actinstians 0.99 0.99
Cusack et al. 1999 Linguloids 0.97 0.99
Gatesy et al. 2004 Crocodilians 0.87 0.93
Gentry and Hooker 1988 Artiodactyls 0.75 0.75
Jeffrey and Emlet 2003 Temnopleurids 0.78 0.89
Lieberman and Kloc 1997 Asteropygines 0.96 0.98
Littlewood and Smith 1995 Echinoids 0.81 0.90
Lloyd in prep. Lungfish 0.99 0.99
Lloyd in prep. Sphenodontids 0.96 0.98
Moore et al. in prep. Xiphosurans 0.94 0.97
Rieppel and deBraga 1996 Reptiles 0.95 0.97

16. Taxon sampling vs. stratigraphic fit
(Division of total timespan of
clade into five equal bins)
older younger

17. Questions
• Was Westoll right about lungfish
evolution?
• Do other ‘living fossils’ show the same
pattern?
• Do other taxa show a different pattern?
• Are these results methodological artefacts
or peculiarities of the fossil record?

18. Acknowledgements
This project was initially conceived by my supervisors, Mike Benton and
Phil Donoghue. Rachel Moore, Matt Friedman and Hans-Peter Schultze
kindly provided me with copies of their unpublished matrices. Members of
Bristol’s Palaeontology Discussion Group provided useful comments and
advice on an earlier version of this presentation. This work represents part
of my Ph.D. which is supported by NERC studentship
NER/S/A/2004/12222.

19. FREE Postgraduate Conference
Dept. of Earth Sciences, University of Bristol
13th-14th April 2007
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Photo © S. Jasinoski