Systematic and Palaeobiological Implications of Postcranial Morphology in the Diprotodontidae (Marsupialia)
Systematic and palaeobiological implications of postcranial morphology in the Diprotodontidae (Marsupialia)
Aaron B. Camens
School of Earth and Environmental Sciences Discipline of Ecology and Evolutionary Biology The University of Adelaide South Australia
A thesis submitted in partial fulfilment of the degree of Doctor of Philosophy at the University of Adelaide
February 2010 II
Declaration
This work contains no material which has been accepted for the award of any other degree or diploma in any university or other tertiary institution to Aaron Camens and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text.
I give consent to this copy of my thesis when deposited in the University Library, being made available for loan and photocopying, subject to the provisions of the Copyright Act 1968.
The author acknowledges that copyright of published works contained within this thesis (as listed below) resides with the copyright holder(s) of those works.
I also give permission for the digital version of my thesis to be made available on the web, via the University’s digital research repository, the Library catalogue, the Australasian Digital Theses Program (ADTP) and also through web search engines, unless permission has been granted by the University to restrict access for a period of time.
Publications in this thesis include:
Camens, A. B. and Wells, R.T. 2009. Diprotodontid footprints from the Pliocene of Central
Australia. Journal of Vertebrate Paleontology 29: 863-869. Copyright held by Taylor and
Francis.
Camens, A. B. and Wells, R.T. 2010. Palaeobiology of Euowenia grata (Marsupialia:
Diprotodontinae) and its presence in Northern South Australia. Journal of Mammalian
Evolution 17: 3-19, DOI 10.1007/s10914-009-9121-2. Copyright held by Springer.
………………………… Aaron Camens
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Table of Contents
CHAPTER 1 Introduction 1 1.1 Introduction to the Diprotodontidae 1
1.2 Systematic relationships in the Diprotodontidae 2 1.2.1 Sub-family incertae sedis 3 1.2.1.1 Nototherium 3 1.2.1.2 Sthenomerus 5 1.2.2 Sub-family Diprotodontinae 5 1.2.2.1 Ngapakaldia 5 1.2.2.2 Pitikantia 6 1.2.2.3 Bematherium 6 1.2.2.4 Pyramios 7 1.2.2.5 Euowenia 7 1.2.2.6 Meniscolophus 8 1.2.2.7 Euryzygoma 8 1.2.2.8 Diarcodon 8 1.2.2.9 Diprotodon 9 1.2.3 Sub-family Zygomaturinae 11 1.2.3.1 Raemeotherium 11 1.2.3.2 Silvabestius 12 1.2.3.3 Alkwertatherium 12 1.2.3.4 Nimbadon 13 1.2.3.5 Neohelos 13 1.2.3.6 Plaisiodon 14 1.2.3.7 Kolopsis 14 1.2.3.8 Kolopsoides 15 1.2.3.9 Maokopia 15 1.2.3.10 Hulitherium 16 1.2.3.11 Zygomaturus 16 1.3 Diprotodontid palaeobiology 18 1.3.1 Sub-family Diprotodontinae 18 1.3.1.1 Ngapakaldia 18 1.3.1.2 Pitikantia 19 1.3.1.3 Pyramios 19 1.3.1.4 Meniscolophus 19 1.3.1.5 Euowenia 19 1.3.1.6 Euryzygoma 19 1.3.1.7 Diprotodon 20 1.3.2 Sub-family Zygomaturinae 23 1.3.2.1 Raemeotherium 23 1.3.2.2 Silvabestius 23 1.3.2.3 Alkwertatherium 23 1.3.2.4 Nimbadon 23 1.3.2.5 Neohelos 23 1.3.2.6 Plaisiodon 24 1.3.2.7 Kolopsis 24 IV
1.3.2.8 Kolopsoides 24 1.3.2.9 Maokopia 24 1.3.2.10 Hulitherium 25 1.3.2.11 Zygomaturus 25 1.4 Thesis aims 27 1.5 References 28 1.6 Appendix 1 35
CHAPTER 2 Camens, A.B., Wells, R.T. (2010). Palaeobiology of Euowenia 37 grata (Marsupialia: Diprotodontinae) and its presence in northern South Australia. Journal of Mammalian Evolution. DOI 10.1007/s10914-009-9121-2.
CHAPTER 3 Camens, A.B., Wells, R.T. (2009). Diprotodontid footprints from 55 the Pliocene of Central Australia. Journal of Vertebrate Paleontology 29, 863-869.
CHAPTER 4 Camens, A.B., Carey, S.P., Cupper, M.L., Grün, R., Hellstrom, J.C., 63 McKnight, S.W., McLennan, I., Trusler, P. and Aubert, M. (to be submitted) Megamarsupial palaeobiology revealed from fossil trackways of the Victorian Volcanic Plains, Australia. Quaternary Science Reviews.
CHAPTER 5 Diprotodontid functional morphology and palaeobiology inferred 116 from postcranial anatomy. 5.1 Introduction 116 5.2 Methods 119 5.2.1 Included taxa 119 5.2.2 Abbreviations 119 5.2.2.1 Institutions 119 5.2.2.2 Hind limb abbreviations 120 5.2.2.3 Fore limb abbreviations 121 5.2.3 Measurements 121 5.3 Results 5.3 Morphological descriptions 122 5.3.1 Subfamily Diprotodontinae 122 5.3.1.1 Ngapakaldia 122 5.3.1.1.1 Morphology of the hindlimb 122 5.3.1.1.2 Morphology of the forelimb 129 5.3.1.2 Euowenia 136 5.3.1.1.2.1 Morphology of the hindlimb 136 5.3.1.1.2.2 Morphology of the forelimb 142 5.3.1.3 Diprotodon 147 5.3.1.3.1 Morphology of the hindlimb 147 5.3.1.3.2 Morphology of the forelimb 155 5.3.2 Subfamily Zygomaturinae 162 5.3.2.1 Nimbadon 162 5.3.2.1.1 Morphology of the hindlimb 162 5.3.2.1.2 Morphology of the forelimb 168 5.3.2.2 Neohelos 176 5.3.2.2.1 Morphology of the hindlimb 176 5.3.2.2.2 Morphology of the forelimb 181 5.3.2.3 Plaisiodon 185 V
5.3.2.3.1 Morphology of the hindlimb 185 5.3.2.3.2 Morphology of the forelimb 191 5.3.2.4 Kolopsis 195 5.3.2.4.1 Morphology of the hindlimb 195 5.3.2.4.2 Morphology of the forelimb 200 5.3.2.5 Zygomaturus 204 5.3.2.5.1 Morphology of the hindlimb 204 5.3.2.5.2 Morphology of the forelimb 212 5.4 Discussion 219 5.4 Functional morphological and palaeobiological interpretations 219 5.4.1 Sub-family Diprotodontinae 221 5.4.1.1 Ngapakaldia 221 5.4.1.1.1 Hindlimb morphological implications 221 5.4.1.1.2 Forelimb morphological implications 223 5.4.1.2 Euowenia 226 5.4.1.2.1 Hindlimb morphological implications 226 5.4.1.2.2 Forelimb morphological implications 227 5.4.1.3 Diprotodon 229 5.4.1.3.1 Hindlimb morphological implications 229 5.4.1.3.2 Forelimb morphological implications 233 5.4.2 Sub-family Zygomaturinae 237 5.4.2.1 Nimbadon 237 5.4.2.1.1 Hindlimb morphological implications 237 5.4.2.1.2 Forelimb morphological implications 239 5.4.2.2 Neohelos 242 5.4.2.2.1 Hindlimb morphological implications 242 5.4.2.2.2 Forelimb morphological implications 244 5.4.2.3 Plaisiodon 246 5.4.2.3.1 Hindlimb morphological implications 246 5.4.2.3.2 Forelimb morphological implications 247 5.4.2.4 Kolopsis 248 5.4.2.4.1 Hindlimb morphological implications 248 5.4.2.4.2 Forelimb morphological implications 250 5.4.2.5 Zygomaturus 252 5.4.2.5.1 Hindlimb morphological implications 252 5.4.2.5.2 Forelimb morphological implications 254 5.5 Conclusion 257 5.6 References 259 5.7 Appendices 269 5.7.1 Appendix 1: List of non-diprotodontid specimens used 269 5.8 Figures 271
CHAPTER 6: A phylogeny of the Diprotodontidae (Marsupialia) based on 295 postcranial morphology. 6.1 Introduction 295 6.1.1 Interfamilial relationships 296 6.1.2 Intrafamilial relationships 299 6.1.3 Postcrania in the Diprotodontidae 302 6.2 Methods 303 VI
6.2.1 Included taxa 303 6.2.2 Institutions 304 6.2.3 Abbreviations 304 6.2.3.1 Hind limb abbreviations 304 6.2.3.2 Fore limb abbreviations 305 6.2.4 Phylogenetic analyses 306 6.2.5 Character description 309 6.2.5.1 Characters relating to the hindlimbs 310 6.2.5.1.1 The Pes 310 6.2.5.1.2 Characters relating to bones of the hind limb 321 6.2.5.2 Forelimb characters used in cladistic analysis 325 6.2.5.2.1 The Manus 325 6.2.5.2.2 Characters relating to the forelimb bones 332 6.3 Results 337 6.3 Phylogenetic analysis 337 6.3.1 Hindlimb character set only 337 6.3.1.1 Intrafamilial analyses 337 6.3.1.2 Interfamilial analyses 343 6.3.1.3 Character states related to functional grouping 354 6.3.2 Forelimb character set only 357 6.3.2.1 Intrafamilial analyses 357 6.3.2.2 Interfamilial analyses 363 6.3.2.3 Character states related to functional grouping 378 6.3.2.4 Character states related to phylogenetic grouping 381 6.3.3 Combined analyses (forelimb and hindlimb) 384 6.3.3.1 Intrafamilial analyses 384 6.3.3.2 Interfamilial analyses 385 6.3.4 Comparison to forelimb-only and hindlimb-only analyses 388 6.4 Discussion 389 6.4 Phylogenetic implications of postcranial anatomy 389 6.4.1 Hindlimb analyses 379 6.4.2 Forelimb analyses 391 6.5 Conclusion 398 6.6 References 399 6.7 Appendices 409 6.7.1 Appendix 1: List of non-diprotodontid specimens used 409 6.7.2 Appendix 2: Character matrix 410 6.7.3 Appendix 3: Supporting characters for various nodes 410 6.8 Figures 421
CHAPTER 7: General Discussion 454 7.1 Thesis summary and aims 454 7.2 Project findings 454 7.2.1 The functional morphology of the hindlimb of E. grata 454 7.2.2 Trackways: Pliocene diprotodontid footprints from the Lake Eyre Basin 455 7.2.3 Trackways: a Pleistocene megafaunal footprint assemblage from the 456 Victorian Volcanic Plains 7.2.4 Functional and phylogenetic analysis of diprotodontid hindlimb and 457 forelimb anatomy 7.3 Future Directions 459 7.3.1 Trace fossils 459 7.3.2 Functional and phylogenetic analysis of the Diprotodontidae 460 7.3.2.1 Functional analyses 460 VII
7.3.2.2 Phylogenetic analyses 461 7.3.2.3 Molecular analyses 461 7.4 References 462
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Abstract
This thesis is focused on the information that can be gained from examining diprotodontid forelimb and
hindlimb anatomy in a morphological, functional, palaeobiological, and phylogenetic context. This
research is complemented through a study of diprotodontid fossil trackways, allowing testing of the
hypotheses developed through study of skeletal anatomy, as well as providing insights into the
palaeobiology of taxa that are not evident through study of skeletal anatomy.
The discovery of an articulated hindlimb of Euowenia grata, from the Warburton River, allowed
an investigation of the functional capabilities of this taxon (Chapter 2). It is shown that the development
of the graviportal limb morphology exemplified by Diprotodon optatum was already well underway
during the early Pliocene in E. grata. It is also suggested that the hindlimb morphology of E. grata is
indicative of the ability to rear up against trees. In addition, the pedal digits of Pliocene diprotodontines
demonstrate a similar degree of reduction to that seen later Pleistocene taxa such as D. optatum.
Pliocene trackways from the Warburton River in central Australia, representing the oldest
known Australian mammal trackways, are described in Chapter 3. The track-maker is identified as
Euowenia grata, and the six individual trackways indicate gregarious behaviour in this species.
Similarities in trackway proportions and pad morphology demonstrate an affinity with D. optatum.
Australia’s most speciose and best preserved fossil mammal trackway site is described in
Chapter 4. The trackways provide information about palaeoecological species associations. Individual
trackways at the site demonstrate that D. optatum had the ability to vary trackway gauge without
significantly varying speed. The trackways also record important new information about manual and
pedal pad morphology.
Functional morphological analyses of the hindlimb and forelimb anatomy of diprotodontids are
presented in Chapter 5. These investigations suggested that the plesiomorphic diprotodontids
Ngapakaldia and Nimbadon may have been scansorial. This is more remarkable in the latter, given that
all other Miocene diprotodontid taxa studied demonstrate distinct adaptations towards a terrestrial
lifestyle. It was also found that the limbs of the Plio-Pleistocene diprotodontines (Euowenia and
Diprotodon) may have been restricted to a locomotory role, whereas the limbs of the Pleistocene IX
zygomaturine, Zygomaturus, were probably adapted for a wider range of functions including: moving
over soft substrates, scratch-digging, defence and sexual competition.
Phylogenetic analyses, based on hindlimb and forelimb morphology (undertaken in Chapter 6),
demonstrated that significant homoplasy exists in the postcrania of the Diprotodontidae. Functional
groupings arising from these analyses supported the hypothesis that Ngapakaldia and Nimbadon were
scansorial. It was also found that forelimb and hindlimb morphological characters fail to consistently
distinguish between the two diprotodontid subfamilies, instead forcing taxa to group based on their
locomotory habits. The phylogenetic signal provided here by postcranial morphology consistently placed
Ngapakaldia outside the other diprotodontids studied, and little or no evidence was found for uniting this
taxon with Plio-Pleistocene diprotodontines. Postcranial morphology instead indicated that the most
parsimonious phylogeny involves diprotodontines arising from within the Zygomaturinae during the
middle Miocene, and suggests that Ngapakaldia should occupy a position basal to both diprotodontines
and zygomaturines.
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Acknowledgements
I would firstly like to thank my supervisors Mike Lee and Rod Wells for their support and
guidance during my PhD. They have always been readily accessible and have provided useful
input while still allowing me a large degree of freedom in the preparation of my thesis. Mike
has maintained his open door policy throughout my PhD and has been readily forthcoming with
advice on all things cladistic and has helped me maintain focus. Rod has provided me with
many opportunities to experience mammalian palaeontological fieldwork throughout South
Australia and his in-depth knowledge of how animals are put together, not to mention his
writing coaching skills, have been extremely helpful.
I thank Trevor Worthy for the huge amount of time and effort he has put towards various
parts of this project; from assistance in the field, to comments on manuscripts and advice on
scientific method, Trevor has been both a friend and mentor and has assisted my development
as a scientist.
I especially thank the hordes of volunteers that have assisted in various field excursions. For
help with megafaunal excavations at Burra I thank Rod Wells, locals Christine Brinkworth and
Harvey Neil, parks representatives Ian Falkenburg and Kate Burton, as well as volunteers
Trevor Worthy, Beck Candy, Nic Rawlence, Jamie Wood, Haydn Geraldene, Jo Sullivan, my
parents Margaret and Bruce Camens and brother Josh, Ruth Norris, Luke Schulz, Dave Ellis,
Carey Burke, Vicki Thomson, Daniel, Simon Ong and Hayley Purcell. For help on the
Warburton River I thank Rod Wells, Trevor Worthy, Dick and Vivian Tedford, Cate Burke,
Chris Von der Borch, David and Erica Woodgate, Ian Smith and Bob and Sue Tulloch. For
assistance in the Lake Frome Basin I thank Rod Wells, Trevor Worthy, Dick Richards, Beck
Candy, landowner Alec Wilson and the Sir Mark Mitchell Foundation for funding. For saving
me hours of labour with his superior Excel knowledge I thank Julien Soubrier. For assistance
with the VVP megafaunal trackways site I thank Stephen Carey, Ian Mclennan, Dave Pickering,
the anonymous landowners, Peter Swinkels and his crew of preparators from Museum Victoria XI
who moulded major sections of the trackways; students, staff and friends of the University of
Ballarat and DAP’s crew of volunteers who helped lay out the grid, measure the tracks and
excavate the skeletal fossils; Matt Gibson of the University of Ballarat who prepared the map of
the locality; Steven Bourne (Naracoorte Caves World Heritage Site), Peter Dahlhaus
(University of Ballarat), Bernie Joyce (University of Melbourne), John Long (formerly Museum
Victoria), Tony Martin (Emory University), Wayne Stephenson (University of Melbourne), Rod
Wells (Flinders University), Barbara Triggs and Fons VandenBerg (Geoscience Victoria) for
discussion about potential track makers; Peter Trusler for providing foot-pad reconstructions
and Matt Cupper, Rainer Grün, John C. Hellstrom, Stafford McKnight and Maxime Aubert for
their assistance in dating the site.
My thanks also got to the numerous people who have assisted me in the examination of
fossils at various institutions including: David Stemmer, Cath Kemper, Jim McNamara and
Neville Pledge (SAM); Scott Hocknull and Gilbert Price (QM); Karen Black, Vera Weisbecker,
Anna Gillespie and Mike Archer (UNSW); Robert Jones (AM); Dave Pickering (MV); Peter
Murray and Dirk Megirian (NTMAG); Liz Reed and Steve Bourne (Naracoorte Caves); Craig
Reid, Lisa Gershwin, Annette Vains and Alice-Ann (QVMAG), Andrew Rozefelds, Carole
Hammond and Cobus van Breda (HM); Gavin Prideaux and Rod Wells (FU Palaeontology
Collection).
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I would like to dedicate this thesis to my partner
Althea Walker-Hallam
without whose constant support
(in more ways than one)
the undertaking of this thesis would not
have been possible
NOTE: Pagination after page 62 begins again as page 55 in the digital copy and the print copy of the thesis held in the University of Adelaide Library.