Talk given at Progressive Palaeontology, May 2016, Oxford. On tetrapod diversity across the Jurassic/Cretaceous transition

1. A moderately interesting event
at the Jurassic/Cretaceous
boundary
Jon Tennant
Images from Phylopic

2. Thanks! • NERC
• PALASS
• SVP

3. History of the Jurassic/Cretaceous boundary
• Pioneering work by Newell,
Raup, Sepkoski
• Originally considered to be a
‘major extinction’
• The ‘Sepkoski Compendium’
• Understood general controls
on the fossil record
• Evaluations at a very coarse
level
Jon Tennant Background
Raup (1976)
Raup and Sepkoski (1982)

4. History of the Jurassic/Cretaceous boundary
• Taxonomic selectivity
• Geographic constraints
• Not a mass extinction
• Changes caused by
regional facies shifts
Jon Tennant Background
Hallam (1986)

5. The era of not much happening
Jon Tennant Background
Bambach (2006)

6. The structure of the fossil record
Jon Tennant Sampling issues
Smith and McGowan (2011)

7. The structure of the fossil record
Jon Tennant Sampling issues
Smith and McGowan (2007)

8. Evidence for a faunal turnover on land?
Jon Tennant Current understanding
Zanno and Makovicky (2013)
Bronzati et al. (2015)
Newham et al. (2014)

9. Evidence for a faunal turnover in the oceans?
Jon Tennant Current understanding
Benson and Butler (2011) Nicholson et al. (2015)

10. What do we want to know?
•Can we quantify changes in tetrapod
diversity over the J/K transition?
•What is the spatial structure of these
changes?
•What external environmental parameters
were responsible for mediating diversity?
Jon Tennant Methods

11. The fully-functional Paleobiology Database
• 4907 species
• 15,472 occurrences
• 7314 references
• Split into higher taxonomic
clades
• Fully aquatic or non-marine
• Palaeocontinents
• Time binning methods
Jon Tennant Methods

12. Methodological approach
•Shareholder Quorum Subsampling
(SQS)
•Model-fitting of environmental
parameters
•Extinction and origination rates
•Regional sampling proxies
Jon Tennant Methods

13. Jurassic/Cretaceous tetrapod occurrences
Jon Tennant Results

14. Subsampled tetrapod diversity (I)
Jon Tennant Results

15. Subsampled tetrapod diversity (II)
Jon Tennant Results

16. Subsampled tetrapod diversity (III)
Jon Tennant Results

17. Subsampled tetrapod diversity (IV)
Jon Tennant Results

18. 3T extinction rates
Jon Tennant Results
Stage Aves Chel Chor
Crocs (non-
marine)
Crocs
(marine)
Ichthy Lepid Liss Mamm Ornith Plesio Ptero Sauro Test Thero
Maastrichtian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
Campanian 0.693 NA NA NA NA NA 1.038 1.03 1.658 0.916 NA 0.452 NA NA 0.84
Santonian NA NA NA NA NA NA 0.345 NA NA 0.511 0.875 0.606 NA 1.01 NA
Coniacian NA NA NA NA NA NA 0.345 NA NA 1.897 2.955 0.724 3.519 NA NA
Turonian 0.693 NA NA NA NA NA NA NA NA 0.916 1.569 NA NA NA NA
Cenomanian NA NA NA NA NA NA 1.038 NA NA NA 1.569 NA 2.575 NA 1.805
Albian NA NA NA 0.956 NA 0.305 1.038 2.02 1.658 1.427 NA NA 1.322 NA 1.245
Aptian NA NA NA 1.361 NA 0.305 0.345 NA 1.253 NA NA NA NA NA 0.552
Barremian NA NA NA 0.262 NA 0.305 0.345 0.63 0.56 NA NA NA NA NA NA
Hauterivian NA NA NA 0.262 NA NA NA 0.63 NA NA NA NA NA NA 1.245
Valanginian NA NA NA 0.262 0.125 NA NA 1.32 NA NA NA NA NA NA 1.245
Berriasian NA NA NA 0.55 0.818 NA NA NA NA 1.204 NA NA NA 2.11 0.958
Tithonian NA NA NA 0.956 1.378 1.404 1.731 NA 3.268 2.015 NA 0.724 NA 2.62 2.855
Kimmeridgian NA NA NA 0.262 0.307 0.305 0.345 0.63 0.56 0.511 NA NA NA 1.01 NA
Oxfordian NA NA NA NA 0.125 0.305 0.633 NA NA 0.511 0.875 NA NA NA NA
Callovian NA NA NA NA 0.125 NA NA NA NA 0.511 NA NA NA NA 0.552
Bathonian NA NA NA NA 0.125 NA NA NA 0.56 0.511 NA NA NA NA NA
Bajocian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
Aalenian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
Toarcian NA NA NA NA NA 0.999 NA NA NA NA NA NA NA NA NA
Pliensbachian NA NA NA NA NA 0.999 0.345 NA NA NA NA NA NA NA NA
Sinemurian NA NA NA NA NA 0.305 1.038 NA NA NA NA NA NA NA NA
Hettangian NA NA NA NA NA 0.711 NA NA NA NA NA NA NA NA NA

19. 3T origination rates
Jon Tennant Results
Stage Aves Chel Chor
Crocs (non-
marine)
Crocs
(marine)
Ichthy Lepid Liss Mamm Ornith Plesio Ptero Sauro Test Thero
Maastrichtian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
Campanian 1.792 NA NA NA NA NA 1.038 3.231 1.658 3.114 2.955 1.705 NA NA 2.056
Santonian NA NA NA NA NA NA 1.038 NA NA 1.609 NA 1.299 NA 1.705 NA
Coniacian NA NA NA NA NA NA 0.345 NA NA 0.511 0.875 1.012 1.322 NA NA
Turonian 1.386 NA NA NA NA NA NA NA NA 1.204 2.955 NA NA NA NA
Cenomanian NA NA NA NA NA NA 1.443 NA NA NA 1.569 NA 1.727 NA 1.245
Albian NA NA NA 0.668 NA 0.999 0.345 2.238 0.56 1.204 NA NA 3.268 NA 1.399
Aptian NA NA NA 1.649 NA 0.305 1.731 NA 1.658 NA NA NA NA NA 2.344
Barremian NA NA NA 0.262 NA 0.305 0.345 1.034 1.253 NA NA NA NA NA NA
Hauterivian NA NA NA 0.262 NA NA NA 1.322 NA NA NA NA NA NA 0.552
Valanginian NA NA NA 0.262 0.125 NA NA 0.629 NA NA NA NA NA NA 0.552
Berriasian NA NA NA 0.262 0.125 NA NA NA NA 0.511 NA NA NA 1.012 1.245
Tithonian NA NA NA 0.55 0.125 0.999 0.345 NA 0.56 0.511 NA 0.318 NA 2.11 1.651
Kimmeridgian NA NA NA 2.054 0.462 0.711 0.633 2.42 2.575 2.708 NA NA NA 2.621 NA
Oxfordian NA NA NA NA 0.818 0.305 0.345 NA NA 0.511 0.875 NA NA NA NA
Callovian NA NA NA NA 0.531 NA NA NA NA 0.511 NA NA NA NA 0.552
Bathonian NA NA NA NA 0.818 NA NA NA 0.56 0.511 NA NA NA NA NA
Bajocian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
Aalenian NA NA NA NA NA 0.305 NA NA NA NA NA NA NA NA NA
Toarcian NA NA NA NA NA 0.999 NA NA NA NA NA NA NA NA NA
Pliensbachian NA NA NA NA NA 0.305 0.345 NA NA NA NA NA NA NA NA
Sinemurian NA NA NA NA NA 0.305 0.345 NA NA NA NA NA NA NA NA
Hettangian NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

20. Regional sampling structure (N. America)
Jon Tennant Results

21. Regional sampling structure (Europe)
Jon Tennant Results

22. Is global subsampled diversity biased?
Jon Tennant Results
Group
Non-marine
rho p-value
Adjusted
p-value
r p-value
Adjusted
p-value
Aves 0.321 0.498 0.988 -0.174 0.708 0.865
Choristoderes -0.500 1.000 1.000 -0.509 0.660 0.865
Crocodyliformes 0.273 0.448 0.988 0.015 0.967 0.967
Lepidosauromorphs 0.050 0.912 1.000 0.317 0.406 0.757
Lissamphibians 0.000 1.000 1.000 -0.340 0.371 0.757
Mammaliaformes 0.079 0.838 1.000 -0.292 0.413 0.757
Ornithischians 0.209 0.539 0.988 0.424 0.539 0.847
Pterosaurs 0.521 0.123 0.451 0.309 0.387 0.757
Sauropodomorphs 0.736 0.024 0.264 0.733 0.031 0.171
Testudines -0.117 0.776 1.000 -0.094 0.810 0.891
Theropods 0.531 0.079 0.435 0.790 0.004 0.044
Marine
Chelonioides -0.500 1.000 1.000 -0.474 0.686 0.842
Crocodyliformes 0.690 0.069 0.138 0.740 0.036 0.144
Ichthyopterygians 0.612 0.060 0.138 0.479 0.166 0.332
Sauropterygians 0.335 0.263 0.351 0.061 0.842 0.842
Spearman's rank Pearson's PMCC
Tetrapod-bearing
Collections
Same pattern with
Formations

23. What controls regional subsampled diversity?
(Europe)
Jon Tennant Results
rho p-value
Adjusted
p-value
r p-value
Adjusted
p-value
Raw richness 0.671 0.006 0.034 0.513 0.042 0.167
Collections 0.468 0.070 0.140 0.474 0.064 0.167
Occurrences 0.512 0.045 0.135 0.446 0.084 0.167
Good's u -0.147 0.616 0.660 -0.348 0.223 0.267
Formations 0.326 0.173 0.259 0.328 0.171 0.256
Global sea-level -0.115 0.660 0.660 -0.153 0.557 0.557
Subsampled richness
Crocodyliformes 0.036 0.964 0.964 0.381 0.400 0.599
Lepidosauromorpha 0.657 0.175 0.525 0.449 0.372 0.599
Ornithischia 0.091 0.811 0.964 0.323 0.363 0.599
Pterosauria -0.107 0.840 0.964 0.277 0.547 0.657
Testudines -0.257 0.658 0.964 0.034 0.949 0.949
Theropoda 0.527 0.123 0.525 0.605 0.064 0.383
Europe
Pearson's PMCCSpearman's rank
rho p-value
Adjusted
p-value
r p-value
Adjusted
p-value
Raw richness -0.217 0.318 0.547 -0.141 0.521 0.625
Collections -0.164 0.456 0.547 -0.173 0.430 0.625
Occurrences -0.228 0.293 0.547 -0.180 0.411 0.625
Good's u -0.547 0.046 0.275 -0.429 0.126 0.625
Formations 0.179 0.438 0.547 0.174 0.451 0.625
Global sea-level -0.069 0.795 0.795 -0.018 0.945 0.945
Subsampled richness
Crocodyliformes 0.143 0.752 0.759 0.239 0.569 0.569
Ichthyopterygia 0.115 0.759 0.759 -0.309 0.385 0.569
Sauropterygia 0.321 0.368 0.759 0.347 0.325 0.569
Spearman's rank Pearson's PMCC
Europe
Non-marine Marine

24. What controls regional subsampled diversity? (N.
America)
Jon Tennant Results
rho p-value
Adjusted
p-value
r p-value
Adjusted
p-value
Raw richness 0.346 0.206 0.309 0.278 0.315 0.464
Collections 0.446 0.097 0.292 0.561 0.030 0.089
Occurrences 0.386 0.157 0.309 0.388 0.153 0.305
Good's u -0.073 0.839 0.965 -0.290 0.387 0.464
Formations -0.012 0.965 0.965 -0.146 0.589 0.589
Global sea-level 0.581 0.016 0.098 0.630 0.007 0.040
Subsampled richness
Ornithischia 0.150 0.708 0.708 0.268 0.485 0.485
Theropoda -0.452 0.268 0.536 -0.404 0.321 0.485
North America
Pearson's PMCCSpearman's rank
rho p-value
Adjusted
p-value
r p-value
Adjusted
p-value
Raw richness 0.429 0.113 0.332 0.509 0.053 0.133
Collections 0.154 0.584 0.683 0.454 0.089 0.133
Occurrences 0.146 0.602 0.683 0.474 0.074 0.133
Good's u 0.300 0.683 0.683 0.298 0.626 0.626
Formations 0.479 0.166 0.332 0.457 0.185 0.221
Global sea-level 0.463 0.063 0.332 0.702 0.002 0.010
North America
Spearman's rank Pearson's PMCC
Non-marine Marine

25. Environmental factors governing diversity
Jon Tennant Results
Likelihood Weight rho
adjusted
p-value
r
adjusted
p-value
Crocodyliformes (marine) Palaeotemp. 22.741 0.237 -0.524 0.634 -0.522 0.678
Crocodyliformes (non-marine) Sea level 26.285 0.969 0.750 0.175 0.846 0.028
Lissamphibia Palaeotemp. 38.260 0.796 0.700 0.301 0.742 0.154
Mammaliaformes Sea level 51.394 0.931 -0.450 0.537 -0.666 0.301
Ornithischia Sea level 60.106 0.391 0.200 0.681 0.047 0.898
Pterosauria Sea level 33.261 0.872 0.714 0.406 0.647 0.581
Sauropodomorpha Sea level 41.191 0.501 0.310 0.810 0.457 0.564
Sauropterygia Sea level 41.820 0.409 0.055 0.906 0.065 0.985
Testudines Palaeotemp. 50.648 0.258 0.343 0.880 0.462 0.891
Theropoda Sea level 72.931 0.534 -0.018 0.968 0.037 0.954
AICc Pearson's PMCCSpearman's rank
Group Parameter

26. Conclusions I
• Faunal turnover in both marine and non-marine realms
• Tempo, mode and magnitude of decline highly variable
• Evidence for an ‘extinction wave’ and ecological reorganisation
• Primary driver was eustatic sea level
• Also impacted the marine realm:
• Low-latitude shelf-dwelling faunas primarily affected
• Marine revolution in micro-organism communities
Jon Tennant Conclusions

27. Conclusions II
• Cannot rule out
singular catastrophic
events