Samples collected at Bethulie were keyed to a measured section quite close to the one

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1 GSA Data Repository Kenneth G. MacLeod, Page C. Quinton, and Damon J. Bassett, 2017, Warming and increased aridity during the earliest Triassic in the Karoo Basin, South Africa: Geology, doi: /g Supplementary file: Sample base Samples analyzed were collected in Samples collected at Bethulie were keyed to a measured section quite close to the one presented in Smith (1995) with the 0 m datum at the level of the Caledon River. Roger Smith (as well as Allison Crean and Paul October) of the South African Museum (now Iziko Museums of South Africa) participated in field work facilitating locating the samples at the correct position in the section. Samples ID s presented in the data tables are unique to samples collected in They are the same samples analyzed and interpreted in MacLeod et al. (2000). As we were sampling for planned destructive analyses, we tried to be conservative in the amount of tusk material removed, and we only sampled from skulls for which we felt our field dentistry would be unlikely to damage high quality specimens (e.g., we did not sample from relatively complete specimens) or otherwise compromise possible future work. At the request of a reviewer, we have made a dedicated effort to match coordinates for these Bt specimens to samples in the P/T Boundary database that underpins the analysis presented in Smith and Botha-Brink (2014). Unfortunately, we could not confidently and consistently make such assignments. Possible reasons include relatively low accuracy and precision of the GPS unit/gps signal in 1996 and uncertainty in which geodectic datum we used then. In addition, at least some samples collected in 1996 were not logged into the P/T Boundary database likely because only limited taphonomic and/or taxonomic information could be gathered for those specimens and/or because the specimens were not relocated. Regardless of the reasons, the two datasets are, and should be, viewed as separate. Some specimens occur in both, but both also have unique entries.

2 That said, this effort to correlate samples between data sets led us to rigorously compare the stratigraphic position of logged Bethulie tusk (Bt) and nodule (Bn) specimens to published figures. To facilitate comparisons with recent literature, all stratigraphic levels have been converted to corresponding nearest meter levels shown in Figure 4 of Smith and Botha-Brink (2014) and that column was redrafted and used in our Figure 2. Meter levels presented for samples in the figures and data tables differ from the meter levels for the same samples shown in MacLeod et al. (2000) largely due to the fact the Smith and Botha-Brink (2014) place the 0 m datum ~ 10 m above the Caledon River. Other differences are due to rounding errors and at least one apparent instance of previous miscounting or data entry error in the MacLeod et al. (2000) data tables (Bn-16). All samples discussed, including Bt-07 Bt-13, are plotted at the accurate level in the section to the best of our knowledge regardless of whether the compilation presented by Smith and Botha-Brink (2014) show samples at the same level. The Doornplaats section was measured by the lead author on the Doornplaats Farm ~20 km NW of Graaf-Reinet. The base of the section starts in a gully on the relatively flat valley floor north of highway R63 and continues up a series of ephemeral stream gullies to the top of the hill Boesmanskop. The ~330 m of section examined is composed dominantly of green, gray, and maroon mudstones. Color differences are bedding parallel on the outcrop scale but express patchy and mottled lateral variation on the centimeter to 10-meter scale. Mudstones contain horizons of cm-sized ovoid nodules, slickensided surfaces, vertebrate fossils, mud cracks, and burrows. The mudstones are interbedded with siltstones and fine to medium sandstones that are centimeters to several meters thick. The sandstones are thin to medium bedded, contain tabular, trough, and epsilon cross-beds as well as planar laminations. They commonly are channel formed, at least in part. Lateral continuity of these beds range from 10 s of meters to several kilometers. U-Pb dates on zircons yielded age of Ma for a 5 cm thick ash collected at 2.5 m in the Doornplaats section in 1996 and augmented by additional material collected later (Rubidge et al., 2013). The ash was placed at or near the top of the Cistecephalus Zone (Rubige et al., 2013), but subsequent revision to the definition of the top of

3 that Zone suggests this ash is within the Daptocephalus Zone (Viglietti et al., 2016) based on reexamination of the genus Dicynodon by Kammerer et al. (2011). The top of the section does not reach Triassic strata. Thus, the Doornplaats section is considered to fall entirely within the Late Permian Daptocephalus Zone. Only 7 tusks were found and sampled in the field. To increase sampling density and stratigraphic coverage, the lead author trimmed small portions of tusks from an additional 12 samples collected at Doornplaats and housed in the South African Museum (now Iziko Museums of South Africa) in September, The samples were projected onto the measured section based on elevation at which they were collected. Error in placing the specimens on the section is reduced by the minimal dip in the region and proximity of the collection sites to the transect along which the section was measured. Further, none of the arguments presented in the paper depend on highly accurate stratigraphic placement for these samples (there are no apparent stratigraphic trends in isotopic results through the Doornplaats section, and Doornplaats isotopic values are treated as a pooled population representative of the latest Permian for the site in all discussion). Still, it should be noted that uncertainty in the stratigraphic position for the museum samples is high. Tabulated results Results for phosphate 18 O analyses are shown in Supplementary Table 1. All data are previously unreported. Each point plotted in text figure 2 represents all analyses run on each separate of powdered tusk. That is, for samples where dissolution of bioapatite and precipitation of Ag 3 PO 4 yielded enough material for replicate analyses, those replicates analyses are pooled prior to plotting. Results for trace carbonates in tusks are presented in Supplementary Table 2 and represent a combination of data from MacLeod et al. (2000) and new data as indicated. Supplementary Table 3 shows comparison of 18 O values for trace carbonates and phosphate analyses in tusks. Because different powder aliquots were used for trace carbonate and

4 phosphate analyses, the average values for each tusk are used in calculating the differences between trace carbonate and phosphate values. Statistical test of trends in values All statistical tests were done using Excel functions. For comparisons among tusk values, T-tests (2 tails) were used to compare among results for Doornplaats samples, Permian samples at Bethulie (below the boundary placed at 51 m (Smith and Botha-Brink, 2014)), and Triassic samples at Bethulie. The statistical tests were run both on individual analyses and on average values for all analyses for a given tusk. Both approaches yield the same conclusions about statistical significance. F-test comparison fails to reject the null hypothesis of equal variance when comparing Permian samples at Bethulie to Doornplaats samples but does reject the null hypothesis when comparing Permian and Triassic samples at Bethulie. F-test Doornplaats vs. Permian at Bethulie all analyses tusk average p-value Permian at Bethulie vs. Triassic at Bethulie all analyses tusk average p-value 1.8E E-04 T-test demonstrates differences among populations are statistically significant. T-test, 2 tails using assumptions about variance from F-test Doornplaats vs. Permian at Bethulie all analyses tusk average p-value 4.9E E-02 Permian at Bethulie vs. Triassic at Bethulie all analyses tusk average p-value 3.7E E-08

5 R 2 values reported for trace carbonate 18 O values and nodule 18 O values vs. stratigraphic height are based on a linear regression. Arguments regarding temperature and 18 O soil water for nodule 18 O values Temperatures cited in text were based on paleotemperature equation for synthetic calcite of Kim and O Neil (1997) as reformulated by Grossman (2012): T( C) = ( 18 O c - 18 O w ) (( 18 O c - 18 O w ) 2 where the temperature at the time of formation is related to the isotopic composition of the pedogenic calcite ( 18 O c ) and groundwater in which it formed ( 18 O w ) on the PDB and VSMOW scales. Values for 18 O c cited are based on average values for stratigraphic interval discussed using data from (MacLeod et al., 2000). Values for 18 O w are based on assumed 22 offset between tusk phosphate and surface water (Amiot et al., 2004) modified by evaporative enrichment of 18 O in remaining liquid water as discussed in the text. References: Amiot, R., Lecuyer, C., Buffetaut, E., Fluteau, F., Legendre, S., and Martineau, F., 2004, Latitudinal temperature gradient during the Cretaceous Upper Campanian Middle Maastrichtian: delta O 18 record of continental vertebrates: Earth and Planetary Science Letters, v. 226, p Grossman, E.L., Applying Oxygen Isotope Paleothermometry in Deep Time. in L. C. Ivany and B. T. Huber (eds.), Reconstructing Earth s Deep Time Climate The State of the Art in 2012: Paleontological Society Papers, v. 18., p Kammerer, C.F., Angielczyk, K.D., and Fröbisch, J., 2011, A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy: Journal of Vertebrate Paleontology, v. 31, p Kim, S. T., and O Neil J. R., 1997, Equilibrium and nonequilibrium oxygen isotope effects in synthetic carbonates: Geochimica et Cosmochimica Acta, v. 61, p MacLeod, K. G., Smith, R. M. H., Koch, P. L., and Ward, P. D., 2000, Timing of mammal like reptile extinctions across the Permian Triassic boundary in South Africa: Geology, v. 28, p Rubidge, B. S., Erwin, D. H., Ramezani, J., Bowring, S. A., and de Klerk, W. J., 2013, Highprecision temporal calibration of Late Permian vertebrate biostratigraphy: U Pb zircon constraints from the Karoo Supergroup, South Africa: Geology, v. 41, p

6 Smith, R. M. H., 1995, Changing Fluvial Environments across the Permian Triassic Boundary in the Karoo Basin, South Africa and Possible Causes of Tetrapod Extinctions: Palaeogeography Palaeoclimatology Palaeoecology, v. 117, p Smith, R. M. H., and Botha Brink, J., 2014, Anatomy of a mass extinction: Sedimentological and taphonomic evidence for drought induced die offs at the Permo Triassic boundary in the main Karoo Basin, South Africa: Palaeogeography Palaeoclimatology Palaeoecology, v. 396, p Viglietti, P.A., Smith, R.M.H, Angielczyk, K.D., Kammerer, C.F., Fröbisch, J., and Rubidge, B.S., 2016, The Daptocephalus Assemblage Zone (Lopingian), South Africa: A proposed biostratigraphy based on a new compilation of stratigraphic ranges: Journal of African Earth Sciences, v. 113, p

7 TABLE DR1. PHOSPHATE d180 Sample Section height (m) taxon* Avg. for sample single analysis result s results based on analysis of 2 or more replicates of precipitated crystals avg. rep. rep. avg. rep. rep. avg. rep. rep. rep. rep. Bt08 Bethulie 127 Lystrosaurus Bt09 Bethulie 127 Lystrosaurus Bt10 Bethulie 127 Lystrosaurus Bt11 Bethulie 127 Lystrosaurus Bt12 Bethulie 127 Lystrosaurus Bt13 Bethulie 126 Lystrosaurus Bt07 Bethulie 123 Lystrosaurus Bt01 Bethulie 119 Lystrosaurus Bt02 Bethulie 119 Lystrosaurus Bt03 Bethulie 119 Lystrosaurus Bt04 Bethulie 119 Lystrosaurus Bt05 Bethulie 119 Lystrosaurus Bt06 Bethulie 119 Lystrosaurus Bt14 Bethulie 111 Lystrosaurus Bt33 Bethulie 105 Lystrosaurus Btf9-14 Bethulie 99 Lystrosaurus Bt34 Bethulie 97 Lystrosaurus Bt35 Bethulie 89 Lystrosaurus Bt36 Bethulie 83 Lystrosaurus Bt17 Bethulie 78 Lystrosaurus Bt18 Bethulie 71 Lystrosaurus Bt19 Bethulie 65 Lystrosaurus Bt20 Bethulie 61 Lystrosaurus Bt21 Bethulie 54 Lystrosaurus? Bt24 Bethulie 47 Dicynodon Bt25 Bethulie 47 Lystrosaurus Bt22 Bethulie 46 Lystrosaurus Bt23 Bethulie 46 Dicynodon Btf4 Bethulie 46 Dicynodon? Bt26 Bethulie 37 Lystrosaurus Bt27 Bethulie 34 Lystrosaurus Bt28 Bethulie 31 Dicynodon Bt30 Bethulie 31 Dicynodon Bt29 Bethulie 22 Dicynodon Bt31 Bethulie 17 Diictodon? Bt32 Bethulie 12 Dicynodon? Bt16 Bethulie -2 Dicynodon Bt15 Bethulie -4 Dicynodon SAM-PK-K7258 Doornplaats 327 Dicynodon SAM-PK-K7595 Doornplaats 217 Dicynodon SAM-PK-K7217 Doornplaats 156 Dicynodon SAM-PK-K7818 Doornplaats 143 Dicynodon SAM-PK-K7865 Doornplaats 126 Dicynodon SAM-PK-K7364 Doornplaats 126 Diictodon SAM-PK-K7375 Doornplaats 95 Diictodon Dt1 Doornplaats 85 Dicynodon SAM-PK-K7543 Doornplaats 65 Diictodon Dt6 Doornplaats 64 Dicynodon SAM-PK-K7355 Doornplaats 34 Diictodon SAM-PK-K7237 Doornplaats 34 Diictodon

8 SAM-PK-K7227 Doornplaats 34 Dicynodon Dt5 Doornplaats 32 Diictodon Dt2 Doornplaats 5 Dicynodon Dtc Doornplaats 4 theriodont Dt4 Doornplaats 4 Diictodon Dt3 Doornplaats 3 unknown museum samples (highlighted in yellow) projected onto measured section based on field data provided by RM Smith and S. Kaal (Iziko Museums of South Africa) values highlighted in green plotted as diamonds in text figure 2 in the text values highlighted in blue plotted as triangles in text figure 2 *specimen ID's are based on field observations and 1996 taxonomy. Whereas many "Dicynodon " are probably Daptocephalus, that probability can not be confirmed and updates where not

9 TABLE DR2. TUSK TRACE CARBONATES Sample Section height (m) taxon* results on V-PDB scale 13 C 18 O 13 C 18 O Bt08 Bethulie 127 Lystrosaurus Bt09 Bethulie 127 Lystrosaurus Bt10 Bethulie 127 Lystrosaurus Bt11 Bethulie 127 Lystrosaurus Bt12 Bethulie 127 Lystrosaurus Bt13 Bethulie 126 Lystrosaurus Bt07 Bethulie 123 Lystrosaurus Bt01 Bethulie 119 Lystrosaurus Bt02 Bethulie 119 Lystrosaurus Bt03 Bethulie 119 Lystrosaurus Bt04 Bethulie 119 Lystrosaurus Bt05 Bethulie 119 Lystrosaurus Bt06 Bethulie 119 Lystrosaurus Bt14 Bethulie 111 Lystrosaurus Bt33 Bethulie 105 Lystrosaurus Btf9-14 Bethulie 99 Lystrosaurus nd nd Bt34 Bethulie 97 Lystrosaurus Bt35 Bethulie 89 Lystrosaurus Bt36 Bethulie 83 Lystrosaurus Bt17 Bethulie 78 Lystrosaurus Bt18 Bethulie 71 Lystrosaurus Bt19 Bethulie 65 Lystrosaurus Bt20 Bethulie 61 Lystrosaurus nd nd Bt21 Bethulie 54 Lystrosaurus? Bt24 Bethulie 47 Dicynodon Bt25 Bethulie 47 Lystrosaurus Bt22 Bethulie 46 Lystrosaurus Bt23 Bethulie 46 Dicynodon Btf4 Bethulie 46 Dicynodon? Bt26 Bethulie 37 Lystrosaurus Bt27 Bethulie 34 Lystrosaurus Bt28 Bethulie 31 Dicynodon Bt30 Bethulie 31 Dicynodon Bt29 Bethulie 22 Dicynodon

10 Bt31 Bethulie 17 Diictodon? Bt32 Bethulie 12 Dicynodon? nd nd Bt16 Bethulie -2 Dicynodon Bt15 Bethulie -4 Dicynodon SAM-PK-K7258 Doornplaats 327 Dicynodon SAM-PK-K7595 Doornplaats 217 Dicynodon SAM-PK-K7217 Doornplaats 156 Dicynodon SAM-PK-K7818 Doornplaats 143 Dicynodon SAM-PK-K7865 Doornplaats 126 Dicynodon SAM-PK-K7364 Doornplaats 126 Diictodon SAM-PK-K7375 Doornplaats 95 Diictodon Dt1 Doornplaats 85 Dicynodon SAM-PK-K7543 Doornplaats 65 Diictodon Dt6 Doornplaats 64 Dicynodon SAM-PK-K7355 Doornplaats 34 Diictodon SAM-PK-K7237 Doornplaats 34 Diictodon SAM-PK-K7227 Doornplaats 34 Dicynodon Dt5 Doornplaats 32 Diictodon Dt2 Doornplaats 5 Dicynodon Dtc Doornplaats 4 theriodont Dt4 Doornplaats 4 Diictodon Dt3 Doornplaats 3 unknown museum samples (highlighted in yellow) projected onto measured section based on field data provided by RM Smith and S. Kaal (Iziko Museums of South Africa); isotpic values in blue italics from MacLeod et al., 2000, Geology, v. 28, p ; *specimen ID's are based on field observations and 1996 taxonomy. Whereas many "Dicynodon" are probably Daptocephalus, that probability can not be confirmed and updates where not made

11 TABLE DR3. TUSK COMPARISON tusk oxygen isotope comparison Sample Section height (m) taxon phosphate trace - trace SMOW SMOW phosphate Bt08 Bethulie 127 Lystrosaurus Bt09 Bethulie 127 Lystrosaurus Bt10 Bethulie 127 Lystrosaurus Bt11 Bethulie 127 Lystrosaurus Bt12 Bethulie 127 Lystrosaurus Bt13 Bethulie 126 Lystrosaurus Bt07 Bethulie 123 Lystrosaurus Bt01 Bethulie 119 Lystrosaurus Bt02 Bethulie 119 Lystrosaurus Bt03 Bethulie 119 Lystrosaurus Bt04 Bethulie 119 Lystrosaurus Bt05 Bethulie 119 Lystrosaurus Bt06 Bethulie 119 Lystrosaurus Bt14 Bethulie 111 Lystrosaurus Bt33 Bethulie 105 Lystrosaurus Btf9-14 Bethulie 99 Lystrosaurus nd 6.4 nd Bt34 Bethulie 97 Lystrosaurus Bt35 Bethulie 89 Lystrosaurus Bt36 Bethulie 83 Lystrosaurus Bt17 Bethulie 78 Lystrosaurus Bt18 Bethulie 71 Lystrosaurus Bt19 Bethulie 65 Lystrosaurus Bt20 Bethulie 61 Lystrosaurus nd 7.4 nd Bt21 Bethulie 54 Lystrosaurus? Bt24 Bethulie 47 Dicynodon Bt25 Bethulie 47 Lystrosaurus Bt22 Bethulie 46 Lystrosaurus Bt23 Bethulie 46 Dicynodon Btf4 Bethulie 46 Dicynodon? Bt26 Bethulie 37 Lystrosaurus Bt27 Bethulie 34 Lystrosaurus Bt28 Bethulie 31 Dicynodon Bt30 Bethulie 31 Dicynodon Bt29 Bethulie 22 Dicynodon

12 Bt31 Bethulie 17 Diictodon? Bt32 Bethulie 12 Dicynodon? nd 5.5 nd Bt16 Bethulie -2 Dicynodon Bt15 Bethulie -4 Dicynodon SAM-PK-K7258 Doornplaats 327 Dicynodon SAM-PK-K7595 Doornplaats 217 Dicynodon SAM-PK-K7217 Doornplaats 156 Dicynodon SAM-PK-K7818 Doornplaats 143 Dicynodon SAM-PK-K7865 Doornplaats 126 Dicynodon SAM-PK-K7364 Doornplaats 126 Diictodon SAM-PK-K7375 Doornplaats 95 Diictodon Dt1 Doornplaats 85 Dicynodon SAM-PK-K7543 Doornplaats 65 Diictodon Dt6 Doornplaats 64 Dicynodon SAM-PK-K7355 Doornplaats 34 Diictodon SAM-PK-K7237 Doornplaats 34 Diictodon SAM-PK-K7227 Doornplaats 34 Dicynodon Dt5 Doornplaats 32 Diictodon Dt2 Doornplaats 5 Dicynodon Dtc Doornplaats 4 theriodont Dt4 Doornplaats 4 Diictodon Dt3 Doornplaats 3 unknown museum samples (highlighted in yellow) projected onto measured section based on field data provided by RM Smith and S. Kaal (Iziko Museums of South Africa); oxygen isotopic results on the PDB scale converted to the SMOW according to the formula: δ18o(smow) = * δ18o(pdb); values highlighted in green are average of analyses for samples where replicates were run; nd = no data; *specimen ID's are based on field observations and 1996 taxonomy. Whereas many "Dicynodon" are probably Daptocephalus, that probability can not be confirmed and updates where not made