TABLE 1. Taxon list (compiled from Leakey and Walker, 1985; van der Made, 1996; Leakey et al., 2011; Geraads and Miller, 2013; Morlo et al., 2020; Sanders et al. in prep, E.M.L and E.R.M. pers obs).
| Order | Family | Taxon | Isotopic Sampling |
| Primates | Catarrhini | Afropithecus turkanensis | |
| (Family incertae sedis) | |||
| Catarrhini spp. | |||
| Victoriapithecidae | Noropithecus bulukensis | ||
| Carnivora | Amphicyonidae | Cynelos jitu | |
| Cynelos macrodon | |||
| Viverridae | cf. Mioprionodon | ||
| Feliformia | Feliformia indet. | ||
| (Family incertae sedis) | |||
| Hyaenodonta | Hyainailouros sulzeri | ||
| Hyainailouros cf. napakensis | |||
| Hyaenodonta indet. | |||
| Cetartiodactyla | Anthracotheriidae | cf. Sivameryx africanus | Yes |
| Suidae | Lopholistriodon pickfordi | ||
| cf. Kenyasus rusingensis | |||
| Megalochoerus marymuunguae | Yes | ||
| Sanitheriidae | Diamantohyus africanus | Yes | |
| Tragulidae | Dorcatherium pigotti | Yes | |
| Dorcatherium chappuisi | |||
| Pecora | Canthumeryx sirtensis | Yes | |
| (Family incertae sedis) | |||
| cf. Propaleoryx nyanzae | |||
| Pecora indet. | |||
| Perissodactyla | Rhinocerotidae | Brachypotherium minor | Yes |
| Rhinocerotidae sp. | Yes | ||
| Hyracoidea | Titanohyracidae | Afrohyrax championi | Yes |
| Proboscidea | Deinotheriidae | Prodeinotherium hobleyi | Yes |
| Mammutidae | Zygolophodon sp. nov. | Yes | |
| Gomphotheriidae | Archaeobelodon sp. nov. | Yes | |
| Gomphotherium sp. | |||
| Protanancus sp. nov. | Yes | ||
| Afrochoerodon kisumuensis | Yes | ||
| Family indet | Elephantimorph indet. | Yes |
TABLE 2. Fossil sites compared in this study.
| Site | Age | Mean δ13Cenamel | Median δ13Cenamel | SD |
| Morotoa | 21 Ma | -10.4 | -10.3 | 1.6 |
| Buluk | 17.2 Ma | -10.7 | -10.8 | 0.8 |
| Mabokob | ~16-13.7 Ma c | -12 | -12 | 1 |
| Fort Ternand | 13.7 Ma e | -11.7 | -11.8 | 1 |
a δ13Cenamel values and age from MacLatchy et al., (2023)
b δ13Cenamel values from Arney et al., (2022)
c Age from Feibel and Brown (1991)
d δ13Cenamel values from Cerling et al., (1997)
e Age from Pickford et al., (2006)
TABLE 3. Summary statistics for δ13Cenamel and δ18Oenamel.
| Taxa | N | δ13Cenamel(‰) | δ18Oenamel(‰) | ||||||
| Mean | Median | Min | Max | Mean | Median | Min | Max | ||
| Hyracoidea | |||||||||
| Afrohyrax championi | 2 | -11.4 | -11.4 | -11.5 | -11.4 | 0.7 | 0.7 | -0.1 | 1.6 |
| Deinotheriidae | |||||||||
| Prodeinotherium hobleyi | 19 | -11.5 | -11.6 | -12.6 | -10.4 | -2.9 | -2.4 | -6.4 | -0.2 |
| Gomphotheriidae | |||||||||
| Archaeobelodon sp. nov. | 2 | -10.5 | -10.5 | -10.7 | -10.4 | -2.7 | -2.7 | -2.8 | -2.6 |
| Afrochoerodon kisumuensis | 1 | -9.8 | -9.8 | - | - | -2.1 | -2.1 | - | - |
| Protanancus sp. nov. | 1 | -10.3 | -10.3 | - | - | -1.3 | -1.3 | - | - |
| Mammutidae | |||||||||
| Zygolophodon sp. nov. | 1 | -10.1 | -10.1 | - | - | -3.2 | -3.2 | - | - |
| Elephantimorph | |||||||||
| Elephantimorph | 8 | -10.3 | -10.4 | -10.6 | -10 | -4.7 | -5.1 | -6.4 | -2.3 |
| Rhinocerotidae | |||||||||
| Brachypotherium minor | 7 | -11.9 | -11.8 | -12.9 | -11.4 | -1.3 | -1.2 | -3.6 | 0.2 |
| Rhinocerotidae sp. | 3 | -12 | -11.4 | -13.1 | -11.4 | -1.5 | -1.3 | -2.5 | -0.6 |
| Giraffidae | |||||||||
| Canthumeryx sirtensis | 6 | -11.3 | -11.2 | -12.9 | -9.9 | 1.9 | 2.2 | -0.6 | 3.5 |
| Tragulidae | |||||||||
| Dorcatherium cf. pigotti | 5 | -10.7 | -10.5 | -11 | -10.3 | -2.8 | -3 | -4.5 | -0.3 |
| Sanitheriidae | |||||||||
| Diamantohyus africanus | 3 | -10.5 | -10.2 | -11.2 | -10 | -2.6 | -2.7 | -2.8 | -2.2 |
| Suidae | |||||||||
| Megalochoerus marymuunguae | 5 | -11.6 | -11.8 | -11.9 | -11 | 0.2 | 0.5 | -1 | 1.4 |
| Anthracotheriidae | |||||||||
| cf. Sivameryx africanus | 4 | -10.8 | -10.9 | -11.1 | -10.8 | -2.7 | -3.9 | -5.2 | -4.6 |
TABLE 4. Significance levels from pair-wise Mann-Whitney U tests of bulk δ13Cenamel values between sites. Results considered significant at α ≤ 0.05 are bolded.
| Site (n) | Moroto | Buluk | Maboko | Fort Ternan |
| Moroto (26) | - | |||
| Buluk (67) | 0.07 | - | ||
| Maboko (79) | <0.001 | <0.001 | - | |
| Fort Ternan (21) | <0.001 | <0.001 | 0.17 | - |
