Table 2. Work sheet for likelihood estimation of the time of origin of Archaeoceti. The fossil record of archaeocetes begins at about 49.5 Ma and ends at about 36 Ma, an interval of about 13.5 m.y. (Haq et al. 1987 temporal calibration). There are 42 independently-sampled fossil localities known from sites on six continents (Table 1). Analysis here takes account of exponentially decreasing area of sedimentary rocks of older ages exposed at the earth's surface and linear diversification through the inferred temporal range of archaeocetes before their earliest fossil record (see Fig. 4). Interpolated 50% and 5% likelihood limits for the time of origin of mesonychians are shown in bold face. Results are not accurate to more than one decimal place and must be interpreted in context of the particular temporal calibration used to quantify the geological time scale (50.0 and 51.6 Ma are both late early Eocene). | ||||||||
1. Increment of origination volume 2. Hypothesized time of origin 3. Origination volume B 4. Fossil record volume C 5. Extinction volume D |
6. Hypothesized time of extinction 7. Volume quotient (probability) 8. Exponentiated quotient (probability) 9. Likelihood ratio |
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1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. |
0.0000 | 49.5000 | 0.0000 | 0.0583 | 0.0000 | 36.0000 | 1.0000 | 1.0000 | 1.0000 |
--- | 49.9869 | --- | --- | --- | --- | --- | --- | 0.5000 |
0.0010 | 49.9899 | 0.0010 | 0.0583 | 0.0000 | 36.0000 | 0.9831 | 0.4979 | 0.4979 |
0.0020 | 50.4698 | 0.0020 | 0.0583 | 0.0000 | 36.0000 | 0.9668 | 0.2508 | 0.2508 |
0.0030 | 50.9498 | 0.0030 | 0.0583 | 0.0000 | 36.0000 | 0.9511 | 0.1278 | 0.1278 |
0.0040 | 51.4297 | 0.0040 | 0.0583 | 0.0000 | 36.0000 | 0.9358 | 0.0658 | 0.0658 |
--- | 51.6352 | --- | --- | --- | --- | --- | --- | 0.0500 |
0.0050 | 51.9196 | 0.0050 | 0.0583 | 0.0000 | 36.0000 | 0.9210 | 0.0343 | 0.0343 |
Volume quotient is the fossil record volume (C here and in Fig. 4) divided by the sum of the hypothesized origination volume plus the fossil record volume (B + C here and in Fig. 4). Exponentiated quotient is (B / B + C)n where n is the number of independent samples drawn from B + C and falling in C (here n = 42).
Table 4. Work sheet for likelihood estimation of the time of origin of Mesonychia (here Mesonychidae and Hapalodectidae). The fossil record of Mesonychia begins at about 63 Ma and ends at about 33 Ma, an interval of about 30 m.y. (Haq et al. 1987 temporal calibration). There are some 56 independently-sampled fossil localities known from northern continents (Table 3). Analysis takes account of exponentially decreasing area of sedimentary rocks of older ages exposed at the earth's surface and linear diversification through the inferred temporal range of mesonychians before their earliest fossil record (see Fig. 6). Interpolated 50% and 5% likelihood limits for the time of origin of mesonychians are shown in bold face. Results are not accurate to more than one decimal place and must be interpreted in context of the particular temporal calibration used to quantify the geological time scale (63.8 Ma is early Paleocene and 66.7 Ma is very latest Cretaceous). | ||||||||
1. Increment of origination volume 2. Hypothesized time of origin 3. Origination volume B 4. Fossil record volume C 5. Extinction volume D |
6. Hypothesized time of extinction 7. Volume quotient (probability) 8. Exponentiated quotient (probability) 9. Likelihood ratio |
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1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. |
0.0000 | 63.0000 | 0.0000 | 0.1260 | 0.0000 | 33.0000 | 1.0000 | 1.0000 | 1.0000 |
0.0010 | 63.5199 | 0.0010 | 0.1260 | 0.0000 | 33.0000 | 0.9921 | 0.6474 | 0.6474 |
--- | 63.8308 | --- | --- | --- | --- | --- | --- | 0.5000 |
0.0020 | 64.0398 | 0.0020 | 0.1260 | 0.0000 | 33.0000 | 0.9844 | 0.4206 | 0.4206 |
0.0030 | 64.5600 | 0.0030 | 0.1260 | 0.0000 | 33.0000 | 0.9767 | 0.2741 | 0.2741 |
0.0040 | 65.0801 | 0.0040 | 0.1260 | 0.0000 | 33.0000 | 0.9692 | 0.1793 | 0.1793 |
0.0050 | 65.6002 | 0.0050 | 0.1260 | 0.0000 | 33.0000 | 0.9618 | 0.1176 | 0.1176 |
0.0060 | 66.1303 | 0.0060 | 0.1260 | 0.0000 | 33.0000 | 0.9545 | 0.0774 | 0.0774 |
0.0070 | 66.6504 | 0.0070 | 0.1260 | 0.0000 | 33.0000 | 0.9474 | 0.0511 | 0.0511 |
--- | 66.6781 | --- | --- | --- | --- | --- | --- | 0.0500 |
0.0080 | 67.1705 | 0.0080 | 0.1260 | 0.0000 | 33.0000 | 0.9403 | 0.0339 | 0.0339 |
Volume quotient is the fossil record volume (C here and in Fig. 6) divided by the sum of the hypothesized origination volume plus the fossil record volume (B + C here and in Fig. 6). Exponentiated quotient is (B / B + C)n where n is the number of independent samples drawn from B + C and falling in C (here n = 56).