Supporting Information Silcox et al. 10.1073/pnas.0812140106 SI Text cercus lowii having much smaller optic foramina than diurnal Activity Pattern in Ignacius graybullianus. In living primates with Tupaia glis (5). Bloch and Silcox (5) argued that the very small crania less than 75 mm long, there is a consistent relationship optic foramen size in the plesiadapiform Carpolestes simpsoni between orbit size relative to cranial length and activity period, suggested that it was nocturnal despite its small orbit size. with diurnal forms having smaller orbits than nocturnal ones A measurement of the optic foramen for I. graybullianus has (1–4). This relationship does not hold outside of Primates, with never been published. Although it has been suggested (8) that this foramen may be preserved in UM 65569, our examination of regression lines for ln orbit diameter vs. ln cranial length for photographs of this specimen taken by D. Boyer suggests that it nocturnal and diurnal noneuprimate mammals falling nearly on is too damaged to unambiguously identify the foramina that it top of one another (5) (Fig. S2). Because plesiadapiforms are preserves. The optic foramen is not preserved on the surface of stem primates (6), it is unclear whether or not they exhibit the USNM 421608 (8). However, on the endocast for USNM 421608, same scaling relationships as living members of the order, so roots of the optic nerves can be seen—these represent the casts while I. graybullianus and all other plesiadapiforms that have of the first portion of the optic canal, which should also serve as been measured have relatively small orbits (1, 5) (see Fig. S2), a proxy for the size of the optic nerve. Therefore, the diameters it is not clear that this represents compelling evidence of a of these roots were measured in Amira 3.1.1 (Table 1) and used diurnal activity period. Another measure that scales to some in lieu of the optic foramen to calculate values of optic foramen extent with activity period in living primates is the size of the index (1.82) and optic foramen quotient (–37.65) (2). These optic foramen (2, 7). Diurnal haplorhines in particular have large values fall within the range of diurnal haplorhines (Fig. S3) and optic foramina. A similar relationship holds for a small sample approach the values for Tupaia glis (5), which suggests that I. of other euarchontans, with nocturnal dermopterans and Ptilo- graybullianus was diurnal. 1. Kay RF, Cartmill M (1977) Cranial morphology and adaptations of Palaechthon nacimi- 9. Stephan H, Bauchot R, Andy OJ (1970) in The Primate Brain, eds Noback CR, Montagna enti and other Paromomyidae (Plesiadapoidea, ?Primates), with a description of a new W (Appleton-Century-Crofts, New York), pp 289–297. genus and species. J Hum Evol 6:19–53. 10. Stephan H, Frahm H, Baron G (1981) New and revised data on volumes of brain 2. Kay RF, Kirk EC (2000) Osteological evidence for the evolution of activity pattern and structures in insectivores and primates. Folia Primatol 35:1–29. visual acuity in Primates. Am J Phys Anthrop 113:235–262. 11. Gurche JA (1982) in Primate Brain Evolution: methods and concepts, eds Armstrong E, 3. Heesy CP, Ross CF (2001) Evolution of activity patterns and chromatic vision in primates: Falk D (Plenum, New York), pp 227–246. morphometrics, genetics and cladistics. J Hum Evol 40:111–149. 12. Kielan-Jaworowska Z (1984) Evolution of the therian mammals in the Late Cretaceous of 4. Ni X, Wang Y, Hu Y, Li C (2004) A euprimate skull from the early Eocene of China. Nature Asia. Part VI. Endocranial casts of eutherian mammals. Acta Palaeontol Pol 46:157–171. 427:65–68. 13. Novacek MJ (1982) The brain of Leptictis dakotensis, an Oligocene leptictid (Eutheria: 5. Bloch JI, Silcox MT (2006) Cranial anatomy of Paleocene plesiadapiform Carpolestes Mammalia) from North America. J Paleontol 56:1177–1186. simpsoni (Mammalia, Primates) using ultra high-resolution X-ray computed tomogra- 14. Pirlot P, Kamiya T (1982) Relative size of brain and brain components in three gliding phy, and the relationships of ‘‘plesiadapiforms’’ to Euprimates. J Hum Evol 50:1–35. placentals (Dermoptera; Rodentia). Can J Zool 60:565–572. 6. Bloch JI, Silcox MT, Boyer DM, Sargis EJ (2007) New Paleocene skeletons and the 15. Martin RD (1990) Primate Origins and Evolution (Princeton University Press, Princeton). relationship of ‘‘plesiadapiforms’’ to crown-clade primates. Proc Natl Acad Sci 16. Stephan H (1972) in The Functional and Evolutionary Biology of Primates, ed Tuttle R 104:1159–1164. (Aldine-Atherton, New York), pp 155–174. 7. Kirk EC, Kay RF (2004) in Anthropoid Origins: New Visions, eds Ross CF, Kay RF (Kluwer, 17. Cartmill M (1970). The orbits of arboreal mammals: a reassessment of the arboreal Boston), pp 539–602. theory of primate evolution. PhD dissertation (University of Chicago). 8. Kay RF, Thewissen JGM, Yoder AD (1992) Cranial anatomy of Ignacius graybullianus 18. Kirk EC (2006) Visual influences on primate encephalization. J Hum Evol 51:76–90. and the affinities of the Plesiadapiformes. Am J Phys Anthrop 89:477–498. Silcox et al. www.pnas.org/cgi/content/short/0812140106 1of10 Fig. S1. Bivariate plots of ln olfactory bulb volume vs. (A) ln intracranial volume and (B) ln body mass for an array of living and fossil mammals. Range of values presented for Ignacius in (B) reflects varying body mass estimates, including confidence intervals (see Table 2). Data from multiple sources (9–15) and the current study (see Table S1). Designation of taxa as ‘‘basal’’ vs. ‘‘progressive’’ insectivores follows Stephan (16), who indicated that the basal forms had relatively primitive cerebral patterns, while the progressive forms ‘‘reveal distinct marks of higher development.’’ Note that while Ignacius falls within the range of variation of euprimates for the volume of the olfactory bulbs relative to body mass, they have relatively larger bulbs relative to brain mass than in any euprimate. Silcox et al. www.pnas.org/cgi/content/short/0812140106 2of10 Fig. S2. Bivariate plot of ln orbital diameter vs. ln cranial length. Data from multiple sources (2, 4, 5, 17) and the current study. Note that I. graybullianus has a relatively small orbital diameter for its cranial length compared to most modern mammals sampled. Silcox et al. www.pnas.org/cgi/content/short/0812140106 3of10 Fig. S3. Box plots for optic foramen index (OFI) and optic foramen quotient (OFQ) for I. graybullianus, Carpolestes simpsoni, and select extant euarchontans. OFI and OFQ were calculated following Kay and Kirk (2). The measurement of the stem of the optic nerve from the endocast of I. graybullianus (Table 1) was used as a proxy for optic foramen size. Note that I. graybullianus ’ values for OFI and OFQ are much higher than those calculated for C. simpsoni, falling within the range for diurnal haplorhines, and approaching the values for diurnal Tupaia glis. Silcox et al. www.pnas.org/cgi/content/short/0812140106 4of10 Fig. S4. Bivariate plot of relative endocranial volume vs. relative optic foramen area, redrawn from Kirk (18), with the addition of data for I. graybullianus. Vertical lines connect multiple estimates of endocranial volumes for the same specimens. Values were calculated as residuals from the following equations, 3/2 3 3 derived from a sample of extant primates (7): Log10(OFA ) ϭ 0.652(Log10PI )-2.698, Log10ECV ϭ 0.942(Log10PI )-3.907 in which OFA ϭ olfactory foramen area, PI ϭ prosthion-inion cranial length, and ECV ϭ endocranial volume. Silcox et al. www.pnas.org/cgi/content/short/0812140106 5of10 Table S1. Data for Fig. S1 Body mass (g) Total brain volume (net; mm3) Olfactory bulb volume (mm3) Sorex minutus 5.3 103 8.7 Sorex araneus 10.3 188 14.2 Crocidura russula 11 178 16.4 Crocidura occident 28 408 37.8 Suncus murinus 35 354 34.4 Echinops telfairi 87.5 569 65.7 Hemicentetes semisp. 110 757 93.8 Setifer setosus 243 1,404 210 Tenrec ecaudatus 832 2,336 293 Erinaceus europaeus 860 2,969 350 Aethechinus algirus 700 3,174 297 Solenodon paradoxus 900 4,262 478 Nesogale talazaci 50.4 741 74.6 Limnogale mergulus 92 1,046 43.2 Potamogale velox 660 3,822 87 Neomys fodiens 15.2 299 15.9 Talpa europaea 76 953 60 Galemys pyrenaicos 57.5 1,230 39.2 Desmana moschata 440 3,620 142 Chorotalpa stuhimanni 39.8 693 60.8 Elephantulus fuscipes 57 1,233 63.9 Rhynchocyon stuhimanni 490 5,680 427 Tupaia glis 150 2,959 128 Tupaia minor (2) 70 2,430 94.3 Urogale everetti 275 3,997 186 Microcebus murinus 54 1,663 40.3 Cheirogaleus medius 177 2,941 99.3 Cheirogaleus major 450 6,323 155 Lepilemur ruficaud. 915 7,167 131 Hapalemur simus 1,300 8,868 79.4 Eulemur fulvus 1,400 22,053 229 Varecia variegatus 3,000 29,713 374 Avahi laniger 860 9,075 80.6 Propithecus verr. 3,480 25,080 168 Indri indri 6,250 36,159 142 Daubentonia madagasc. 2,800 42,611 693 Loris gracilis 322 6,269 88.1 Nycticebus cougang 800 11,755 164 Perodicticus potto 1,150 13,212 312 Galago demidovii 81 3,203 84.4 Galago senegalensis 186 4,512 81.8 Galago crassicaudatus 850 9,602 180 Tarsius syrichta 87.5 3,416 18.1 Callithrix jacchus 260 7,248 28.4 Saguinus oedipus 405 10,576 24.6 Saguinus tamarin 340 9,459 16.8 Aotus trivirgatus 850 15,229 60.3 Callicebus moloch 650 14,434 16.8 Pithecia monacha 1,500 32,836 38.2 Alouatta seniculus 6,400 47,749 45.2 Cebus ap.