Supplementary Figure 1. Strict consensus of 49 trees (TL = 1169) resulting from parsimony

Transcription

1 Supplementary Figure 1. Strict consensus of 49 trees (TL = 1169) resulting from parsimony analysis with topological constraints corresponding to Laurasiatheria and Afrotheria. Shaded areas indicate Perissodactyla sensu stricto (blue) and Afrotheria (red). Cambaythere taxa are indicated in orange, anthracobunid taxa in blue, and the artiodactyl Diacodexis in purple.

2 Supplementary Figure 2. Strict consensus of 4 trees (TL = 1173) resulting from parsimony analysis with topological constraints uniting anthracobunids with proboscideans. Shaded areas indicate Perissodactyla sensu stricto (blue) and Afrotheria (red). Cambaythere taxa are indicated in orange, anthracobunid taxa in blue, and the artiodactyl Diacodexis in purple.

3 Supplementary Figure 3. Majority rule consensus of 29 shortest trees (TL = 1159) resulting from parsimony analysis excluding scorings for characters based on the supposed Anthracobune astragalus described by Gingerich et al. 1. Shaded areas indicate Perissodactyla sensu stricto (blue) and Afrotheria (red). Bold taxa indicate cambaytheres (green) and anthracobunids (blue). Insets in lower left indicate alternate positions of Radinskya and anthracobunids found in the remaining trees. Numbers above the branches indicate Bremer decay index (indices of 10 or more specified as >9), and numbers below the branches indicate bootstrap support (values <50 not shown).

4 Supplementary Figure 4. Strict consensus of 4 trees (TL = 1174) resulting from parsimony analysis with topological constraints uniting cambaytheres and anthracobunids with afrotheres. Shaded areas indicate Perissodactyla sensu stricto (blue) and Afrotheria (red). Cambaythere taxa are indicated in orange, anthracobunid taxa in blue, and the artiodactyl Diacodexis in purple.

5 Supplementary Table 1. Measurements (mm) and statistics of lower teeth of Cambaytherium thewissi. P 1 L P 1 W P 2 L P 2 W P 3 L P 3 W P 4 L P 4 W M 1 L M 1 W tri M 1 W tal M 2 L M 2 W tri Number of Individuals Minimum Maximum Range Arithmetic Mean Standard Deviation Coefficient of Variation Shapiro-Wilk Statistic Shapiro-Wilk P Value M 2 W tal M 2 W tal M 3 L M 3 W tri M 3 W tal DP 2 L DP 2 W DP 3 L DP 3 W DP 4 L DP 4 W tri DP 4 Wtal Number of Individuals Minimum Maximum Range Arithmetic Mean Standard Deviation Coefficient of Variation Shapiro-Wilk Statistic Shapiro-Wilk P Value

6 Supplementary Table 2. Measurements (mm) and statistics of upper teeth of Cambaytherium thewissi. P 2 L P 2 W P 3 L P 3 W P 4 L P 4 W M 1 L M 1 W ant M 1 W post M 2 L M 2 W ant M 2 W post Number of Individuals Minimum Maximum Range Arithmetic Mean Standard Deviation Coefficient of Variation Shapiro-Wilk Statistic Shapiro-Wilk P Value M 3 L M 3 W ant M 3 W post DP 3 L DP 3 W DP 4 L DP 4 W ant DP 4 Wpost Number of Individuals Minimum Maximum Range Arithmetic Mean Standard Deviation Coefficient of Variation Shapiro-Wilk Statistic Shapiro-Wilk P Value

7 Supplementary Table 3. Comparison of various parsimony analyses performed for this study, in terms of topological constraints, inclusion or exclusion of astragalar characters for Anthracobune, and tree length. Analysis Constraint Anthracobune Tree Length astragalar characters 1 None Included None Excluded Perissodactyla and Artiodactyla united Included 1169 in Laurasiatheria 4 Cambaytheres, anthracobunids, and Included 1174 afrotheres monophyletic 5 Anthracobunids and proboscideans Included 1173 monophyletic

8 Supplementary Note 1. List of specimens of Cambaytherium thewissi in the study sample. GU, Department of Geology, H.N.B. Garhwal University, Srinagar, Uttarakhand, India (these specimens are cataloged as either GU/RSR/VAS (Vastan mine) or GU/RSR/MN (Mangrol mine); WIF/A, Wadia Institute of Himalayan Geology, Dehradun, Uttarakhand, India. Crania GU 402, GU 730 Dentaries GU 401, GU 403, GU 736, GU 776, GU 1595, GU 1596, GU 1700, GU 1701, GU 1710, GU 1711, GU 7001, GU 7004 Teeth GU 2, GU 3, GU 4, GU 10, GU 18, GU 201-GU 204, GU 206, GU 209, GU 221, GU 222, GU 225, GU 404, GU 406, GU 409, GU 412-GU 415, GU 417, GU 418, GU 424- GU 426, GU 428, GU 430, GU 432, GU 433, GU 626, GU 658-GU 665, GU 731-GU 734, GU 784, GU 785, GU 792, GU 823, GU 833, GU 1221-GU 1223, GU 1515, GU 1516, GU 1592-GU 1594, GU 1597, GU 1598, GU 1615, GU 1616, GU 1672, GU 1675, GU 1676, GU 1678, GU 1679, GU 1682, GU 1683, GU 1708, GU 1709, GU 1727, GU 7002, GU 7011, GU 7012, GU 7015-GU 7018, GU 7022, GU 7023, GU 8002-GU 8005, GU 8007, GU 8008, GU 8010-GU 8016, GU 8019-GU 8028, GU 8030-GU 8034 Vertebrae GU 773-GU 775, GU 782, GU 783, GU 786-GU 791, GU 824, GU 825, GU 7003, GU 8017 Sternal segment GU 7010 Scapulae GU 820, GU 1213 Humeri GU 270, GU 737, GU 738, GU 778, GU 809, GU 834, GU 1211, GU 1214, GU 7006 Radii GU 274, GU 280, GU 771, GU 777, GU 842, GU 7019 Ulnae GU 1215, GU 1216, GU 7005

9 Carpals GU 293-GU 296, GU 333, GU 835, WIF/A 1192 Metacarpals GU 292, GU 815, GU 817, GU 818, GU 822, GU 832, GU 847, GU 848, GU 1217, GU 1704, GU 7007 Femur GU 198, GU 1218, GU 1219, GU 7026 Patella GU 8018 Tibia GU 278, GU 739, GU 779, GU 1220 Fibula GU 300 Tarsals GU 297, GU 304, GU 768-GU 770, GU 772, GU 780, GU 814, WIF/A 1190 Metatarsals GU 275, GU 735, GU 816, GU 819, GU 821, GU 831, GU 846 Phalanges GU 280-GU 282, GU 828-GU 830, GU 843-GU 845, GU 7008, GU 7009, GU 7020, GU 7021, GU 8006, GU 8029 Supplementary Note 2. Character descriptions. Corresponding characters from other studies are indicated in parentheses, with previous studies abbreviated as follows: F02, Froehlich 2 ; FT93, Fischer and Tassy 3 ; H09, Holbrook 4 ; HD04, Hooker and Dashzeveg 5 ; KL12, Kondrashov and Lucas 6 ; LMS10, Ladevèze et al Posterior nasal narrow, not contacting lacrimal (0); broad contact with frontal (1). (H09:1) 2. Length of postorbital portion of skull shorter than preorbital portion (0); about equal to preorbital portion (1); longer than preorbital portion (2). (F02:14) 3. Position of orbits over molars (0); over premolars or more anterior (1). (FT:56 4. Premaxilla small, ascending process contacts nasals (0); ascending process present, no nasal contact (1). (H09:2) 5. Incisive foramen paired (0); single median (1). (H09:3)

10 6. Tuber maxillae weak or absent in adult (0); prominent in adult (1). (FT93:67) 7. Orbital portion of maxilla separated from frontal (0); contacting frontal (1). (LMS10:20) 8. Sphenopalatine foramen middle of orbit (0); near maxillary foramen (1). (H09:4) 9. Contribution of ascending lamina of palatine in orbit forms significant part of medial orbital wall (0); very small or absent from medial orbital wall (1). 10. Palatal vacuities present (0); absent (1). 11. Facial exposure of lacrimal large or moderate, not contacting nasal (0); large or moderate, contacting nasal (1); small, not contacting nasal (2); absent (3). (H09:5) 12. Supraorbital process absent, region over orbit does not project laterally from sagittal plane (0); present, short (1); present, long and extending ventrally (2). (LMS10:19, modified) 13. Supraorbital foramen or notch present (0); absent (1). (H09:6) 14. Optic foramen anteriorly placed (0); posteriorly placed (1). (H09:7) 15. Sphenorbital fissure separate from foramen rotundum (0); confluent with foramen rotundum (1). (LMS10:15) 16. Alisphenoid canal (posterior opening) present (0); absent (1). (LMS10:13) 17. Posterior opening of alisphenoid canal separate from foramen ovale (0); in common depression with foramen ovale (1). (LMS10:14) 18. Foramen ovale separate (0); confluent with mid lac for (1). (H09:8) 19. Foramen ovale position anterior to glenoid fossa (0); medial to glenoid fossa (1). (LMS10:12) 20. Orbital portion of parietal contacting alisphenoid (0); not contacting alisphenoid (1).

11 21. Anterior extent of jugal and zygomatic portion of maxilla jugal extends anteriorly, forms anteroventral border of orbit (0); zygomatic portion of maxilla large, jugal more posterior and does not contribute to anteroventral border of orbit (1). (FT93:32) 22. Posterior extent of jugal strong, contributes to anterior portion of glenoid fossa (0); strong, extends to posterior border of glenoid fossa without contributing to articular surface (1); weak, splint-like, extends to anterior edge of glenoid fossa (2). (FT93:34, modified) 23. Zygomatic process of squamosal narrow (0); laterally expanded (1). (FT93:58) 24. Preglenoid process absent (0); present (1). (H09:9) 25. Postglenoid process facing anteriorly (0); facing anterolaterally (1). (H09:10) 26. Postglenoid foramen present (0); absent (1). (H09:11) 27. Posttympanic process about the same size as postglenoid process (0); shortened relative to postglenoid process (1). (H09:12) 28. Exposure of mastoid broad, posterior (0); narrow, lateral (1); absent (amastoidy) (2). (H09:13) 29. Mastoid foramen present, between mastoid and occipital-supraoccipital (0); absent (1). (LMS10:16) 30. Posttemporal (or percranial) canal present at petrosal-squamosal suture, canal continues within suture (0); absent (1). 31. Sulcus for internal carotid artery transpromontorial, forms anteroposterior groove on promontorium (0); absent (1). (LMS10:5) 32. Sulcus for proximal stapedial artery present, forms groove that branches from transpromontorial sulcus anteromedial to fenestrae vestibuli and cochleae (0); absent (1). (LMS10:6)

12 33. Tympanic aperture of hiatus Fallopii absent (0); present (1). (LMS10:9) 34. Foramen for ramus superior of stapedial artery present, through petrosal or petrosal squamosal suture on dorsolateral edge of epitympanic recess (0); present and anterolateral, through basioccipital (1); absent (2). (LMS10:11) 35. Ectotympanic not attached (0); attached (1); attached and forms bulla (2). (H09:14) 36. Hypoglossal foramen present (0); absent (1). (FT93:35) 37. Height of mandibular condyle below level of dentition (0); even with superior aspect of dentition (1); substantially superior to dentition (2). (LMS10:22) 38. Coronoid canal of dentary absent (0); present (1). 39. Number of thoracic vertebrae fewer than 19 (0); more than 19 (1). (FT93:74) 40. Number of sacral vertebrae three or fewer (0); four (1); five (2); six (3). 41. Acromion process present (0); absent (1). (H09:15) 42. Bicipital groove of humerus simple (0); with distinct "facet" (1). (H09:16) 43. Ridge from deltopectoral crest extending onto distal anterior shaft of humerus present (0); absent (1). 44. Supinator crest of humerus well-developed and prominent (0); present but restricted to distal third of shaft (1); weak or absent (2). (KL12:45) 45. Lateral articular shelf absent or indistinct (0); present, tapered distally (1); present, extended distally (2). (H09:17) 46. Proximolateral part of lateral articular shelf flat or convex (0); concave and elaborated (1). 47. Entepicondylar foramen present (0); absent (1). (H09:18) 48. Medial epicondyle very prominent, expands medially (0); prominent but not expanded (1); weak or absent (2). (KL12:44, modified)

13 49. Supratrochlear foramen of humerus absent (0); present (1). (KL12:43) 50. Capitulum of humerus round (0); gently keeled (1); distinctly, sharply keeled (2). 51. Proximal radius with single fossa for humeral capitulum and trochlea (0); with separate fossae for capitulum and trochlea (1). (LMS10:45, modified) 52. Proportions of head of radius low width to depth ratio (0); high width to depth ratio (1). 53. Lateral process of radius absent or weak (0); present (1). 54. Articular surface of lateral process of proximal radius shallowly concave (0); shallowly convex (1). 55. Extent of proximal ulnar facet on posterior aspect of proximal radius restricted to lateral half of face (0); extending medially as narrow strip across width of head (1). 56. Shape of lateral process of proximal radius not beveled (0); beveled to accommodate capitular tail (lateral articular shelf) (1). 57. Styloid process of distal radius distinct and projecting distally (0); weak or absent (1). 58. Facets on distal radius single concave fossa (0); split into separate scaphoid and lunar fossae (1). (LMS10:46) 59. Articular surface of distal radius restricted to distal face (0); convex extension onto distopalmar surface (1). 60. Contact between lunar and unciform present (0); absent (1). (FT93:24) 61. Contact between lunar and trapezoid absent (0); present (1). (FT93:25) 62. Centrale present as separate ossification (0); absent or fused to scaphoid (1). (LMS10:47) 63. First metacarpal present (0); absent (1). 64. Fifth manual digit present with phalanges (0); present without phalanges (1); absent (2). (H09:19, modified)

14 65. Anterior iliac crest round (0); slightly concave or straight (1); deeply concave (2). 66. Fovea capitis of femur centrally located (0); marginal (1). (H09:20) 67. Height of greater trochanter lower than head (0); about even with head (1); higher than head (2). (F02:116) 68. Orientation of lesser trochanter of femur medially (0); posteromedially (1). (KL12:51) 69. Size third trochanter of femur small (0); large (1); absent (2). (KL12:52, in part) 70. Supracondylar fossa of femur absent (0); present (1). (H09:22) 71. Trochlear ridges of distal femur subequal (0); medial expanded with tuberosity (1). (H09:23) 72. Ossified patella absent (0); present (1). 73. Medial malleolus of tibia forms well-developed medial wall (0); prominent anteriorly, reduced and beveled posteriorly (1). 74. Posterior process and median ridge of distal articulation of tibia absent (0); present (1). 75. Astragalar canal present (0); absent (1). (FT93:27) 76. Orientation of trochlear ridges of astragalus not oblique (essentially vertical) (0); oblique (1). 77. Depth of trochlear groove of astragalus nearly flat to concave (0); shallow groove, less than 25% of trochlea width (1); deep groove, more 25% of trochlear width (2). (LMS10:50) 78. Distal extent of medial trochlear ridge of astragalus separate from distal edge of astragalus (0); reaching distal edge of astragalus (1). 79. Cotylar fossa absent (0); present (1). (LMS10:54) 80. Lateral process of astragalus small (0); large and shelf-like (1). KL12:56) 81. Tuberculum mediale of astragalus absent (0); present (1). (FT93:28) 82. Squatting facet on dorsal side of astragalar neck absent (0); present (1). (LMS10:53)

15 83. Sustentacular facet of astragalus separate from distal calcaneal and ectal facets (0); confluent with distal calcaneal facet (1); J-shaped (2); confluent with ectal facet (3). (H09:24) 84. Posterior tubercle of medial trochlear facet small (0); protruding (1); extending proximomedially (2). 85. Proximal calcaneal facet of astragalus without distoectal lappet (0); with distoectal lappet (1). 86. Navicular facet of astragalus spherical or convex (0); saddle-shaped (1); trochleated (2). (H09:25) 87. Lateral groove on calcaneus present, broad (0); absent or indistinct (1). This is a broad groove bordered by a shelf of bone that housed the tendon of m. adductor digiti quinti. 88. Orientation of astragalar facet of calcaneus in lateral view sloping proximally, with no angle formed within facet (0); sloping slightly proximally, facet has a rounded angle within it (1); perpendicular to long axis, facet forms sharp angle (2). 89. Orientation of astragalar facet of calcaneus in anterior view oriented at angle to long axis (0); oriented perpendicular to long axis (1); elongated along long axis (2). 90. Shape of facet of sustentaculum of calcaneus round or oval (0); narrow, straight on lateral edge (1). 91. Orientation of distal edge of calcaneus between sustentaculum and cuboid facet makes wide angle with long axis (0); makes acute angle with long axis (1); expanded into distal shelf that forms right angle (2). 92. Shape of cuboid facet of calcaneus not crescent-shaped (0); crescent-shaped (1). 93. Peroneal tuberosity of calcaneus large (0); present, moderate, projecting distally (1); small, indistinct, or absent (2). (KL12:70, modified) 94. Anterior contact between navicular and calcaneus absent (0); present (1).

16 95. Plantar process of navicular present and prominent (0); weak or absent (1). 96. Navicular and proximal ectocuneiform facets of cuboid not confluent (0); confluent with distinct ridge (1). 97. Entocuneiform medially placed (0); posteriorly placed (1); absent (2). (H09:26) 98. Entocuneiform and mesocuneiform separate (0); fused (1). 99. Mesocuneiform and navicular facets of entocuneiform along anterior margin (0); mesocuneiform facet posterolateral to navicular facet (1) Cuboid not contacting third metatarsal (MT III) (0); contacts MT III (1). (H09:27) 101. First metatarsal present with phalanges (0); present without phalanges, medially positioned (1); small and lacking phalanges, articulating with posterior MT III (2); absent (3). (LMS10:57) 102. Fifth metatarsal present with phalanges (0); present without phalanges (1); absent (2). (LMS10:58, modified) 103. Distal phalanges laterally compressed, as claws (0); dorsoventrally compressed, as hooves (1). (KL12:49, modified) 104. Canine size large (0); small (1); absent (2). (KL12:23) 105. Postcanine diastema short (0); long (1); absent (2). (H09::28) 106. Cusp relief of cheek teeth sharp, generally conical (0); tall, bunodont cusps with little or no loph development (1); low, bunodont to bunolophodont (2); well-developed lophodonty with high lophs (3) Cheek tooth enamel surface smooth (0); rugose (1) Fifth premolar present (0); absent (1) P1 present with diastema (0); present without diastema (1); absent (2). (H09:29)

17 110. Diastema posterior to P2 absent (0); long (greater than P3 length) (1); short (less than or equal to P3 length) (2) P2 metacone absent (0); present, small, close to paracone (1); present, about as large as and separate from paracone (2) P2 metacone position close to paracone (0); distant from paracone (1) P2 lingual cusps none (0); one (1); two (2). (H09:31) 114. P3 size smaller or nearly equal to P4 (0); larger than P4 (1) P3 parastyle protruding, P3 mesial edge concave (0); not protruding, P3 mesial edge convex (1) P3 paraconule absent or indistinct (0); present (1); present and lingually positioned (2) P3 preparaconule crista in line with connection to protocone (0); angled more labially than connection to protocone (1) P3 metacone absent (0); present, much smaller than paracone (1); present, comparable in size to paracone (2). (KL12:2) 119. P3 metaconule absent or indistinct (0); present, small relative to paraconule (1); present, similar in size to paraconule (2) P3 metaloph none, metaconule separate from ectoloph and protocone (0); metaconule connected to protocone but not to ectoloph (1); metaconule connects to ectoloph but not to protocone (2); metaloph complete but weak (3); metaloph complete and prominent (4) P3 protocone absent (0); present (1) P3 endoprotocrista absent (0); present, distal ridge (1); present, forming hypocone (2) P4 protocone absent or indistinct (0); present, close to paracone in size (1). (KL12:3) 124. P4 paraconule large and distinct (0); small (1); indistinct (2). (KL12:7, in part)

18 125. P4 preparaconule crista orientation toward parastyle (0); toward paracone (1) P4 metacone present, distinctly smaller than paracone (0); present, about equal in size to paracone (1); absent (2). (LMS10:27) 127. P4 metaconule present, similar in size to paraconule (0); present, significantly smaller than paraconule (1); absent or indistinct (2). (KL12:7, in part) 128. P4 metaconule position distal to line connecting protocone and metacone (0); on line connecting protocone and metacone (1); mesial to line connecting protocone and metacone (2) P4 endoprotocrista absent (0); present as ridge joined to protocone (1); present, forming hypocone (2) P4 metaloph absent, no connections between protocone (or hypocone), metaconule, and ectoloph (0); metaconule connects to ectoloph, but not protocone or hypocone (1); metaconule connects to protocone or hypocone, but not ectoloph (2); metaloph complete but low or weak (3); metaloph complete and high (4) P4 hypocone absent (0); present, weak or poorly separated from protocone (1); present, strong and separate from protocone (2) P3 and P4 metacone position distal to paracone (0); distolingual to paracone (1) P3-4 cross lophs not u-shaped (0); u-shaped (1). (H09:35) 134. M1 size smaller or nearly equal to M2 (0); larger than M2 (1). (FT93:9) 135. M1 ectocingulum absent (0); present but broken at paracone (1); present and continuous (2) M2 ectocingulum absent (0); present but broken on paracone (1); present and continuous (2) Upper molar centrocrista poorly developed (0); present, labially flexed (1); present, not flexed (2). (H09:36)

19 138. Upper molar mesostyle absent (0); weak, cingular (1); strong (2). (H09:37) 139. Upper molar paracone not flattened (0); flattened buccally (1); pinched (2). (H09:38) 140. Lingual crest on paracone absent (0); present (1) Upper molar metacone not flattened (0); flattened buccally (1); part of convex ectoloph (2). (H09:39) 142. Upper molar metacone tilting vertical, in line with paracone (0); metacone lingually tilted (1) M1-2 postmetacrista weak or absent (0); present and in line with paracone and metacone (1); present and labially deflected (2) M3 postmetacrista weak or absent (0); present and in line with paracone and metacone (1); present and labially deflected (2) Upper molar protocone and hypocone shape vertical (0); mesially recurved (1) Upper molar paraconules large and distinct (0); small or indistinct (1); merged into protoloph (2). (H09:40, modified) 147. Upper molar paraconule position midway between paracone and protocone (0); closer to protocone (1); closer to paracone (2) Upper molar metaconules present (0); very small (1); absent (2). (H09:41, modified) 149. Upper molar metaconules or corresponding part of metalophs on line between metacone and hypocone (0); mesial to line connecting metacone and hypocone (1) Upper molar parastyles small (0); large, teardrop-shaped (1); form crest with pa (2); absent (3). (H09:42) 151. Main mass of upper molar parastyle in line with pa and me (0); buccal to line connecting pa and me (1). (F02:40)

20 152. Upper molar parastyles not recurved (0); distally recurved (1). (HD04:42) 153. M3 parastyle similar to that of M1-2 (0); projecting buccally (1). (HD04:43, modified) 154. M1-2 paracone and metacone size paracone distinctly larger than metacone (0); paracone and metacone about same size (1) Upper molar preparaconule crista toward parastyle (0); toward paracone, does not join (1); joined with paracone (2). (H09:46) 156. Upper molar ectoloph-metaloph junction anterior to metacone, separate (0); anterior to me, premetaconule crista bends back to join (1); joins at metacone (2). (H09:47) 157. M1-2 hypocone absent (0); present (1). (LMS10:32) 158. M2 posthypocrista absent or indistinct (0); distinct, short, and mesiobuccally directed (1); distinct, long, and mesially directed (2); distinct, long, mesiobuccally directed, forming basin distal to metaloph (3) M2 lingual cingulum absent (0); present only as ridge spanning central valley (1); present, except at hypocone (2); present across entire lingual face (3) Labial crest of upper molar hypocone absent (0); present (1) M3 size distinctly smaller than M2 (0); about same size as M2 (1); distinctly larger than M2 (2). (KL12:9, modified) 162. M3 metacone similar to that of M2 (0); lingually shifted (1); lingually shifted to nearly touching hypocone (2). (F02:61) 163. M3 hypocone absent (0); present, but distinctly smaller than M3 protocone (1); present, similar in size to M3 protocone (2). (HD04:22, modified) 164. M3 hypocone position at about same level as protocone (0); labially shifted relative to protocone (1); lingually shifted relative to protocone (2).

21 165. M3 hypostyle absent (0); small or narrow cingulum (1); large shelf or cusp (2); posthypocrista continuous with postmetacrista, enclosing basin (3) M1-2 square or longer than broad (0); broader than long (1). (F02:64) 167. Second lower incisor not tusk-like (0); enlarged, procumbent, and tusk-like (1) Distal cusp on i3 absent (0); present (1). (H09:50) 169. p1 present with short diastema (0); present with no diastema (1); absent (2). (H09:51) 170. Post-p2 diastema absent (0); short (less than or equal to p3) (1); long (greater than p3) (2) p2 paraconid absent (0); large and distinct without paralophid (1); present with paralophid (2); paralophid forming loop enclosing mesial basin (3) p2 metaconid absent (0); very small swelling on protoconid slope (1); distinct, small, and distolingual to protoconid (2); large and lingual to protoconid (3) p2 talonid shelf or ridge with no distinct cusps (0); small, medially-placed hypoconid present (1); large, medially-placed hypoconid with well-developed metalophid (2); large, labially-placed hypoconid with well-developed metalophid, entoconid absent (3); large, labiallyplaced hypoconid with well-developed metalophid, entoconid present (4) p3 metaconid absent (0); present, close to protoconid (1); present, closer to margin of tooth than to protoconid (2). (F02:69) 175. p3 metaconid size less than half the height of protoconid (including absent) (0); more than half the height of protoconid but still distinctly smaller (1); about equal in size to protoconid (2) p3 hypoconid small (0); large (1); absent (2) p3 entoconid absent (0); present, distinctly smaller than hypoconid (1); present, comparable in size to hypoconid (2). (FT93:13)

22 178. p3 paraconid or paralophid paraconid not distinct, paralophid no more than short, mesial preprotocristid (0); paraconid distinct cusp, with or without paracristid (1); paralophid well developed without distinct paraconid, defines valley between paralophid and metaconid/protoconid (2) p4 paraconid and paralophid absent (0); distinct cusp, with or without paracristid (1); paralophid well developed without paraconid, mesially or mesiolingually directed (2); paralophid well developed without paraconid, extends lingually close to mesial wall (3) p4 width distinctly narrower than m1 (0); as wide or almost as wide as m1 (1); wider than m1 (2). (KL12:28) 181. p4 metaconid absent (0); present, much smaller than protoconid (1); present, about same size as protoconid (2); present, taller than protoconid (3). (KL12:26) 182. p4 entoconid absent or weak (0); present and distinct (1). (F02:75) 183. m1 paraconid or paralophid distinct, separate paraconid cusp (0); distinct paraconid at lingual end of paralophid appressed to protolophid (1); paralophid extending lingually without distinct paraconid, separate from metaconid (2); paralophid extending lingually and connected to mesial crest from metaconid (3); paralophid extending mesiolingually with valley between it and protolophid (4); short lingually-extending paralophid and labially extending crest from metaconid meeting at mid-protolophid (5); paraconid and paralophid absent or indistinct (6). (LMS10:38, modified) 184. m3 protolophid shape straight (0); labial portion angled more distolingually than lingual portion (1); lingual portion angled more distolingually than rest (2) Lower molar protolophid notch deeply notched nearly to base of cusps (0); shallowly notched to flat (1).

23 186. Lower molar twinned metaconids absent (0); present (1). (H09:54) 187. Lower molar protolophid connection to metaconid protolophid connects to mesial metaconid or between mesial and distal metaconids (0); protolophid connects exclusively to distal metaconid (1) Lower molar metaconid buttress absent (0); lingual (1); labial (2). (HD04:13, modified) 189. Mesial crest of molar metaconid present (0); absent (1) Lower molar metastylids strong (0); weak (1); absent (2) Lower molar cristid obliqua oblique, contacts middle of protolophid (0); oblique, contacts lingual cusps (1); longitudinal (2). (H09:56) 192. m2 cristid obliqua shape straight (0); bowed buccally (1); bowed buccally forming continuous arc with hypolophid (2); bowed lingually (3) m3 cristid obliqua shape straight (0); bowed buccally (1); forming continuous arc with hypolophid (2); bowed lingually (3) Height of cristid obliqua within valley between trigonid and talonid cristid obliqua very low or interrupted, valley wide and deep (0); valley filled or reduced by cristid obliqua or encroaching bases of cusps (1) Lower molar talonid height much lower than trigonid (0); about same height as trigonid (1). (KL12:29, modified) 196. m3 hypolophid incomplete (0); complete, lingual and labial cristids about equal (1); complete, labial cristid longer than lingual (2). (H09:58) 197. m3 hypolophid shape straight (0); labial portion angled more distolingually than lingual portion (1); slightly concave distally (2); lingual portion angled more distolabially than labial portion (3).

24 198. Lower molar posthypocristid present (0); absent (1) Lower molar postentocristid absent (0); present (1) m3 postentoconulid absent (0); present, small (1); present, large (2); medial extension of lophoid loop (3). (FT93:3, modified) 201. m1 and m2 hypoconulids large (0); small (1); absent or cingular (2); form enlarged cingular shelf (3) m1 and m2 hypoconulid position buccal (0); medial (1); lingual (2) m2 hypoconulid separate from hypolophid (0); closely appressed to hypolophid (1) m3 hypoconulid present, large (0); small (1); absent or reduced to cingulum (2). (H09:59) 205. m3 hypoconulid position completely distal of hypoconid and entoconid (0); between hypoconid and entoconid, forming part of hypolophid where present (1) m3 hypoconulid connection separate (0); joining mid-hypolophid (1); joins postcristid from hypoconid (2); joins postcristid from entoconid (3). (H09:60) 207. Lower molar entoconulid distinct (0); indistinct or absent (1) Enamel prism decussation horizontal (0); vertical (1). Supplementary Note 3. List of taxa included in parsimony analyses for this study. Cambaytheriidae Cambaytherium thewissi Nakusia shahrigensis

25 Anthracobunidae Anthracobune (A. pinfoldi and A. aijiensis) Pilgrimella pilgrimi HYRACOIDEA Dimaitherium patnaiki Microhyrax lavocati Saghatherium antiquum PROBOSCIDEA Eritherium azzouzorum Phosphatherium escuilliei Moeritherium lyonsi Numidotherium koholense ARTIODACTYLA Diacodexis pakistanensis PERISSODACTYLA Isectolophidae Homogalax protapirinus Cardiolophus radinskyi Isectolophus (I. annectens and I. latidens)

26 Lambdotheriidae Lambdotherium popoagicum Brontotheriidae Eotitanops borealis Palaeosyops robustus Lophiodontidae Lophiodon (L. remensis and L. leptorhynchum) Eomoropidae Eomoropus amarorum Litolophus mongoliensis Chalicotheriidae Moropus elatus Helaletidae Heptodon (H. posticus and H. calciculus) Helaletes nanus Hyrachyidae Hyrachyus modestus Lophialetidae Lophialetes expeditus Schlosseria magister Deperetellidae Teleolophus medius Deperetella cristatum

27 Equidae Pliolophus vulpiceps Eohippus angustidens Protorohippus venticolus Xenicohippus osborni Sifrhippus sandrae Hallensia matthesi Hyracotherium leporinum Propachynolophus gaudryi Eurohippus parvum Orohippus pumilus Epihippus parvus Mesohippus bairdi Palaeotheriidae Palaeotherium crassum Plagiolophus annectens Leptolophus nouleti CONDYLARTHRA Phenacodontidae Tetraclaenodon puercensis Ectocion osborni Phenacodus intermedius

28 Meniscotherium chamense Phenacolophidae Phenacolophus fallax Incertae sedis Radinskya yupingae ASIORYCTITHERIA Asioryctes nemegetensis MARSUPIALIA Didelphis virginiana Supplementary Discussion Summary Description The following description summarizes the most important dental and osteological features of Cambaytherium thewissi. Detailed description accompanied by additional images will be presented elsewhere. The skull (Fig. 1) is generalized, with proportions and shape similar to those of phenacodontid condylarths and primitive perissodactyls. Postmortem distortion obscures many cranial details, but the following features can be confirmed: the nasal incision is shallow at most; the nasofrontal suture is transverse rather than intruding between the frontals; and the orbit is situated above the molars, not more anteriorly as is characteristic of tethytheres 3, 6. The

29 zygomatic arch is complete, like that of perissodactyls, but not inflated or elevated like that of tethytheres 3,6. The auditory region is not preserved. The dental formula (3? incisors-1 canine-4 premolars-3 molars/ ) is the same as in other primitive post-cretaceous placentals. All teeth have enamel marked by conspicuous, coarse perikymata. Both upper and lower incisors are relatively small and of similar size, with crowns that are spatulate or gently rounded. The canines are considerably larger, and the root is much larger than the crown. A short diastema separates the two-rooted, simple P 1 from P 2. P 2-4 are not molariform and have connate paracone and metacone. The protocone is prominent on P 3-4 but variable on P 2, whereas hypocones are absent. Conules are variably present on P 3-4. The upper molars are essentially quadrate and bunodont, with four prominent main cusps paracone, metacone, protocone, and hypocone. The lingual cusps are situated slightly posterior to their buccal counterparts. The molar conules are very prominent and shifted anteriorly relative to the main anterior and posterior cusps, and there is little or no indication of bilophodonty. Stylar cusps are variable, and accessory cuspules are common, especially on M 3. The mandible has a strongly fused symphysis extending back below P 2 (Fig. 1). The ascending ramus is prominent and vertically oriented, with a high condyle positioned well above the tooth row, and a reduced coronoid. The lower premolars are relatively simple and tworooted, dominated by a large trigonid cusp followed by a short talonid cusp. P 4 is shorter than P 2 and P 3. The primary trigonid cusp of P 2-4 typically shows heavy abrasive wear (Fig. 2). The lower molars are bunodont, with crests weakly developed or absent, the metaconid twinned, and the paraconid typically absent. M 3 has an extended third lobe, as in perissodactyls but not phenacodontids, with multiple hypoconulid cusps.

30 Several vertebrae are known from each part of the column. They are generally similar to those of phenacodontids and basal perissodactyls, although the zygapophyses of some lumbar vertebrae are more interlocking than in those taxa. Also of interest is that a sacrum tentatively attributed to the closely related cambaythere Kalitherium marinus (Fig. 3f) consists of four vertebrae. Phenacodus has three or four sacrals 8, whereas the basal perissodactyl Arenahippus has five 9. The humerus of Cambaytherium (Figs. 3, 4) resembles those of both phenacodontids and primitive perissodactyls in having a prominent greater tuberosity and a relatively narrow distal end with a well-defined trochlea, deep olecranon fossa, and large supratrochlear foramen. It is relatively more robust than in primitive perissodactyls and further differs in having a relatively lower greater tuberosity, stronger lateral supracondylar ridge, and a distally extensive deltopectoral crest as in Phenacodus, and in lacking the capitular tail that is characteristic of the distal humeral articulation of primitive perissodactyls. The capitulum is narrower than that of Phenacodus but less constricted than in basal perissodactyls. The medial epicondyle closely resembles that of Homogalax: the entepicondyle is reduced relative to that of phenacodontids, and there is no entepicondylar foramen. The trochlea is about as wide as the capitulum, as in basal perissodactyls, rather than narrower as in phenacodontids, and the medial trochlear rim projects distinctly distally. The antebrachium is relatively robust and short compared to that of Arenahippus. The ulna is distinctly concave posteriorly and has a prominent olecranon process, and the radius is positioned fully anterior to the ulna, as in Phenacodus and primitive perissodactyls. The ulnar facet of the radial head is almost flat and extends across most of the posterior surface. The radial head is elliptical, about 50% wider than deep anteroposteriorly, and articulated with both

31 capitulum and trochlea (as in phenacodontids and perissodactyls). The wide, uneven articular surface of the proximal radius, together with the flat ulnar facet, allowed little or no supination at the elbow. The distal radial articulation is twice as wide transversely as it is in anteroposterior dimension, and the scaphoid and lunar facets are less well differentiated than in basal equids. The manus includes five metapodials, of which four (Mc II-V) are preserved in our sample (Fig. 3g). They are relatively shorter and more robust than in basal perissodactyls such as Arenahippus 9, Homogalax 10, and Heptodon 11. Mc III is slightly larger than the others, and the manus is mesaxonic. Mc V is less reduced than in basal perissodactyls (longer than in Homogalax, stouter than in Arenahippus). An articular facet on the medial side of Mc II indicates the presence of Mc I, presumably vestigial. Numerous phalanges, including proximal, intermediate, and a single hoof-like terminal phalanx, are preserved. Precise positions of these phalanges, and whether they represent manual or pedal phalanges, are uncertain, but their overall similarity suggests that there were no significant differences (other than size) among digits, or between manus and pes. Incomplete femora show cursorial resemblances to both phenacodontids and early perissodactyls. The greater trochanter is less prominent than in perissodactyls. Lesser and third trochanters are well developed. The distal articulation is moderately deep, but less so than in basal perissodactyls. The medial condyle projects caudally more than the lateral condyle. The tibia and fibula are separate. The distal tibial articulation is relatively wider and less deep anteroposteriorly than in primitive perissodactyls, reflecting the wider astragalar trochlea in Cambaytherium. The tarsus is relatively narrower than in Phenacodus but is wider and shorter than in basal perissodactyls. The calcaneus is slightly more gracile than in Phenacodus but wider and

32 more robust than in Arenahippus, and has a rounded posterior astragalar (ectal) facet. In these respects it is more comparable to that of Homogalax. There is no fibular facet. The calcaneus is distally shorter (distal to the ectal facet) than in basal perissodactyls, comparable to Phenacodus (Fig. 5, lateral views). The astragalus has a deep trochlea and shows the diagnostic trait of Perissodactyla, a grooved navicular facet. It is distinct from that of perissodactyls, however, in having a wider and shorter trochlea and a dorsal astragalar foramen or notch, as in phenacodontids; the foramen is not known in any perissodactyl. In contrast to phenacodontids, the medial trochlear rim is longer than the lateral rim. The astragalar neck is longer than that of early perissodactyls, comparable to that of Phenacodus. The navicular facet is more shallowly grooved than in basal perissodactyls. On its lateral border is a narrow facet that articulates with the cuboid. Like the manus, the pes had five metapodials, although our sample includes only Mt III and IV. The central metapodials are shorter and more robust than those of basal perissodactyls and are proportionally similar to those of Phenacodus primaevus. The presence of a presumably vestigial Mt I is inferred from the clear articular facet on the posterior projection of proximal Mt III (Fig. 3h). A similar facet in Tapirus articulates with the vestigial Mt I, which is fused with the entocuneiform or tightly bound by ligaments 12. As the entocuneiform articulates largely with Mt II, we assume it, too, was present. Mt V is inferred from an articular facet on the lateral side of the head of Mt IV. Phylogenetic Analyses There are some aspects of our results that, while they do not affect the conclusions regarding the perissodactyl affinities of cambaytheres, are worth some additional discussion

33 because of how they compare with previous studies. The most surprising is the nesting of anthracobunids within Perissodactyla in some results. While perissodactyl affinities for anthracobunids have been proposed before 13, the union of anthracobunids with the primitive perissodactyls Sifrhippus and Hallensia was unexpected. We suspect that this is a consequence of missing data in anthracobunid taxa. The characters uniting anthracobunids with Sifrhippus and Hallensia are mainly reversals, and if anthracobunids were found to share many of the ancestral cranial and postcranial features described here for cambaytheres, we would expect anthracobunids to have a more basal position relative to perissodactyls. Other unexpected results involve the relationships among perissodactyls. While perissodactyl relationships were not the focus of this study, we did attempt to survey a variety of perissodactyl lineages and to score characters relevant to their interrelationships so that we could test whether cambaytheres were nested within Perissodactyla. The placement of brontotheres (Lambdotherium, Eotitanops, and Palaeosyops) in Tapiromorpha, and the uniting of derived palaeotheres (Palaeotherium, Plagiolophus, and Leptolophus) with the more derived equids in our study (Orohippus, Epihippus, and Mesohippus), were the two most unusual aspects of perissodactyl phylogeny in our results. Regarding the latter, derived palaeotheres and derived equids are united in this study by some features that are thought to have evolved multiple times, such as molarization of premolars and reduction of manual digits. Further testing of this result would require inclusion of additional equoid taxa. The reason for the unusual placement of brontotheres is less clear, but additional brontothere taxa could test this relationship. The positions of phenacodontids and Radinskya in our results deserve comment. In the main analysis, phenacodontids fall within the sister-clade to paenungulates, and Radinskya is sister-taxon to Phenacodus. The position of phenacodontids is consistent with some previous

34 results 14, but others place phenacodontids within Laurasiatheria, at the base of euungulates 15. The position of Radinskya is interesting, since it does not suggest any close relationship with perissodactyls as previously hypothesized 16, but it should be noted that many of the characters diagnosing afrothere clades are unknown in Radinskya, and only characters of the upper dentition provide any basis for allying Radinskya with phenacodontids or paenungulates. Some of the results from our other analyses place phenacodontids outside of a perissodactyl-afrothere clade and Radinskya on the branch leading to perissodactyls. The fact that Radinskya is so poorly known heavily influences its placement in our analyses. Supplementary References 1. Gingerich, P. D., Russell, D. E. & Wells, N. A. Astragalus of Anthracobune (Mammalia, Proboscidea) from the early-middle Eocene of Kashmir. Contrib. Mus. Paleontol. Univ. Michigan 28, (1990). 2. Froehlich, D. J. Quo vadis eohippus? The systematics and taxonomy of the early Eocene equids (Perissodactyla). Zool. J. Linn. Soc. 134, (2002). 3. Fischer, M. & Tassy, P. The interrelation between Proboscidea, Sirenia, Hyracoidea, and Mesaxonia: the morphological evidence, in Mammal Phylogeny, Volume 2, Placentals (eds Szalay, F. S., Novacek, M. J. & McKenna, M. C.) (Springer-Verlag, New York, 1993). 4. Holbrook, L. T. Osteology of Lophiodon Cuvier, 1822 (Mammalia, Perissodactyla) and its phylogenetic implications. J. Vertebr. Paleontol. 29, (2009). 5. Hooker, J. J. & Dashzeveg, D. The origin of chalicotheres (Perissodactyla, Mammalia). Palaeontology 47, (2004).

35 6. Kondrashov, P. & Lucas, S. G. Nearly complete skeleton of Tetraclaenodon (Mammalia, Phenacodontidae) from the early Paleocene of New Mexico: morpho-functional analysis. J. Paleont. 86, (2012). 7. Ladevèze, S., Missiaen, P. & Smith, T. First skull of Orthaspidotherium edwardsi (Mammalia, Condylarthra) from the late Paleocene of Berru (France) and phylogenetic affinities of the enigmatic European family Pleuraspidotheriidae. J. Vertebr. Paleontol. 30, (2010). 8. Cope, E.D. The Vertebrata of the Tertiary formations of the West. Report U.S. Geol. Surv. Territ. 3, (1884). 9. Wood, A. R., Bebej, R. M., Manz, C. L., Begun, D. L., & Gingerich, P. D. Postcranial functional morphology of Hyracotherium (Equidae, Perissodactyla) and locomotion in the earliest horses. J. Mammal. Evol. 18, 1-32 (2011). 10. Rose, K. D. Skeleton of early Eocene Homogalax and the origin of Perissodactyla, in Vol. jubil. D. E. Russell (eds. Godinot, M. & Gingerich, P. D.), Palaeovertebrata 25, (1996). 11. Radinsky, L. B. Evolution of the tapiroid skeleton from Heptodon to Tapirus. Bull. Mus. Comp. Zool. 134, (1965). 12. Radinsky, L. The perissodactyl hallux. Amer. Mus. Novitates 2145, 1-8 (1963). 13. Coombs, W. P. Jr. & Coombs, M.C. Pilgrimella, a primitive Asiatic perissodactyl. Zool. J. Linn. Soc. 65, (1979). 14. Asher, R. J., Novacek, M. J. & Geisler, J. H. Relationships of endemic African mammals and their fossil relatives based on morphological and molecular evidence. J. Mammal. Evol. 10, (2003).

36 15. O Leary, M. A. et al. The placental mammal ancestor and the post-k-pg radiation of placentals. Science 339, (2013). 16. McKenna, M. C., Chow, M., Ting, S. & Luo, Z. Radinskya yupingae, a perissodactyl-like mammal from the late Paleocene of China, in The Evolution of Perissodactyls (eds. Prothero, D. & Schoch, R.) (Oxford University Press, New York, 1989).