Zheng et al. On the absence of sternal elements in Anchiornis (Paraves: Troodontidae) and Sapeornis (Aves: Pygostylia) and the complex early evolution of the avian sternum Supplementary Information 1. Table S1-S4 2. Histology description 3. Figures S1-11 4. References Tables Table 1. List of Anchiornis specimens from the Shandong Tianyu Museum of Nature as well as published material (n = 229) sorted by size. The number of gastralia is only listed when the preserved basket is relatively complete. Brackets indicate incomplete elements. Parentheses indicate number of preserved pairs of gastralia. Collection No. Complete Articulated Soft-tissue Gastralia (pairs) Femur length (>90%) (mm) STM 0-32 x x x (>10) 40 STM 0-39 x x x x 40 STM 0-132 x x — x (13) 40 STM 0-134 x — x — 40 STM 0-148 x x — x 40 STM 0-5 x x x — 41 STM 0-116 — — — — 41 STM 0-142 x x x x 41 STM 0-56 x x x x 42 STM 0-187 x x x x (>8) 42 STM 0-104 x x x x 43 STM 0-140 x x x x 43 STM 0-182 x x x x 43 STM 0-195 — — — — 43 IVPP V14378 - x - x 43.2 holotype STM 0-1 x x x — 44 STM 0-57 x x x — 44 STM 0-85 x x — x (>7) 44 STM 0-121 x x — x (>11) 44 STM 0-153 — — x x 44 STM 0-189 x x — x (>8) 44 STM 0-38 x x x — 45 STM 0-60 — — x x 45 STM 0-167 x x — x (>5) 45 STM 0-212 x x x x (>5) 45 STM 0-65 x x x x 46 STM 0-186 x x x x 46 STM 0-194 x x x x 46 STM 0-223 — x x x 46 STM 0-10 x x — x 47 STM 0-59 x x x x 47 STM 0-82 x x x x 47 STM 0-136 — x x x 47 STM 0-164 x x x x 47 STM 0-113 — — — x 48 STM 0-120 — x x x (14-15) 48 STM 0-163 — — x — 48 STM 0-58 x x x — 49 STM 0-62 x x x — 49 STM 0-77 x x — x 49 STM 0-79 x x x x 49 STM 0-54 x x x — 49.5 STM 0-12 x x x x 50 STM 0-16 x x x x 50 STM 0-24 — x — x 50 STM 0-30 x x x x (10) 50 STM 0-33 — x x — 50 STM 0-41 x x x x 50 STM 0-74 x x — x (>7) 50 STM 0-75 x — — x 50 STM 0-114 — x x — 50 STM 0-141 x — x x 50 STM 0-145 x x — x (>5) 50 STM 0-150 x x x x (>8) 50 STM 0-154 x x x x 50 STM 0-156 x x — x 50 STM 0-174 x x — x (>5) 50 STM 0-183 x x — x (11) 50 STM 0-209 x x x x 50 STM 0-222 — — — — 50 STM 0-78 x x — x 51 STM 0-207 x — x x 51 STM 0-20 x x — x 52 STM 0-21 x — x — 52 STM 0-27 x x x x 52 STM 0-84 — — — x 52 STM 0-171 x x x x 53 STM 0-126 x — x x 54 STM 0-157 x x x x 54 STM 0-190 x x — x 54 STM 0-76 x x x x 55 STM 0-53 x x x x 56 STM 0-168 x x — x (>8) 56 STM 0-52 x x x x (>11) 57 STM 0-110 x x x x 57 STM 0-97 x x — x 58 STM 0-159 — — x x 58 STM 0-211 x x x — 58 STM 0-125 — — x — 59 STM 0-17 x x x x 60 STM 0-42 x x — x 60 STM 0-44 x x — x (>12) 60 STM 0-46 — — — x 60 STM 0-55 x x x x 60 STM 0-64 x x x x 60 STM 0-66 — — x — 60 STM 0-69 x x x x (>5) 60 STM 0-86 — — x x (>6) 60 STM 0-89 x x x x 60 STM 0-95 x — — x (>7) 60 STM 0-101 x x x x 60 STM 0-119 x x x x (>10) 60 STM 0-123 — — x x (>8) 60 STM 0-130 — x — x (>7) 60 STM 0-135 x — — x (>4) 60 STM 0-173 x x x x (>8) 60 STM 0-202 x x x x 60 STM 0-205 — x — — 60 STM 0-225 x x — x (>11) 60 STM 0-25 — — — x (6) 62 STM 0-73 x x — x 62 STM 0-87 — — x x (>8) 62 STM 0-108 — — x x (>5) 62 STM 0-118 x x x x 62 STM 0-203 x x — x 62 STM 0-165 x x x x (~12-14) 63 STM 0-178 x — x x (>7) 63 STM 0-7 x — x — 64 STM 0-71 x x x x (>5) 64 STM 0-92 x x — x (>10) 64 STM 0-170 x x x x 64 STM 0-204 x x x x 64 STM 0-4 x x x — 65 STM 0-9 x x x — 65 STM 0-40 x — x x 65 STM 0-50 x x x x 65 STM 0-70 — — x — 65 STM 0-111 x x x x 65 STM 0-138 x x x x (>10) 65 STM 0-179 x x x — 65 STM 0-185 x x — — 65 STM 0-201 — x x x (>8) 65 STM 0-61 x x — — 66 STM 0-102 x x — x 66 STM 0-218 — — — x 66 LPM-B00169 x x x — 66.2 STM 0-14 x x — x (13) 67 STM 0-37 x — x x (>10) 67 STM 0-49 — — — x 67 STM 0-216 x — x — 67 STM 0-19 x x x x (7) 68 STM 0-47 x x x x (>10) 68 STM 0-143 x x x x 68 STM 0-152 x — x x 68 STM 0-176 x x — x (>6) 68 STM 0-191 x x — x 68 STM 0-215 x x x — 68 STM 0-93 x — x x 69 STM 0-151 x x x — 69 STM 0-177 x x x x 69 STM 0-2 x x — x 70 STM 0-31 x x x x 70 STM 0-34 x x — x 70 STM 0-72 x — — x 70 STM 0-91 — — — x 70 STM 0-127 — — — — 70 STM 0-158 x x x x 70 STM 0-166 x x x x 70 STM 0-172 — x x — 70 STM 0-181 x x x x 70 STM 0-193 x x x x 70 STM 0-198 x — x x 70 STM 0-206 x — x x 70 STM 0-208 x x x — 70 STM 0-217 x x x x 70 STM 0-36 x — x — 71 STM 0-48 x x x x (>10) 71 STM 0-213 x x x x (>8) 71 STM 0-43 — — — — 72 STM 0-105 x x x x 72 STM 0-137 x x x x (>8) 72 STM 0-169 x x x x (>10) 72 STM 0-29 x x x x 73 STM 0-155 x x x x 73 STM 0-221 x x x — 73 STM 0-13 x x — — 73.5 STM 0-18 x x x x (7) 74 STM 0-100 x x — — 74 STM 0-3 x x x x 75 STM 0-23 x — — x 75 STM 0-28 x x x — 75 STM 0-106 x x x x (>6) 75 STM 0-161 x x — x 75 STM 0-175 x x x x (>5) 75 STM 0-188 x x x x 75 STM 0-192 x x — x 75 STM 0-99 x x — x (10-13) 76 STM 0-90 — x x x 79 STM 0-35 x x x x (>9) 80 STM 0-224 x x x x 80 STM 0-8 x x x x 86 STM 0-26 x x — x (11) 93 STM 0-6 — x — x — STM 0-11 — — x x — STM 0-15 — x — x — STM 0-45 — — — — — STM 0-68 x — x x (>11) — STM 0-94 — — — x — STM 0-98 x x x — — STM 0-103 — — — — — STM 0-107 — — x — — STM 0-109 — x x — — STM 0-115 — — x x — STM 0-117 — — x — — STM 0-122 — — x x — STM 0-124 — — x — — STM 0-131 — — x x (>6) — STM 0-133 — — — — — STM 0-139 x x x — — STM 0-146 — — — x — STM 0-149 — — x — — STM 0-160 x x — x — STM 0-180 — — x — — STM 0-184 x x — x — STM 0-196 — — x x (>6) — STM 0-197 — — x x — STM 0-199 — — x x — STM 0-200 x x — x (>7) — STM 0-210 x x x x — STM 0-214 x x x x (>5) — STM 0-226 — — — — — STM 0-22 x x — x — BNHMC Ph828 — x x — — STM 0-81 — x — x [ 32 ] STM 0-80 x x x x [ 38 ] STM 0-83 — — — x [ 39 ] STM 0-67 — — x x (>5) [ 43 ] STM 0-219 — — x x [ 46 ] STM 0-51 — — — x [ 50 ] STM 0-144 x x x x (>8) [ 50 ] STM 0-220 — x x x [ 50 ] STM 0-128 — — — x(>10) [ 50] STM 0-162 x x x x [ 53 ] STM 0-63 — — x x (>8) [ 60 ] STM 0-112 x x x x (>10) [ 63 ] STM 0-147 x — — x (>12) [35] STM 0-129 — — x x (>6) [46] STM 0-96 x — x x [48] STM 0-88 — x — x (>9) [66] Table 2.