1. Genomics and Evolutionary Biology
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New footprints from Laetoli (Tanzania) provide evidence for marked body size variation in early hominins

  1. Fidelis T Masao
  2. Elgidius B Ichumbaki
  3. Marco Cherin Is a corresponding author
  4. Angelo Barili
  5. Giovanni Boschian
  6. Dawid A Iurino
  7. Sofia Menconero
  8. Jacopo Moggi-Cecchi
  9. Giorgio Manzi
  1. University of Dar es Salaam, Tanzania
  2. Università di Perugia, Italy
  3. Sapienza Università di Roma, Italy
  4. Università di Pisa, Italy
  5. Studio Associato Grassi, Italy
  6. Università di Firenze, Italy
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Cite as: eLife 2016;5:e19568 doi: 10.7554/eLife.19568

Figures

Geographical location and site map.

(A) Location of the study area in northern Tanzania. (B) Location of Laetoli within the Ngorongoro Conservation Area, about 50 km south of Olduvai Gorge. (C) Plan view of the area of Laetoli Locality 8 (Sites G and S).

https://doi.org/10.7554/eLife.19568.003
Figure 2 with 3 supplements
Plan view of the four test-pits excavated at Laetoli Site S.

Dashed lines indicate uncertain contours. Some of the most interesting tracks are coloured: hominins in orange (heel drags in dark grey), equid in dark green (M9), rhinoceros in red (M9), giraffe in light brown (M10), and guineafowl in blue (M10). Large roots and the bases of trees are in light green (L8). The main faults/fractures are indicated by brown lines. Raindrop impressions occur in the northern part of L8 (dotted areas).

https://doi.org/10.7554/eLife.19568.004
Figure 2—figure supplement 1
Orthophotos of selected hominin tracks from test-pit L8 at Site S.

(A) L8/S1-1. (B) L8/S1-2. (C) L8/S1-3. (D) L8/S1-4. From left to right: textured models, textured and shaded models, shaded models, and shaded coloured models. Colours represent the density of the point clouds obtained by determining the distance to the nearest neighbour. The surface density is the number of neighbours divided by the neighbourhood surface = N/(πR2).

https://doi.org/10.7554/eLife.19568.005
Figure 2—figure supplement 2
Orthophotos of selected hominin tracks from test-pit M9 at Site S.

(A) M9/S1-2. (B) M9/S1-3. Details as in Figure 2—figure supplement 1.

https://doi.org/10.7554/eLife.19568.006
Figure 2—figure supplement 3
Orthophotos of selected tracks from test-pit M10 at Site S.

(A,B) Small bovid (?Madoqua) and bird (?Numida) tracks. (C) Two giraffe tracks surrounded by small bovid and bird tracks. Details as in Figure 2—figure supplement 1.

https://doi.org/10.7554/eLife.19568.007
Shaded 3D photogrammetric elevation model of the L8 trackway.

Colour renders heights as in the colour bar. The empty circles indicate the position of the targets of the 3D-imaging control point system (see Materials and methods for details).

https://doi.org/10.7554/eLife.19568.008
Shaded 3D photogrammetric elevation model of test-pit L8 and close-up of the best-preserved tracks with contour lines.

Colour renders heights as in the colour bar; distance between elevation contour lines is 2 mm. The empty circles indicate the position of the targets.

https://doi.org/10.7554/eLife.19568.009
Shaded 3D photogrammetric elevation model of the central portion of test-pit M9 and close-up of the best-preserved tracks with contour lines.

Colour renders heights as in the colour bar; distance between elevation contour lines is 2 mm. The empty circles indicate the position of the targets

https://doi.org/10.7554/eLife.19568.010
Shaded 3D photogrammetric elevation model of test-pit TP2 and close-up of the three hominin tracks with contour lines.

Colour renders heights as in the colour bar; distance between elevation contour lines is 2 mm. The empty circles indicate the position of the targets.

https://doi.org/10.7554/eLife.19568.011
Southern part of the hominin trackway in test-pit L8.

Footprints L8/S1-1, L8/S1-2, L8/S1-3 and L8/S1-4 are visible from left to right. The heel drag mark is well visible posteriorly to L8/S1-3.

https://doi.org/10.7554/eLife.19568.012
Test-pit L8 at Laetoli Site S.

In the northern part of the test-pit (at the top), the Footprint Tuff is particularly altered, damaged by plant roots and dislodged along natural fractures.

https://doi.org/10.7554/eLife.19568.013
Central part of the hominin trackway in test-pit M9.

Tracks M9/S1-3 and M9/S1-2 are visible from left to right. The two tracks are crossed by some fractures filled by hard calcite veins, which were not removed. In M9, the Footprint Tuff is in almost pristine condition, and most of the tracks are still filled by compact sediment.

https://doi.org/10.7554/eLife.19568.014
Laetoli Site S geology.

(A) Stratigraphic sketch of the sequence, as in test-pit M9. Numbers on the left (1–5) correspond to the lithologic units observed in the field: 1 — modern soil; 2 — grey augite-rich tuff; 3 — laminated grey tuff; 4 — finely layered grey and white tuff; 5 — light brown tuff. Unit two corresponds to the Augite Biotite Tuff (Hay, 1987); units 3 and 4 correspond respectively to the upper and lower horizons of the Footprint Tuff (Hay, 1987). Numbers on the right indicate the four and fourteen sublevels included, respectively, in the upper and lower part (Hay, 1987). Hominin tracks occur on the topmost sublevel of unit 4 (red line); a similar thick whitish footprint-bearing level can be observed in the same stratigraphic position at Localities 6 and 7. Oblique hatch: open cracks. White patches in unit 5 are burrower tunnels and disturbances. Green rectangle: location of panel B image. (B) Photomosaic showing the Footprint Tuff and part of the overlying unit.

https://doi.org/10.7554/eLife.19568.015
Figure 11 with 1 supplement
Shaded 3D photogrammetric elevation model of a cast of the southern portion of the Site G trackway with close-ups of selected hominin tracks with contour lines.

Colour renders heights as in the colour bar; distance between elevation contour lines is 2 mm. The empty circles and squares indicate the position of the targets.

https://doi.org/10.7554/eLife.19568.017
Figure 11—figure supplement 1
Orthophotos of selected hominin footprints from a cast of the southern portion of the Site G trackway.

(A) G2/3–29. (B) G1-34, G1-35, G2/3–25, G2/3–26. (C) G2/3–18. From left to right: textured models, textured and shaded models, shaded models, and shaded coloured models. Colours represent the density of the point clouds obtained by determining the distance to the nearest neighbour. The surface density is the calculation of number of neighbours divided by the neighbourhood surface = N/(πR2).

https://doi.org/10.7554/eLife.19568.018
Estimates of predicted stature of fossil hominin individuals by species over time for the interval 4–1 Ma.

Solid symbols (or crosses in bold) refer to stature estimates based on actual femur length; open symbols refer to stature estimates based on estimated femur length, in turn based on femur head diameter. For Laetoli and Ileret, stature estimates are based on footprint length (see Materials and methods). For Laetoli, Ileret and Woranso-Mille, the average value and range of predicted stature are shown. Colours are associated to the geographical location of each fossil/footprint site on the map. See Supplementary file 5 for details.

https://doi.org/10.7554/eLife.19568.021

Tables

Table 1

Number of individual tracks (excluding hominins) at Laetoli Site S.

https://doi.org/10.7554/eLife.19568.016

Taxon

L8

M9

TP2

M10

Total

Numididae (?Numida)

-

4

-

9

13

Bovidae, small size (?Madoqua)

107

39

16

211

373

Bovidae, medium size (?Gazella)

39

9

-

21

79

Equidae (?Hipparion)

1

2

-

-

3

Giraffidae

-

-

-

4

4

Lagomorpha (?Lepus)

8

-

-

4

12

Rhinocerotidae

-

1

-

-

1

Unidentified micromammals

-

27

-

17

44

Total

155

82

26

266

529

Table 2

Dimensional parameters measured and derived from the Laetoli Site S tracks and stature and body mass estimates for S1 and S2.

https://doi.org/10.7554/eLife.19568.019

Footprint

Side

Length (mm)

Max width (mm)

Foot index (%)

Heel width (mm)

Angle of gait (degrees)

Estimated stature (cm)

Estimated body mass (kg)

H. sapiens§

H. sapiens°

Au. afarensis

H. sapiens°

Au. afarensis

TP2/S1-1

right

271

101

37.2

83

6

194–170

175.4

167–175

53.8

42.9–50.0

TP2/S1-2

left

271

99

36.6

81

4

193–169

175.1

167–175

53.1

42.8–49.8

M9/S1-1

left

250

102

40.6

73

2

179–156

167.5

154–161

51.6

39.6–46.0

M9/S1-2

right

264

105

39.7

80

3

189–165

172.8

163–171

54.2

41.8–48.7

M9/S1-3

left

268

111

41.2

91

4

192–168

174.3

166–173

56.3

42.5–49.4

M9/S1-4

right

245

101

41.2

71

4

175–153

165.6

151–158

50.9

38.8–45.1

L8/S1-1

right

245

104

42.4

78

8

175–153

165.6

151–158

51.7

38.8–45.1

L8/S1-2

left

265

106

40.0

82

11

189–166

173.1

164–171

54.5

41.9–48.8

L8/S1-3

right

260

103

39.6

77

3

186–163

171.3

161–168

53.1

41.2–47.9

L8/S1-4

left

274

106

38.6

81

10

196–171

176.5

169–177

55.6

43.4–50.5

L8/S1-5

right

-

-

-

-

-

-

-

-

-

-

L8/S1-6

left

-

-

-

86

3

-

-

-

-

-

L8/S1-7

right

258

110

42.7

90

8

184–161

170.3

159–166

54.8

40.7–47.4

Average S1

-

261

104

40.0

81

6

184–163

171.6

161–168

53.6

41.3–48.1

TP2/S2-1

right

231

120*

51.9*

86

-

165–144

160

142–149

46.7

36.5–42.4

Step length

Stride length

Footprints

Side

Step length (mm)

Footprints

Side

Stride length (mm)

TP2/S1-1 → 2

right → left

553

M9/S1-1 → 3

left

1044

M9/S1-1 → 2

left → right

548

M9/S1-2 → 4

right

1069

M9/S1-2 → 3

right → left

505

L8/S1-1 → 3

right

1140

M9/S1-3 → 4

left → right

571

L8/S1-2 → 4

left

1159

L8/S1-1 → 2

right → left

552

L8/S1-4 → 6

left

1284

L8/S1-2 → 3

left → right

587

Average right

1105

L8/S1-3 → 4

right → left

573

Average left

1162

L8/S1-6 → 7

left → right

660

Average

1139

Average right → left

545

Average left → right

591

Average

568

  1. *Values overestimated because of the enlarged morphology of the only preserved track of S2. §Estimation based on the relationship between foot length and stature in Homo sapiens (Tuttle, 1987). °Estimation based on the relationship between footprint length and stature/body mass in H. sapiens (Dingwall et al., 2013). Estimation based on the relationship between foot length and stature/body mass in Au. afarensis (Dingwall et al., 2013). See Materials and methods for details.

Table 3

Data and estimates for the five Laetoli track-makers from Sites S and G. Limited to S1, mean values, standard deviation and range are provided.

https://doi.org/10.7554/eLife.19568.020

Trackway

S1

S2

G1

G2

G3

Number of measurable footprints

11

1

9

2

8

Average footprint length (mm)

261 ± 10.5 (245–273)

231

180

225

209

Average footprint max width (mm)

104 ± 3.7 (99–111)

120*

79

117

85

Average foot index (%)

40.0 ± 1.9 (36.6–42.7)

51.9*

43.8

48.0

41.5

Average step length (mm)

568 ± 44.3 (505–660)

-

416

453

433

Average stride length (mm)

1139 ± 94.0 (1044–1284)

-

829

880

876

Estimated stature (cm)

H. sapiens§

163–186

144–165

113–129

141–161

130–149

H. sapiens°

171.6 ± 5.4

160 ± 5.4

141.4 ± 5.4

158.2 ± 5.4

152.2 ± 5.4

Au. afarensis

161–168

142–149

111–116

139–145

129–135

Estimated body mass (kg)

H. sapiens°

53.6 ± 3.7

46.7 ± 3.8

39.3 ± 3.7

52.6 ± 3.7

43.2 ± 3.7

Au. afarensis

41.3–48.1

36.5–42.4

28.5–33.1

35.6–41.4

33.1–38.5

Walking speed (m/s)

0.47–0.55 (0.93)

0.43–0.50 (1.00)

0.36–0.42 (0.79)

0.39–0.46 (0.88)

Relative speed (s−1)

0.25–0.34 (0.54)

0.33–0.44 (0.71)

0.23–0.30 (0.50)

0.26–0.35 (0.58)

  1. *Values overestimated because of the enlarged morphology of the only preserved track of S2. §As in Table 2. °As in Table 2. As in Table 2. For walking speed and relative speed, values outside the brackets are based on the method of Alexander (1976), those inside the brackets are based on the method of Dingwall et al. (2013). See Materials and methods for details.

Additional files

Supplementary file 1

Footprint imaging, measurement report 1.

https://doi.org/10.7554/eLife.19568.022
Supplementary file 2

Footprint imaging, measurement report 2.

https://doi.org/10.7554/eLife.19568.023
Supplementary file 3

Footprint imaging, measurement report 3.

https://doi.org/10.7554/eLife.19568.024
Supplementary file 4

Footprint imaging, measurement report 4.

https://doi.org/10.7554/eLife.19568.025
Supplementary file 5

Individual fossil ages, localities and estimated statures used to build Figure 12.

https://doi.org/10.7554/eLife.19568.026

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