1. science

.
New theropod and ornithischian dinosaur footprints at the Dinosaur Footprint State Reservation (Early
Jurassic, Portland Formation), Holyoke, Massachusetts, USA
LEPORE, Taormina, University of Massachusetts, Amherst, MA, USA
Figure 2
DFSR Site Map
(Anomoepus prints
shown in red)
Figure 1
Location near
Mount Tom
(Ostrom, 1972)
Table 1: Averages
Genus
Average
Anomoepus
Anomoepus
Average
Grallator
Grallator
Average
Eubrontes
Eubrontes
Eubrontes
FW
FL (cm) (cm)
FP
AD
5.4-16
94
16.1
98
13.1
42-72
14.2
49
11.5
62
<15
289
16.4
296
18.5
10 to 30
12
41
10
31
>25
76
29.8
61
33.1
272
38.5
Average
Anchisauripus
Pr III
(cm)
18
6.4
8
unavailable
12.9
1.1
8.5
1.1
10
10.5
7.5
8.5
14
~2.5-4.0
14.2
9.9
10.7
10.9
1.9
1.4
~2.2
1.6
1.7
1.6
24.2
26.4
26.5
~2.0
58
7.4
3.1
~1.3
1.4
1.9
22.3
24.6
24.5
20-35
10.3
R' (cm) P' (cm)
~1.4-1.5
4.3
3.9
2.2
>1.3<1.8
6.5
11.5
1.7
13.1
2.7
Anchisauripus
123
17.6
10.1
29
2.5
FP=Footprint Number, FL=Footprint Length, FW=Footprint
Width, AD=Angle of divarication between digits II and IV, Pr
III=Projection of digit III, R=Rear projection, L/W=Length to
width ratio, R’=Corrected rear projection of the foot,
P’=Corrected projection of digit III.
15.1
1.7
15.6
7.8
Figure 3
Corresponding
eight meters of
Ostrom’s map
(Ostrom, 1972)
A Flurry of Activity Around Previously-Mapped Eubrontes Tracks
• The Dinosaur Footprint State Reservation (DFSR) site sits in the Hartford Basin in Holyoke, Massachusetts, near
the Northampton, Massachusetts town line (Figure 1). It has been recognized as bearing footprints since the
1830s, when Edward Hitchcock labeled the site “the quarry in Northampton, on the east side of Mount Tom”
(Hitchcock, 1836) and used the locality as the source for his type specimen of the ichnospecies Eubrontes
giganteus (Amherst College (AC) 15/3; Olsen, et al., 1998).
• The site is located in the lower Portland Formation directly above the Hampden Basalt, and is approximately 201
million years old, of Hettangian age. The strata are part of the Newark Supergroup, which parallels much of the
northeast North American Atlantic coast. Situated in the rift lake valleys of Hettangian New England, the shallow
lake associated with this deposit served as a water source for the local ecosystem, as is clear from the vast amount
of bioturbation.
• In summer 2005 I mapped 343 partial or complete dinosaur footprints within the southernmost quarter of the
site, including the theropod ichnogenera Eubrontes, Anchisauripus and Grallator. Among the prints mapped were
eight previously unidentified prints of the ichnogenus Anomoepus, representing a basal ornithischian trackmaker.
The new map (Figure 2) demonstrates the abundance of animal activity. Footprint measurements were taken to
aid in identification, and corroborated with average measurements described by Lull (1953) (Table 1).
• 16 Eubrontes prints corresponding to four trackways were mapped. The trackways were measured to determine
trackmaker velocity and whether the trackmaker was walking, trotting or running (Table 2).
•The site and the rocks adjacent to it have been analyzed by several other workers. In 1972 the site was mapped
partially by Dr. John Ostrom of Yale University, who noted the directionality of nearly all the Eubrontes trackways
and argued the likelihood of gregarious social behavior in theropod dinosaurs (Ostrom, 1972).
Tracks of Eubrontes are by far the most noticeable and largest at the site, and form the only definite footprint
trackways discernable within the first eight meters, in accordance with Ostrom’s map (Figure 3). Ostrom mapped
18 Eubrontes tracks within these eight meters; four on Ostrom’s original map could not be found, and two new
Eubrontes tracks were identified. Although Ostrom’s survey focused on the Eubrontes prints, his map also
included four Anchisauripus trackways or individual footprints, as well as two Grallator trackways—two additional
theropod ichnogenera.
• Olsen et al. (1998) have also studied the footprints in the rocks exposed closer to the river.
• Getty (2004) noted the presence of several Anomoepus trackways and individual footprints, including one
noticeable trackway with a possible tail-drag mark. His observations and the several Anomoepus individual
footprints I observed are clear indication that theropod footprints are not the only footprints located at the DFSR,
contrary to what Ostrom (1972) had previously assumed.
R (cm) L/W
~2
24-40
18.2
46
19.6
42
24
45
15-25
121
3.2
4.6
Table 2: Velocities
Ostrom's Trackways
26 1 (31)
2 (43)
24
1 (61)
2 (76)
3 (40)
4 (51)
5 (58)
25
1 (392)
2 (153)
3 (393)
23
1 (251)
2 (263)
3 (272)
Relative
stride
Average h
length
L (cm) Average L (m)
Velocity (m/s) Average λ (λ/h)
23.5
19.3
21.4
0.96 x
x
x
33.1
29.8
29.8
29.73
1.46
2.26
2.46
1.68
38
35.1
35
36.03
1.77
1.76
2.42
1.37
39
38.75
1.9
1.45
2.27
1.19
x
26.2
x
38.5
Equations
•
•
Footprint Length (L) to Footprint Width (W) ratio: L / W (Olsen, et al., 1998)
Corrected rear projection (R′) of the foot: R′ = R * [1/cos(θ/2)]
where θ is the angle of divarication between digits II and IV. (Olsen, et al., 1998)
• Corrected projection (P’) of digit III: P′ = R′ / (T-R′)
where R′ is the corrected rear projection of the foot and T is total footprint length.
• Hip height of the Eubrontes trackmaker using two equations based on morphometric ratios that utilize total
footprint length, where h is the animal’s height at the hip (Thulborn, 1989, 1990).
For a footprint length >25cm: h ≈ 4.9 * footprint length (FL)
For a footprint length <25 cm: h ≈ 4.5 * footprint length (FL)
• Trackmaker velocity: u ≈ 0.25g0.5 λ1.67 h-1.17
where u is velocity, g is acceleration due to free fall, λ is stride length and h represents the trackmaker’s hip height
(Alexander, 1976).
• Stride to hip height ratio (relative stride length): λ/h = relative stride length
to determine whether the animals were walking, trotting or running, where λ is stride length in meters and h is hip
height (Thulborn, 1982).
Acknowledgements
Literature Cited
Alexander, R. McN. 1976. Estimates of speeds of
dinosaurs. Nature, 261: 129-130.
Getty, P. 2005. Ornithischian ichnites from Dinosaur
Footprint Reservation (Early Jurassic Portland
Formation), Holyoke, MA. Journal of Vertebrate
Paleontology (3, Supplement):63A.
Hitchcock, E.H. 1836. Ornithichnology.—Description
of the footmarks of birds, (Ornithichnites) on New Red
Sandstone in Massachusetts. American Journal of
Science 29(ser. 1):307-340.
Lull, R.S. 1953. Triassic life of the Connecticut valley.
State of Connecticut, State Geological and Natural
History Survey Bulletin 81:1-336.
Olsen, P.E., Smith, J.B., and McDonald, N.G. 1998.
Type material of the type species of the classic
theropod footprint genera Eubrontes, Anchisauripus,
and Grallator (Early Jurassic, Hartford and Deerfield
Basins, Connecticut and Massachusetts, U.S.A.).
Journal of Vertebrate Paleontology, 18(3):586-601.
Ostrom, J.H. 1972. Were some dinosaurs
gregarious? Palaeogeography, Palaeoclimatology,
Palaeoecology, 11:287-301.
Thulborn, R.A. 1982. Speeds and Gaits of Dinosaurs.
Palaeogeography, Palaeoclimatology, Palaeoecology,
38:227-256.
Thulborn, R.A. 1989. The Gaits of Dinosaurs. In
Gillette, D.D., and Lockley, M.G. (eds.), Dinosaur
Tracks and Traces, Cambridge University Press, New
York, pp. 39-50.
Thulborn, R.A. 1990. Dinosaur Tracks. Chapman
and Hall, London, 410 pp.
Above: Anomoepus (scale 10 cm).
Detailed pad definition, relatively short
projection of digit III, metatarsal
impression in line with axis of digit III.
Above: Eubrontes (scale 5 cm).
Note relatively long projection of digit III.
I would like to warmly thank the following
individuals for their invaluable assistance during this
project: Dr. Margery Coombs (UMass Amherst), Dr.
Bruce Byers (UMass Amherst), Sebastian Dalman
(UMass Amherst), Patrick Getty (UMass Amherst),
Eric Dewar (Suffolk), Dr. Rebecca Mattison
(Wellesley), Cynara Cannitella (Wellesley), Liza
Mattison, Jeff Bonzek, Bobbie Douglass, Amanda
Stone, David Freedman, Marlene, Andrew and
Katrina Lepore.
Conclusions
• 38 square meters mapped, 1/4 of total site area
• Cyclical lacustrine environment
• 343 partial or complete bipedal dinosaur footprints
• Individual prints with no apparent preferred orientation, excluding Eubrontes tracks
• Tracks that could be accurately identified to the genus level include the theropod ichnogenera Eubrontes,
Anchisauripus and Grallator. Eight of the prints are Anomoepus, representing a basal ornithischian.
• A new map (Figure 1) demonstrates the abundance of identifiable footprints previously overlooked due to
poor preservation
• The new map shows the spatial relationship between Eubrontes and non-Eubrontes tracks
• 16 Eubrontes tracks corresponding to four trackways, velocities ranging from 1.45 to 2.26 meters per
second (5.22 to 8.14 kilometers per hour), indicating walking trackmakers
• Demonstrates the ecological diversity represented at this site
• Site is badly weathered due to visitor traffic, exposure, weathering of undertracks
•Further exploration of this site will undoubtedly uncover a great deal more of the ecological and behavioral
picture of dinosaurian taxa in the Early Jurassic strata of Massachusetts