Dinosaur tracksites from Portugal, focused on the carbonated platform of north and central Lusitanian Basin

1. Dinosaur tracksites from Portugal, focused on the carbonated
platform of north and central Lusitanian Basin
Authors:
Maria Inês Marques
Escola de Ciências e Tecnologia da Universidade de Évora (UÉ)
Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (FCT-UNL)
Prof. Dr. Octávio Mateus
Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (FCT-UNL)
Museu da Lourinhã

2. Portuguese dinosaur tracksites
• The existing portuguese dinosaur fossils (bones, eggs, and tracks) are from
Middle Jurassic to Late Cretaceous ages, with most being from the Late Jurassic.
• Portuguese dinosaur tracks are known from dozens of places.
• The majority of the portuguese tracksites is in “Orla Mesozóica Ocidental”, but
there are also some tracksites in “Orla Mesozóica Algarvia”.
Theropod track from Cabo Mondego tracksite, Portugal,
now on display at Museu Geológico de Lisboa.
Sauropod tracks at Pedreira do Galinha tracksite, Portugal. Theropod track at Vale de Meios tracksite,
Portugal.

3. Dinosaur tracksites from Portugal, focused on
the carbonated platform of north and central
Lusitanian Basin
• Here, part of the data collected for a master thesis is
presented, for which ten dinosaur tracksites are
studied:
▪ Vale de Ventos (Middle Jurassic);
▪ Praia do Pedrógão, Pedreira/Amoreira, Praia do
Salgado, Serra de Mangues, Salir, Serra do Bouro,
Sobral da Lagoa, Consolação (Upper Jurassic);
▪ and Praia do Magoito (Lower-Upper Cretaceous).
• The tracks described show a high diversity of
trackmakers, being sauropod, theropod, ornithopod and
thyreophoran tracks among the findings.
Location of the ten studied
tracksites in the Lusitanian
Basin (Adapted from Santos et
al., 2013).

4. Material and Methods
1. Fieldwork
1.1. Cleaning of the site: when necessary, the sediments that covered the tracks were
cleaned with tools (brooms, shovels, brushes, etc.);
1.2. Field data collecting: description and measurements of the tracks and trackways,
collection of general field data, photogrammetry with camera and drone (the drones were
used for Praia do Salgado, Serra de Mangues, Serra do Bouro and Sobral da Lagoa
tracksites), stratigraphy of the place constructing lithostratigraphic columns using SedLog
3.1 (Serra do Bouro, Salir and Praia do Magoito);
2. Processing information
2.1. Photogrammetry: construction of 3D models of the tracks based on the pictures
captured with the camera and drones, using Agisoft Metashape Professional (64 bit)
(methodology used for Praia do Salgado, Serra de Mangues, Serra do Bouro, Sobral da
Lagoa, Consolação and Praia do Magoito tracksites);
2.2. Classification and paleobiological studies: identification, determination of the
trackmakers and identification of the possible ecosystem of the past;
2.3. Study of the geology of the tracksites: determination of the nature of the rock, the age,
etc.;
2.4. Musealization proposals.

5. The measurements: tracks
Linear and angular measurements adopted in the characterization of the tracks. A – manus (top) and pes (bottom) of a quadrupedal dinosaur; B – Tridactyl track of a right
foot of a bipedal dinosaur. Modified from Santos (2008). Note that for all the tracks the depth, was also measured, and the direction of progression was registered.

6. The measurements: tracks
Linear measurements adopted in the characterization of the tracks, using the example of a mesaxonic and tridactyl track of a right foot of a bipedal dinosaur. Modified from
Santos (2008). Note that the concept of mesaxony consists in the length/width ratio of the anterior triangle of the track, whose vertices are the distal tips of digits II, III and
IV of tridactyl tracks.

7. The measurements: digit/claw traces
Linear and angular measurements adopted in the characterization of digit/claw traces. Modified from Santos (2008). Note that for all the digit/claw traces the depth, was
also measured, and the direction of progression was registered.

8. The measurements: trackways
Linear and angular measurements adopted in the characterization of the trackways. A – bipedal dinosaur; B – quadrupedal dinosaur. Modified from Santos (2008). Note
that for all the trackways the trackway total length was also measured, and the direction of progression was registered.

9. The estimates: dimensions of the animal
In order to estimate the dimensions of the animal, the formulas proposed by Thulborn & Wade (1984) and
Thulborn (1989, 1990) were used for bipedal dinosaurs:
• h = 4,5 x L for small theropods if L is inferior to 25 cm;
• h = 4,9 x L for large theropods if L is superior to 25 cm;
• h = 4,8 x L for small ornithopods if L is inferior to 25 cm;
• h = 5,9 x L for large ornithopods if L is superior to 25 cm.
When tracks are poorly preserved and is only perceptible that they belong to bipedal animals, is possible to
choose one of the following formulas:
• h = 4,6 x L for small bipeds in general if L is inferior to 25 cm;
• h = 5,7 x L for large bipeds in general if L is superior to 25 cm.
For sauropod dinosaurs the method used was the proposed by Alexander (1976):
• h = 4 x L
For thyreophoran dinosaurs the method used was the proposed by Cobos et al. (2010):
• h = 6 x W
In all of the formulas, h is the height of the posterior limb, from the ground to the acetabulum of the animal and L
is the length of the pes impression. In the thyreophoran dinosaurs formula, W is the width of the pes impression.

10. The estimates: velocity of the trackmaker and
caracterization of the locomotion
In order to estimate the velocity of the trackmaker was used the formula proposed by Alexander
(1976):
V = 0,25 x 𝑔0,5 x 𝜆1,67 x ℎ−1,17,
where g is the value of gravitational acceleration; λ is the value of the stride; and h is the height of
the posterior limb, from the ground to the acetabulum of the animal.
For the characterization of the locomotion was used the index proposed by the same author:
λ/h,
where λ is the value of the stride and h is the height of the posterior limb, from the ground to the
acetabulum of the animal.
The differentiation of the modes of locomotion is based in Thulborn (1982); Thulborn & Wade (1984);
and Thulborn (1990):
λ/h < 2,0, if the animal is walking;
2,0 < λ/h < 2,9, if the animal is trotting;
λ/h > 2,9, if the animal is galloping.

11. Praia do Salgado tracksite
• Age: Kimmeridgian (Upper Jurassic);
• Location: municipality of Nazaré, district of Leiria;
• Number of layers: 3;
• Number of tracks: approximately 146;
• Trackmakers: theropods, sauropods, possible
thyreophorans, and possible ornithopods;
• Paleoenvironment: transition from strict sea or
brackish environment to platform sea (Fatela, 1990).
Location of the ten studied
tracksites in the Lusitanian
Basin (Adapted from Santos et
al., 2013).

12. Praia do Salgado tracksite
• Lower layer: poorly preserved sauropod tracks,
an isolated possible thyreophoran track, and an
isolated track of unknown affinity;
• Second layer: poorly preserved sauropod
trackways;
• Upper layer: twelve trackways, eleven of them
with tracks that are preserved as elongated
dinosaur tracks with metatarsal impressions
(some with hallux impression), and two
isolated tracks of unknown affinity.
Right: Aerial view of the tracksite (by J.C. Kullberg in December of 2019), with indication of the tracks and trackways.

13. Praia do Salgado tracksite: the upper layer
PS-L3-T3/1 elongated dinosaur track. PS-L3-T10/2 dinosaur track with an arrow indicating the
hallux impression.
PS-L3-T2/13 theropod slender track.

14. Praia do Salgado tracksite: elongated dinosaur tracks
with metatarsal impressions
Left: PS-L3-T3/1 elongated dinosaur track; Right: Three-
dimensional computer reconstruction of theropod foot
movements producing an elongate print in deep mud.
Penetration through the substrate surface is shown in red.
The hallux, which is not ‘reversed’ as in modern birds,
leaves a posteromedially oriented entry furrow (a, b) as the
digit plunges down and forward. The ankle is not
immediately lifted during the stance phase, and as a result
a metatarsal impression is created (c), elongating the track
posteriorly. All digits converge beneath the surface and
emerge together from the anterior end of the track (d).
Retrieved from Gatesy et al. (1999).

15. • In the particular case of the elongated tracks of Praia do
Salgado, were measured:
▪ the length;
▪ the length without the metatarsal (LWM);
▪ the width;
▪ the free digit length (FDL);
▪ and the digit width.
• For the trackways composed of elongated tracks, were made the
same measurements as indicated previously for the trackways
of bipedal animals and was obtained also the direction of the
tracks or trackways.
• In this type of preservation, the footprint length/footprint width
must be calculated using the LWM rather that the length.
Praia do Salgado tracksite: elongated dinosaur tracks
with metatarsal impressions
Linear measurements adopted in the characterization of elongated dinosaur tracks, present in Praia do Salgado tracksite.

16. • Layer 1:
▪ Poorly preserved sauropod tracks: height from the ground to the acetabulum between
2,40 m and 3,88 m.
▪ Isolated possible thyreophoran track: height from the ground to the acetabulum of
approximately 3,42 m.
▪ Isolated track of unknown affinity: height from the ground to the acetabulum of
approximately 2,57 m.
• Layer 2:
▪ Poorly preserved sauropod trackways: height from the ground to the acetabulum
between 1,26 m and 3,60 m. . For one of the trackways was obtained a velocity of the
trackmaker of 16,74 km/h, that indicates that the animal was trotting.
• Layer 3:
▪ Twelve trackways: height from the ground to the acetabulum between 87,86 cm and 1,88
m. For one of the trackways was obtained a velocity of the trackmaker of 16,98 km/h, that
indicates that the animal was running, and for another was obtained a velocity of the
trackmaker of 13,14 km/h, that indicates that the animal was trotting. These are rare
cases in Portugal;
▪ Two isolated tracks of unknown affinity: for one of them (possibly attributable to a
thyreophoran) was calculated an height from the ground to the acetabulum of 1,32 m.
Praia do Salgado tracksite: the estimates

17. Conclusions
• The tracks studied show a high diversity of trackmakers, being sauropod, theropod,
ornithopod and thyreophoran tracks among the findings;
• Praia do Salgado tracksite shows also a high diversity of trackmakers, being sauropod,
theropod, possible thyreophoran and possible ornithopod tracks among the findings;
• The upper layer of Praia do Salgado tracksite contains eleven trackways with tracks that
are preserved as elongated dinosaur tracks with metatarsal impressions (some with
hallux impression). These elongated tracks are an unique case in the country, in
Kimmeridgian rocks;
• For one of the sauropod trackways of Layer 2 was obtained a velocity of the trackmaker
of 16,74 km/h, that indicates that the animal was trotting; for one of the trackways of
Layer 3 was obtained a velocity of the trackmaker of 16,98 km/h, that indicates that the
animal was running; and for another trackway of Layer 3 was obtained a velocity of the
trackmaker of 13,14 km/h, that indicates that the animal was trotting. These are rare
cases in Portugal.

18. Thanks for your attention!
Acknowledgments
Prof. Dr. José Carlos Kullberg;
Students from the eighth edition of the Master in Paleontology of FCT-UNL (Faculdade de Ciências e Tecnologia da Universidade Nova de
Lisboa) and UÉ (Universidade de Évora);
Laura Maria;
Eduardo Puértolas-Pascual;
ICNF (Instituto da Conservação da Natureza e das Florestas), including Lia Mergulhão;
PNSAC (Parque Natural das Serras de Aire e Candeeiros);
António Buzaco;
Bruno Pereira and the rest of the AGEO (Associação Geoparque Oeste) team;
Simone Conti;
Matteo Belvedere;
Museu da Lourinhã team;
Miguel Castro, from Intertidal;
Bruno Camilo e Silva, from SHN (Sociedade de História Natural);
my mom, dad, sister and Ricardo.