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Dinosaur footprints from the Lower Jurassic of northeastern Italy are well known and, since the first discoveries in the early 1990s, many sites have been described. Tracks are mostly found in the peritidal limestones of the Calcari Grigi Group, deposited on the Trento carbonate platform, now cropping out in the Southern Alps. In 2011, a group of speleologists discovered a new tracksite in the Lower Jurassic Calcari Grigi Group exposed almost at the top of Mt. Pelmo (Dolomites), 3037 m above sea level. Footprints are generally poorly preserved, but it proved possible to recognise some tridactyl footprints with theropodian features (i.e., elongated digit III and narrow interdigital angle) and some possible quadruped tracks whose configuration resembles that of a sauropodomorph trackmaker. Careful examination of the depressions excludes their inorganic origin (chemical weathering). Despite the poor quality of the traces, the Pelmo site is significant because it is the most easterly site ever found on the Trento Platform and the only one which is located north of the Valsugana Fault. This fault system is a major alpine tectonic lineament that separates the classical successions of the Calcari Grigi Group in the Italian Prealps from those located in the Dolomites. Moreover, the discovery of the Pelmo tracks considerably expands the documented area of movement of Early Jurassic terrestrial vertebrates in the northern part of the Trento Platform, extending the size of the Early Jurassic megatracksites of the Southern Alps. RIASSUNTO-[Orme di dinosauro dalla cima del Mt. Pelmo: nuovi dati sulla paleogeografia del Giurassico Inferiore delle Dolomiti (NE Italia)]-Le impronte di dinosauri del Giurassico Inferiore del nordest italiano sono ben note e, dopo la prima scoperta all'inizio degli anni Novanta, sono stati riconosciuti diversi siti. Le impronte si trovano nei calcari pertitidali del Gruppo dei Calcari Grigi, depositatosi sulla piattaforma di Trento e affiorante oggi nelle Alpi Meridionali. Nel 2011, un gruppo di speleologi scoprì un nuovo sito nel Giurassico Inferiore dei Calcari Grigi, situato a 3037 m sul livello del mare, quasi alla sommità del Mt. Pelmo (Dolomiti). La qualità di conservazione delle orme è generalmente scarsa, tuttavia è possibile riconoscere alcune orme tridattile con caratteristiche teropodiane (dito III molto allungato, angolo interdigitale stretto) e alcune orme quadrupedi con una configurazione simile a quella dei sauropodi (o sauropodomorfi). L'attenta analisi delle depressioni esclude la loro origine inorganica (erosione chimica, carsismo). Nonostante la scarsa qualità delle orme, la scoperta del Pelmo è significativa perché il sito è il più orientale mai rinvenuto e l'unico situato a nord della Linea della Valsugana, un importante lineamento tettonico che separa le classiche successioni dei Calcari Grigi nelle Prealpi da quelle delle Dolomiti. Grazie al sito del Pelmo l'area dove si riscontra la presenza dei vertebrati nel Giurassico Inferiore si allarga alla parte settentrionale della Piattaforma di Trento, estendendo le dimensioni del mega-sito ad impronte del Giurassico Inferiore delle Alpi Meridionali.
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Bollettino della Società Paleontologica Italiana, 56 (2), 2017, i-viii. Modena
ISSN 0375-7633 doi:10.4435/BSPI.2017.10
Dinosaur footprints from the top of Mt. Pelmo:
new data for Early Jurassic palaeogeography of the Dolomites (NE Italy)
Matteo Belvedere, Marco Franceschi, Francesco sauro & Paolo Mietto
M. Belvedere, Ofce de la culture, Paléontologie A16, Hôtel des Halles, P.O. Box 64, CH-2900 Porrentruy 2, Switzerland; Museum für Naturkunde -
Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, D-10115 Berlin, Germany; matteo.belvedere@hotmail.com
M. Franceschi, University of Padova, Department of Geosciences, Via Gradenigo 6, I-35137 Padova, Italy; University of Ferrara, Department of Physics
and Earth Sciences, Via Saragat 1, I-44100 Ferrara, Italy; marco.franceschi79@gmail.com
F. Sauro, University of Bologna, Department of Biological, Geological and Environmental Sciences, Via Zamboni 67, I-40126 Bologna, Italy; Associazione
di Esplorazioni Geograche la Venta, Via Priamo Tron 35/F, I-31030 Treviso, Italy; cescosauro@gmail.com
P. Mietto, University of Padova, Department of Geosciences, Via Gradenigo 6, I-35137 Padova, Italy; paolo.mietto@unipd.it
KEY WORDS - Dinosaur tracks, Palaeogeography, Early Jurassic, Calcari Grigi Group, Southern Alps.
ABSTRACT - Dinosaur footprints from the Lower Jurassic of northeastern Italy are well known and, since the rst discoveries in the
early 1990s, many sites have been described. Tracks are mostly found in the peritidal limestones of the Calcari Grigi Group, deposited on
the Trento carbonate platform, now cropping out in the Southern Alps. In 2011, a group of speleologists discovered a new tracksite in the
Lower Jurassic Calcari Grigi Group exposed almost at the top of Mt. Pelmo (Dolomites), 3037 m above sea level. Footprints are generally
poorly preserved, but it proved possible to recognise some tridactyl footprints with theropodian features (i.e., elongated digit III and narrow
interdigital angle) and some possible quadruped tracks whose conguration resembles that of a sauropodomorph trackmaker.
Careful examination of the depressions excludes their inorganic origin (chemical weathering). Despite the poor quality of the traces, the
Pelmo site is signicant because it is the most easterly site ever found on the Trento Platform and the only one which is located north of the
Valsugana Fault. This fault system is a major alpine tectonic lineament that separates the classical successions of the Calcari Grigi Group
in the Italian Prealps from those located in the Dolomites. Moreover, the discovery of the Pelmo tracks considerably expands the documented
area of movement of Early Jurassic terrestrial vertebrates in the northern part of the Trento Platform, extending the size of the Early Jurassic
megatracksites of the Southern Alps.
RIASSUNTO - [Orme di dinosauro dalla cima del Mt. Pelmo: nuovi dati sulla paleogeograa del Giurassico Inferiore delle Dolomiti
(NE Italia)] - Le impronte di dinosauri del Giurassico Inferiore del nordest italiano sono ben note e, dopo la prima scoperta all’inizio degli
anni Novanta, sono stati riconosciuti diversi siti. Le impronte si trovano nei calcari pertitidali del Gruppo dei Calcari Grigi, depositatosi
sulla piattaforma di Trento e aforante oggi nelle Alpi Meridionali. Nel 2011, un gruppo di speleologi scoprì un nuovo sito nel Giurassico
Inferiore dei Calcari Grigi, situato a 3037 m sul livello del mare, quasi alla sommità del Mt. Pelmo (Dolomiti). La qualità di conservazione
delle orme è generalmente scarsa, tuttavia è possibile riconoscere alcune orme tridattile con caratteristiche teropodiane (dito III molto
allungato, angolo interdigitale stretto) e alcune orme quadrupedi con una congurazione simile a quella dei sauropodi (o sauropodomor).
L’attenta analisi delle depressioni esclude la loro origine inorganica (erosione chimica, carsismo). Nonostante la scarsa qualità delle
orme, la scoperta del Pelmo è signicativa perché il sito è il più orientale mai rinvenuto e l’unico situato a nord della Linea della Valsugana,
un importante lineamento tettonico che separa le classiche successioni dei Calcari Grigi nelle Prealpi da quelle delle Dolomiti. Grazie al sito
del Pelmo l’area dove si riscontra la presenza dei vertebrati nel Giurassico Inferiore si allarga alla parte settentrionale della Piattaforma
di Trento, estendendo le dimensioni del mega-sito ad impronte del Giurassico Inferiore delle Alpi Meridionali.
INTRODUCTION
Dinosaur footprints from the Early Jurassic of the
Southern Alps of Italy have been studied since the early
1990s (Lanzinger & Leonardi, 1992; Leonardi & Avanzini,
1994). Most of the documented trampled surfaces come
from megatracksites (Lockley, 1991) discovered at four
stratigraphic levels in the shallow water carbonates of the
Calcari Grigi Group (Leonardi & Mietto, 2000; Avanzini et
al., 2001, 2006, 2007; Avanzini & Petti, 2008), which were
deposited on the Trento Platform between the Hettangian
and the Pliensbachian. Subsurface evidence from the
Venetian Plain demonstrates that during the Sinemurian
a large peritidal carbonate platform occupied the entire
area that is now the Southern Alps, and this shallow-water
shelf depositional environment was interrupted by the
Belluno Basin (Masetti et al., 2012). The dismemberment
of this large carbonate shelf was initiated by rifting activity
and the morphological high of the Trento Platform was
formed. Most of the outcrops of the Calcari Grigi Group
are found to the south of the Valsugana Fault, a major E-W
trending thrust, part of the Southern Alps compressional
regime. Nevertheless, signicant outcrops are also found
in the Dolomite area to the north of this main tectonic
fault. The Valsugana Fault partly reactivated an important
tectonic threshold which was last active in the Permian
(Selli, 1998) and in the Early Jurassic as suggested by the
variations in thickness of the Calcari Grigi Group in the
NNW/SSE and ENE/WSW direction (Doglioni, 1987;
Franceschi et al., 2014a).
The area to the south of the Valsugana Fault has been
the focus of most stratigraphic and palaeontological
studies because of the abundance of stratigraphic sections
and the classical stratigraphy of the Calcari Grigi Group
was dened there. It is, therefore, not surprising that
most of the Early Jurassic tracksites are found in the
south-western Southern Alps, and that no evidence of
tracksites located north of the Valsugana Fault have been
published online
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Bollettino della Società Paleontologica Italiana, 56 (2), 2017
ii
reported so far. Indeed, the Lower Jurassic carbonates in
that area are less well investigated for three main reasons:
1) the relative scarcity of outcrops with respect to the
south-western Southern Alps; 2) the chronostratigraphic
uncertainties of the stratigraphic succession as compared
to the classical sequence described to the south of the
Valsugana Fault; 3) the lesser abundance of widely
exposed surfaces of Lower Jurassic carbonates. These
latter, are instead found abundant in the surroundings of
the Adige Valley, and often host the major tracksites (e.g.,
Lavini di Marco, nearby the town of Rovereto).
In 2011, during a speleological expedition made by
the team La Venta Esplorazioni Geograche, who were
exploring caves located in the central Dolomites on the north-
eastern ank of Mt. Pelmo (Veneto, Italy) (Fig. 1), several
hollows were discovered that were afterwards interpreted as
possible dinosaur footprints (Mietto et al., 2012).
A second prospection was carried out in 2014, and
was dedicated to clean and enlarge the extent of the
exposed trampled surface and to characterize the traces.
This survey conrmed the Early Jurassic age of the site
and the presence, although very weathered, of dinosaur
tracks and allowed the identication of more footprints,
recognizing the Mt. Pelmo site as the highest tracksite
in Italy (3037 m a.s.l.). Mt. Pelmo was already known
in the ichnological literature for being the rst Italian
site with dinosaur footprints, but they were recorded in
the uppermost Carnian-Norian (Late Triassic) Dolomia
Principale formation on a rockslide boulder almost at the
base of the mountain (Mietto, 1985).
Here we report the description and interpretation
of some footprints with theropod morphological
characteristics and of others with uncertain afnity whose
configuration resembles that of a sauropod(omorph)
trackmaker. The study of the Mt. Pelmo tracksite, which
represents the rst Early Jurassic tracksite discovered
north of the Valsugana Fault, contributes to a better
knowledge of the palaeogeography of the area and of the
distribution of Early Jurassic terrestrial vertebrates in the
northern part of the Trento Platform.
GEOLOGICAL SETTING
The bio-chronostratigraphy of the Calcari Grigi
Group is based on benthic foraminifera faunas (Bosellini
Fig. 1 - Location and palaeogeographical reconstruction of the site. a) Location of the Mt. Pelmo site. b) Schematic palaeogeographical
reconstruction of the Trento Platform and surrounding basins in the Early Jurassic (modied after Franceschi et al., 2014b). Orange footprint
indicates the Mt. Pelmo site position, the white tracks the known sites from the Calcari Grigi Group. The Valsugana fault is indicated as thick
black lines. c) Aerial view of the NE anks of Mt. Pelmo with the position of the tracksite (photo by C. Allois). d) View of the tracksite.
Footprint Pelm.A is located at the end of the surface, roughly where the people stand, as indicated by the arrow.
iii
M. Belvedere et alii - Dinosaur tracks from Mt. Pelmo
& Broglio Loriga, 1971; Fugagnoli & Broglio Loriga,
1998; Fugagnoli, 2004; Romano et al., 2005), calibrated
through ammonoids in Morocco (Septfontaine, 1985),
on very rare ammonite ndings (Sarti & Ferrari, 1999)
and on Sr and C isotope stratigraphy (Woodne et al.,
2008; Franceschi et al., 2014b). Four main formations are
recognized (Avanzini et al., 2007; Avanzini & Petti, 2008):
the Monte Zugna Formation (Hettangian-Sinemurian), the
Loppio Oolitic Limestone (Middle to Upper Sinemurian),
the Rotzo Formation (Sinemurian-Pliensbachian) and the
Massone Oolitic Limestone (Upper Pliensbachian).
The Monte Zugna Formation in the Adige Valley area
hosts important dinosaur track sites, particularly in its
middle peritidal portion. In one case, the abundance of
tracks led to the institution of a megatracksite (Avanzini
et al., 2006).
The lithostratigraphic characters and the scarcity of
fossil markers in the Calcari Grigi Group in the Dolomites
make difficult the recognition of the classical units:
the classical Calcari Grigi Group units are not clearly
identiable, hence, most recent geological maps (Neri et
al., 2007) refer only to the Calcari Grigi sensu lato. The
differences with respect to the classical succession led
to informally referring to this part of the Early Jurassic
carbonate platform as the “northern Trento Platform”
(Zempolich, 1993). Masetti & Bottoni (1978) document
the presence of an important hiatus at the top of the
Calcari Grigi Group in the northern Trento Platform,
testied by the absence of the Pliensbachian units. These
are locally replaced by the crinoidal grainstones of the
Fanes Encrinite (Masetti et al., 2006; Neri et al., 2007).
Elsewhere the Rosso Ammonitico Veronese directly
overlies the unconformity.
The Calcari Grigi succession is rather homogeneous
and can be subdivided in an upper and a lower portion.
The lower part is characterized by shallowing up peritidal
cycles, 50 to 70 cm thick and is referred to as the Monte
Zugna Formation. It is in this lower portion that the
Pelmo tracksite is located (Fig. 2). In the upper portion,
layers become thinner and marly interlayers are present.
Characteristic of the upper portion of the Rotzo Formation
is the presence of thick-shelled large bivalves that can be
referred to as the “Lithiotis Fauna”, typical of the upper
portion of the Rotzo Formation, and whose diffusion
is considered synchronous at the scale of the Trento
Platform and referred to as the Protodactyloceras davoei-
Amaltheus margaritatus ammonoid zones (Franceschi et
al., 2014b).
METHODS
The tracksite is situated on the north-eastern shoulder
of Mt. Pelmo, on a rocky platform which is accessible
only by climbing or by helicopter transportation. In
2014, given the short time available and the effort
Fig. 2 - Schematic stratigraphic log of the Calcari Grigi Group with
the position of the known tracksites in the Southern Alps (redrawn
and modied after Avanzini et al., 2008). The blue arrow indicates
the supposed position of the trampled surface.
Bollettino della Società Paleontologica Italiana, 56 (2), 2017
iv
spent in cleaning and enlarging the surface, tracks and
trackways were only rapidly studied in the eld. However,
the entire surface, as well as each trackway and track,
was photographed with a DSLR camera (Canon 70D);
a Canon 18-135 mm STS lens or a wide-angle lens
(Canon 10-18 mm STS) were used to take the pictures to
generate photogrammetric 3D models. Agisoft Photoscan
Pro (v.1.2.3, www.agisoft.com) was used to generate,
orient, rene and scale the models (Fig. 3b) following
the procedures detailed in Mallison & Wings (2014).
The scaled mesh, exported Stanford PLY les, were then
processed in CloudComapre (www.cloudcomapre.com),
where the meshes were accurately oriented through the
generation of a plane intersecting the surface, to avoid
imprecise alignment due to the roughness and irregularity
of the surface and later measured. Rhinoceros (v. 5.12)
was then used to create contour lines. The photos of the
surface were taken holding a tripod over the head and
using the wide-angle lens. A total of 144 photos were
used to generate the model (Fig. 3a, Supplementary data
1: https://doi.org/10.6084/m9.gshare.3113824) which
was then downscaled to 25 million faces to be easily used
to generate contour maps and outline drawings of the site
(Fig. 3b). Scaling was made using relatively short (from
10 to 50 cm) coded scale bars and two tape measures (>
10 m).
Due to the lack of time and the complex logistics, no
casts were made on the site, but detailed 3D models of the
site and the footprints, together with the raw photos used
to generate them are made available as supplementary
material, for future comparisons of these specimens to
be made.
Fig. 3 - 3D models and outline drawings of main track site. a) Photogrammetric model of the surface. b) Schematic sketch of the trampled
surface.
v
M. Belvedere et alii - Dinosaur tracks from Mt. Pelmo
STUDIED MATERIAL
Footprint identication and weathering processes
Twenty probable footprints have been recognized on
the exposed surface (Fig. 3, Supplementary data 1: https://
doi.org/10.6084/m9.gshare.3113824), and attributed
to three, possibly four trackways, based on correlation
between dimensions, alignments, pace and morphologies.
However, the preservation of the tracks is generally poor
and only a few cases provide morphological details. This
is mainly due to the location of the site on the lateral side
of a glacial cirque and to frost and solution weathering
processes locally reworking the limestone formation.
All the tracks occur as negative, usually very shallow,
epireliefs (impressions) that were originally infilled
with rock fragments. However, sporadically shallow
displacement rims are present that make them distinctive
from karstic depressions, like kamenitze (Perna & Sauro,
1978; Lundberg, 2013). Other morphological characters
allow us to exclude a karstic origin of these depressions: 1)
most of them have an uneven bottom which is uncommon
in typically at-oored solution pans due to karstication;
it is also worth noting that, in most cases, it is not
possible to correlate the uneven bottom with any ssure
or fracture system on the surface, thus strengthening the
non-karstic origin of the depressions; 2) the tracksite
almost completely lacks other surface karst morphologies
like karren or microkarren which are normally associated
with karstic solution pans (Lundberg, 2012). Instead, frost
weathering at this height in the Dolomites (3037 m a.s.l.)
is expected to be the predominant weathering process
(Panizza, 2009), and responsible for the bad preservation
of the footprints, their secondary enlargement and inlling
with angular centimetre-sized rock fragments (Walder
& Hallet, 1986). Preservation grades are determined
according to Belvedere & Farlow (2016).
Track description and interpretation
PelM.a1 - This footprint is located on the same surface
but far from the main site, on the northern edge of the
studied area (Fig. 4a, Supplementary data 2: https://doi.
org/10.6084/m9.gshare.3113824). It is a shallow tridactyl
track, with all three digits preserved, but no clear internal
morphologies. These features give a preservation grade of
1.5. The footprint seems to be slightly longer than wide,
although digit III is incomplete and the total length cannot
be evaluated (approx. PL = 23 cm, PW = 20 cm), quite
symmetrical (II^III = 21.2°; III^IV = 21.7°), and, although
digits are tapering, no clear claw marks are present.
This footprint, despite the poor preservation and the
lack of the distal digit III, is similar to the morphotype
described in the Coste dell’Anglone site (Petti et al.,
2011) and assigned to Kayentapus Welles, 1971. Despite
the similarities, however, we prefer not to assign an
ichnotaxonomical attribution for Pelm.A1, which is
therefore classied as an indeterminate theropod track.
PelM.B - The trackway is composed of ve, possibly
six footprints aligned along the same direction, and very
likely left by a bipedal dinosaur. Most of the footprints
are preserved merely as irregular depressions with no
morphological details (grade 0). It is, however, possible
to measure pace and stride, which are quite regular for
the length of the trackway, supporting the hypothesis
of a bipedal trackmaker. Only one track, Pelm.B5 (Fig.
4b, Supplementary data 3: https://doi.org/10.6084/
m9.gshare.3113824), despite some deformation in the
depth due to secondary karst weathering, shows some
better details (preservation grade 1); it is tridactyl,
longer than wide (PL = 21.3 cm, PW = 14.4) and slightly
asymmetric (II^III = 17°, III^IV = 20°). Digit III is the
longest and is quite elongated. All digits, especially
digit III, have tapering endings, probably due to claw
marks and then highlighted by the weathering of the
footprints, suggesting a theropod trackmaker. A possible
impression of digit I and of the distal part of metatarsus
may be present in the posterior part of the impression,
but it is very difcult, even looking at the 3D models, to
discriminate whether they are true morphological features
or deformation due to the erosion of the footprint.
The elongated digit III and the narrow interdigital
angles are features of the ichnotaxon Grallator Hitchcock,
1845, a theropod ichnogenus very common in the
Early Jurassic. However, due to the preservation, it
is impossible to reliably assign the Pelm.B to any
ichnotaxon and therefore we consider it an indeterminate
theropod trackway. It is impossible to determine whether
the trackmaker of Pelm.B was different from that of
Pelm.A: the differences in the shape of the tracks (e.g.,
divarication angles differences) can be due either to real
differences of the autopodia (i.e., different trackmaker)
or to extramorphological factors, e.g., the softness of
the substrate at the moment of the impression; the poor
preservation of both tracks prevents discrimination
between either of the two hypotheses.
PelM.C - Three small elliptical depressions were
mapped. They have a longer axis of about 10 cm. The
preservation is too poor to make any determination and
even to discriminate if they are prints or only weathering
structures. Some other depressions were mapped, but due
to the preservation, and to the alignment with major cracks
of the surface, it was impossible to determine if they were
tracks or erosional structures.
PelM.d - The trackway is composed of six large
impressions, elliptical or bell-shaped, longer than wide
(average PL = 34 cm; PW = 20) and not very deep
(Fig. 4c, Supplementary data 4: https://doi.org/10.6084/
m9.gshare.3113824). In one case, on the external side
of Pelm.D1, it is possible to observe a smaller, elliptical
(ML = 7.4 cm; MW = 8.3 cm) impression which has been
interpreted as the forelimb print of a quadrupedal animal
and highlights very marked heteropody. Unfortunately,
the trackway lies on a large crack in the surface which is
very rough and deteriorated and which led to a maximum
quality value of 0.5, as no internal morphologies are
preserved, but manus and pes prints are discernible. The
incompleteness of the trackway (which is quite narrow)
prevents the quantication of the trackway gauge both
using the PTR (Romano et al., 2007) and WAP/PL ratio
(Marty, 2008) methods.
Although poorly preserved theropods may appear as
oval footprints, and despite the marked heteropody, these
tracks are attributed to a sauropodomorph trackmaker
based on the shape and the overall quadrupedal
Bollettino della Società Paleontologica Italiana, 56 (2), 2017
vi
conguration of the footprints. Sauropodomorph tracks
are quite common in the coeval levels of the Monte Zugna
Formation of the Trento Platform, and at the Lavini di
Marco site, a new ichnotaxon was erected: Lavinipes
cheminii Avanzini et al., 2003. The tracks of the Pelmo
site, however, do not show the peculiar features of
Lavinipes, such as the occurrence of clearly separated digit
impressions, with a marked digit I, and the pentadactyl or
semi-circular manus tracks.
A similar heteropody is also present in the ichnogenus
Tetrasauropus Ellenberger, 1972 (amended by D’Orazi
Porchetti & Nicosia, 2007). Tetrasauropus trackway
conguration, however, seems to be more wide-gauge
than in the studied specimens, and there are no other
recognizable morphological remarks, e.g. the curved digits
with distinct claw marks both in the pes and in the manus,
or the entaxony of the pes. Moreover, Tetrasauropus
has almost always been reported from the Late Triassic;
there is only one occurrence in the Early Jurassic of this
ichnotaxon (Milàn et al., 2008), but the poor preservation
of the studied tracks prevents any reliable comparison.
Parabrontopodus isp. tracks have been recorded at Mt.
Finonchio, from the younger upper supratidal unit of the
Monte Zugna Formation (Avanzini et al., 2008). These
tracks have similar preservation, a marked heteropody and
comparable morphology of the pes. Given the similarities
with the Mt. Finonchio footprints, Pelm.D tracks
could be assigned to Parabrontopodus isp., although
Parabrontopodus Lockley et al., 1994 has become a
wastebasket ichnotaxon, including any poorly preserved,
elliptical quadrupedal track. For these reasons, we prefer
not to assign Pelm.D to any ichnotaxon and classify it
as footprints of uncertain afnity whose conguration
resembles a sauropod(morph).
CONCLUSIONS
Despite the small size of the trampled surface and
the poor preservation, the tracks of the Mt. Pelmo
site depict at least three different ichnomorphotypes
occurring on the same level, suggesting the presence of
theropods and quadruped dinosaurs. The association of
Kayentapus-like theropod tracks and sauropodomorph
tracks (Parabrontopodus Lockley et al., 1994; Lavinipes
Avanzini et al., 2003) is very common in the Early Jurassic
of Southern Alps and can be easily linked to the other sites
of the peritidal unit the Monte Zugna Formation. The same
association, in fact, even if more complete and of better
preservation, occurs in the famous Lavini di Marco site,
and in many other coeval localities of north-eastern Italy
(Avanzini & Petti, 2008). It is not possible to assign a
precise age to the Pelmo tracksite. Since the stratigraphic
level of their nding is ascribed to the middle peritidal unit
of the Calcari Grigi Group, the trampled surface can be
broadly referred to the middle portion of the Sinemurian
(e.g., Masetti et al., 2016).
The Mt. Pelmo tracksite nding is the rst recorded
north of the Valsugana Fault, in the so-called “northern
Trento Platform” (Fig. 1), and considerably extends
the northern limit of at least temporarily exposed lands
that could be reached by dinosaurs. According to this
hypothesis, supported by the ichnoassociation that the
Pelmo tracksite could be attributed to deposits coeval
to the middle peritidal unit of the Calcari Grigi Group,
its nding expands the boundaries of the Calcari Grigi
megatracksite (Avanzini et al., 2006). In terms of
palaeogeography, this extension is likely considerably
larger than the present recorded distance to the other
tracksites located in the southern Trento Platform because
of the tectonic shortening that occurred during Alpine
orogenesis along the Valsugana Fault, which is estimated
by Schönborn (1999) in some 22 km.
It is very likely that future investigations on the same
surface or on other areas of the Mt. Pelmo outcrops of the
Fig. 4 - 3D models and outline drawings of the best-preserved
tracks. Grey lines indicate cracks on the surface. a) Pelm.A1 isolated
tridactyl footprint. b) Pelm.B5, deep tridactyl track, possibly part of
a trackway; it was the rst track discovered during the speleological
investigations. c) Pelm.D1 impressions of the manus and pes of a
sauropodomorph.
vii
M. Belvedere et alii - Dinosaur tracks from Mt. Pelmo
Calcari Grigi Group will provide more ichnological data,
possibly higher quality as to allow proper comparisons and
better constrain the age of the site. Mt. Pelmo tracksite
has the potential to contribute to increasing the knowledge
of the Early Jurassic terrestrial vertebrates in the northern
part of the Trento Platform, extending the size of the Early
Jurassic megatracksites of the Southern Alps.
SUPPLEMENTARY DATA ARCHIVING
All the Supplementary data of this work are available at
the Figshare https://doi.org/10.6084/m9.gshare.3113824.
ACKNOWLEDGEMENTS
This work is a contribution to the call for papers arising from
the Fourth International Congress on Ichnology “Ichnia 2016 -
Ichnology for the 21st century: (palaeo)biological traces towards
sustainable development”, held in Idanha-a-Nova (Portugal), 6-9
May 2016.
We are in debt with Mauro Olivotto and La Venta Esplorazioni
Geograche for discovering the tracks and promptly sharing the
information. We are very thankful to the Museo Palazzo Corte Metto
(Auronzo di Cadore), the Museo V. Cazzetta (Selva di Cadore), the
Associazione Amici del Museo V. Cazzetta, the Museo delle Regole
of Cortina d’Ampezzo for the nancial and logistical support to the
eld work. MB was supported by an Alexander von Humboldt-
Stiftung fellowship grant. Many thanks to Daniela Barbieri, Paolo
Tassi, Mauro Lampo, Chiara Siorpaes and Gianni Lovato, without
whose help and work it would have been impossible to clean the
trampled surface. We need to thank EliFriulia S.r.l. for the exibility
shown to meet our needs, too. Claudio Allois for the aerial gure of
the NE anks of Mt. Pelmo. We also wish to thank Andrea Baucon
and Carlos Neto de Carvalho for editing this special volume, the
editors of the BSPI, and the two reviewers, Vanda Faria dos Santos
and Lara Sciscio, for their precious comments that increased the
quality of this work.
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Manuscript received 14 December 2016
Revised manuscript accepted 8 March 2017
Published online 4 August 2017
Guest Editors Andrea Baucon & Carlos Neto de Carvalho
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