Lorenzo Marchetti_report annuale IIII

Scuola di Dottorato in Scienze della Terra,
Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2013-2014
EARLY PERMIAN VERTEBRATE ICHNOFAUNA FROM SOUTH ALPINE REGION
(NORTHERN ITALY): ICHNOSYSTEMATICS, PALEOECOLOGY AND
STRATIGRAPHIC MEANING
Ph.D. candidate: LORENZO MARCHETTI, III course
Tutor: Prof. STEFANO MONARI
Cycle: XXVI
Abstract
The Early Permian vertebrate ichnofauna of Italy is known since the 19th century, but a comprehensive study has never
been tempted. This work of revision, on classical collections, specimens never described and new sampling, pointed to better
reconstruct the real significance of the Italian ichnoassociation, in a wider global context. Two ichnogenera new for the
Southern Alps were identified: Hyloidichnus and Limnopus. Those confirmed are: Amphisauropus, Batrachichnus, Dromopus,
Erpetopus, and Varanopus. Optimally-preserved specimens allowed taxonomical and behavioral studies. All the data indicate
that the Italian ichnofauna is larger and better preserved than previously known. The stratigraphic meaning is important,
because it is well time-constrained (Early Kungurian, from radiometric dates). The main difference with contemporary
associations is the lack of some bigger forms, like Ichniotherium and Dimetropus. This could have a stratigraphic or a
paleoenvironmental explanation. The differences observed in different Italian basins and sites seem to be facies-related.
Introduction
The Early Permian of the Southern Alps is characterized by the development of some continental pullapart basins, along a E-W transect. The deposition was strongly controlled by tectonic forces, and
volcanic and plutonic activity was very intense. The sedimentary infilling of the basins reflects alluvialfan to sand sheet and floodplain-lacustrine environments, passing from unsorted conglomerates to
stratified sandstones and laminated siltstones and mudstones. These latter preserve common evidences of
subaerial exposure, like rain drops, mud cracks and fossil footprints of vertebrates and invertebrates.
The fossiliferous basins are, from the E to the W: the Orobic Basin, the Collio Basin and the sedimentary
sub-basins of the Athesian Volcanic Group.
The first documented studies are from the 19th century (Curioni, 1870). Subsequent works proved the
poorness of the Italian ichnoassociation, further accentuated in the younger strata (Conti et al. 1997,
Nicosia et al., 2000, Avanzini et al., 2008). The studies on Early Permian Italian ichnofauna are generally
descriptions of new material from a specific site, or works of partial revision, so a real comprehensive
study on all the Early Permian material of the Southern Alps has never been tempted.
The purpose of this study was to revise all the material coming from the Italian sites, with a mixture of
modern and traditional techniques and following a precise and uniform approach. This was associated
with new field work, necessary to better locate the fossiliferous localities, in a precise stratigraphic and
paleoenvironmental context.
Material and methods
The specimens analyzed (about 1000), are stored in different museums and institutions, which are:
Natural History Museum of Milano, Natural History Museum "E. Caffi" of Bergamo, Natural History
Museum of Brescia, Natural History Museum of Morbegno, Natural History Museum of Bolzano,
Museum of Sciences MUSE of Trento, Ecomuseum of Val Gerola, Paleontological Museum of the
University "La Sapienza" of Rome, and University of Pavia.
The methods include a mixture of traditional (free line drawings, photos) and modern techniques
(computer drawings, 3D acquisition and modelling), to obtain the most precise interpretative drawings
and 3D models, necessary to the measure of the ichnologic parameters (Leonardi, 1987). The state of
preservation of the material and the extramorphologies were carefully evaluated. The 3D acquisition
methods include laser scanning and photogrammetry.
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Scuola di Dottorato in Scienze della Terra,
Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2013-2014
Discussion
The results of this complete work of revision strongly modifies the previous ideas on the Early Permian
Italian ichnoassociation.
Two ichnospecies, previously unknown for these basins, were identified: Hyloidichnus bifurcatus
Gilmore, 1927 and Limnopus heterodactylus (King, 1845). They correspond to captorhinomorphs and
temnospondyls (basal amphibians) of medium size, respectively.
These ichnogenera were confirmed: Amphisauropus, Batrachichnus, Dromopus, Erpetopus, and
Varanopus. Taxonomic studies on extensive material prove the existence of both the ichnospecies
Erpetopus willistoni and E. cassinisi, as supposed by Santi (2007); also Varanopus is present, but it seems
different from both the known ichnospecies, so another name should be utilized.
Behavioral studies proved the existence of simultaneous gait of Amphisauropus and Erpetopus, and
peculiar sinusoidal arrangement of tail impression in some Amphisauropus specimens (the only similar
impression is from Canada, Van Allen et al., 2005).
The stratigraphic meaning of the association is important, because it is strongly age-constrained (at least
in Collio Basin and Athesian District), and so highly correlable. The age is Early Kungurian (from U-Pb
radiometric dates on volcanic rocks). The most remarkable difference with Early Permian ichnofaunas of
Europe and USA, is the lack of some bigger forms, like Dimetropus and Ichniotherium. Two hypothesis
could be advanced: the trackmakers were declining or were extinct in the Kungurian (Gand & Durand,
2006, Lucas, 2007) or the paleoenvironment was different.
The ichnoassociation lists the same forms in the two main Basins (Orobic and Collio Basins), but the
proportions are quite different. The Collio Basin is characterized by a predominance of areoscelid traces
(Dromopus, 81% of specimens), the Orobic Basin of captorhinomorph traces (Erpetopus-HyloidichnusVaranopus, 63% of specimens), this probably have an environmental explanation, since the stratigraphic
position is similar.
FIG 1. Photos and interpretative drawings of Hyloidichnus bifurcatus Gilmore, 1927. FIG 2. Photos and interpretative
drawings of Limnopus heterodactylus (King, 1845).
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Scuola di Dottorato in Scienze della Terra,
Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2013-2014
New field work interested three sections in the Trentino-Alto Adige region (Val Aperta, Tregiovo, Monte
Luco), in the context of the project: "The Permian-Triassic ecological crisis in the Dolomites: extinction
and recovery dynamics in Terrestrial Ecosystems". The new data indicate that the ichnofauna of this
region is poorer, but the cause is probably not stratigraphic or paleoenvironmental, it is likely a bias.
Field work also interested the Val Gerola, Laghi Gemelli, Val Brembana and Val Trompia sites, with the
purpose of better relate the fossil localities with the study of stratigraphy and facies. These preliminary
studies emphasize the richness of the Val Gerola and Laghi Gemelli sites, and indicate that the
distribution of forms is facies-related.
Conclusions
The Italian Early Permian ichnoassociation results larger and better preserved than previously known, and
it is well comparable to contemporary associations of Germany, France and USA.
The age is Early Kungurian, and it is composed by seven different ichnogenera: Amphisauropus,
Batrachichnus, Dromopus, Erpetopus, Hyloidichnus, Limnopus,Varanopus. The ichnofaunal composition
is similar in the Orobic and Collio Basins, although with different proportions, instead taxa from the
Athesian Complex are fewer, but this seems a bias.
The main difference with contemporary associations is the lack of the ichnogenera Dimetropus and
Ichniotherium, this could have a stratigraphic or paleoenvironmental explanation.
References
AVANZINI, M., NERI, C., NICOSIA, U. and CONTI, M.A. 2008. A new Early Permian ichnocenosis
from the “Gruppo vulcanico atesino” (Mt. Luco, Southern Alps, Italy). Studi Trentini di Scienze Naturali.
Acta Geologica, 83: 231-236.
CURIONI, G. 1870. Osservazioni geologiche sulla Val Trompia. Rendiconti Istituto Lombardo di Scienze
e Lettere, Arti, Memorie , Serie 3(2): 1-60.
CONTI, M. A., MARIOTTI, N., NICOSIA, U. and PITTAU, P. 1997. Succession of selected bioevents in
the continental Permian of the Southern Alps (Italy): improvements in intrabasinal and interregional
correlations. In: Dickins J.M., Zunyi Y., Yhongfu Y., Lucas S.G. and Acharyya S.J. (Eds), Late Paleozoic
and Early Mesozoic Circumpacific events and their global correlation. Cambridge University, p: 51-65.
GAND, G., and DURAND, M. 2006. Tetrapod footprint ichno-associations from French Permian basins.
Comparisons with other Euramerican ichnofaunas. Geological Society, London, Special
Publications, 265(1): 157-177.
LEONARDI, G. 1987. Glossary and manual of tetrapod footprint palaeoichnology. Departamento
Nacional de Produção Mineral, Brasilia, 117 p.
LUCAS, S.G. 2007. Tetrapod footprint biostratigraphy and biochronology. Ichnos, 14(1-2): 5-38.
NICOSIA, U., RONCHI, A. and SANTI, G. 2000. Permian tetrapod footprints from W Orobic Basin
(Northern Italy). Biochronological and evolutionary remarks. Geobios , 33 (6): 753-768.
SANTI, G. 2007. A Short Critique of the Ichnotaxonomic Dualism Camunipes-Erpetopus, Lower
Permian Ichnogenera from Europe and North America. Ichnos , 14: 185-191.
VAN ALLEN, H. E. K., CALDER, J. H. and HUNT, A. P. 2005. The trackway record of a tetrapod
community in a walchian conifer forest from the Permo-Carboniferous of Nova Scotia. New Mexico
Museum of Natural History and Science Bulletin, 30: 322-332.
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Scuola di Dottorato in Scienze della Terra,
Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2013-2014
SUMMARY OF ACTIVITIES
Courses:
F. REMONDINO, A. RIZZI, F. MENNA, G. AGUGIARO: "Fotogrammetria e 3D Laser Scanning". Dipartimento di
Geoscienze, Università degli Studi di Padova
L. SALMASO, L. CORAIN, S. BONNINI, R. ARBORETTI: "Statistica applicata alla sperimentazione scientifica". Centro
Studi per l'Ambiente Alpino di S. Vito di Cadore (BL)
E. CALANDRUCCIO: "Corso di Inglese Parlato" Dipartimento di Geoscienze, Università degli Studi di Padova
S. MILLI, F. FONNESU: "Processi ed architetture deposizionali in sistemi torbiditici" X convegno annuale dei geologi del
sedimentario - Geosed 2012, Città di Feltre
W. HELLAN-HANSEN: “Sequence stratigraphy: principles and applications” Dipartimento di Geoscienze, Università degli
Studi di Padova.
R. J. ANGEL: "Scientific Communication in English" Dipartimento di Geoscienze, Università degli Studi di Padova
L. GULICK: "Corso Avanzato di Inglese Scientifico", Università degli Studi di Padova
Communications:
MARCHETTI, L., AVANZINI, M. and BERNARDI, M. 2012. Impronte di tetrapodi nel Permiano inferiore del Sudalpino:
nuove scoperte e siti di interesse. In: Giornate di Paleontologia XII Edizione. Abstracts. Catania, Italy.
MARCHETTI, L. and AVANZINI, M. 2013. Revision of Early Permian tetrapod ichnofauna, new insights from Lombardy
and Trentino Alto-Adige (N Italy). In: Giornate di Paleontologia XIII Edizione. Abstracts. Perugia, Italy.
MARCHETTI, L., AVANZINI, M., CONTI M. A. and SANTI, G. 2013. Early Permian vertebrate ichnology of the Southern
Alps (N Italy): new discoveries and sites of interest. In: Second Latin-American Symposium on Ichnology, SLIC 2013.
Abstracts. Santa Rosa, Argentina.
Posters:
MARCHETTI, L., SANTI, G. and AVANZINI, M. 2012. The problem of small footprints in paleoichnology related to
extramorphologies: new data from the Early Permian Erpetopus. In: X annual meeting of sedimentary geologists "Geosed
2012". Abstracts. Feltre, Italy.
MARCHETTI, L., BERNARDI, M. and VOIGT, S. 2013. On locomotion of seymouriamorpha: An unusual trackway of
Amphisauropus from the Early Permian of northern Italy. In: Giornate di Paleontologia XIII Edizione. Abstracts. Perugia,
Italy.
MARCHETTI, L., RONCHI, A, SANTI, G. and VOIGT, S. 2013. The Early Permian Gerola Valley ichnosite (W Orobic
Basin, N Italy): taxonomical revision and paleoenvironmental reconstruction. In: Second Latin-American Symposium on
Ichnology, SLIC 2013. Abstracts. Santa Rosa, Argentina.
Publications:
MARCHETTI, L., BERNARDI, M. and AVANZINI, M. 2013. Some insights on well-preserved Amphisauropus and
Erpetopus trackways from the Eastern Collio basin (Trentino-Alto Adige, NE Italy). Bollettino della Società Paleontologica
Italiana, 52(1), 55-62.
MARCHETTI, L., AVANZINI, M. and CONTI, M. A. 2013. Hyloidichnus bifurcatus Gilmore, 1927 and Limnopus
heterodactylus (King, 1845) from the Early Permian of Southern Alps (N Italy): A New Equilibrium in the Ichnofauna.
Ichnos, 20(4), 202-217.
MARCHETTI, L., SANTI, G. and AVANZINI, M. The problem of small footprints in paleoichnology: remarks on the Early
Permian ichnotaxon Erpetopus cassinisi, a local morphotype from Southern Alps (northern Italy). Rivista Italiana di
Paleontologia e Stratigrafia, accepted
Teaching activities:
Teaching assistant: 21 hours, “Paleontologia”, Laurea di primo livello in Scienze Geologiche (2012/2013).
Teaching assistant: 21 hours, “Paleontologia”, Laurea di primo livello in Scienze Geologiche (2013/2014).
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Scuola di Dottorato in Scienze della Terra,
Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2013-2014
Other:
Collaboration with Natural History Museums of Bolzano and Trento for the project: "The Permian-Triassic ecological crisis in
the Dolomites: extinction and recovery dynamics in Terrestrial Ecosystems" financed by the Promotion of Educational
Policies, University and Research Department of the Autonomous Province of Bolzano - South Tyrol.
Temporary assignment at the Natural History Museum "E. Caffi" of Bergamo, to reclassify the Permian fossil footprints
collection of the Museum. Study of the Early Permian vertebrate footprint collection of the "Universidad Nacional de La
Pampa", Santa Rosa, Argentina. Field work in a new Early Permian ichnosite in Austria.
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