[dinosaur] Monti Pisani (Italy) tetrapod track associations and Middle Triassic dinosauromorphs

Ben Creisler

A new paper:

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Lorenzo Marchetti, Alberto Collareta, Matteo Belvedere Â& Giuseppe Leonardi (2021)
Ichnotaxonomy, biostratigraphy and palaeoecology of the Monti Pisani tetrapod ichnoassociation (Tuscany, Italy) and new insights on Middle Triassic Dinosauromorpha.
Palaeogeography, Palaeoclimatology, Palaeoecology 110235 (advance online publication)
doi: https://doi.org/10.1016/j.palaeo.2021.110235
https://www.sciencedirect.com/science/article/abs/pii/S0031018221000201

Highlights

We revise the famous Triassic tetrapod ichnoassociation of Monti Pisani (Italy).
It is diverse and rich in Rhynchosauroides, especially in coastal pond deposits.
It is referred to the Atreipus-Grallator footprint biochron and dated to the Ladinian.
The base of the above footprint biochron is moved at the Anisian-Ladinian transition.
A wide dispersal of Dinosauromorpha as early as the Middle Triassic is proposed.

Abstract

The Middle Triassic is a key time span for understanding the evolution of archosaurs and the rise of Dinosauromorpha. A further source of information on this issue may be provided by the study of tetrapod footprints. We revise the tetrapod ichnoassociation of the Quarziti del Monte Serra Formation (Verrucano Group, Monti Pisani, Italy) and identify the following ichnotaxa: cf. Atreipus isp. (dinosauromorph), Chirotherium barthii, C. gallicum (archosauriforms), Rotodactylus isp. and Synaptichnium pseudosuchoides (archosauromorphs), Rhynchosauroides cf. palmatus (neodiapsid), cf. Circapalmichnus isp. and Procolophonichnium haarmuehlensis (therapsids). The ichnoassemblage is diverse and dominated by Rhynchosauroides tracks in the coastal pond deposits and non-diverse and dominated by archosaur tracks in the coastal sandflat deposits. Bivalve biostratigraphy supports the Ladinian age of the Quarziti del Monte Serra Formation inferred by the tetrapod ichnoassociation. The stratigraphically oldest occurrences of Atreipus from Italy, France, Morocco and Germany are likely Ladinian, which highlights a wide dispersal of dinosauromorphs as early as the Middle Triassic.

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