A new phytosaur from the Late Triassic of Jameson Land, East Greenland

1. Master Thesis
A new phytosaur from the Late
Triassic of Jameson Land, Greenland
V. LÓPEZ-ROJAS, O. MATEUS, J. MILÀN, O. WINGS,
N. KLEIN, L.B. CLEMMENSEN

2. PALEOGEOGRAPHY CONTEXT
- Phytosaur remains
- Greenland’s phytosaur
Scotese (2018)

3. GEOLOGICAL CONTEXT
2016 QUARRY
Clemmensen et al. (2020)
Marzola et al. (2017a)
Clemmensen et al. (2020)
GeocenterMoensKlint youtube channel
Fleming Fjord Group is predominantly
made by cyclically lacustrine deposits of
continental origin of Norian-Rhaetian.
Divided in three formations
(Edderfugledal, Malmros Klint, and Ørsted
Dal), is rich in vertebrate fossils.
The “Phytosaur Bone Bed” is located in
Mateus Quarry, at Lepidopteris Elv
locality (middle of Malmros Klint
Formation)

4. GEOLOGICAL CONTEXT
Modified from
Clemmensen et al. (2020)
The Formation is comprised
of a sedimentary cyclicity,
and divided into a lower
sandstone-siltstone rich
unit, an upper claystone-
rich unit, and topped by a
dolomitic paleosol

5. • Post-cranial material: 60,4%
• Vertebrae: 8,5%
• Ribs: 24.4%
• Limbs: 11,6%
• Girdles: 4,3%
• Dermal armor: 11,6%
• Cranial material: 39,6%
• Skull + Mandible: 9,1%
• Teeth: 30,5%
TAPHONOMY
Vertebrae Ribs Limbs
Girdles Dermal armor Skull
Teeth
Quarry map (2012)
Witzman et al., 2014
This research is focused on
the material collected during
the expeditions of 2012 and
’16.
Most of the material is from
the post-cranial region, and
are complete, or nearly
complete, bones. However,
the skull and mandible
material is not only scarce,
but partial remains.
One third of the cranial
material are isolated teeth.

6. At least 4 individuals
Different ontogenetic stages
ONTOGENICAL STAGES
All the bones were photographed by Marco Marzola and Octávio Mateus
10cm
10cm
5cm
2cm
“Baby”
JUVENILE
ADULTS
Scapula
Dorsal vertebra
Two
left
humeri
Greenland phytosaur, exposed in the
Denmark Natural History Museum

7. Jones & Butler (2018)
Matrix from Jones & Butler (2018) – 94 characters
Additional Ch.95 – Degree of heterodonty (=Ch.5
Hungerbühler, 2002) – Due to the high number of teeth found
PHYLOGENETICS
Hungerbülher (2002)
2cm

8. TREES RECOVERED: 30
TREE LENGTH: 348 STEPS
CONSENSUS LENGTH: 367 STEPS
CONSISTENCY INDEX: 0,391
RETENTION INDEX: 0,698
PHYLOGENY

9. Mystriosuchus steinbergeri
Mystriosuchus planirostris
Mystriosuchus westphali
Greenland’s Mystriosuchus
Possession of an interpremaxillary
fossa narrow slit
Mystriosuchus steinbergeri
Greenland‘s Mystriosuchus
WHY IS A MYSTRIOSUCHUS
Hungerbühler (2002)
Stocker (2010)
Butler et al. (2019)
Photographed by Marco Marzola and Octávio Mateus
Butler et al. (2019)

10. Proximal section of postorbital descending
process where posterior border of orbit
meets skull roof, the posterior border of
orbit remains thin until it reaches skull roof
WHY IS A MYSTRIOSUCHUS
Mystriosuchus planirostris
Mystriosuchus westphali
Greenland’s Mystriosuchus
Hungerbühler (2002)
Stocker (2010)
Mystriosuchus planirostris Mystriosuchus westphali Greenland‘s Mystriosuchus
Photographed by Marco Marzola
and Octávio Mateus

11. PALEOBIOGEOGRAPHICAL
- Mystriosuchus species are
restricted to the Norian (Middle-
Late Norian), which correlates
with the data from Malmros
Klint Fm locality
- Two ways of isolation:
geographical and climatical
IMPLICATIONS
Scotese (2018)

12. CONCLUSIONS
• More than 150 bones of phytosaur, from four individuals of three different
ontogenetical stages.
• Bones are attributed to the genus Mystriosuchus, potentially to a new
species.
• First Mystriosuchus confirmed found outside of Europe. It reinforces the
idea of European affinity of the fauna by Late Triassic in East Greenland.

13. Acknowledgements
We gratefully acknowledge the support from GeoBioTec-GeoBioSciences, GeoTechnologies
and GeoEngineering NOVA [GeoBioCiências, GeoTecnologias e GeoEngenharias], grant
UIDB/04035/2020 by the Fundação para a Ciência e Tecnologia, Dronning Margrethes og Prins
Henriks Fond, Arbejdsmarkedets Feriefond, Oticon Fonden, Knud Højgaards Fond, Louis
Petersens Legat, Det Obelske Familiefond, Ernst og Vibeke Husmans Fond, the Carlsberg
Foundation, the Independent Research Fund Denmark, and Geocenter Møns Klint. The material
was professionally prepared by Verena Régent, as well as Museu de Lourinhã preparators,
especially Carla Alexandra Tomás and Micael Martinho. A special acknowledgment goes for
Nils Natrop that made 2012 expedition possible. We are also grateful to Nadia Rosendal
Nielsen, Eliza Estrup and Nils Natrop from the Geocenter Møns Klint for their participation in
excavations. To Marco Marzola for his previous work And Vincent Cheng for his work in the
revision of the document.

14. Master Thesis
A new phytosaur from the Late
Triassic of Jameson Land, Greenland
V. LÓPEZ-ROJAS, O. MATEUS, J. MILÀN, O. WINGS,
N. KLEIN, L.B. CLEMMENSEN