Stagonolepis
Name:
Stagonolepis
(Ornamented scale).
Phonetic: Stag-on-oh-lep-is.
Named By: Louis Agassiz - 1844.
Synonyms: Aetosauroides? Calyptosuchus?
Classification: Chordata, Reptilia, Aetosauria,
Stagonolepididae.
Species: S. robertsoni
(type), S. olenkae, S. wellesi?
Diet: Herbivore.
Size: Up to about 3 meters long.
Known locations: Europe, Scotland -
Lossiemouth Sandstone Formation and Poland - Drawno Beds
Formation. Possibly North America and even South America.
Time period: Carnian of the Triassic.
Fossil representation: Multiple individuals.
Stagonolepis
had the typical aetosaur
body form, quadrupedal, short legs and
osteoderms than ran down the length of the body. This form could be
described as crocodile-like, but caution should be exercised before
assuming that Stagonolepis lived like a crocodile
as well.
Stagonolepis had neither piercing or slicing
teeth, but peg-like
teeth adapted for stripping the foliage from ferns. Stagonolepis
also
had a toothless beaked tip to the front of the jaws which could have
been used for digging up buried plants. As such the osteoderm armour
of Stagonolepis was probably more for protection
from the jaws of
archosaurian predators of the time possibly similar to Smok
(though
this particular genus lived slightly later).
There
is still some confusion about Stagonolepis,
specifically regarding if
any other genera are synonymous to it. Calyptosuchus
from North
America has for some time been considered to be a synonym to
Stagonolepis, something which led to the creation
of the species S.
wellesi. Aetosauroides from South
America has
also been considered
to be a synonym to Stagonolepis with smaller
individuals belonging to
S. robertsoni, larger ones to S.
wellesi. Later studies of
these fossils have now yielded the opinion that both Calyptosuchus
and
Aetosauroides are actually valid as distinct
genera. If this is
correct, then the species of Stagonolepis will be
reduced to just
two, S. robertsoni from Scotland and S.
olenkae from Poland.
Needless to say this will also mean that Stagonolepis
only has a
European distribution.
Further reading
- South American occurrences of the Adamanian (Late Triassic:
latest Carnian) index taxon Stagonolepis
(Archosauria:
Aetosauria) and their biochronological significance, A. B.
Heckert - 2002.
- Aetosaur dermal armor from the Late Triassic of southwestern North
America, with special reference to material from the Chinle Formation
of Petrified Forest National Park, R. A. Long and K. L.
Ballew. 1985.
- The skull of an early Late Triassic aetosaur and the evolution of
the stagonolepidid archosaurian reptiles, Tomasz Sulej - 2010.
- A reappraisal of the taxonomic status of Aetosauroides
(Archosauria, Aetosauria) specimens from the Late Triassic of
South America and their proposed synonymy with Stagonolepis,
J. B.
Desojo & Martin D. Ezcurra - 2011.
- Osteology of a forelimb of an aetosaur Stagonolepis olenkae
(Archosauria: Pseudosuchia: Aetosauria) from the Krasiejów locality in
Poland and its probable adaptations for a scratch-digging behavior. -
PeerJ. 6: e5595. - Dawid Dróżdż - 2018.
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