MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
Jaw biomechanics in the South American aetosaur Neoaetosauroides engaeus.
Autor/es:
DESOJO, J. B.; VIZCAINO, S.
Revista:
Paläontologische Zeitschrift
Editorial:
Springer
Referencias:
Lugar: Munchen, Germany; Año: 2009 vol. 83 p. 499 - 510
ISSN:
1867-6812
Resumen:
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The function of the jaw apparatus and the possible
dietary habits of the aetosaur Neoaetosauroides engaeus from the
Triassic of South America was analyzed in comparison with Northern Hemisphere
aetosaurs Desmatosuchus haplocerus and Stagonalepis robertsoni
and the living short-snouted crocodile Alligator mississippiensis. The
adductor and depressor jaw musculature of these was reconstructed based on
dental and skeletal comparisons with living closest relatives (EPB), followed
by the analysis of the moment arms of these muscles to infer feeding
habits. The aetosaurian skull design indicates that the total leverage of the
inferred jaw musculature provides force rather than speed. However, within
aetosaurs, the high ratios of muscle moment arms to bite moments indicate
stronger bites in the northern Hemisphere forms, and faster ones in Neoaetosauroides.
These differences indicate more developed crushing, chopping, and slicing
capacities, especially at the back of the tooth series for D. haplocerus
and S. robertsoni; while it opens a window to consider different
abilities in which speed is involved for N. engaeus. There are
differences among aetosaurs in dental characters, position of the supratemporal
fenestra, location of the jaw joint relative to the tooth row, and shape of the
lower jaw. Neoaetosauroides does not show evidence of dental serrations
and wear facets, probably consistent with a relatively soft and non-abrasive
diet, such as soft leaves and/or larvae and insects without hard structures. It
might be possible that Neoaetosauroides represents a tendency towards
insectivorous feeding habits, exploiting a food source that was widespread in
continental environments throughout the Triassic.