MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A new basal archosauriform from the Middle-Late Triassic of Brazil, the monophyly of Doswelliidae
Autor/es:
DESOJO, J. B.; EZCURRA, M.; SCHULTZ, C.
Lugar:
San Luis
Reunión:
Jornada; XXV Jornadas Argentinas de Paleontología de Vertebrados; 2010
Institución organizadora:
Universidad Nacional de San Luis
Resumen:
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";
mso-ansi-language:ES-AR;}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 3.0cm 70.85pt 3.0cm;
mso-header-margin:36.0pt;
mso-footer-margin:36.0pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
<!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;
mso-font-alt:??¡§??;
mso-font-charset:134;
mso-generic-font-family:auto;
mso-font-format:other;
mso-font-pitch:variable;
mso-font-signature:1 135135232 16 0 262144 0;}
@font-face
{font-family:"\@SimSun";
panose-1:0 0 0 0 0 0 0 0 0 0;
mso-font-charset:134;
mso-generic-font-family:auto;
mso-font-format:other;
mso-font-pitch:variable;
mso-font-signature:1 135135232 16 0 262144 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:SimSun;
mso-ansi-language:ES-AR;
mso-fareast-language:ZH-CN;}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 3.0cm 70.85pt 3.0cm;
mso-header-margin:36.0pt;
mso-footer-margin:36.0pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
We describe here a new archosauriform specimen
collected from the lower levels of the Santa Maria Formation (Middle-Late
Triassic) of southern Brazil (CPEZ 239a). It is based
on a basicranium, dorsal and sacral vertebrae, ten paramedian and three lateral
osteoderms, and right humerus, ulna, ilium, ischium, femur, and tibia. A
cladistic analysis was conducted and nested CPEZ 239a within a monophyletic
group of basal archosauriforms, also composed of Doswellia from the Late Triassic of USA and Tarjadia
from the Middle-Late Triassic of Argentina. This group is identified as Doswelliidae
and it is supported by the presence of osteoderm ornamentation coarse,
incised, composed of regular pits of equal size and contour, and the presence
of an un-ornamented anterior articular bar. In addition, CPEZ 239a is more closely related to Doswellia than to other archosauriforms due to the presence of basipterygoid processes anterolaterally
oriented, dorsal vertebra centra with a convex lateral surface, width of the neural arch plus
ribs of the first sacral three times the length of the neural arch, and iliac
blade laterally deflected, with a
strongly convex dorsal margin, and a maximum length less than 3 times
its maximum height. Since Doswelliidae
was previously considered a monospecific clade, this study supports for the
first time its validity and incorporates it to the traditionally known
lineages of basal archosauriforms (e.g. Proterosuchidae, Erythrosuchidae,
Proterochampsidae). The present phylogenetic analysis indicates that Doswelliidae
is the closest large monophyletic entity to Archosauria, which reaches a wide
paleolatitudinal distribution during the Middle-Late
Triassic time span.