INVESTIGADORES
LECUONA Agustina
congresos y reuniones científicas
Título:
New interpretations of the holotype of Arganasuchus dutuiti Jalil and Peyer 2007 (Archosauria, Pseudosuchia), and its taxonomic impact
Autor/es:
LECUONA, A.; JALIL, N.-E.
Lugar:
Haarlem
Reunión:
Congreso; XIV Annual Meeting of the European Association of Vertebrate Palaeontologists; 2016
Institución organizadora:
Teylers Museum
Resumen:
The hypodigm of the pseudosuchian ?rauisuchid? Arganasuchus dutuiti consists ofseveral cranial and postcranial isolated elements coming from the TimezgadiouineFormation (Carnian, Upper Triassic) of the Argana Basin, Morocco. Its holotype is aputative proximal fragment of right pubis (MNHN.F AZA 904), bearing a diagnosticanteroventral orientation of the acetabular rim parallel to pubic shaft and a largecontribution to the acetabulum. In the last decade, several new pseudosuchians and?rauisuchians? have been discovered and important advances on their anatomy andphylogeny were made. A complete revision of Arganasuchus and its phylogeneticrelationships are being conducted under the light of the current knowledge. Therevision of the holotype allows for the recognition of the pubic peduncle of the iliumfused to the proximal pubis, as suggested but then rejected by the original authors.The contact between the bones is not visible due to a fully sutured contact, a rarecondition among pseudosuchians but already reported in North Americanpoposauroids. Consequently, both formerly supposed diagnostic characters cannotbe considered as such, the large acetabular region mostly or completely belongs tothe ilium and the pubic portion of the acetabular rim is anterodorsally inclined like inother pseudosuchians. However, this reinterpretation highlights other diagnosticcharacters, such as a considerably deep longitudinal groove in the anterior surface ofthe pubic peduncle; an anterolateral short groove lateral to the previous one; ananteriorly wide pubic tubercle. Consequently, Arganasuchus dutuiti can still beconsidered a valid taxon. The inclusion of MNHN.F AZA 904 in a phylogeneticanalysis along with Stagonosuchus and six new characters (489 characters, 90 taxa;data matrix derived from a large scope archosauriform analysis) depicted it as abasal Loricata and sister taxon of Batrachotomus. The latter group is supported byone of the new characters, presence of a longitudinal groove on the anterior surfaceof the pubis. Loricata shows a polytomy formed by Prestosuchus, Saurosuchus,Stagonosuchus, Batrachotomus+MNHN.F AZA 904, and Fasolasuchus+morederived loricatans, which is due to the instability of Stagonosuchus. The currentrevision of Arganasuchus is highly important for a better understanding of the LateTriassic archosaur assemblages of Northern Africa.