Welcome to dinosauria.ucoz.com!
Here you will find the information on dinosaurs and other reptiles! The registered user will get access to scientific publications (section "Files Archive")!
Etymology – In honor of Dra. Ana María Pechen, Main head of the National University of Comahue (2002-2006), who supported the study of dinosaur fossils in Neuquén Province, Patagonia.
Horizon, age and locality: Portezuelo Formation, Río Neuquén Subgroup, Neuquén Group, Late Cretaceous, Late Turonian-Early Coniacian (after LEANZA & HUGO, 2001). The fossils come from Loma del Lindero site, 10km West to Rincón de los Sauces City, Neuquén Province, Patagonia, Argentina.
Holotype – MRS-PV 207, a braincase including partial frontal and parietal, basioccipital, incomplete basipterigoid process, supraoccipital, exoccipital, basisphenoidals tubers, orbitosphenoids, and incomplete parasphenoids.
Specimens – The holotype and paratypes of Muyelensaurus pecheni sp.nov. correspond to four adult and one juvenile individuals. All fossil remains were found disarticulated but associated in the same site and include cranial remains, cervical, dorsal, sacral, and caudal vertebrae, and appendicular bones (Fig.2). Duplicate bones represented by appendicular bones exhibit the same morphological characters. This evidences the presence of a monospecific assemblage.
Muyelensaurus pecheni gen. et sp.nov., preserved bones (in black) shown in a titanosaur skeletal reconstruction of LEHMAN & COULSON (2002).
Diagnosis – Slender Rinconsauria characterized by the following association of autapomorphies: basal tubera diverge 70 degree from each other; extensive, thin and concave medial lamina that unit basal tubera ventrally, basioccipital condyle wider than the proximal portion of the basal tubera; posterior dorsal neural spines with large prespinal lamina reinforced by two small accessory laminae, distal end of pubic blade rectangular and medially thick. In contrast to Rinconsaurus, Muyelensaurus gen.nov has anterior dorsals with neural spines posteriorly directed less than 45 degree with respect to the vertical, posterior dorsals with large and deep infradiapophyseal fossa and ventral face of posterior cervical centra narrow and strongly concave at level of the parapophysis. Moreover, different from Rinconsaurus, Muyelensurus gen.nov. lacks an accessory centroparapophyseal lamina in posterior dorsals, anterior caudals with postzygapophyseal process, and amphicoelousbiconvex or amphicoelous-opisthocoelous-biconvex caudal centra.
RINCONSAURIA
Etymology – In reference to Rincón de los Sauces area, Neuquén Province, Patagonia, Argentina. Definition – Muyelensaurus, Rinconsaurus, their most recent common ancestor and all of its descendants. Diagnosis – Titanosaurids with the following association of characters: suboval teeth with labial and lingual faces well differentiated by crests, bony processes that support the postzygapophyseal facets in middle caudal vertebrae, and posterior caudal centra depressed posteriorly. Included species – Rinconsaurus caudamirus Calvo & González Riga, 2003, and Muyelensaurus pecheni Calvo, Gonzalez-Riga, Porfiri, 2007
ABSTRACT: The discovery of Muyelensaurus pecheni gen. et sp.nov., a new slender titanosaurid, is relevant from anatomical and systematic viewpoints. The specimens come from the Upper Cretaceous strata of the Portezuelo Formation (Turonian-Early Coniacian) at Loma del Lindero, Rincón de los Sauces area, Neuquén Province, Argentina. The remains include a braincase, cervical, dorsal, sacral and caudal vertebrae, and numerous appendicular bones. It is characterized by the following association of autapomorphies: basal tubera diverge 70 degrees from each other; thin and concave lamina that unit basal tubera ventrally, basioccipital condyle wider than the proximal portion of the basal tubera; posterior dorsal neural spines with large prespinal lamina reinforced by two small accessory laminae, distal end of pubic blade rectangular and medially thick. A cladistic phylogenetic analysis placed Muyelensaurus pecheni gen. et sp.nov. and Rinconsaurus caudamirus in a new eutitanosaur clade named herein Rinconsauria. This new clade include middle-sized sauropods different from Aeolosaurini, Opisthocoelicaudiinae or Saltasaurinae taxa.
RESUMEN: Un nuevo saurópodo Titanosaurio del Cretácico superior de Neuquén, Patagonia, Argentina. El descubrimiento de Muyelensaurus pecheni gen. et. sp. nov., un nuevo y esbelto titanosaurio, es relevante tanto desde el punto de vista anatómico como sistemático. Los especimenes proceden de los estratos del Cretácico superior de la Formación Portezuelo (Turoniano-Coniaciano temprano) de Loma del Lindero, en la zona de Rincón de los Sauces, Provincia del Neuquén, Argentina. Los restos incluyen un basicráneo, vértebras cervicales, dorsales, sacras y caudales y numerosos huesos apendiculares. Esta caracterizado por la siguiente asociación de autopomorfías: tubera basal diverge 70 grados una de otra; tubera basal unida ventralmente por una lámina delgada y cóncava; cóndilo basioccipital mas ancho que la porción proximal de la tubera basal; espinas neurales en la vértebras dorsales posteriores con una lámina preespinal larga y reforzada por dos pequeñas láminas accesorias; extremo distal de la lámina púbica de forma rectangular y gruesa medialmente. El análisis filogenético cladístico ubica a Muyelensaurus pecheni gen. et sp. nov. y a Rinconsaurus caudamirus en un nuevo clado de Eutitanosaurio que denominamos aquí como Rinconsauria. Este clado incluye a saurópdos de mediano tamaño diferentes de otros taxa de Aeolosaurini, Opisthocoelicaudiinae o Saltasaurinae.
A most parsimonious tree determined by cladistic analysis showing the phylogenetic relationships of Muyelensaurus pecheni gen. et sp.nov. References: Aeolosaurini (node 14), Rinconsauria (node 15), Opisthocoelicaudinae (node 16) and Saltasaurinae (node 9).
References Calvo, J.O., Gonzalez-Riga, B.J., & Porfiri, J.D. 2007. Muyelensaurus pecheni gen. et sp. nov., a new titanosaur sauropod from the Late Cretaceous of Neuquén, Patagonia, Argentina. Arquivos do Museu Nacional. v.65, n.4, p.485-504
