INVESTIGADORES
BOND mariano
congresos y reuniones científicas
Título:
Reconstruction of the dentition of Propyrotherium Ameghino, 1891 (Mammalia, Pyrotheria). Taxonomic and phylogenetic implications
Autor/es:
KRAMARZ, A. Y M., BOND
Lugar:
Buenos Aires
Reunión:
Jornada; XXVI Jornadas Argentinas de Paleontología Vertebrados; 2012
Institución organizadora:
Universidad Maimónides
Resumen:
Reconstruction of the dentition of Propyrotherium Ameghino, 1891 (Mammalia,Pyrotheria). Taxonomic and phylogenetic implications.A.G. KRAMARZ1,2 and M. BOND1,3Propyrotherium saxeum Ameghino is one the lesser known member of Pyrotheria, anenigmatic group of giant, endemic South American ?ungulates?. The species wasoriginally described based upon two isolated cheek teeth and two tusk fragments(MACN). Latter authors assigned additional isolated teeth to this taxon, but the positionwithin the tooth row of all these teeth remained uncertain, preventing an accurate dentalcharacterization and taxonomic distinction from other related species. Here we reexaminethe type specimens of P. saxeum and additional materials (AMNH) previouslyreported as belonging to this species, and analyze several lots of still undescribedspecimens (MLP), in order to reconstruct the cheek teeth series. Based on comparisonswith better known pyrotheres, we conclude that the most probable cheek teeth formulais P2-M3/p2-m3, the cheek teeth series increase in size gradually from front to back,and the upper series has a gradual increase of the lophs curvature, as in PyrotheriumAmeghino. All cheek teeth are bilophodont, but in the premolars (upper and lowers) theanterior loph/id is transversally shorter than the posterior. All cheek teeth have lingualcingulum/id; P3-M3 are sub-quadratic and have three roots; p4-m3 are longer thanwide, two rooted, and bear a variably developed vestige of cristid obliqua.Propyrotherium is morphologically distinguishable from Griphodon Antony andBaguatherium Salas et al., but the distinction between the two latter, based on noncomparable materials, is unverifiable with the current evidences. A revised cladisticanalysis confirms that Propyrotherium is one of the earliest diverging pyrotheriid, butthe elucidation of its relationships with Griphodon and Baguatherium requires furtherevidences.1 CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas)2 Sección Paleontología de Vertebrados, Museo Argentino de Ciencias Naturales Bernardino Rivadavia,Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina, agkramarz@macn.gov.ar3 Departamento Científico Paleontología de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, LaPlata B1900FWA