Three Ways To Be a Saber-Toothed Cat

Abstract

Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore.

New saber-toothed cat records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange

“…Homotherium ischyrus, H. johnstoni, H. crenatidens, and H. problematicus, as well as Xenosmilus hodsonae and H. hadarensis, all have anteriorly unpocketed masseteric fossa (Fabrini, 1890;Merriam, 1905;Ballesio, 1963;Collings, 1972;Martin et al, 2000), as in H. venezuelensis. In H. latidens and H. serum, however, the anterior part of the masseteric fossa is pocketed.…”

“…Homotherium and Xenosmilus also share the following features: p4 with three well developed cusps; the lower carnassials do not have a talonid; in the upper carnassials the protocone is fused with the tooth, and the protocone root disappears; the metastyle and parastyle blades are of equal size (Meade, 1961). Xenosmilus differs from Homotherium in the following features: p3 is absent; narrower frontals; temporal fossa and sagittal crest are elongated; limbs are shortened and robust (Martin et al, 2000).…”

El cambio de ideas acerca de la evolución y morfología functional de los félidos Machairodontinos

“…The discovery of the shortlimbed homotheriin genus Xenosmilus in Pleistocene deposits in Florida (Martin et al, 2000) has provided a clear example of a machairodontine combining scimitar-like canines with an extremely robust skeleton, showing that these felids had considerable evolutionary plasticity and were not constrained by a rigid ecomorph model. The Oligocene nimravid Dinictis is also poorly characterised as a scimitar-tooth (Scott & Jepsen, 1936) because its upper canines, while not as high-crowned as those of other nimravids such as Hoplophoneus or Eusmilus, were neither exceptionally flattened nor coarsely crenulated and its limbs, while relatively gracile, had remarkably short, probably semi-plantigrade feet very different from the long, digitigrade feet of Neogene felids such as Homotherium.…”

Systematic review and antiquity of Smilodontidion riggii (Carnivora, Felidae, Ma-chairodontinae)

“…Otros ca-racteres que lo diferencian de este género son: porción distal de la fíbula no recurvada; diáfisis del fémur curvada dorsoventralmente; tubércu-los presentes en la cara caudal de la extremidad distal no expandidos en sentido caudal más allá de la articulación; astrágalo con un surco más ancho entre las carillas articulares para el calcá-neo. Martin et al, posee miembros cortos y robustos, y un tamaño simi-lar a S. populator y S. fatalis (Martin et al, 2000). Este género fue descrito recientemente y es co-nocido a partir de 2 ejemplares recolectados en USA (Martin et al, 2000).…”

“…Martin et al, posee miembros cortos y robustos, y un tamaño simi-lar a S. populator y S. fatalis (Martin et al, 2000). Este género fue descrito recientemente y es co-nocido a partir de 2 ejemplares recolectados en USA (Martin et al, 2000). Lamentablemente, el postcráneo de este taxón sólo fue descrito y figu-rado someramente, por lo que es difícil compa-rarlo con el MACN Pv 6802.…”