Smilodon Lund 1842
Creators: name: Chahud, Artur
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Carnivora
Felidae
Smilodon

description: Genus SMILODON Lund, 1842
Figure 2, Figure 3, Figure 4, Figure 5
Type species. Smilodon populator Lund, 1842
Material. The identified material consists of a fragmented right calcaneal (CVL2 15315), complete left calcaneal (CVL2 12157), complete proximal phalanx (CVL2 14207), four intermediate phalanges (CVL2 13300, CVL2 13333, CVL2 13400, CVL2 15187), two fragmented distal phalanges (CVL2 14309, CVL2 14532), distal part of metatarsal (CVL2 12475) and one right ectocuneiform bone (CVL2 13122).
General characteristics and comparison. It is possible to compare the osteological material found with large species attributed to the genus Panthera. In Figures 2-4 the calcaneal and ectocuneiform bones were compared to the equivalents of an adult lioness (Panthera leo).
Calcaneal. Comparing the calcaneal, the specimen found in the Cuvieri Cave has the most robust and dense tuberosity (tuber calcis), and the astragalar facets are larger, wider and slightly closer to the cuboid rim than in that of the lioness.
The sustentacular facets, As2 and As3 (Figure 2), have great contact with each other, and As3 basically represents an extension of As2. Compared to the genus Panthera, it has a small extension that links these facets (Figure 3 A-D). The process supporting the second facet (As2) or support is more robust and prominent in proportion to the total size of the calcaneal, mainly seen in dorsal view (Figure 3).
The As3 astragalar facet is larger and more evident than in the lioness and extends to the cuboid facet. The navicular facet (Na) is next to the As3 facet and both are in direct contact with the cuboid articular facet.
The ectal facet (As1) is larger, wider, and less elongated than observed in the genus Panthera and does not invade the tuberosity.
The cuboid facet (C) differs from the lioness since it occupies a larger area, reaching the plantar border, being straight and flat on this side to the central part (Figure 3E), but presents a concavity close to the contact with the navicular facets (Na) and of the astragalar facet (As3).
Ectocuneiform. The right ectocuneiform is more compressed in proximo-distal direction than those in recent large felines. The plantar projection with groove to the tendon of the long fibular muscle has an open hook shape and less prominent curvature than that of the lioness (Figure 4 C-D).
The articulating facet with the navicular tapers and stretches to the plantar region, while observing a small projection on the lioness (Figure 4B).
The opposite facet, which articulates to the metatarsal III, is very similar in both (Figure 4A). The plantar projection of this surface is much shorter and relatively small compared to that of a lion of similar size (Figure 4 C-E).
Viewed from the inside, the plantar facet of the second metatarsal spans the distal border near the dorsal part of the ectocuneiform. On the outer surface, the cuboid facet is larger than that of the lioness and extends along the proximal edge and approaches the dorsal edge.
Metatarsal and phalanges. The metatarsal and phalanges are indistinguishable in size to those from a recent large feline, such as tigers, lions, or jaguars, as observed in the single phalanx, CVL2 14207. The other specimens had wear, polish (Figure 5 E-H), or many breaks, as in the case of the ungual phalanges and the metatarsal (Figure 5A, 5 C-D).
The main measurements performed are available in Table 1.
Discussion. Smilodon populator was considered to be the sole representative of the genus Smilodon in South America until evidence was found in the Andean region of Ecuador and Peru, and recently in Uruguay of S. fatalis (Kurten and Werdelin, 1990; Manzuetti et al. 2018) and S. gracilis in the Venezuelan Andes (Rincón et al, 2011). Manzuetti et al. (op. cit.) suggested that S. populator and S. fatalis lived together at the same time and region and Christiansen and Harris (2005) commented that although S. populator is larger, it is not uncommon to find adult individuals of similar size to S. fatalis.
Comparing the ectocuneiform and calcaneal sizes it is possible to infer that the specimen is close to the Pleistocene felines Smilodon fatalis, S. populator and Panthera gombaszogensis, and P. onca augusta (Merriam and Stock, 1932; Hemmer et al., 2010, Argant and Argant, 2011; Baryshnikov, 2011; Scaferla et al., 2013) in length and width and smaller than that of large extinct felines such as P. atrox and P. fossilis (Merriam and Stock, 1932; Sabol, 2014; Chimento and Agnolin, 2017).
The proportions of left calcaneal and right ectocuneiform width and length measurements of the Cuvieri Cave specimen with those described for S. fatalis, by La Brea by Merriam and Stock (1932), the Brazilian specimen is slightly more robust than would be expected for a S. populator of similar size to S. fatalis.
Smilodon populator occurrences are common in southeastern Brazil. Lund (1842) originally identified and described this species in the Lagoa Santa region, where several specimens were found in various caves, including phalanges and large canine teeth. Other specimens were dated and described, being the specimen found in the Abismo Iguatemi Cave, State of São Paulo, which presented the best specimen with the skull and several preserved bone parts (Ferreira and Karmann, 2002; Castro and Langer, 2008, 2011; Hubbe et al., 2013), revealing important information about the species.
The existence of several specimens of Smilodon populator allowed the registration of various ages for several specimens in South America, and it is clear that the specimens occurred during the late Pleistocene, especially in the last 100,000 years from the Pleistocene to the Early Holocene. Most of the reported ages ranged from 25,000 - 9,000 years (Berta, 1985; Kurtén and Werdelin, 1990; Hubbe et al., 2013; Prevosti and Martin, 2013; Prevosti et al., 2013; Bocherens et al., 2016), with one exception coming from northeast Brazil dating from 93,900 years, using the ESR method, being the oldest of this species (Kinoshita et al., 2017).
description: Published as part of Chahud, Artur, 2020, Occurrence of the sabretooth cat Smilodon populator (Felidae, Machairodontinae) in the Cuvieri cave, eastern Brazil, pp. 1-10 in Palaeontologia Electronica (a 24) (a 24) 23 (2) on pages 2-6, DOI: 10.26879/1056, http://zenodo.org/record/10961813