Dinofelis sp.

Herries, AIR, Menter, CG & Adams, JW, 2015, First description of in situ primate and faunal remains from the Plio-Pleistocene Drimolen Makondo palaeocave infill, Gauteng, South Africa, Palaeontologia Electronica (Basel, Switzerland) 28 (6), pp. 1-21 : 10-11

Dinofelis sp.

Figure 5 , Table 4

Referred material. DNM 2, left second metatarsal; DNM 54-1, left distal partial calcaneus; DNM 54-2, left proximal partial calcaneus.

Description. Only a single left metatarsal II (DNM 2) and a poorly-preserved left calcaneus in two pieces (DNM 54-1, 54-2) from the Makondo infill are identifiable as Dinofelis . While the metatarsal and calcaneus could represent elements from the same individual there is no direct association between the remains (the calcaneus was found ~ 50 cm above the metatarsal).

DNM 2 is a complete, well-preserved left second metatarsal that is only missing small portions of the diaphyseal cortex at midshaft ( Figure 5.1–6 ). The overall length of DNM 2 is intermediate between modern Panthera pardus and Panthera leo ( Lewis, 1995; Table 4), and lacks the proximodistal elongation of the diaphysis expressed in Acinonyx jubatus . In comparison to the Dinofelis aff. piveteaui DN 12 second metatarsal described from the Drimolen Main Quarry ( O’Regan and Menter, 2009), DNM 2 is larger and more elongate and gracile in appearance ( Table 4). Proximally, the metatarsal III articular surface of DNM 2 is continuous from the dorsal to plantar surface, but is interrupted by a distinct concavity in DN 12. In addition, a distinct fossa plantar to the metatarsal III facet on the DN 12 specimen is absent in DNM 2 ( O'Regan and Menter, 2009). The plantar aspect of the proximal articular surface of DNM 2 is flat and broadly supported along the plantar metaphysis, contrasting the plantar articular aspect of DN 12 that is both concave and supported by a mediolaterally ‘pinched’ ridge on the plantar metaphysis. On the medial aspect, DNM 2 preserves a continuous ridge on the metaphysis and proximal diaphysis extending from the proximal articular surface, whereas in DN 12 there is a distinct, isolated tuberosity. Distally, the epicondylar region appears less robust than in DN 12, while simultaneously the articular surface is more heavily developed ( Table 4).

The left calcaneus, DNM 54-1 and DNM 54-2, is broken obliquely at the approximate midpoint of the element ( Figure 5.7 ). As both element components are partially decalcified, most of the fine features were obliterated and only gross measurements and observations were possible. The distal portion (DNM 54-1) preserves the articular surfaces for both the astragalus and cuboid, but lacks the sustentaculum tali. The proximal portion (DNM 54-2) preserves the body and a robust tuberosity. The specimen is visibly larger than both the DN 2149a and DN 2092 Dinofelis aff. piveteaui specimens from the Drimolen Main Quarry (unmeasured because of damage), but smaller than that of Homotherium sp. and extant P. leo ( Lewis, 1995) . Indeed, DNM 54 is larger than all published Dinofelis calcanei thus far described ( Werdelin and Lewis, 2001; O’Regan and Menter, 2009).

Discussion. Although both DNM 2 and DNM 54-1/ 54-2 are both metrically and morphologically consistent with Dinofelis to the exclusion of other felid genera, the poor preservation of the calcaneous and paucity of specifically attributed second metatarsals prevents a more specific attribution of these specimens. We note, however, that the metric and morphological differences of the Makondo infill specimens to the Main Quarry Dinofelis aff. piveteaui remains may reflect either the sampling of a different Dinofelis species, significant postcranial population variability or sexual dimorphism, and/or differences in the depositional timing of the remains.

Figures

FIGURE 5. Dinofelis sp. postcranial specimens from the Drimolen Makondo. 1–6, DNM 2, left second metatarsal; 1, proximal and 2, distal articular surfaces, 3, medial, 4, dorsal, 5, ventral, and 6, lateral views. 7, DNM 54-1 and 54-2, left calcaneus in articulation; anterior view. Scale bars equal 1 cm.

FIGURE 6. Chasmaporthetes?nitidula postcranial specimens from the Drimolen Makondo. 1–5, DNM 3-4, partial left fourth metatarsal; 1, proximal articular surface, 2, lateral, 3, ventral, 4, dorsal, and 5, medial views. 6–8, DNM 3-3, pedal proximal phalanx; 6, dorsal, 7, lateral, and 8, ventral views. 9–11, DNM 3-2, pedal middle phalanx; 9, dorsal, 10, lateral, and 11, ventral views. 12–14, DNM 3-6, pedal terminal phalanx; 12, dorsal, 13, lateral, and 14, ventral views. Scale bars equal 1 cm.