Machairodus aphanistus (Kaup, 1832)

Peigné, Stéphane, 2016, Carnivora, Geodiversitas 38 (2), pp. 197-224 : 217-219

Machairodus aphanistus (Kaup, 1832)

( Figs 7 D-N, 8; Tables 9, 10, 11)

REFERRED MATERIAL FROM KÜÇÜKÇEKMECE. — Çukurçesme Quarry unnumbered, fragment of right m1; IU 01, distal half of a left humerus; MNHN.F.TRQ700, proximal fragment of proximal phalanx;TRQ694, fragment of right Mt III; TRQ1213, right m1; TRQ1214, right p4; TRQ1215, right P4. The two last specimens present the same colour and wear pattern and might belong to the same individual.

DESCRIPTION

Dentition

Lower dentition ( Fig. 7 D-G). The p4 ( Fig. 7 D-E) is very well preserved and nearly unworn. In occlusal view the crown forms roughly an elongated rectangular. The main cuspid is sharp, with a convex distal crest and a nearly rectilinear mesial crest. In labial view it is oriented somewhat distally relative to the crown-root junction. The accessory cuspids are large and sharp, the mesial cuspid being slightly larger than the distal cuspid. Both are separated from the main cuspid by deep notches. The distal cingulid is marked but short and extended lingually rather than labially. The crown of m1 (MNHN.F.TRQ1213, Fig. 7 F-G; Çukurçesme unnumbered) and the mesial root (Çukurçesme unnumbered) are preserved. In both specimens it is heavily worn labially along the paraconid and protoconid crests at the level of the carnassial notch and on the distolabial face of the protoconid. The protoconid is taller and longer than the paraconid. In TRQ1213 there is no metaconid distinct from the talonid. The latter appears very short and sharp, and separated from the distal rim of the protoconid by a deep notch.

Upper dentition ( Fig. 7 H-J). The P4 presents a similar size and wear pattern as the p4 MNHN.F.TRQ1214 and could belong the same individual. The paracone tip and the protocone are broken off. The labial cusps are narrow and trenchant. The metastyle/metacone blade and the paracone are approximately the same length. The notches that separate the metacone, paracone and parastyle are deep. The parastyle is very large and tall. There is a small ectoparastyle (or ectostyle) mesial to the parastyle.

Postcranium ( Figs 7 K-N, 8)

Three postcranial specimens are assigned to M. aphanistus . IU 01 is a fragment of left humerus broken across the middiaphysis ( Fig. 8 ). The shaft and the olecranon fossa are also damaged. The maximum width of the distal epiphysis is 88.3 mm and the maximum width of the articulation is 58.6 mm. The anteroposterior diameter of the medial part is 44.4 mm, while that of the lateral part is 49.5 mm. The overall morphology of this specimen is similar to that of specimens assigned to Amphimachairodus giganteus (Wagner, 1848) from Maragheh (MN11, Iran) and Pikermi that were used in comparison (MNHN.F.PIK3358 andPIK3361, MNHN.F.MAR3410 and specimens figured in Roussiakis 2002) and to that of published material related to M. aphanistus from the Vallès-Penedès Basin (Madurell-Malapeira et al. 2014) and Montredon ( Beaumont 1988: pl. 4, fig. 10). Our specimen is a little bit more robust, especially compared to the specimen from Pikermi figured by Roussiakis (2002: fig. 12-1). The medial epicondyle is medially and proximodistally more extended than in the specimen from Montredon ( M. cf. aphanistus ), but not especially more than in the compared specimens of A. giganteus that display great morphological variability regarding this feature. MNHN.F.TRQ700 ( Fig. 7M, N ) is a proximal fragment of a proximal phalanx with a proximal mediolateral width of 21.5 mm and a proximal dorsoventral height of 17 mm. The phalanx is robust, with a dorsoventrally compressed shaft and a slightly asymmetrical proximal articulation. It is very similar to the proximal phalanges of the associated forelimb of A. giganteus MNHN.F.PIK 3241 from Pikermi (see Table 11). The fragmentary Mt III ( Fig. 7K, L ) lacks the distal epiphysis and the ventral part of the proximal articular surface. The proximal width of the head is 25.4 mm. The fragment is approximately 110 mm long. In lateral view the diaphysis is curved dorsally.

COMPARISONS AND DISCUSSION

Machairodus aphanistus is a relatively common Vallesian-early Turolian (MN9-MN11) species of Europe, where it is known from a number of localities in Germany, Spain, France, Austria, Switzerland, Bulgaria, Hungary and Turkey (see Madurell-Malapeira et al. 2014). In Turkey, remains of the species are rare, however, and is known only from Kemiklitepe D (MN11) and Mahmutgazi (MN11). The dental material described here represents at least 3 individuals: two are represented by the m1 (MNHN.F.TRQ1213 and Çukurçesme unnumbered), and the third individual is documented by TRQ1214, a p4, and TRQ1215, a P4. The two first individuals are rather small and about the size of early Vallesian (MN9) specimens such as those from Los Valles de Fuentidueña (including specimens assigned to M. alberdiae Ginsburg et al., 1981 , a junior synonym of M. aphanistus ; see Peigné et al. 2005), Höwenegg, and Can Llobateres ( Table 9). The third individual is of average size for the species, with dental lengths within the range of populations such as that from Batallones (MN10, Spain; Monescillo et al. 2014; Tables 9, 10). I consider that the material from Küçükçekmece belongs to a single species displaying a large size variability that could be related to sexual dimorphism. Machairodus aphanistus was one of the most dimorphic known felids, together with the extant Panthera leo (Linnaeus, 1758) and Panthera pardus (Linnaeus, 1758) ( Monescillo et al. 2014) . Morphologically, the material from Küçükçekmece does not differ from that of the other sites where the species is known, especially the large sample from Batallones ( Antón et al. 2004; Monescillo et al. 2014).

The fragmentary postcranial remains belong to different individuals also. The measurements of the humerus are within the range of those of the humerus of extant P. leo and P. tigris ( Peigné et al. 2005: table 2), of Amphimachairodus giganteus from Pikermi and Maragheh ( Table 11), and of M. aphanistus from Montredon and the Vallès-Penedès Basin. The mediolateral width of the proximal articulation of the Mt III and the size and proportions of the proximal phalanx are within the size range of specimens of Machairodus aphanistu s and Amphimachairodus giganteus ( Table 11). Specimens MNHN.F.PIK3278, PIK3279, PIK3280, PIK3240 and PIK3244 from Pikermi, described as metatarsals by Özkurt et al. (2015), are all metacarpals and therefore not comparable to the material from Küçükçekmece.

Figures

FIG. 7. — A-C,cf.Thalassictis sp.: Kadi Mezarligi Quarry unnumbered,right m1 in labial (A), occlusal (B), and lingual (C) views;D-N, Machairodus aphanistus (Kaup, 1832): MNHN.F.TRQ1214, right p4 in occlusal (D) and labial (E) views; TRQ1213, right m1 in labial (F) and occlusal (G) views; TRQ1215, right P4 in occlusal (H), lingual (I), and labial (J) views; TRQ694, fragment of right Mt III in proximal (K) and anterior (L) views; TRQ700, proximal fragment of proximal phalanx in proximal (M) and anterior (N) views. Scale bars: 10 mm.

FIG. 8. — Distal fragment of right humerus (IU unnumbered) of Machairodus aphanistus (Kaup,1832) in anterior (A) and posterior (B) views.Scale bar:20 mm.