Homotherium latidens ( Owen, 1846 )

Koufos, George D., Kostopoulos, Dimitris S. & Merceron, Gildas, 2020, The saber-toothed cat Homotherium latidens (Owen, 1846) from the lower Pleistocene locality Dafnero, Western Macedonia, Greece, Geodiversitas 42 (10), pp. 139-149 : 142-144

Homotherium latidens ( Owen, 1846)

Machairodus latidens Owen, 1846: 179 .

Homotherium latidens – Galobart et al. 2003: 99-141.

HOLOTYPE. — The upper canine described and figured as Machairodus latidens by Owen (1846: fig. 69). In total there are five upper canines and two I3 from Kent’s Cave; the holotype, numbered 443/ 103 in the Museum of the Royal College of Surgeons, is that described by Owen, but it was destroyed during bombing in 1941 ( Barnett 2014).

TYPE LOCALITY. — Kent’s Hole, Torquay, England.

LOCALITY. — Dafnero-3, DFN3, Grevena Basin, Western Macedonia, Greece.

DESCRIPTION

Cranium

The cranium DFN3-152 is dorsoventrally compressed, deformed and damaged in the occipital region ( Fig. 1 ). The dentition preserves both I3, the left canine and part of the left carnassial. The worn incisors and carnassial indicate an old individual. The premaxillae are well developed and projected rostrally to protrude the large incisors. The incisor row is semicircular as in the Senèze ( France) cranium FSL- 210 991 ( Ballesio 1963: fig. 11d) and the Incarcal ( Spain) crania IN-I-929 and IN-II-37 ( Galobart et al. 2003: figs 3, 4). The incisor row of the Perrier cranium of Homotherium (MNHN.F.PET2000) is less convex than that of DFN3-152, while that of IN-I- 825 from Incarcal is straight ( Bonis 1976; fig. 3; Galobart et al. 2003: fig. 1). Between the canine and I3 of DFN3-152, there is a short diastema (4.3 mm) as in the Senèze (FSL-210 991; 9.0 mm), ( Ballesio 1963) and Perrier crania (7.7mm; MNHN.F.PET2001). In the Incarcal crania the diastema varies greatly; it is long in IN-I929 and absent in IN-I-825 and IN-II-37 ( Galobart et al. 2003). A large diastema (16.0 mm) also exists between the canine and the P 3 in DFN3-152, as in the Senèze cranium and the Incarcal crania IN- I-1929 and IN-I-825 ( Table 1 ).

The maxillary bones are relatively small and have a swelling that corresponds to the strong root of the upper canine. The nasals are rectangular, like in all machairodontines; their posterior margin is almost straight and their suture with the frontals is a straight line, which coincides with the line connecting the anterior margins of the orbits. This feature is clear in the Senèze and Perrier crania ( Ballesio 1963: fig. 11d; Bonis 1976: fig. 9a). The nasal cavity is large, sub- rectangular and higher than wide; the index height/breadth of the nasal cavity is 89, versus 91 for the Senèze and 81-95 for the Incarcal crania ( Galobart et al. 2003).

The right orbit is better preserved and not deformed; it is rounded, with its anterior margin above the distal end of the carnassial. The infraorbital foramen is very large ( Fig. 1A ; Table 1 ). Its anterior margin is situated above the mesial part of the P3, while the posterior margin is above the parastyle of the carnassial. The zygomatic arches are small, relatively low and close to the braincase, starting just behind the distal end of the carnassial and directed slightly externally to connect with the glenoid fossa. The frontals are compressed and deformed; however, the groove between them and its continuity with the nasals is clearly distinguished. The sagittal crest is poorly preserved but based on its remnants seems to be thick and high. Although the development of the sagittal crest varies in the known material of Homotherium as a result of sexual dimorphism ( Galobart et al. 2003), it is impossible to determine the sex of DFN3-152.

The palate is elongated, wide and bears two strong crests running mesio-distally ( Fig. 1D ). The choanae are poorly

preserved, deep and their anterior margin is situated behind the distal end of the carnassials. The mandibular fossa is long, with strong retroarticular process. The retroarticular foramen is situated in a large and deep fossa between the mandibular fossa and the tympanic bulla. The right part of the occipital is well preserved, having a rounded shape with strong nuchal and external occipital crests; the distal margin of the occipital bone does not exceed the level of the occipital condyles.

Dentition

The third incisors are worn and partially broken ( Fig. 1D ). They are large, canine-like, slightly inclined distally, with almost rounded occlusal outline, and bear a small lingual cusp. The canine is well preserved, long, narrow, sharp, inclined distally, like a double-edged knife. Although the wear is advanced, clear serration can be distinguished on its mesial and distal borders, like in Homotherium ( Fig. 1E, F ). The canine is strongly compressed laterally; the breadth/ length index is 42. The root is very strong and elongated, running parallel to the margin of the nasal cavity to the end of the nasal bone. There is no trace of the P2, while there is a clear alveolus for the P3; its dimensions are 10.5 × 5.1 mm. The P4 is damaged and only the paracone and the worn metacone are preserved. The carnassial is elongated and relatively narrow. Although it is damaged there is evidence of a pre-parastyle, and the paracone is strong and high. There is no apparent protocone but as the tooth is very worn the presence of a small one as in all Homotherium , but totally worn down, cannot be ruled out.

Humerus

The humerus DFN3-153 is complete but the epiphyses are badly preserved ( Fig. 2 ). The articular surface of the humerus caput is flattened, as in Homotherium from Incarcal ( Anton et al. 2005). The major tubercle is well developed, and the articular head is wide and projected, like in the Incarcal Homotherium material. The intertubercular groove is wide. The diaphysis is long and straight; the deltoid ridge is strong and is not projected laterally. The distal epiphysis is wide and bears a large trochlea, and the olecranon fossa is deep.

Figures

FIG. 1. — Homotherium latidens (Owen, 1846),Dafnero 3, Macedonia Greece,middle Villafranchian,cranium DFN3-152,in: A, left lateral;B, right lateral;C, dorsal; D, ventral; E, detailed canine views. Scale bar: 5 cm.

FIG. 2. — Homotherium latidens (Owen, 1846), Dafnero 3, Macedonia Greece, middle Villafranchian,humerus DFN3-153 in:A, anterior;B, posterior;C, lateral; D, medial views. Scale bar: 5 cm.