Majoreas cf. elegans ( Ozansoy, 1965 )

Kostopoulos, Dimitris S. & Sen, Sevket, 2016, Suidae, Tragulidae, Giraffidae, and Bovidae, Geodiversitas 38 (2), pp. 273-298 : 290-291

Majoreas cf. elegans ( Ozansoy, 1965)

( Fig. 11 ; Table 8)

Helicotragus rotundicornis – Malik & Nafiz 1933: 55. — Nicolas 1978: 456.

Palaeoreas lindermayeri – Malik & Nafiz 1933: 59.

MATERIAL EXAMINED. — Küçükçekmece West: basal part of right horn-core MNHN.F.TRQ636, TRQ635, TRQ637, TRQ632; basal part of left horn-core TRQ627, TRQ638; distal part of

horn-core TRQ634, TRQ644. Provisionally attributed: right M3, TRQ407 (L = 10.3 mm, W = 9.1 mm); m1/2 TRQ406 (L = 14.7 mm, W = 8.6 mm).

Küçükçekmece East: provisionally attributed part of mandibular ramus with p3-m2, ITU369 (p2: Lalveolar = 7.2 mm; p3: L = 9.4 mm, W = 5.7 mm; p4: L = 10.3 mm, W = 6.1 mm; m1: L = 10.9 mm, W = 7.5 mm; m2: L = -, W = 8.5 mm).

Rami Sand Quarry: ITU350; basal part of a right horn-core.

MEASUREMENTS. — See Table 8.

DESCRIPTION AND REMARKS

A group of partially preserved horn-cores in MNHN represents another heteronymous spiral horned antelope in the Küçükçekmece West fauna ( Fig. 11 B-D; Table 8). The postcornual groove is large and deep. The pedicel is higher than in Prostrepsiceros sp. from the same locality. The horn-cores are placed above the orbits. They have a sharp anterior keel descending anteromedially, and they show a rather strong mediolateral compression (63.3-78% at the base, n = 6) probably increasing toward the apexes ( Fig. 11D ). Spiralling is weakly developed but axial torsion is quite strong. The greater diameter at the horn-core base is trending anteroposteriorly. The specimen referred by Malik & Nafiz (1933: pl IX, fig. 5) to as Helicotragus rotundicornis (Weithofer, 1888) should also be ascribed to this species.

Teeth dimensions are about 20% larger than those of Prostrepsiceros sp. from the same locality. The p3 is simple with well-developed paraconid and hypoconid, and distally directed metaconid ( Fig. 11E ). The p4 is quite similar to that of Prostrepsiceros sp. but with less developed paraconid, deeper distal valley and more vertically placed metaconid. Mesial fold and basal pillar are present on the lower molars, which also show a rounded hypoconid.

The morphological and metrical characters of the Küçükçekmece West horn-cores, such as the weak spiralling, the fairly strong torsion, the sharp anterior keel descending anteromedially, the strong mediolateral compression and the large and deep postcornual grooves set them apart from Palaeoreas Gaudry, 1861 , Prostrepsiceros and Nisidorcas Bouvrain, 1979 , recalling Palaeoreas elegans Ozansoy 1965 from Yassiören, Turkey. Kostopoulos (2004) revised “ Palaeoreas ” elegans and Prostrepsiceros woodwardi Pilgrim & Hopwood, 1928 , suggesting their inclusion into a separate genus Majoreas . As far, Majoreas elegans is poorly known from the Vallesian localities Yassiören and Loc. 49 of Middle Sinap, Turkey ( Ozansoy 1965; Köhler 1987; Gentry 2003), whereas M. woodwardi is known from the early Turolian faunas of Samos, Halmyropotamos, Kemiklitepe D, Çorakyerler and Garkin ( Kostopoulos 2004; Geraads 2013). The basal horn-core dimensions of the Küçükçekmece West species ( Fig. 12 ) appear smaller on the average than those of Samos and Kemiklitepe D, close to the specimens of M. elegans from the type locality and within the range of the Çorakyerler sample. There is probably some morphological progression from Middle Sinap to Çorakyerler to Samos/Kemiklitepe D (see also Gentry 2003: 349) with an overall increase in size, a medial shift of the insertion point of the anterior keel, an increase of spiralling and a frontal rise. As the Küçükçekmece species fits better the more primitive condition of this taxonomic group both in size ( Fig. 12 ) and morphology, it is referred to as Majoreas cf. elegans .

The single horn-core from the Rami Sand Quarry ( Fig. 11A ) displays again a strong anterior keel but it is slightly tighter twisted in its preserved basal part and less compressed mediolaterally that the MNHN sample ( Table 8), making its inclusion into the same taxon more friable.

Figures

FIG. 11. — A, cf. Majoreas from Rami Sand Quarry; B-E, Majoreas cf. elegans from Küçükçekmece West, Turkey. A, proximal horn-core, ITU350 dex in frontal (left) and lateral (right) views; B, proximal horn-core, MNHN.F.TRQ637 dex in medial view; C, proximal horn-core, MNHN.F.TRQ636 dex in frontal view; D, distal horn-core, MNHN.F.TRQ634 dex in frontal view; E, p3-m2, ITU369 in buccal view. Scale bars: 2 cm.

FIG. 12. — Comparison of the basal horn-core dimensions of several Majoreas Kostopoulos, 2004 populations., Küçükçekmece West sample; D, Samos, Greece;, Kemiklitepe D, Turkey;, Middle Sinap,Turkey;¢, Çorakyerler,Turkey;two specimens of M. elegans: namely MTA Museum Ankara,#1921 () and no numbered specimen in MNHN (). Data from Ozansoy (1965),Kostopoulos (2004), Gentry (2003), Geraads (2013).