Paraoioceros, Meladze, 1985

Kostopoulos, Dimitris S., 2014, Taxonomic re-assessment and phylogenetic relationships of Miocene homonymously spiral-horned antelopes, Acta Palaeontologica Polonica 59 (1), pp. 9-29 : 17-18

Paraoioceros wegneri ( Andrée, 1926)

1985 Paraoioceros improvisus Meladze, 1985; Meladze 1985: 28, pl. 2. Holotype: Skull, PIM 141 ( Andrée 1926: pl. 15: 3, 6).

Type locality: Samos, Greece (unknown level).

Type horizon: Turolian, Late Miocene.

Material.—Skull, PIM 141; frontlet, PIM− 140; frontlets GNMT R−555, NHMI no number.

Emended diagnosis (modified from Bouvrain and Bonis 1985).—Medium size; face long and deep, with the anterior rim of the orbit located posterior to M3; opisthocranium short and slightly widening anteriorly; orbits strongly protruding laterally; strong basicranial flexion; frontals thick, pneumatized, and strongly elevated between the horncores; interfrontal suture constricted and forming a sharp crest anterior to the horncores; supraorbital foramina large and located in deep and wide depressions far from the horncore bases; infraorbital foramina located dorsal to P2; ethmoidal fissure long and narrow; temporal lines weak and rapidly converging posteriorly; auditory bullae moderately large and compressed, extending ventrally below the level of the basioccipital; basioccipital short and bearing a medial longitudinal groove; pedicles very short anteriorly and absent posteriorly; horncore long, slightly compressed anteroposteriorly, inserted above the posterior border of the orbit, and gradually tapering; horncores closely spaced, moderately to strongly diverging distally, and showing double flexion in lateral view, curving posterolaterally at mid−height and upwards distally; basal horncore surface bearing between one and four wide and deep, anterolaterally to anteriorly descending furrows with sharp edges, with the lateral edge of the posteriormost furrow usually developed into a keel; premolars short compared to molars; weakly molarized P2 and P3; presence of central islets on the upper molars, and goat folds on the lower ones.

http://dx.doi.org/10.4202/app.2011.0013

Remarks.—Although the skull features of this species are mainly known from the holotype, the horncore structure and variation are better documented by five additional frontlets from Samos, Turkey, and Georgia. The horncores of the illustrated frontlet from Rustavi ( Meladze 1985: pl. 2; GNMT R−555) and that of the Kavakdere specimen ( NHMI PV−186) are strongly divergent from the base, and bear a single, wide, and rather deep anterolaterally descending furrow with sharp edges, with the lateral edge being shaped like a keel. By contrast, in the holotype, and probably the poorly preserved specimen from Eski Bayirkoy ( NHMI no number), the horncores are less divergent and become sub−parallel along their distal parts. In addition to a main furrow resembling that of the specimens from Rustavi and Kavakdere, there are two additional, smaller furrows descending more anteriorly. Meladze (1985) reports a similar condition in other specimens from Rustavi. In PIM 140 from Samos and in the specimen from Duzyayla ( NHMI PV−348), the divergence is similar to that of the holotype, but the horncores bear four similarly sized and equally spaced furrows, with the lateral keel being poorly developed or absent. However, all specimens preserving enough of the horncores ( PIM 140, PIM 141, NHMI PV−186, GNMT R−555) display double horncore flexion in lateral view.

Roussiakis (2003) concluded that P. wegneri differed from both Oioceros and Samotragus , but avoided a final systematic decision. The cranial, dental and horncore features of the specimens described here clearly distinguish them from Oioceros , supporting a distinction at the generic level as proposed by Meladze (1985) for the material from Rustavi. By contrast, the differences between the horncores of the individual specimens still seem to fall within the limits of intraspecific variation.

Geographic and stratigraphic range.—The holotype of this species and an additional frontlet ( PIM 140) were found in an unknown fossiliferous level of Samos, Greece. The species is further represented by cranial remains occurring at the early to middle Turolian localities of Mahmutgazi ( MN 11), Garkin ( MN 11) ( Köhler 1987), Eski Bayirkoy ( MN 11), Kavakdere ( MN 11), and Duzyayla ( MN 12?) of Turkey, as well as at the latest Vallesian/earliest Turolian site of Rustavi, Georgia ( Meladze 1985).

? Paraoioceros occidentalis ( Masini and Thomas, 1989)

1989 Samotragus occidentalis Masin and Thomas ; Masini and Thomas

1989: 309; pl. 1.

Holotype: Frontlet, MCSNF BRS 5−29 ( Masini and Thomas1989:pl.1: 1).

Type locality: Monticino quarry site BRS5, Brisighella, Italy.

Type horizon: Latest Turolian (MN13), Late Miocene.

Emended diagnosis (modified from Masini and Thomas 1989).—Small−sized species characterized by protruding orbital rims, a pinched interfrontal suture, the presence of well−developed postcornual fossae, and moderately grooved, distally diverging horncores.

Remarks.—Although the material from Brisighella is currently insufficient for a definitive generic assignment, most of the dental and horncore features seem to indicate an association with Paraoioceros (e.g., Kostopoulos and Koufos 1996), rather than Samotragus , as originally proposed by Masini and Thomas (1989). The strongly and distinctly grooved lateral horncore surfaces of the Brisighella frontlet, combined with its long and gradually tapering horncores, the presence of well−developed and posteriorly located postcornual fossae, the pinched interfrontal suture, the thickened frontals ( Masini and Thomas 1989: 310), the relatively long lacrimal fossae ( Masini and Thomas 1989: pl. 1: 2), the hypsodont dentition, the length of the lower premolar tooth rows, the hint of a goat fold on the lower molars, the strong paracone rib in a central position on the upper molars, and the presence of a strong mesostyle ( Masini and Thomas 1989: pl. 1: 2, 7) all resemble Paraoiocerus wegneri . Although the posterior curvature of the Brisighella horncores is comparable to that of Samotragus crassicornis , the overall spiraling is closer, resembling S. praecursor and P. wegneri . By contrast, the presence of a main lateral furrow linked to the postcornual fossa is a feature also seen in some Hispanodorcas , whereas the two structures are separate in both Samotragus and P. wegneri .

Geographic and stratigraphic range.—Latest Turolian (Late Miocene) of Italy.