A new late Miocene bovid (Mammalia: Artiodactyla: Bovidae) from ˙ orakyerler (Turkey) Author Kostopoulos, Dimitris S. Author Erol, Ayla Sevim Author Yavuz, Alper Yener Author Mayda, Serdar text Fossil Record 2021 2021-02-03 24 1 9 18 http://dx.doi.org/10.5194/fr-24-9-2021 journal article 298354 10.5194/fr-24-9-2021 ee72e69c-03cc-45c7-82a0-cc0872099b33 2193-0074 10965816 45161598-BE2C-4660-9BAD-00395D493D85 Gangraia anatolica sp. nov. ( Figs. 1–3 ) Etymology From the geographic area of Anatolia that makes up most of modern Turkey . Holotype ˙O 3187, partial cranium with braincase and both horn cores. Paratypes ˙O 3476, partial cranium with braincase and both horn cores; ˙O 3124, partial cranium with braincase and both horn cores; ˙O 683, part of cranium with complete right and basal part of the left horn core; ˙O 1427, frontlet. Type locality ˙orakyerler fossil site near ˙ankırı, Turkey . Type horizon Tüglu Formation (Upper Miocene) in ˙ankırı Basin, Turkey . Age Late Miocene. Geraads (2013) suggests an early Turolian age for the ˙orakyerler fauna. Magnetostratigraphic correlation by Kaya et al. (2016) frames the fauna between 8.11 and 7.64 Ma. Kostopoulos et al. (2020) suggest an age around the Vallesian–Turolian boundary (∼ 8.7 Ma). Host institution ˙ankırı Museum, Turkey . Figure 1. Gangraia anatolica gen. and sp. nov. from ˙orakyerler, Turkey. Holotype cranium ˙O 3187 in (a) dorsal, (b) ventral, (c) caudal, (d) right lateral, and (e) frontal views. (f) Detail of the dorsal parietal surface; (g) close up of auditory bulla; (h) antero-medial view of the left horn core; and (i) ventral view of the frontals. (a)–(e) Scale bar: 5 cm; (f)–(i) not to scale. Abbreviations: stylf: stylohyal fossa; aub: auditory bulla; intpr: interparietal; pboss: parietal boss; tmpc: temporal crest; tps: temporo-parietal suture; cors: coronal suture; pstcf: postcornual fossa; orb: orbit; mfrs: median frontal sinus; lfrs: lateral frontal sinus; homts: homonymous torsion; trrdg: transverse ridges; and bhcsw: basal horn core swelling. Diagnosis Same as for the genus. Description Both ˙O 3187 ( Fig. 1 ) and ˙O 3476 ( Fig. 2a ) appear barely affected by taphonomic deformation, which is rather common on the site; hence, the description is based mainly on these two crania. ˙O 3124 ( Fig. 3 ) is somehow rostrocaudally compressed; as a result, braincase shortening is exaggerated. In some cases (i.e. Table 1 ), one of the two horn cores of the same individual appear more rostrocaudally compressed than the other, especially at its proximal part; we suspect that this is also due to postmortem compression, and we suggest considering the less compressed dimensions as the most reliable. Figure 2. Gangraia anatolica gen. and sp. nov. , from ˙orakyerler, Turkey. Paratype cranium ˙O 3476 (a) and female frontlet ˙O 1427 (b) ; (1) frontal views; (2) caudal views; (a3) dorsal view; (a4) close up of the base of the left horn core in lateral view showing the single sinus occupying the pedicle and the basal horn core (arrows indicate the pedicle–horn core contact); (a5) close up of the dorsal parietal surface with marked anatomical details; and (b3) lateral view. The arrow in (b1) indicates the frontal sinus occupying the pedicle. Abbreviations: bhcs: basal horn core sinus; phdpr: post horn core depression; pboss: parietal boss; tmpc: temporal crest; tps: temporo-parietal suture; nc: nuchal crest; intpr: interparietal; and sulc: sulcus. (a1)–(a3) and (b1)–(b3) scale bar: 5 cm; (a4) and (a5) not to scale. ˙O 3187, ˙O 3476, ˙O 3124, and ˙O 683 form a very homogeneous sample in terms of their morphology, absolute dimensions, and proportions ( Table 1 ; Figs. 1–3 ). On the other hand, the frontlet ˙O 1427 ( Fig. 2b ) has significantly (20 %) slimmer horn cores and consequently a less broad cranium at the lateral horn core level (∼ 9 %), though the braincase width just behind the horn cores is not much narrower ( Table 1 ). The morphological features of the frontal area in ˙O 1427 are also very similar to those of the holotype , but the interfrontal suture is not pinched but smoothly convex and less complicated. The great length of the horn cores prevents the possibility of a young male individual; we interpret therefore the observed differences between ˙O 1427 and the rest of the crania as representing sexual dimorphism. The braincase is short and wide ( Figs. 1a , 2a . 3, 3a ) with a length to width ratio (length: from the junction of coronalinterfrontal sutures to inion; width: maximum braincase width) between 59 % and 62 % ( n = 2). Placing in a horizontal position the glenoid articular surface, the basioccipital forms an angle of about 70 ◦ with the horizontal plane, inferring a strongly angled braincase compared to the face ( Figs. 1d , 3c ). The dorsal braincase plane forms an angle of 115 ◦ (in ˙O 3187) to 125 ◦ (in ˙O 3476) with the occipital plane. The temporal crests are weak but visible ( Figs. 1a, f, Figure 3. Gangraia anatolica gen. and sp. nov. , from ˙orakyerler, Turkey. Paratype cranium ˙O 3124 in (a) dorsal, (b) ventral, (c) right lateral, and (d) caudal view. Scale bar: 5 cm. 2a.3, a.5); they are wide-apart and run parallel to each other on the dorsal surface of the braincase till the interparietal which is transversally elongated and rather narrow ( Figs. 1f , 2a .5). A distinct large parietal boss occurs behind the coronal suture (˙O 3124, 3476; Figs. 1f , 2a . 3 , a.5, 3a). The occipital condyles with the occipital plane form a ∼ 100 ◦ angle (upper) and are directed caudally. The occipital faces dorso-caudally and has a semi-circular contour defined dorsally by a moderate to strong nuchal crest ( Figs. 1c , 2a.2 , 3d ). The occipital protuberance is weak to moderate, and the mid-occipital crest is slight pinched, surrounded by two well-defined ligament depressions (less deep in ˙O 3187 than in ˙O 3476, in which the occipital relief is much more intense and the occiput projects caudally compared to the main occipital level; Figs. 1c , 2a.2 ). The paroccipital processes are compressed, broad at their bases (22.5 mm in ˙O 3187 and 29.3 mm in ˙O 3476), fast tapering and curving caudo-ventrally, and overpassing the ventral condyle level. The auditory bulla ( L : 36 mm ; TD: 21.4 mm; ˙O 3187) is long, narrow, and slightly curved rostrocaudally, associated with a large stylohyal fossa ( Fig. 1g ). The basioccipital is weakly angled on the basisphenoid (∼ 160 ◦ ; ˙O 3476). It is short, quadrangular to square in shape, and grooved with very strong anterior tuberosities, the latter extending significantly rostrally ( Figs. 1b , 3b ). The foramen oval is moderately large ( 12 mm × 6 mm in ˙O 3187), opens at the level of the anterior tuberosities of the basioccipital, and faces mostly ventrally. The mastoids are relatively small and face mostly laterally ( Fig. 1d ). The temporo-parietal suture is directed obliquely upwards till the interparietal, and it is raised, defining with the nuchal crest a markedly depressed area (sulcus) at the latero-caudal part of the braincase for the temporal musculature (˙O 3187, 3124, 3474; Figs. 1d , 2a .5). The orbital rims protrude significantly laterally ( Fig. 1e ). The orbits are rather small compared to the cranium size (APD: 35 mm in ˙O 3124) and rounded ( Fig. 3c ). The frontals are significantly angled in sagittal profile (110– 130 ◦ ). The frontal area between the orbits is extensively pneumatized: in each half, a medial sinus (TD: 16.8 mm; H : 14.5 mm) is associated with a larger lateral one (TD: 19.0 mm; H : 25.8 mm) ( Fig. 1i ). This lateral sinus is separated by a thin septum from a single large sinus occupying the rest of the pedicle and the base of the horn core, as is clearly seen in ˙O 3476 and ˙O 1427 ( Fig. 2a .4, b.1). The interfrontal suture is tightly zigzag in shape (simpler in ˙O 1427); it is slightly raised at the caudal part and in front of the horn cores and appears much more pinched in the specimen ˙O 3476 ( Figs. 1e , 2a .5) than in the rest of the examined crania. The fronto-parietal (coronal) suture passes directly behind the pedicles, and it is slightly curved with a medial indentation toward the frontals ( Figs. 1f , 2a .5); the two frontal subsectors defined by the coronal and the interfrontal suture appear weakly (˙O 3187, ˙O 683) to strongly (˙O 3476) depressed ( Fig. 2a .5). The supraorbital foramina are very small, not sunken into pits, and widely apart from each other (∼ 59 mm ). They extend rostrally on the frontals by weak furrows. A large ( H : 28 mm ; TD: 10 mm in ˙O 3476) but very shallow postcornual groove is located below the horn core base (detected also on the right side of ˙O 3124 and ˙O 683; in most other specimens, it is barely or not recognized due to post-burial alterations) ( Fig. 1d ). Table 1. Gangraia anatolica gen. and sp. nov. , from ˙orakyerler, Turkey: measurements of holotype (˙O 3187) and paratype crania (in millimetres except if marked otherwise).
˙O 3187 ˙O 3124 ˙O 3476 ˙O 1427
Width of the skull at the posterolateral edges of the horn cores 136.3 129 138 122.8
Width of the skull just behind the horn cores 89.2 95.3 89.7 89.6
Bi-orbital width (158) 158.0
Maximum width of the braincase 98.8 (89) 97.3
Bi-mastoid width 117.0 117.0 129.5
Bi-condylar width 80.0 70.6 71.2
Width at the posterior tuberosities of the basioccipital 42.6 34.0 37.0
Width at the anterior tuberosities of the basioccipital 35.6 30.0 (32)
Width of foramen magnum 26.0 27.1 29.0
Length from bregma to inion 58.7 60.7
Height of occiput 48.2 (57.8) 49.5
Height from basion to inion 66.0 78.3 78.0
Maximum diameter of auditory bulla 36.0
Angle of horn core insertion (compared to cranial roof) 75◦ 80◦
The pedicles are short with sloping sides. Their major basal axis (as that of the horn cores) forms a strong oblique angle compared to the sagittal plane (40–60 ◦ ). The horn cores are inserted widely apart above the orbits forming a 75–80 ◦ angle with the dorsal braincase plane ( Figs. 1a, c– d , 2a.1–2 , b. 3, 3a, c ). They are moderately long to long ( Fig. 3c ) compared to the cranium size; their length along the anterior surface ranges from 275–280 mm (˙O 1427, ˙O 3187, ˙O 3476) to 420 mm (˙O 3124). They are keelless and slightly twisted homonymously. In frontal view, they appear openly lyrated with an internal distance at the apexes reaching 400 mm (˙O 3187, ˙O 3124) and the divergence angle ranging from 55 to 80 ◦ . In lateral view, they delineate a very open “S”; their anterior edge is convex at the proximal fifth, then gently concave, leading to straight up or slightly forward re-curved tips ( Figs. 1d, h , 2a . 1, b.1 , 3c ). They are moderately to strongly compressed rostrocaudally (mean compression index 58 %) with an oval to elliptical cross section throughout their length, flattened posterior, and slightly more convex anterior surface. In ˙O 3187, CO 3476, and ˙O 683, the horn cores taper rather fast upwards but more regularly on ˙O 3124 and ˙O 1427. The horn core surface shows clear developmental transverse ridges all along its length ( Figs. 1h , 2a ). Thin irregular longitudinal furrows run along the horn core surface, but more deep and distinct grooves can also be seen, especially in the basal part at the middle of the anterior surface (one to two grooves vanished from the upper and lower third) and at the posterior surface (one main deep groove vanishing towards the two extremes) ( Figs. 1c, e , 3d ). Cranial and horn core dimensions are given in Tables 1 and 2 .