Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 79. (Budapest 1987)

Kordos, L.: Description and reconstruction of the skull of Rudapithecus hungaricus Kretzoi (Mammalia)

during the following year two cubic meters of sedimentary material were examined for bones at the same site, and further bones were found. Accordingly, altogether 101 items and 8 upper teeth had been collected by September 1986. Already in the same month the skull, in its present state, was assembled by the author (Figs 7-10). This fossil find of great significance was first published announced on 11th December, 1986, first at a press conference, and then at a scientific session. The present paper attempts to give both the anatomical description and the phylogenetic aspects of the skull's reconstruction for the first time. Description of the skull The Frontal Bone — The most informative section of RUD-77 is the undeformed frontal bone that has been pieced together from 24 fragments by applying direct bone-bone connection. Because of the lack of visible suture it is probable that parietal bone is also included in the frontal region. For the moment the other neurocranial bones attached to the frontal bone are totally missing (c. g. sphenoidal, temporal bones, etc.). In the direction of the midline of the cranium no sagittal crest can be found on the external surface. The bilateral temporal lines starting from zygomatic part of the frontal bone can be clearly seen. On the top of the cranium, along the temporal lines, the bone is thicker, hence the midline, in a shallow band type manner leads from the bregma to the opisthocranion. The frontal bone is thin, only 2-4 mm. The right-side bones of the cranium indicate the skull's length (euryon), and thus it is possible to take measurements and to depict the shape of the cranium. The endocranial surface of the frontal bone is well preserved. The endocranial crest along the midline can be clearly distinguished from its setting, that slightly widens towards the occipital bone. The different sulci, crests and protuberances can be well distinguished on the cranial surface. Luckily enough the orbital part of the frontal bone has been preserved. Its main feature is that neither browridge, nor supraorbital tori developed. The supraorbital margins reach the maximum maturity of the superciliary arch, and between them the glabella is flat. The interorbital region is wide. The orbital contours are of a D-shape. The supraorbital notch is well-developed on the superciliary arch, and in its vicinity the supraorbital foramen can be pointed out. The marked temporal lines turn sharply towards the midline forming a frontal trigon to the apex. The nasal region of the frontal bone below the glabella contains one impression on the external, while two impressions on the internal surface. The superior orbital margin is joined to the zygomatic bone on the left side by a suture. The zygomatic bone — The zygomatic bone plays an important role in the formation of the characteristics of the orbital contours. The zygomatic process below the orbit is missing, but on the basis of the arc of the lateral part is probably not deep. The internal orbital surface of the zygomatic part embracing the orbit can be clearly seen on the zygomatico-orbital foramen, and on its external surface a smaller zygomatic-facial foramen can be distinguished. The zygomatic arch is missing but its joining to the zygomatic bone at the level of the lower margin of the orbit can be supposed. From a phylogenetic point of view, an important feature of the zygomatic bone is that laterally the orbital margin is straight, and even together with the supraorbital margin it constitutes only a mild arch. The occipital bone — Of the occipital bone only a small fragment of anatomically important position was found, which could be joined to the calvaria by using a metal band. It is the opisthocranion where the temporal lines meet in the nuchal line, and constitute a protuberance. The cranial contour in lateral view and the arch of the temporal lines make possible the determination of the proper position of the opisthocranion. Hence it is possible to take further measurements of the skull. The basis fragment — From the bones making up the basis part only fragments of the corpus of the sphenoidal bone and the bilateral processes could be identified. Its probable location as related to the other cranial bones determines the cranial capacity and the position of the foramen magnum. The sub nasal maxillary bone — The most ambiguous part of RUD-77 is that referred to author as subnasal region, which is a symmetrical bone. The nasal aperture widens towards the premaxillary direction, and it may narrow towards the orbits. The lateral margin of the nasal aperture, as compared to the horizon of the vomer, is inclined towards the orbit by 25-30 degrees. The premaxilla is concave from both lateral and frontal view between the nasoalveolar clivus and the nasal aperture. The upper teeth and the fragment of the palatine — The well-preserved left P

3-M

3

, the right M

x-M

z and the fragment of the palatine unfortunately cannot be directly joined to the supposed subnasal maxillary part. Among the teeth the lingual side of M

1 and M~ are deeply,