Pleistocene vertebrates from Celebes : XI. Molars and a tusked mandible of Archidiskodon celebensis Hooijer

The species mentioned in the title of the present contribution was first described on the base of two incomplete upper molars, some fragments, and two portions of limb bones (Hooijer, 1949). The two and only complete molars were described later (Hooijer, 1953a). To this has been added the description of the milk dentition and of three premolars (Hooijer, 1953c). There are, however, important lacunae in our knowledge of the molar dentition to be filled. It remains as yet uncertain whether the type upper molar of 1949 represents M2 or M3, while the smaller of the complete lower molars of 1953 could be either M1 or M2. The prolonged study of the fragmentary molars in the Celebes collection has now made it possible to assemble the full set of upper and lower molars, and to determine the correct serial position of the previously described specimens. This study further showed the occasional presence of tusks in the mandible, the first time that incisive tusks have been found to occur in the lower jaw of an Archidiskodon. The problem of the descent of the archidiskodonts, and thereby of the elephantids in general, has to be reconsidered in the light of this unexpected discovery. I wish, again, to express my feelings of gratitude toward Prof. Dr. A. J. Bernet Kempers, former Head of the Dinas Purbakala R.I. at Djakarta, Java, who entrusted the material to me for study, and to Mr. H. R. van Heekeren to whom we owe the discovery of the Pleistocene vertebrate fauna of Celebes. Archidiskodon celebensis Hooijer Archidiskodon celebensis Hooijer, Zool. Med. Museum Leiden, vol. 30, no. 14, 1949, p. 206, pis. VIII-IX; Chronica Naturae, vol. 105, 1949, p. 149; The Scientific Monthly,