Revision of Large Anthracotheres from the Early Miocene of Moghara, Egypt

At the time that Fourtau (1918,1920) wrote about the Moghara anthracotheres, there were no complete mandibles of Brachyodus from Europe available for comparison, and only a few upper molars and premolars had been illustrated. The most complete mandible known at that time, and the only one in which the symphysis is (partly) preserved, was a crushed juvenile specimen from Horta das Tripas, Lisbon Basin, Portugal (Roman, 1907, text fig.3, pl.2, fig.1) the symphyseal area of which differs markedly from mandibles of Brachyodus onoideus and Brachyodus depereti, a fact that misled Fourtau (1918) into thinking that his holotype mandible of species depereti belonged to a different genus, Masritherium. Even though the Horta das Tripas specimen is quite well preserved, the morphology of the symphyseal region differs from the adult condition. The other reason that Fourtau (1918) erected the new genus Masritherium was that the sample of upper premolars and molars that he had from Moghara differed from those of Brachyodus onoideus, an observation that is borne out by the present study, some of the specimens representing the genus Jaggermeryx Miller etal. (2014) but others the new genus Aegyptomeryx.Even in Europe, researchers experienced difficulties matching anterior teeth of anthracotheres to their cheek teeth, and the Moghara specimens have posed comparable problems. Mayet (1908) for example, attributed a premaxilla of Brachyodus onoideus containing the incisors, to a carnivore (Pseudocyon depereti), and Fourtau (1918) erroneously identified two anthracothere mandibular symphyses as Proboscidea (see also Tobien, 1973). Furthermore, by 1918, no neurocrania of Brachyodus onoideus had been described. Working in Egypt on the fossils during and immediately after the First World War meant that Fourtau was handicapped by a lack of access to much of the relevant literature - for the sections on Brachyodus and Masritherium, he cited only the works of Depéret (1895) Andrews (1899) and Mayet (1908).Discoveries of mandibles and skull fragments of early Miocene anthracotheres in Africa and Europe after 1920 reveal that a large proportion of the specimens attributed by Fourtau (1918,1920) to Brachyodus and to Masritherium belong to other genera. The smaller specimens attributed by him to Brachyodus moneyi were subsequently assigned by Black (1978) to the genus Hyoboops Trouessart (1904) and then to Sivameryx by Pickford (1991) because Hyoboops is a junior synonym of Sivameryx Lydekker (1877).The larger specimens attributed to Masritherium and Brachyodus by Fourtau (1918, 1920) proved to be difficult to identify correctly. The neurocranium that he included in Brachyodus africanus is hypsicephalic, unlike the less tall skull of Brachyodus onoideus - the morphology of the neurocranium of which was described many years later (Dineur, 1982, plateVIII). The edentulous mandible that Fourtau (1918, fig.31) identified as Brachyodus africanus differs markedly from lower jaws of Brachyodus, as was realised by Miller etal. (2014) who attributed it to Jaggermeryx naida (Jaggermeyx africanus in this paper). Fourtau (1918) noted that this mandible was radically different from that of the holotype lower jaw of Masritherium depereti, which is a correct observation. His attribution of the specimen to Andrews' 1899 species Brachyodus africanus is also correct. What he did not realise, due mainly to the paucity of the fossil record in Europe, where no adult lower jaws with symphyses of Brachyodus had been described at the time that he worked, was that the type specimen of Masritherium depereti is in fact a lower jaw of Brachyodus, being a close match to European specimens from MN 4 attributed to Brachyodus onoideus, and somewhat different from jaws of Brachyodus intermedius from MN3. The latter species possessed a central incisor on each side between the two tusk-like teeth at the antero-lateral corners of the symphysis, whereas Brachyodus onoideus and