Maomingosuchus petrolica, a restudy of ‘Tomistoma’ petrolica Yeh, 1958

Tomistoma petrolica Yeh, 1958 is restudied here based on 18 new specimens from the same horizon of the type and a previously referred specimen (IVPP V 5015) in Maoming, Guangdong Province. Our restudy reveals that ‘T.’ petrolica is morphologically incomparable with the extant species Tomistoma schlegelii and other species referred to Tomistoma in a number of osteological features, such as the penetration by the first dentary tooth in the anterior tip of the rostrum, the premaxilla-maxillary suture on the palate with a strong anterior projection, the jugal-quadratojugal suture starting from the posteroventral corner of the infratemporal fenestra, the sharp anterior process of the palatine relatively long, the palatine-pterygoid suture anteriorly positioned, and the broad tip of the neural spine of the third cervical vertebra. Therefore, a new genus, Maomingosuchus, is erected to include Maomingosuchus petrolica. This study also supports the previous view that a common pattern of the phylogenetic relationships among the Tomistominae cannot be established before collecting more specimens of the fragmentary taxa and sampling a suitable set of characters for the phylogenetic analysis of the group. However, this study suggests that M. petrolica may be grouped in a lineage also including Tomistoma lusitanica (Portugal), Gavialosuchus eggenburgensis (Austria), the living species T. schlegelii, Paratomistoma courti (northern Africa), and Tomistoma coppensi (central Africa). Within the lineage, M. petrolica appears to be more closely related to T. schlegelii than to the P. courti-T. coppensi clade and T. schlegelii is most probably related to the T. lusitanica-G. eggenburgensis clade rather than to M. petrolica. With the addition of M. petrolica, our phylogenetic results indicate that the origin and dispersal history of the extant species were much more complicated than what we previously thought.