Four neogondolellid conodont interval zones were recognized across the Changhsingian stage at Ganxi section, western Hubei Province, south China. They are in ascending order: the Clarkina wangi Zone, the Clarkina changxingensis changxingensis Zone, the Clarkina changxingensis yini Zone, and the Clarkina meishanensis meishanensis Zone. The present study suggests that the base of the Changhsingian can be defined by the first appearance datum (FAD) of Clarkina wangi within an evolutionary lineage from Clarkina longicuspidata to Clarkina wangi. The WuchiapingianChanghsingian boundary can be placed at the base of bed 104 at Ganxi section, south China because of the first occurrence of Clarkina wangi.
We describe a new record of the dyrosaurid crocodyliform genus Hyposaurus, from the ?Campanian-Maastrichtian Shendi Formation of Sudan, based on a partial mandibular symphysis, two posterior portions of the upper jaw, and a fused frontal bone, all belonging to a single individual. The material can be assigned to Hyposaurus on the basis of the elliptical shape of the mandibular symphysis (wider than high) and the overall flat shape of the mandible. At the same time, the fossil material differs from other species of Hyposaurus in having (1) an enlarged eighth alveolus of the dentary relative to the other alveoli; (2) a reduced interalveolar space between the ninth and tenth alveoli; and (3) a prominent ridge and groove sculpturing on the dorsal side of the mandible along the symphyseal region. However, due to the fragmentary nature of the material, we refrain from drawing any higher-resolution taxonomic conclusions. The occurrence of Hyposaurus within the Shendi Formation represents the first record of this genus from the Late Cretaceous of Africa and potentially extends its temporal range to the Campanian. Whereas this occurrence in the Late Cretaceous of Sudan supports previous hypotheses of an African origin for Hyposaurus, more complete material is needed for evaluating these hypotheses in a phylogenetic framework. We also wish to stress that the genus Hyposaurus requires detailed revision.
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