First Marine Fossil Otoliths (Teleostei) from East Africa (Tanzania)
2025
Werner W. Schwarzhans | Laura J. Cotton
Otoliths are common in the fossil record and can provide important insight into the evolution and spatial and stratigraphic distribution of fishes, but have remained understudied in many areas of the world. Here, we describe the first marine otolith assemblage from East Africa. The material is from Tanzania Drilling Project cores of late Eocene to early Oligocene age, spanning the Eocene-Oligocene transition (EOT). The assemblage consists of 10 identifiable species of which 5 are new, and 4 remain in open nomenclature. The new species are as follows: <i>Protanago africanus, Bregmaceros tanzaniensis</i>, <i>Ortugobius pandeanus</i>, “<i>Serranus</i>” <i>plasmaticus,</i> and <i>Acanthocepola signanoae</i>. The association of shallow and deep-water taxa along with the dominance of the family Cepolidae, which has not been observed in either the extant or fossil record, makes the faunal composition unusual. However, when taxon occurrences are correlated with stable isotope records from the same cores and compared with previous studies, it is clear the otoliths reflect the sea-level fall known to occur during the EOT, with deeper dwelling taxa in the late Eocene and taxa preferring shallower, which are more shelf-like environments in the early Oligocene.
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