†<i>Tugenchromis pickfordi</i>, gen. et sp. nov., from the upper Miocene—a stem-group cichlid of the ‘East African Radiation’

The highly diverse tropical freshwater fish family Cichlidae is sparsely represented in the fossil record. Here we describe the new cichlid †<i>Tugenchromis pickfordi</i>, gen. et sp. nov., from the Upper Miocene (9–10 Ma) of central Kenya. The new taxon possesses a unique combination of characters, including six lateral line foramina on the lacrimal, three lateral line segments, cycloid scales, and a low number of vertebrae (29), dorsal fin spines (13), and dorsal soft rays (9). Its lacrimal morphology and tripartite lateral line suggest an affinity with the present-day Lake Tanganyika tribes Ectodini and Limnochromini, and thus with members of the ‘East African Radiation’ among the African cichlids. To further elucidate the relationships of †<i>T. pickfordi</i>, we used a comprehensive comparative data set comprising meristic data from all present-day tribes of the ‘East African Radiation.’ Principal coordinates analyses support links between the fossil and Ectodini + Limnochromini, and additionally with modern Haplochromini. We conclude that †<i>T. pickfordi</i> could be an extinct lineage within the ‘most ancient Tanganyika tribes,’ or a stem lineage of the ‘ancient Tanganyika mouthbrooders.’ A direct relationship to the Haplochromini is unlikely because its members do not exhibit the derived characteristics of the lacrimal as seen in †<i>T. pickfordi</i>. Because Lake Tanganyika is located in the western branch of the East African Rift System, †<i>T. pickfordi</i> from the eastern branch supports the ‘melting-pot Tanganyika hypothesis,’ which posits that the cichlids of modern Lake Tanganyika are derived from riverine lineages that had already diversified prior to the lake formation. http://zoobank.org/urn:lsid:zoobank.org:pub:37520070-99B3-463C-B8E6-9452D1F62722 SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP. Citation for this article: Altner, M., U. K. Schliewen, S. B. R. Penk, and B. Reichenbacher. 2017 . †<i>Tugenchromis pickfordi</i>, gen. et sp. nov., from the upper Miocene—a stem-group cichlid of the ‘East African Radiation’. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1297819.